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Article

Efficient Charge Separation and Transport in Fullerene-CuPcOC8 Donor–Acceptor Nanorod Enhancing Photocatalytic Hydrogen Generation †

by
Zihui Hua
1,2,
Bo Wu
1,2,*,
Yuhe Zhang
1,
Chong Wang
1,2,
Tianyang Dong
1,
Yupeng Song
2,3,
Ying Jiang
1,2 and
Chunru Wang
1,2,*
1
Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
2
University of Chinese Academy of Sciences, Beijing 100049, China
3
Key Laboratory of Photochemical Conversion and Optoelectronic Materials and CityU-CAS Joint Laboratory of Functional Materials and Devices, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
*
Authors to whom correspondence should be addressed.
†
Dedicated to Professor Chunli Bai on the occasion of his 70th birthday.
Nanomaterials 2024, 14(3), 256; https://doi.org/10.3390/nano14030256
Submission received: 18 December 2023 / Revised: 1 January 2024 / Accepted: 2 January 2024 / Published: 24 January 2024
(This article belongs to the Special Issue Nanostructured Functional Materials for Photocatalysis)
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Abstract

:
Photocatalytic hydrogen generation via water decomposition is a promising avenue in the pursuit of large-scale, cost-effective renewable hydrogen energy generation. However, the design of an efficient photocatalyst plays a crucial role in achieving high yields in hydrogen generation. Herein, we have engineered a fullerene-2,3,9,10,16,17,23,24-octa(octyloxy)copper phthalocyanine (C60-CuPcOC8) photocatalyst, achieving both efficient hydrogen generation and high stability. The significant donor–acceptor (D–A) interactions facilitate the efficient electron transfer from CuPcOC8 to C60. The rate of photocatalytic hydrogen generation for C60-CuPcOC8 is 8.32 mmol·g−1·h−1, which is two orders of magnitude higher than the individual C60 and CuPcOC8. The remarkable increase in hydrogen generation activity can be attributed to the development of a robust internal electric field within the C60-CuPcOC8 assembly. It is 16.68 times higher than that of the pure CuPcOC8. The strong internal electric field facilitates the rapid separation within 0.6 ps, enabling photogenerated charge transfer efficiently. Notably, the hydrogen generation efficiency of C60-CuPcOC8 remains above 95%, even after 10 h, showing its exceptional photocatalytic stability. This study provides critical insight into advancing the field of photocatalysis.

1. Introduction

The photocatalytic decomposition of water, a pivotal process enabling hydrogen generation from solar energy, stands as a promising solution to address the global energy crisis [1,2,3,4]. Since the pioneering work on utilizing TiO2 for hydrogen generation in 1972 [5], the primary research focus in this field has centered on inorganic semiconductors [6,7,8]. There are inherent defects in most inorganic semiconductor photocatalysts, such as wide forbidden bandwidths, rapid photogenerated carrier recombination, inefficient utilization of sunlight, and photo-corrosion during prolonged light exposure [9]. These restrict their further development and application. Conversely, there has been a recent surge of interest in organic semiconductor photocatalysts owing to their diverse functionalities, various synthesis methods, tunable energy bands, and wide absorption range [10,11,12]. Various organic semiconductor photocatalysts, including metal–organic frameworks (MOFs) [13], covalent organic frameworks (COFs) [14], graphitic carbon nitride (g-C3N4) [15], and linear conjugated polymers [16], have been utilized in the photocatalytic decomposition of water to produce hydrogen. The main challenge lies in the rational design of highly efficient photocatalysts. It includes the method to optimize their light trapping capability, efficient charge separation and transport, and long-term stability [17].
The donor–acceptor (D–A) structures in organic photocatalysts provide an effective strategy to enhance their catalytic activity [18,19]. Induced by the distinct electron affinities of the donor and acceptor units, the electron push–pull effect facilitates the directed migration of photogenerated electrons from the donor to the acceptor unit. It promotes the separation of photogenerated electrons and holes. This narrowing of the energy band gap of organic photocatalysts through the recombination of the highest occupied molecular orbitals (HOMOs) and the lowest unoccupied molecular orbitals (LUMOs) effectively enhances their light absorption capacity [20]. Moreover, the uneven distribution of positive and negative molecular charges leads to the formation of significant molecular dipole moments [21]. Notably, the magnitude of the molecular dipole moment exhibits a positive correlation with the strength of the internal electric field (IEF). The deliberate establishment of a robust IEF within a molecule effectively facilitates the separation and transportation of photogenerated carriers, making it one of the most efficient methods to enhance photocatalytic activity [22,23,24].
Fullerenes possess a three-dimensional symmetric structure with exceptional electron-accepting capabilities and commendable physical and chemical stability [25,26]. Copper phthalocyanine (CuPc) is an excellent organic pigment with high chemical stability to light and temperature [27]. CuPc is an effective donor material with remarkable tunability and high visible light absorption [28,29]. Due to these exceptional properties, a series of CuPc photocatalysts have been employed in the field of photocatalytic hydrogen generation [28,30,31,32]. However, the current efficiency of most Pc-based photocatalysts for hydrogen generation is unsatisfactory. In this study, a novel donor–acceptor (D–A)-type photocatalyst C60-CuPcOC8 was devised with the aim of enhancing photocatalytic hydrogen generation. C60-CuPcOC8 demonstrates exceptional hydrogen evolution activity, achieving a rate of 8.32 mmol·g−1·h−1. The introduction of octoctyloxy modification to CuPc is aimed at enhancing the solubility of phthalocyanine in organic solvents and allowing for the fine-tuning of the physicochemical properties of phthalocyanine derivatives [33]. The non-covalently supramolecular photocatalyst C60-CuPcOC8 was obtained by using the liquid–liquid interface precipitation method. The hydrogen generation working principal diagram of the C60-CuPcOC8 assembly is illustrated in Scheme 1. C60-CuPcOC8 assembly exhibits a broad spectral response range spanning from 300 to 800 nm, allowing efficient utilization of solar energy. Additionally, the C60-CuPcOC8 manifests a robust IEF owing to the D–A interaction. This robust IEF promotes the efficient separation and transport of photogenerated charges. It can then be expected that C60-CuPcOC8 photocatalytic hydrogen generation activity will be significantly enhanced.

2. Experimental

2.1. C60-CuPcOC8 Fabrication

The C60-CuPcOC8 assembly was prepared via the liquid–liquid interfacial precipitation method as shown in Scheme 2. Initially, C60 and CuPcOC8 powders were dissolved in homo-trimethylbenzene. Subsequently, the solutions were sonicated for 30 min at room temperature. The sonicated solution was then mixed and filtered. Following this, 15 mL isopropanol was added to 5 mL C60-CuPcOC8 solution. The mixed solution was left to stand for three hours to obtain a precipitate. The resulting precipitate was then filtered and washed three times with methanol. Finally, the desired C60-CuPcOC8 assembly product was obtained after the vacuum drying. The self-assemblies of C60 and CuPcOC8 were achieved using an identical method.

2.2. C60-CuPcOC8 Characterizations

The powders for assembly or self-assembly were evenly distributed in a sample well. The phase structure was determined using a powder X-ray diffractometer (PXRD) (D/max2550VB/PC, Rigaku, Tokyo, Japan) equipped with Cu Kα radiation. The morphological and structure analysis was conducted by field emission scanning electron microscopy (FE-SEM) (Regulus 8100, Hitachi, Tokyo, Japan), transmission electron microscopy (TEM) (HT-7700, Hitachi, Tokyo, Japan), and high-resolution transmission electron microscopy (HRTEM) (JEM-2100F, JEOL, Tokyo, Japan). To conduct SEM testing, the prepared assembly/self-assembly was dispersed in ethanol to form a suspension and then added dropwise onto a silicon wafer. Similarly, TEM testing was performed by adding the suspension dropwise onto a copper microgrid. The UV-Vis diffuse reflectance spectra (DRS) were acquired with a Lambda 1050 UV/VIS/NIR Spectrometer (PerkinElmer, Waltham, MA, USA). The tests were performed with an integrating sphere attachment. The integrating sphere attachment comprised a spherical cavity with an inner wall coated with a highly reflective substance, and BaSO4 was employed as the standard reflectance material.

2.3. Photocatalytic Hydrogen Generation

The photocatalytic hydrogen generation was conducted employing a 300 W xenon lamp (CEL-HXUV300, CeAulight, Beijing, China) in conjunction with an all-glass automated online trace gas analysis system (Perfect Light Labsolar-6A, PerfectLight, Beijing, China). The dispersion of 5 mg photocatalyst powder in 100 mL of de-ionized water was achieved through ultrasonic treatment.
The ascorbic acid (AA), at a concentration of 0.2 mol·L−1, was employed as a hole sacrificial agent. The hole sacrificial agent can consume photogenerated vacancies. Additionally, 3 wt% Pt was loaded as a co-catalyst on the photocatalysts by photodeposition. Photodeposition is a technique based on light-induced electrochemistry. The process of photodeposition of Pt depends mainly on the photoelectrochemical reaction induced by photocatalysts. The equation for the reductive photodeposition of Pt is as follows.
P t C l 6 2 − a q + 4 e − → P t 0 ( s ) + 6 C l −
Evacuating the ambient air from the system was imperative before light irradiation. A 300 W Xe lamp (light intensity: 280 mW/cm−2) with AM 1.5 filter was used as the light source. During light irradiation, continuous stirring of the reaction compounds was maintained using a magnetic stir bar. The system temperature was diligently maintained at 5 °C through the circulation of cooling water. The resulting hydrogen yield was quantified using an online gas chromatograph (GC7920, CeAulight, Beijing, China), and argon used as the carrier gas.
Furthermore, monochromatic light with specific wavelengths (400 nm, 420 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, and 700 nm) was applied from a 300 W xenon lamp to quantify the apparent quantum efficiency (AQE). Average intensity per unit area was determined using a radiometer (CEL-NP2000-2A, CeAulight, Beijing, China), followed by AQE calculation through the subsequent formula:
A Q E = 2 × t h e   n u m b e r   o f   h y d r o g e n   m o l e c u l e s   p r o d u c e d t h e   n u m b e r   o f   i n c i d e n t   p h o t o n × 100 %

2.4. Photoelectrochemical Evaluation

The photoelectrochemical properties were examined using a conventional three-electrode system in combination with an electrochemical workstation (CHI 760e, Chenhua, Shanghai, China). The electrolyte was a 0.5 M Na2SO4 solution. The reference electrode was used as a saturated Ag/AgCl electrode, while the counter electrode was a platinum wire. To prepare the working electrode, a dispersion liquid was formed by employing 5 mg of the sample in a solvent mixture of 0.4 mL of water and 0.6 mL of isopropanol. Subsequently, 100 µL of this dispersion liquid was applied onto an ITO glass substrate and subjected to vacuum drying. A light source comprising an AM 1.5 filter using a xenon lamp with a power of 300 W was employed. For electrochemical impedance spectroscopy (EIS), an AC perturbation of 5 mV was applied, spanning a frequency from 10−2 to 105 Hz. Mott–Schottky plots were generated at frequencies of 500 Hz and 1000 Hz, scan rate of 2 mV·s−1. Photocurrent response tests were executed under a constant potential of 0.1 V, with illumination by a xenon lamp with a power of 300 W (AM 1.5). The surface photovoltage (SPV) was assessed using the CEL-SPS1000 test system. This system comprises a lock-in amplifier (Stanford), chopper, monochromator (Stanford), and a 500 W xenon lamp as the light source.

2.5. Transient Absorption Experiments

A custom-built spectrometer was employed for conducting femtosecond transient absorption (TA) measurements. The fundamental pulses were obtained from a Ti: Sa amplified laser system (Legend Elite-1K-HE, Coherent, Santa Clara, CA, USA). The laser delivered 25 fs pulses at 1 kHz, and the output was split for white-light continuum generation and optical pumping in the UV region. The excitation wavelength was obtained from a tunable optical parametric amplifier (TOPAS-C, Light Conversion, Vilnius, Lithuania) and selected at 380 nm pump pulse for excitation. The generation of supercontinuum white light with 800 nm pumped CaF2 results in a spectral window spanning from 350 nm to 800 nm. Control over the delay in time between the pump and probe pulses was achieved through the application of an optical delay stage. A fiber spectrometer (AvaSpec-ULS2048CL-EVO, Avantes, Apeldoorn, The Netherlands) was used to collect visible transient absorption probe signals. Throughout the experiments, the intensity of the 380 nm laser pulses used for pumping was consistently maintained at 400 nJ. Then, the femtosecond TAS data were input into the “Glotaran” software (Glotaran 1.5.1) for global fitting [34,35]. Glotaran is a graphical user interface (GUI) based on the R-package TIMP for global and target analysis of time-resolved spectroscopy. Based on the singular value decomposition (SVD), the evolution-associated spectra were generated using a sequential kinetic model.

3. Results and Discussion

3.1. Morphology and Structural Characterization

A detailed depiction of the morphological characteristics of the C60-CuPcOC8 is presented in Figure 1. A rod-like structure with diameters ranging from 100 to 150 nm was revealed by SEM. This unique morphology stands in contrast to the individual C60 and CuPcOC8 (Figure S1). Furthermore, a uniform crystal lattice pattern of C60-CuPcOC8 was elucidated by HRTEM in Figure 1b. The interplanar spacing of C60-CuPcOC8 was 0.68 nm, 0.99 nm, and 1.47 nm, corresponding to the (301), (101), and (200) crystallographic planes, respectively [36,37,38]. Subsequently, the PXRD profiles confirm that the identified peaks are 13.4°, 8.96°, and 5.98° (Figure 1c), aligning with the HRTEM analysis.
The molecular frontier orbitals of the C60-CuPcOC8 are further computed using density functional theory (DFT) at the b3lyp/6-31g(d) level [39]. The HOMO and LUMO of C60-CuPcOC8 are situated in the phthalocyanine and the C60 segment, respectively (Figure S2). This D–A structure is helpful to promote charge separation [40]. A broad absorption spectrum spanning from 300 to 800 nm is exhibited by C60-CuPcOC8, as demonstrated in the UV-Vis DRS analysis (Figure 1d). In contrast to C60 and CuPcOC8, the absorption onset of C60-CuPcOC8 undergoes broadening and a red shift. This can be attributed to the strong electron donor–acceptor interactions within C60-CuPcOC8, as well as the π–π stacking effect that enhances electronic wavefunction conjugation [41].

3.2. Efficient Photocatalytic Activity of the D-A Structure

The molecular orbitals engage in linear interactions via π–π interactions, resulting in the emergence of semiconductor energy bands [42]. The electrochemical Mott–Schottky analysis of C60-CuPcOC8 reveals positive slopes (Figure S3), indicating the n-type semiconductor. The flat band potential of C60-CuPcOC8 is estimated to be the conduction band (CB). Importantly, the computed CB value for C60-CuPcOC8 is −0.88 eV. It meets the thermodynamic conditions for hydrogen generation (E(H+/H2) = −0.41 eV, pH = 7) compared to the normal hydrogen electrode (NHE) reference at pH 7.
Following the optimization of catalyst and co-catalyst dosages (Figure S4), a notably efficient hydrogen evolution efficiency of 8.32 mmol·g−1·h−1 was achieved by employing C60-CuPcOC8 across the entire spectrum (Figure 2a). It surpassed the individual CuPcOC8 or C60 by two orders of magnitude (Figure 2b). The solubility of CuPc was improved in organic solvents by modifying CuPc with octoctyloxy. C60-CuPcOC8 assembly was obtained through the interfacial assembly of CuPcOC8 and C60, leading to a broad spectral absorption range of 300–800 nm. In comparison to other reported phthalocyanine-based organic photocatalysts (as summarized in Table 1), C60-CuPcOC8 exhibited remarkable photocatalytic performance, making it a promising candidate for hydrogen generation applications. Furthermore, the apparent quantum efficiency (AQE) of C60-CuPcOC8 was evaluated at various wavelengths to evaluate its capability for absorbing visible light. The wavelength-dependent AQE values of C60-CuPcOC8 closely paralleled the outcomes obtained from DRS. The trends of the AQE values at different single wavelengths are identical to those of the DRS absorption intensities. The outcomes suggest that the efficiency of light conversion is highly dependent on the range of light response [43].
Furthermore, stability plays a pivotal role in determining the feasibility of photocatalyst recovery and recycling processes. After undergoing five consecutive cycles of photocatalytic evaluation, the photocatalytic effectiveness of C60-CuPcOC8 was maintained at levels surpassing 95%, with no discernible deactivation observed (Figure 2d). Additionally, the structural integrity was confirmed through characterizations of XRD, XPS, and TEM analyses, as presented in Figure S5. These results emphasize the stability and sustainable nature of C60-CuPcOC8 as a photocatalyst for hydrogen generation.

3.3. Construction of the D–A Structure Establishes a Robust IEF

The IEF stands as the primary driving force governing the separation and transport of photogenerated charges [55]. A systematic investigation was conducted to understand the precise factors that contribute to the exceptional photocatalytic performance. The electrostatic potential map for C60-CuPcOC8 is depicted in Figure 3a [56]. The positive potentials are observed at the core of the C60 sphere, while negative potentials are concentrated within the copper phthalocyanine ring. A propensity for charge transfer from CuPcOC8 to C60 is suggested by this distribution, facilitating charge separation upon photoexcitation. Given the strong donor–acceptor interaction, the calculated dipole moment of the C60-CuPcOC8 molecular complex is approximately 2.90 Debye. This result is helpful to the formation of a robust IEF. It facilitates the rapid separation of photogenerated charge carriers. The strength of the IEF is quantified using the model developed by Kanataeet et al., as illustrated in Figure S6 [57]. Surprisingly, the IEF strength within C60-CuPcOC8 is 16.86 times higher than CuPcOC8. This enhancement significantly contributes to the facilitation of the separation and transport of photogenerated charges. Ultimately, it leads to a noteworthy enhancement in the photocatalytic activity for hydrogen generation in C60-CuPcOC8 compared to CuPcOC8.

3.4. The D-A Structure Facilitates Charge Separation and Transport

Femtosecond transient absorption spectroscopy (TAS) measurements were conducted to explore the complex kinetics involved in the separation of photogenerated charges. Following laser irradiation at 380 nm, the early femtosecond TAS of C60-CuPcOC8 reveals excited-state absorption occurring at approximately 540 nm, concurrent with stimulated emission signals observed at 610 nm. Such characteristics are ascribed to the singlet excited state of CuPcOC8 [58,59]. Following this excited state evolution, a novel set of excited state absorption (ESA) features emerge in close proximity to 560 nm, 710 nm, and 1030 nm in Figure 4b. The distinctive TA peaks within the visible spectrum bear a remarkable resemblance to the CuPcOC8 cation radicals [60,61]. Simultaneously, the ESA signal was detected at 1030 nm in the near-infrared (NIR) region with the emergence of C60 anion radicals [62]. This offers compelling evidence for the intrinsic occurrence of photo-induced charge separation phenomena within the C60-CuPcOC8 system. By employing a global analysis, through the utilization of a sequential kinetic model for a comprehensive analysis, three distinct kinetic components are elucidated in Figure 4c,d [63]. The initial phase is attributed to a “hot” exciton state stemming from the high-energy CuPcOC8 material within the instrumental response window of approximately ~0.3 picoseconds [64]. Subsequently, this “hot” exciton state expeditiously propels charge separation, occurring within 0.6 ps [65]. The charge-separated state C60·−-CuPcOC8·+ (CS1) state undergoes evolution into a third component within approximately 29 ps, identified as the long-lived charge-separated state C60·−-CuPcOC8·+ (CS2), with a determined lifetime of 0.94 ns. On the contrary, the femtosecond TAS of CuPcOC8 exhibits characteristics indicative of localized excited states, as illustrated in Figure S7, without charge separation. Therefore, according to the TAS study, ultra-fast and long-lived charge separation do exist in C60-CuPcOC8.
Besides charge separation, the charge transport property holds equal significance in the process of photocatalysis. The electrochemical impedance spectra were initially examined in Figure 4a. The charge transfer impedance (Rct) was indicated by the diameter of the arc in the EIS results [66]. Notably, a significantly reduced Rct was observed for C60-CuPcOC8 compared to CuPcOC8, effectively enhancing its charge transport capability. Upon exciting the CuPcOC8 and C60-CuPcOC8 assemblies at 600 nm, a quenched fluorescence absorption signal was observed from CuPcOC8 at 710 nm (Figure 4b). This phenomenon was attributed to the promotion of charge separation by the D–A structure of the C60-CuPcOC8 assemblies. Consequently, the excited electrons no longer underwent radiative transitions but returned to the ground state through a charge transfer or energy transfer process instead. Additionally, the time–current curves of C60-CuPcOC8 and CuPcOC8 under steady potential conditions are depicted in Figure 4c. In comparison to CuPcOC8, a more robust photocurrent response is exhibited by C60-CuPcOC8. The enhanced response is attributed to the improvement of charge transfer efficiency. In the surface photovoltage (SPV) spectrum (Figure 4d), a significantly elevated positive photovoltage signal is observed in the 300 to 520 nm range for C60-CuPcOC8. Notably, this signal is approximately ten times stronger than that observed in CuPcOC8. This notable difference implies a substantial increase in the migration of photogenerated charges toward the surface within the C60-CuPcOC8 assembly.
Drawing upon the preceding discussion, a plausible mechanism for the photocatalytic is proposed in Figure 5. The strong D–A interactions of C60-CuPcOC8 play a pivotal role in establishing a robust IEF. The robust IEF facilitates charge separation and transfer. Photogenerated electrons migrate to the surface, accelerating a reduction reaction yielding hydrogen, wherein Pt functions as a co-catalyst. Concurrently, the photogenerated holes engage in reactions with the sacrificial agent, ascorbic acid. In brief, the C60-CuPcOC8 system achieves efficient separation of photogenerated electron–hole pairs, resulting in an efficient photocatalytic hydrogen generation.

4. Conclusions

In summary, we have utilized the light-harvesting CuPcOC8 donor and efficient-electron-transport C60 acceptor to synthesize a novel photocatalyst, C60-CuPcOC8. The photocatalyst exhibits a broad spectral absorption range spanning from 300 to 800 nm, facilitating excellent photocatalytic hydrogen generation. The incorporation of a D–A architecture within C60-CuPcOC8 results in a larger molecular dipole moment, facilitating the creation of a robust IEF. This IEF promoted the separation and transportation of the photogenerated charge carriers. Consequently, C60-CuPcOC8 demonstrates exceptional hydrogen evolution activity, achieving a rate of 8.32 mmol·g−1·h−1. This rate surpasses that of C60 and CuPcOC8 monomers by two orders of magnitude. This research introduces a novel approach for designing highly active supramolecular photocatalytic materials, offering valuable insights for the construction of an efficient photocatalytic hydrogen generation system.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/nano14030256/s1, Figure S1. SEM for (a) C60 and (b) CuPcOC8; Figure S2. (a) LUMO and (b) HOMO of C60-CuPcOC8; Figure S3. (a) Tauc-plots of C60-CuPcOC8, (b) Mott–Schottky plots of C60-CuPcOC8, (c) schematic representation of the redox potential of C60-CuPcOC8; Figure S4. Photocatalytic H2 evolution rate of C60-CuPcOC8 with varied (a) weight and (b) loading amount of Pt under full-spectrum light; Figure S5. (a) PXRD of C60-CuPcOC8 before and after photocatalytic hydrogen generation; (b) Cu elemental XPS of C60-CuPcOC8 before and after photocatalytic hydrogen generation; HRTEM of C60-CuPcOC8 (c) before and (d) after photocatalytic hydrogen generation; Figure S6. Surface charge density of (a) CuPcOC8 and (b) C60-CuPcOC8; Figure S7. Evolution-associated spectra (EAS) of the CuPcOC8 at 380 nm (1 × 10−5 M, aqueous dispersion).

Author Contributions

Conceptualization, B.W. and C.W. (Chunru Wang); methodology, Z.H. and Y.Z.; validation, Z.H. and B.W.; formal analysis, Z.H., C.W. (Chong Wang), T.D., Y.S. and Y.J.; investigation, Z.H. and Y.Z.; resources, B.W. and C.W. (Chunru Wang); data curation, Z.H.; writing—original draft preparation, Z.H.; writing—review and editing, B.W.; supervision, C.W. (Chunru Wang); project administration, B.W. and C.W. (Chunru Wang); funding acquisition, B.W. and C.W. (Chunru Wang). All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by the National Natural Science Foundation of China (52072374, 52322204, 51832008) and the Ministry of Science and Technology of China (2022YFA1205900). B. Wu particularly thanks the Youth Innovation Promotion Association of CAS (Y2022015).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data presented in this study are available upon reasonable request from the corresponding author.

Acknowledgments

Thank you to Jing Li at the Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, for the help with transient absorption measurements. Thank you to Jing Tai at the Institute of Chemistry, Chinese Academy of Sciences, for the valuable assistance in obtaining high-resolution transmission electron microscope images.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Xu, Q.; Zhang, L.; Cheng, B.; Fan, J.; Yu, J. S-Scheme Heterojunction Photocatalyst. Chem 2020, 6, 1543–1559. [Google Scholar] [CrossRef]
  2. Liang, Y.; Li, T.; Lee, Y.; Zhang, Z.; Li, Y.; Si, W.; Liu, Z.; Zhang, C.; Qiao, Y.; Bai, S.; et al. Organic Photovoltaic Catalyst with Σ-π Anchor for High-Performance Solar Hydrogen Evolution. Angew. Chem. Int. Ed. 2023, 62, e202217989. [Google Scholar] [CrossRef] [PubMed]
  3. Zhu, Y.; Zhang, Z.; Si, W.; Sun, Q.; Cai, G.; Li, Y.; Jia, Y.; Lu, X.; Xu, W.; Zhang, S.; et al. Organic Photovoltaic Catalyst with Extended Exciton Diffusion for High-Performance Solar Hydrogen Evolution. J. Am. Chem. Soc. 2022, 144, 12747–12755. [Google Scholar] [CrossRef] [PubMed]
  4. Liu, A.; Gedda, L.; Axelsson, M.; Pavliuk, M.; Edwards, K.; Hammarström, L.; Tian, H. Panchromatic Ternary Polymer Dots Involving Sub-Picosecond Energy and Charge Transfer for Efficient and Stable Photocatalytic Hydrogen Evolution. J. Am. Chem. Soc. 2021, 143, 2875–2885. [Google Scholar] [CrossRef] [PubMed]
  5. Fujishima, A.; Honda, K. Electrochemical Photolysis of Water at a Semiconductor Electrode. Nature 1972, 238, 37–38. [Google Scholar] [CrossRef] [PubMed]
  6. Rabell, G.O.; Cruz, M.R.A.; Juárez-Ramírez, I. Hydrogen Production of ZnO and ZnO/Ag Films by Photocatalysis and Photoelectrocatalysis. Mater. Sci. Semicond. Process. 2021, 134, 105985. [Google Scholar] [CrossRef]
  7. Lange, T.; Reichenberger, S.; Ristig, S.; Rohe, M.; Strunk, J.; Barcikowski, S.; Schlögl, R. Zinc Sulfide for Photocatalysis: White Angel or Black Sheep? Prog. Mater. Sci. 2022, 124, 100865. [Google Scholar] [CrossRef]
  8. Liang, Z.; Ouyang, B.; Wang, T.; Liu, X.; Huo, H.; Liu, D.; Feng, H.; Ma, J.; Deng, K.; Li, A.; et al. Pt Modified TiO2/NiO p-n Junction with Enhanced Surface Reaction and Charge Separation for Efficient Photocatalytic Hydrogen Evolution. Int. J. Hydrogen Energy 2022, 47, 10868–10876. [Google Scholar] [CrossRef]
  9. Qi, M.-Y.; Conte, M.; Anpo, M.; Tang, Z.-R.; Xu, Y.-J. Cooperative Coupling of Oxidative Organic Synthesis and Hydrogen Production over Semiconductor-Based Photocatalysts. Chem. Rev. 2021, 121, 13051–13085. [Google Scholar] [CrossRef]
  10. Niu, P.; Dai, J.; Zhi, X.; Xia, Z.; Wang, S.; Li, L. Photocatalytic Overall Water Splitting by Graphitic Carbon Nitride. InfoMat 2021, 3, 931–961. [Google Scholar] [CrossRef]
  11. Banerjee, T.; Podjaski, F.; Kröger, J.; Biswal, B.P.; Lotsch, B.V. Polymer Photocatalysts for Solar-to-Chemical Energy Conversion. Nat. Rev. Mater. 2020, 6, 168–190. [Google Scholar] [CrossRef]
  12. Ghosh, S.; Nakada, A.; Springer, M.A.; Kawaguchi, T.; Suzuki, K.; Kaji, H.; Baburin, I.; Kuc, A.; Heine, T.; Suzuki, H.; et al. Identification of Prime Factors to Maximize the Photocatalytic Hydrogen Evolution of Covalent Organic Frameworks. J. Am. Chem. Soc. 2020, 142, 9752–9762. [Google Scholar] [CrossRef] [PubMed]
  13. Lu, L.; Wu, B.; Shi, W.; Cheng, P. Metal–Organic Framework-Derived Heterojunctions as Nanocatalysts for Photocatalytic Hydrogen Production. Inorg. Chem. Front. 2019, 6, 3456–3467. [Google Scholar] [CrossRef]
  14. Wang, X.; Chen, L.; Chong, S.Y.; Little, M.A.; Wu, Y.; Zhu, W.-H.; Clowes, R.; Yan, Y.; Zwijnenburg, M.A.; Sprick, R.S.; et al. Sulfone-Containing Covalent Organic Frameworks for Photocatalytic Hydrogen Evolution from Water. Nat. Chem. 2018, 10, 1180–1189. [Google Scholar] [CrossRef] [PubMed]
  15. Zhu, Q.; Xu, Z.; Qiu, B.; Xing, M.; Zhang, J. Emerging Cocatalysts on g-C3N4 for Photocatalytic Hydrogen Evolution. Small 2021, 17, 2101070. [Google Scholar] [CrossRef] [PubMed]
  16. Zhao, C.; Chen, Z.; Shi, R.; Yang, X.; Zhang, T. Recent Advances in Conjugated Polymers for Visible-Light-Driven Water Splitting. Adv. Mater. 2020, 32, 1907296. [Google Scholar] [CrossRef]
  17. Tong, H.; Ouyang, S.; Bi, Y.; Umezawa, N.; Oshikiri, M.; Ye, J. Nano-Photocatalytic Materials: Possibilities and Challenges. Adv. Mater. 2012, 24, 229–251. [Google Scholar] [CrossRef]
  18. Kosco, J.; Bidwell, M.; Cha, H.; Martin, T.; Howells, C.T.; Sachs, M.; Anjum, D.H.; Gonzalez Lopez, S.; Zou, L.; Wadsworth, A.; et al. Enhanced Photocatalytic Hydrogen Evolution from Organic Semiconductor Heterojunction Nanoparticles. Nat. Mater. 2020, 19, 559–565. [Google Scholar] [CrossRef]
  19. Yang, J.; Jing, J.; Zhu, Y. A Full-spectrum Porphyrin–Fullerene D–A Supramolecular Photocatalyst with Giant Built-in Electric Field for Efficient Hydrogen Production. Adv. Mater. 2021, 33, 2101026. [Google Scholar] [CrossRef]
  20. Yang, Q.; Luo, M.; Liu, K.; Cao, H.; Yan, H. Covalent Organic Frameworks for Photocatalytic Applications. Appl. Catal. B 2020, 276, 119174. [Google Scholar] [CrossRef]
  21. Yao, H.; Qian, D.; Zhang, H.; Qin, Y.; Xu, B.; Cui, Y.; Yu, R.; Gao, F.; Hou, J. Critical Role of Molecular Electrostatic Potential on Charge Generation in Organic Solar Cells: Critical Role of Molecular Electrostatic Potential on Charge Generation in Organic Solar Cells. Chin. J. Chem. 2018, 36, 491–494. [Google Scholar] [CrossRef]
  22. Guo, Y.; Zhou, Q.; Nan, J.; Shi, W.; Cui, F.; Zhu, Y. Perylenetetracarboxylic Acid Nanosheets with Internal Electric Fields and Anisotropic Charge Migration for Photocatalytic Hydrogen Evolution. Nat. Commun. 2022, 13, 2067. [Google Scholar] [CrossRef] [PubMed]
  23. Deng, A.; Sun, Y.; Gao, Z.; Yang, S.; Liu, Y.; He, H.; Zhang, J.; Liu, S.; Sun, H.; Wang, S. Internal Electric Field in Carbon Nitride-Based Heterojunctions for Photocatalysis. Nano Energy 2023, 108, 108228. [Google Scholar] [CrossRef]
  24. Zhou, Q.; Guo, Y.; Ye, Z.; Fu, Y.; Guo, Y.; Zhu, Y. Carbon Nitride Photocatalyst with Internal Electric Field Induced Photogenerated Carriers Spatial Enrichment for Enhanced Photocatalytic Water Splitting. Mater. Today 2022, 58, 100–109. [Google Scholar] [CrossRef]
  25. Pan, Y.; Liu, X.; Zhang, W.; Liu, Z.; Zeng, G.; Shao, B.; Liang, Q.; He, Q.; Yuan, X.; Huang, D.; et al. Advances in Photocatalysis Based on Fullerene C60 and Its Derivatives: Properties, Mechanism, Synthesis, and Applications. Appl. Catal. B 2020, 265, 118579. [Google Scholar] [CrossRef]
  26. Huo, J.; Zeng, H. A Novel Triphenylamine Functionalized Bithiazole–Metal Complex with C60 for Photocatalytic Hydrogen Production under Visible Light Irradiation. J. Mater. Chem. A 2015, 3, 6258–6264. [Google Scholar] [CrossRef]
  27. Guo, Z.; Chen, B.; Zhang, M.; Mu, J.; Shao, C.; Liu, Y. Zinc Phthalocyanine Hierarchical Nanostructure with Hollow Interior Space: Solvent–Thermal Synthesis and High Visible Photocatalytic Property. J. Colloid Interface Sci. 2010, 348, 37–42. [Google Scholar] [CrossRef]
  28. Yang, Q.; Zhu, H.; Ji, X.; Zhang, Y.; Yu, L. Nanoarchitectonics of Core-Shelled Hollow CuPc/Zn0.5Cd0.5S Photocatalyst for Stable Hydrogen Evolution under Visible-Light Irradiation. J. Alloys Compd. 2022, 926, 166890. [Google Scholar] [CrossRef]
  29. Keizer, S.P.; Mack, J.; Bench, B.A.; Gorun, S.M.; Stillman, M.J. Spectroscopy and Electronic Structure of Electron Deficient Zinc Phthalocyanines. J. Am. Chem. Soc. 2003, 125, 7067–7085. [Google Scholar] [CrossRef]
  30. Moon, H.S.; Yong, K. Noble-Metal Free Photocatalytic Hydrogen Generation of CuPc/TiO2 Nanoparticles under Visible-Light Irradiation. Appl. Surf. Sci. 2020, 530, 147215. [Google Scholar] [CrossRef]
  31. Keshipour, S.; Mohammad-Alizadeh, S.; Razeghi, M.H. Copper Phthalocyanine@graphene Oxide as a Cocatalyst of TiO2 in Hydrogen Generation. J. Phys. Chem. Solids 2022, 161, 110434. [Google Scholar] [CrossRef]
  32. Men, C.; Chen, L.; Ji, H.; Qin, Z.; Su, T. Synergistic Effect of Internal Electric Field and Ligand-to-Metal Charge Transfer in Z-Scheme CuPc/ZnIn2S4 for Boosting Photocatalytic Hydrogen Evolution. Chem. Eng. J. 2023, 473, 145173. [Google Scholar] [CrossRef]
  33. Vadakel, V.T.; Menon, C.S. Optical and Surface Morphological Studies on CuPcOC8 Thin Films Prepared by Physical Vapour Deposition. Mater. Sci.-Pol. 2013, 31, 391–396. [Google Scholar] [CrossRef]
  34. Mullen, K.M.; Stokkum, I.H.M.V. TIMP: An R Package for Modeling Multi-Way Spectroscopic Measurements. J. Stat. Softw. 2007, 18, 1–46. [Google Scholar] [CrossRef]
  35. Van Stokkum, I.H.M.; Larsen, D.S.; Van Grondelle, R. Global and Target Analysis of Time-Resolved Spectra. Biochim. Biophys. Acta Bioenerg. 2004, 1657, 82–104. [Google Scholar] [CrossRef] [PubMed]
  36. Tang, Q.; Li, H.; Liu, Y.; Hu, W. High-Performance Air-Stable n-Type Transistors with an Asymmetrical Device Configuration Based on Organic Single-Crystalline Submicrometer/Nanometer Ribbons. J. Am. Chem. Soc. 2006, 128, 14634–14639. [Google Scholar] [CrossRef] [PubMed]
  37. Ai, X.; Lin, J.; Chang, Y.; Zhou, L.; Zhang, X.; Qin, G. Phase Modification of Copper Phthalocyanine Semiconductor by Converting Powder to Thin Film. Appl. Surf. Sci. 2018, 428, 788–792. [Google Scholar] [CrossRef]
  38. Warner, M.; Mauthoor, S.; Felton, S.; Wu, W.; Gardener, J.A.; Din, S.; Klose, D.; Morley, G.W.; Stoneham, A.M.; Fisher, A.J.; et al. Spin-Based Diagnostic of Nanostructure in Copper Phthalocyanine–C60 Solar Cell Blends. ACS Nano 2012, 6, 10808–10815. [Google Scholar] [CrossRef]
  39. Yanai, T.; Tew, D.P.; Handy, N.C. A New Hybrid Exchange–Correlation Functional Using the Coulomb-Attenuating Method (CAM-B3LYP). Chem. Phys. Lett. 2004, 393, 51–57. [Google Scholar] [CrossRef]
  40. Lim, H.; Yang, S.; Lee, S.-H.; Lee, J.-Y.; Lee, Y.; Situmorang, A.B.; Kim, Y.-H.; Kim, J.W. Influence of the Metal Phthalocyanine Molecular Orientation on Charge Separation at the Organic Donor/Acceptor Interface. J. Mater. Chem. C 2021, 9, 2156–2164. [Google Scholar] [CrossRef]
  41. Heutz, S.; Sullivan, P.; Sanderson, B.M.; Schultes, S.M.; Jones, T.S. Influence of Molecular Architecture and Intermixing on the Photovoltaic, Morphological and Spectroscopic Properties of CuPc–C60 Heterojunctions. Sol. Energy Mater. Sol. Cells 2004, 83, 229–245. [Google Scholar] [CrossRef]
  42. Saito, G.; Yoshida, Y. Development of Conductive Organic Molecular Assemblies: Organic Metals, Superconductors, and Exotic Functional Materials. Bull. Chem. Soc. Jpn. 2007, 80, 1–137. [Google Scholar] [CrossRef]
  43. Chen, C.; Xiong, Y.; Zhong, X.; Lan, P.C.; Wei, Z.; Pan, H.; Su, P.; Song, Y.; Chen, Y.; Nafady, A.; et al. Enhancing Photocatalytic Hydrogen Production via the Construction of Robust Multivariate Ti-MOF/COF Composites. Angew. Chem. Int. Ed. 2022, 61, e202114071. [Google Scholar] [CrossRef] [PubMed]
  44. Genc, E.; Yüzer, A.C.; Yanalak, G.; Harputlu, E.; Aslan, E.; Ocakoglu, K.; Ince, M.; Patir, I.H. The Effect of Central Metal in Phthalocyanine for Photocatalytic Hydrogen Evolution via Artificial Photosynthesis. Renew. Energy 2020, 162, 1340–1346. [Google Scholar] [CrossRef]
  45. Huang, J.; Wu, Y.; Wang, D.; Ma, Y.; Yue, Z.; Lu, Y.; Zhang, M.; Zhang, Z.; Yang, P. Silicon Phthalocyanine Covalently Functionalized N-Doped Ultrasmall Reduced Graphene Oxide Decorated with Pt Nanoparticles for Hydrogen Evolution from Water. ACS Appl. Mater. Interfaces 2015, 7, 3732–3741. [Google Scholar] [CrossRef]
  46. Takanabe, K.; Kamata, K.; Wang, X.; Antonietti, M.; Kubota, J.; Domen, K. Photocatalytic Hydrogen Evolution on Dye-Sensitized Mesoporous Carbon Nitride Photocatalyst with Magnesium Phthalocyanine. Phys. Chem. Chem. Phys. 2010, 12, 13020. [Google Scholar] [CrossRef]
  47. Wang, D.; Huang, J.; Li, X.; Yang, P.; Du, Y.; Goh, C.M.; Lu, C. Photocatalytic H2 Production under Visible-Light Irradiation Based on Covalent Attachment of Manganese Phthalocyanine to Graphene. J. Mater. Chem. A 2015, 3, 4195–4202. [Google Scholar] [CrossRef]
  48. Xiao, B.; Zhu, M.; Li, X.; Yang, P.; Qiu, L.; Lu, C. A Stable and Efficient Photocatalytic Hydrogen Evolution System Based on Covalently Linked Silicon-Phthalocyanine-Graphene with Surfactant. Int. J. Hydrogen Energy 2016, 41, 11537–11546. [Google Scholar] [CrossRef]
  49. Zhang, X.; Peng, T.; Yu, L.; Li, R.; Li, Q.; Li, Z. Visible/Near-Infrared-Light-Induced H2 Production over g-C3N4 Co-Sensitized by Organic Dye and Zinc Phthalocyanine Derivative. ACS Catal. 2015, 5, 504–510. [Google Scholar] [CrossRef]
  50. Zhang, X.; Yu, L.; Li, R.; Peng, T.; Li, X. Asymmetry and Electronic Directionality: A Means of Improving the Red/near-IR-Light-Responsive Photoactivity of Phthalocyanine-Sensitized Carbon Nitride. Catal. Sci. Technol. 2014, 4, 3251. [Google Scholar] [CrossRef]
  51. Zhang, X.; Yu, L.; Zhuang, C.; Peng, T.; Li, R.; Li, X. Highly Efficient Visible/near-IR-Light-Driven Photocatalytic H2 Production over Asymmetric Phthalocyanine-Sensitized TiO2. RSC Adv. 2013, 3, 14363. [Google Scholar] [CrossRef]
  52. Zhang, W.; Zhou, X.; Huang, J.; Zhang, S.; Xu, X. Noble Metal-Free Core-Shell CdS/Iron Phthalocyanine Z-Scheme Photocatalyst for Enhancing Photocatalytic Hydrogen Evolution. J. Mater. Sci. Technol. 2022, 115, 199–207. [Google Scholar] [CrossRef]
  53. Genc Acar, E.; Yüzer, A.C.; Kurtay, G.; Yanalak, G.; Harputlu, E.; Aslan, E.; Ocakoglu, K.; Güllü, M.; Ince, M.; Patir, I.H. Improving the Photocatalytic Hydrogen Generation Using Nonaggregated Zinc Phthalocyanines. ACS Appl. Energy Mater. 2021, 4, 10222–10233. [Google Scholar] [CrossRef]
  54. Miao, X.; Wang, B.; Fan, H.; Zhang, P.; Bai, S.; Liu, W. Tremella-like Boron-Doped Hierarchical CN and Dispersion Co Phthalocyanine Assembling Heterojunction for Photocatalytic Hydrogen Evolution. Chem. Eng. J. 2023, 465, 142775. [Google Scholar] [CrossRef]
  55. Yue, X.; Fan, J.; Xiang, Q. Internal Electric Field on Steering Charge Migration: Modulations, Determinations and Energy-Related Applications. Adv. Funct. Mater. 2022, 32, 2110258. [Google Scholar] [CrossRef]
  56. Lu, T.; Chen, F. Multiwfn: A Multifunctional Wavefunction Analyzer. J. Comput. Chem. 2012, 33, 580–592. [Google Scholar] [CrossRef] [PubMed]
  57. Xi, Y.; Chen, W.; Dong, W.; Fan, Z.; Wang, K.; Shen, Y.; Tu, G.; Zhong, S.; Bai, S. Engineering an Interfacial Facet of S-Scheme Heterojunction for Improved Photocatalytic Hydrogen Evolution by Modulating the Internal Electric Field. ACS Appl. Mater. Interfaces 2021, 13, 39491–39500. [Google Scholar] [CrossRef]
  58. Huang, P.; Hernández, A.; Kazim, S.; Follana-Berná, J.; Ortiz, J.; Lezama, L.; Sastre-Santos, Á.; Ahmad, S. Asymmetrically Substituted Phthalocyanines as Dopant-Free Hole Selective Layers for Reliability in Perovskite Solar Cells. ACS Appl. Energy Mater. 2021, 4, 10124–10135. [Google Scholar] [CrossRef]
  59. Jin, S.; Supur, M.; Addicoat, M.; Furukawa, K.; Chen, L.; Nakamura, T.; Fukuzumi, S.; Irle, S.; Jiang, D. Creation of Superheterojunction Polymers via Direct Polycondensation: Segregated and Bicontinuous Donor–Acceptor π-Columnar Arrays in Covalent Organic Frameworks for Long-Lived Charge Separation. J. Am. Chem. Soc. 2015, 137, 7817–7827. [Google Scholar] [CrossRef]
  60. Padgaonkar, S.; Amsterdam, S.H.; Bergeron, H.; Su, K.; Marks, T.J.; Hersam, M.C.; Weiss, E.A. Molecular-Orientation-Dependent Interfacial Charge Transfer in Phthalocyanine/MoS2 Mixed-Dimensional Heterojunctions. J. Phys. Chem. C 2019, 123, 13337–13343. [Google Scholar] [CrossRef]
  61. El-Khouly, M.E.; Kang, E.S.; Kay, K.-Y.; Choi, C.S.; Aaraki, Y.; Ito, O. Silicon-Phthalocyanine-Cored Fullerene Dendrimers: Synthesis and Prolonged Charge-Separated States with Dendrimer Generations. Chem. Eur. J. 2007, 13, 2854–2863. [Google Scholar] [CrossRef] [PubMed]
  62. Chai, Y.; Liu, X.; Wu, B.; Liu, L.; Wang, Z.; Weng, Y.; Wang, C. In Situ Switching of Photoinduced Electron Transfer Direction by Regulating the Redox State in Fullerene-Based Dyads. J. Am. Chem. Soc. 2020, 142, 4411–4418. [Google Scholar] [CrossRef] [PubMed]
  63. Binsl, T.W.; Mullen, K.M.; Stokkum, I.H.M.V.; Heringa, J.; Beek, J.H.G.M.V. FluxSimulator: An R Package to Simulate Isotopomer Distributions in Metabolic Networks. J. Stat. Softw. 2007, 18, 1–17. [Google Scholar] [CrossRef]
  64. Liu, L.P.; Chen, X.J.; Chai, Y.Q.; Zhang, W.N.; Liu, X.L.; Zhao, F.W.; Wang, Z.; Weng, Y.X.; Wu, B.; Geng, H.; et al. Highly Efficient Photocatalytic Hydrogen Production via Porphyrin-Fullerene Supramolecular Photocatalyst with Donor-Acceptor Structure. Chem. Eng. J. 2022, 444, 136621. [Google Scholar] [CrossRef]
  65. Savoie, B.M.; Rao, A.; Bakulin, A.A.; Gelinas, S.; Movaghar, B.; Friend, R.H.; Marks, T.J.; Ratner, M.A. Unequal Partnership: Asymmetric Roles of Polymeric Donor and Fullerene Acceptor in Generating Free Charge. J. Am. Chem. Soc. 2014, 136, 2876–2884. [Google Scholar] [CrossRef]
  66. Wang, W.-R.; Li, J.; Li, Q.; Xu, Z.-W.; Liu, L.-N.; Chen, X.-Q.; Xiao, W.-J.; Yao, J.; Zhang, F.; Li, W.-S. Side-Chain-Extended Conjugation: A Strategy for Improving the Photocatalytic Hydrogen Production Performance of a Linear Conjugated Polymer. J. Mater. Chem. A 2021, 9, 8782–8791. [Google Scholar] [CrossRef]
Nanomaterials 14 00256 sch001
Scheme 1. The working principle diagram of C60-CuPcOC8 assembly.
Scheme 1. The working principle diagram of C60-CuPcOC8 assembly.
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Scheme 2. Illustration of preparation process of C60-CuPcOC8 assembly through the liquid–liquid interface deposition method.
Scheme 2. Illustration of preparation process of C60-CuPcOC8 assembly through the liquid–liquid interface deposition method.
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Figure 1. (a) SEM of C60-CuPcOC8; (b) HRTEM of C60-CuPcOC8; (c) PXRD of C60, CuPcOC8, and C60-CuPcOC8; (d) DRS of C60, CuPcOC8, and C60-CuPcOC8.
Figure 1. (a) SEM of C60-CuPcOC8; (b) HRTEM of C60-CuPcOC8; (c) PXRD of C60, CuPcOC8, and C60-CuPcOC8; (d) DRS of C60, CuPcOC8, and C60-CuPcOC8.
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Figure 2. (a) Photocatalytic hydrogen evolution by C60-CuPcOC8 under AM 1.5 solar illumination; (b) comparison of photocatalytic hydrogen evolution rate of C60, CuPcOC8, and C60-CuPcOC8; (c) wavelength-dependent AQE of photocatalytic hydrogen evolution for C60-CuPcOC8; (d) cyclic performance assessment of hydrogen evolution of C60-CuPcOC8.
Figure 2. (a) Photocatalytic hydrogen evolution by C60-CuPcOC8 under AM 1.5 solar illumination; (b) comparison of photocatalytic hydrogen evolution rate of C60, CuPcOC8, and C60-CuPcOC8; (c) wavelength-dependent AQE of photocatalytic hydrogen evolution for C60-CuPcOC8; (d) cyclic performance assessment of hydrogen evolution of C60-CuPcOC8.
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Figure 3. (a) Molecular dipole and electrostatic potential maps of C60-CuPcOC8 (front and top); (b) femtosecond transient absorption spectra (TAS) of the C60-CuPcOC8 excited at 380 nm (1 × 10−5 M, aqueous dispersion); (c) evolution-associated spectra (EAS) pertaining to the global analysis of C60-CuPcOC8; (d) concentrations of different species for the global fit within C60-CuPcOC8.
Figure 3. (a) Molecular dipole and electrostatic potential maps of C60-CuPcOC8 (front and top); (b) femtosecond transient absorption spectra (TAS) of the C60-CuPcOC8 excited at 380 nm (1 × 10−5 M, aqueous dispersion); (c) evolution-associated spectra (EAS) pertaining to the global analysis of C60-CuPcOC8; (d) concentrations of different species for the global fit within C60-CuPcOC8.
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Figure 4. (a) Electrochemical impedance spectra for CuPcOC8 and C60-CuPcOC8; (b) emission spectra of fluorescence for CuPcOC8 and C60-CuPcOC8; (c) responses of photocurrent for CuPcOC8 and C60-CuPcOC8; (d) surface photovoltage profiles for CuPcOC8 and C60-CuPcOC8.
Figure 4. (a) Electrochemical impedance spectra for CuPcOC8 and C60-CuPcOC8; (b) emission spectra of fluorescence for CuPcOC8 and C60-CuPcOC8; (c) responses of photocurrent for CuPcOC8 and C60-CuPcOC8; (d) surface photovoltage profiles for CuPcOC8 and C60-CuPcOC8.
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Figure 5. Schematic mechanism of photocatalytic reactions of the C60-CuPcOC8.
Figure 5. Schematic mechanism of photocatalytic reactions of the C60-CuPcOC8.
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Table 1. Summary of the phthalocyanine-based materials for photocatalytic H2 evolution activity.
Table 1. Summary of the phthalocyanine-based materials for photocatalytic H2 evolution activity.
CatalystLight SourceHole Sacrificial AgentCo-CatalystH2 Amount (mmol g−1·h−1)References
C60-CuPcOC8AM1.5AA aPt8.32this work
ZnPc/TiO2AM1.5TEOA bPt3.45[44]
CoPc/TiO2AM1.5TEOAPt3.33[44]
N-usRGO/SiPcUV-visTEOAPt0.90[45]
MgPc/mpg-C3N4λ > 400 nmAAPt0.50[46]
MnPcGλ > 420 nmTEOAPt0.86[47]
MnPcGλ > 420 nmTEOA-0.75[47]
SiPc(phenyl)2G2UV-visTEOAPt1.82[48]
SiPc(phenyl)2G2UV-visTEOA-1.26[48]
Zn-tri-PcNc/g-C3N4λ > 420 nmTEOAPt8.82[49]
Zn-tri-PcNc-1/g-C3N4λ > 500 nmAAPt4.06[50]
Zn-tri-PcNc-2/g-C3N4λ > 500 nmAAPt5.26[50]
Zn-tri-PcNc-3/g-C3N4λ > 500 nmAAPt2.02[50]
Zn-tri-PcNc/TiO2λ > 420 nmEDTA cPt3.78[51]
CuPc/Zn0.5Cd0.5Sλ > 400 nmNa2S/Na2SO3-29.16[28]
CdS/FePcAM1.5lactic acid-7.30[52]
ZnPc-1/TiO2λ > 420 nmTEOAPt5.39[53]
ZnPc-2/TiO2λ > 420 nmTEOAPt2.26[53]
B1.5HCN-Co0.5%PCλ > 420 nmTEOAPt5.56[54]
a ascorbic acid, b Trolamine, 2,2′,2″-Nitrilotriethanol, c ethylene diamine tetra-acetic acid.
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Hua, Z.; Wu, B.; Zhang, Y.; Wang, C.; Dong, T.; Song, Y.; Jiang, Y.; Wang, C. Efficient Charge Separation and Transport in Fullerene-CuPcOC8 Donor–Acceptor Nanorod Enhancing Photocatalytic Hydrogen Generation. Nanomaterials 2024, 14, 256. https://doi.org/10.3390/nano14030256

AMA Style

Hua Z, Wu B, Zhang Y, Wang C, Dong T, Song Y, Jiang Y, Wang C. Efficient Charge Separation and Transport in Fullerene-CuPcOC8 Donor–Acceptor Nanorod Enhancing Photocatalytic Hydrogen Generation. Nanomaterials. 2024; 14(3):256. https://doi.org/10.3390/nano14030256

Chicago/Turabian Style

Hua, Zihui, Bo Wu, Yuhe Zhang, Chong Wang, Tianyang Dong, Yupeng Song, Ying Jiang, and Chunru Wang. 2024. "Efficient Charge Separation and Transport in Fullerene-CuPcOC8 Donor–Acceptor Nanorod Enhancing Photocatalytic Hydrogen Generation" Nanomaterials 14, no. 3: 256. https://doi.org/10.3390/nano14030256

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