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Article

Synthesis of PtAu Alloy Nanocrystals Supported on Three-Dimensional Carbon with Enhanced Electrocatalytic Properties

by
Xia Zhang
1,2 and
Zhengkai Cao
1,2,*
1
Dalian Research Institute of Petroleum and Petrochemicals, SINOPEC, Dalian 116045, China
2
China State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China
*
Author to whom correspondence should be addressed.
Catalysts 2023, 13(3), 464; https://doi.org/10.3390/catal13030464
Submission received: 19 December 2022 / Revised: 17 February 2023 / Accepted: 20 February 2023 / Published: 22 February 2023
(This article belongs to the Section Electrocatalysis)
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Abstract

Sub-nanosized PtAu particles within three-dimensional carbon materials were obtained via a mercaptosilane-assisted preparation method. This strategy can effectively control the size of PtAu particles while avoiding the use of an additional carbon precursor. The as-synthesized three-dimensional carbon (3D carbon) material possesses excellent properties compared to other carbon materials. PtAu particles on three-dimensional carbon (PtAu/3D carbon) exhibited superior activities for methanol oxidation and hydrogen evolution reactions compared to Pt/3D carbon and a commercial Pt/Carbon (Pt/C) catalyst. Specifically, the methanol peak current density on PtAu/3D carbon was almost 2.3 times higher than that of Pt/3D carbon and 1.9 times higher than that of commercial Pt/C. The Tafel slopes of PtAu/3D carbon, Pt/3D carbon, and the commercial Pt/C were approximately 112, 124, and 106 mV dec−1, respectively, demonstrating that electrochemical desorption is the rate-limiting step in the hydrogen evolution reaction of the as-synthesized catalysts.

1. Introduction

Pt and Au metals have been widely applied as the active metals for catalysis, optics, and industrial purposes [1,2,3]. Lim et al. used block copolymer micelles to prepare unique mesoporous hemisphere Au nanoparticles. The results show that low current only produced Au seeds in a few places and served as the starting point for the Au-alloy to grow. The shape and size of the particles could be controlled by changing the applied voltage and deposition time. Low voltage produced small particles and large hemispherical AuNPs with mesoporous structure [1]. Lim et al. also compared mesoporous gold and palladium and platinum films for applications in electrocatalysis. The authors described how to create a mesoporous metal film composed of gold, palladium or platinum using a block copolymer micelle template. This indicated that the diameter of the micelles could be controlled by swelling micelles with different solvent mixtures or using block copolymer micelles with different molecular weights. The deposition potential and deposition time allowed further control of the mesoporous structure and its thickness, respectively. Examples of applications included glucose oxidation, ethanol oxidation, and methanol oxidation reactions. The preparation method of mesoporous metal film took about 4 h; the subsequent electrochemical test required about 5 h for glucose sensing and about 3 h for the alcohol oxidation reaction [2]. Bueno et al. investigated the effect of the Pt precursor and loading on the structural parameters and catalytic properties of Pt/Al2O3. The presence of Cl affected the morphology and oxygen coverage of the Pt nanoparticles. However, due to the compensation effect between the core size of Pt0 and the coordinated oxygen (NPt-O) on the shell, these parameters did not affect the surface electronic property. Although there were structural differences, the catalytic activities of the chloride-free sample and the chloride-containing catalyst were similar. The effect of Pt loading was also studied. With the increase in metal loading, the “apparent” catalytic activity of each site of Pt (TOF) decreased. Increased Pt loading led to the increase in Pt0 sites with low coordination on the surface of the NPs, resulting in stronger Pt-CO integration and poisoning of active sites [3].
Hydrogen evolution reaction (HER) is a useful method to resolve the energy crisis resulting from the excessive consumption of fossil fuels [4,5,6,7,8]. Lin et al. developed large-scale non-noble metal catalysts with high performance for promoting the electrochemical production of hydrogen from water. This demonstrated that novel-type TiO2@FeNi2S4 (TiO2@FNS) could be prepared on a large scale (50 cm2) by combining the atomic layer deposition (ALD) TiO2 framework with a simple one-step low temperature (<100 °C) vulcanization method. The array exhibited excellent hydrogen evolution reaction (HER) performance, with an overvoltage of 97 mV at 10 mA cm−2, which was superior to its FNS counterpart (without TiO2 coating) and other reported catalysts. The enhanced HER catalytic performance of TiO2@FNS is due to increased specific surface area and improved structural stability [4]. Zhang et al. reported an effective method to fabricate a novel nitrogen-doped MoS2/COF-C4N vertical heterojunction (N-MoS2/COF-C4N) as a precious-metal-free bifunctional electrocatalyst for HER reaction. Compared with MoS2 and COF-C4N, the obtained vertical N-MoS2/COF-C4N catalyst demonstrated enhanced HER with a low overpotential of 106 mV at 10 mA cm−2, which was six times lower than MoS2 [5]. Sun et al. compared the activity, stability, and durability for hydrogen evolution reaction over potential electrocatalysts such as Ni, Co, NiCo, Fe, Cu, W, Mo, Se, Mn, Zn, V, and metal-free-based earth-abundant electrocatalysts. The authors also reported a strategy for achieving significantly lower overvoltage (including η10: ≤35 mV), high long-term stability (including ≥100 h), high durability (including ≥5000 cycles), and potential rare-earth-rich electrocatalysts for hydrogen evolution reactions in alkaline media, which are superior to or comparable to the most advanced noble metal Pt/C electrocatalysts [6]. Ometto et al. investigated the effects of metal–support interaction in the electrocatalysis of the hydrogen evolution reaction of metal-decorated titanium-dioxide-supported carbon. The results of electrode polarization and electrochemical impedance demonstrated that the metal-TiO2 and metal-C supported catalysts were more active than the corresponding carbon-supported materials in the HER reaction. These differences in HER activity are related to the electronic effects of TiO2/C substrate introduced by the strong metal carrier (SMSI) in the metal-TiO2/C catalyst on Pt and Ag metals [7]. Shinde et al. prepared glycerol-mediated self-growth of 3D dandelion-flower-like nickel chloride from nickel-foam for the first time via a room-temperature processed wet chemical method for electrocatalysis application. The prepared glycerol-mediated self-growing NiCl2 flower presented excellent electrocatalytic performance for hydrogen evolution reaction (HER) that was far superior to NiF (303 mV) and NiCl2 electrodes prepared without glycerol (208 mV) in the same electrolyte solution. Compared with the other two electrodes (NiF (106 mVdec−1) and NiCl2 (56 mV dec−2) without glycerol, the Tafel slope of the NiCl2 flower electrode was 41 mV dec–1, confirming the improvement in reaction kinetics. The stability of the glycerol-based NiCl2 electrode was further cycled 2000 times, and the over-potential only decreased by 8 mV, which confirmed the potential of the glycerol-based NiCl2 electrode on the electrocatalyst of HER kinetics. This simple and easy growth process included nucleation, aggregation, and crystal growth steps, which were used to produce NiCl2 nanostructures for electro-catalytic water cracking applications through the HER process [8]. Anila et al. investigated the applications of MoO3 in hydrogen evolution and oxygen evolution reactions. This work mainly focused on the hydrogen evolution reaction and oxygen evolution reaction of nanostructured molybdenum-trioxide-based materials for energy catalysis. MoO3 is an n-type broadband gap semiconductor with the ability to replace noble metal catalysts. The crystal structure and properties of nanostructured MoO3 were proposed. The latest progress of electrocatalytic hydrogen evolution, photocatalysis hydrogen evolution, photoelectrochemical hydrogen evolution, electrocatalytic oxygen evolution, and photoelectrochemical oxygen evolution in MoO3 based materials were also introduced. By constructing MoO3 nanocomposites, the charge transfer mechanism can be finely amplified. Therefore, the catalytic performance and durability of MoO3 can be improved. It was also reported that oxygen vacancy can significantly improve the catalytic performance of MoO3 [9].
Although high HER activity was obtained using Pt (platinum) and other precious-based catalysts, replacement of noble metals with earth-abundant elements remains an important research direction for hydrogen evolution reaction. Recently, plenty of potential alternatives for platinum catalysts have been investigated, such as transition metal sulfides, alloys, borides, and phosphides [10,11,12]. In particular, Mo, W and other extensively investigated material derivatives are excellent electro-catalysts for hydrogen evolution reaction [13,14,15]. Nevertheless, their higher overpotential and poor activity in comparison with platinum-based electrocatalysts are the main limiting factors for their wider development. Therefore, designing and preparing a high-performance and low-cost Pt-based electrocatalyst is very important for HER [16,17].
Direct methanol fuel cells (DMFCs) are a prospective energy-transfer method due to their high efficiency of transferring chemical energy into electricity and low environmental pollution. Platinum may be a good electro-catalyst for the electro-oxidation reaction of methanol (MOR); however, its high cost and easy poisoning by reaction intermediates are the key limitations to its application. Platinum-based bimetallic alloys (such as PtAu, PtCo, PtFe, and PtNi) are considered the substitute catalysts of monometallic platinum, which is attributed to their excellent electrocatalytic properties and lower price [18,19,20]. The electrocatalytic performances of Pt-based alloys are related to their inner and surface structures and compositions [21,22].
Noble metal nanoparticles supported on materials with a high surface area are of great significance for many heterogeneous reaction processes. A recent study revealed that the catalytic performances of noble metal nanoparticles are sensitive to their particle sizes [23,24]. In particular, ultrafine noble metal nanoclusters with a few to hundreds of atoms have attracted great attention. These ultrafine nanocatalysts possess a high surface-to-volume ratio and a large number of surface atoms [24,25,26,27,28,29]. At present, the strategies of synthesizing noble metal nanoparticle-supported catalysts, including impregnation, coprecipitation, and in situ hydrothermal synthesis, cannot accurately control the particle size. Nanoparticles with a broad size distribution, from a few nanometers to micrometers, are often synthesized during the synthetic process because of the weak interaction between metal precursors and supports [30,31,32]. Additionally, ultrafine noble metal nanoparticles can be pre-synthesized and then loaded on the surface of solid supports through strong interaction [33]. Generally, the synthesis of ultrafine noble metal nanocatalysts involves the addition of a certain amount of capping agent to control their sizes and surface structures. Nevertheless, these capping reagents usually limit the surface accessibility of ultrafine noble metal nanoparticles by blocking active sites and affect their catalytic performance by interacting with reaction intermediates [34,35,36,37,38].
In this research, a facile and general strategy for in situ preparation of PtAu nanoparticles supported on carbon supports is reported. PtAu alloy nanocrystals supported on three-dimensional carbon were successfully synthesized. The synergetic effect of Pt and Au on the electrocatalytic properties was investigated.

2. Results and Discussion

The morphologies of PtAu/carbon ZSBA and PtAu/3D carbon prepared in this research were detected via SEM, and the corresponding results are listed in Figure 1. As has been observed, the length and width of PtAu/carbon ZSBA were ~1200 nm and ~280 nm, respectively. Meanwhile, the morphology of the Pt/carbon ZSBA was similar to that of the PtAu/carbon ZSBA. Therefore, the different reactants and synthetic conditions in the synthesis procedure had little effect on the particle size and structure of the final PtAu/carbon ZSBA and Pt/carbon ZSBA. Additionally, the local curvature energy at the interface of the amphiphilic block copolymer species and inorganic silica, which has an important effect on the structural properties of the final products, was also similar. The morphologies of the PtAu/3D carbon and the Pt/3D carbon after removing SiO2 are listed in Figure 1C,D and Figure 1E,F, respectively. The morphologies of PtAu/3D carbon and Pt/3D carbon were found to be present in the three-dimensional structure. Additionally, the morphology of PtAu/3D carbon was similar to that of Pt/3D carbon, indicating that the element of the alloy over the materials has little effect on the morphology and structure of the final PtAu/3D carbon materials.
XRD characterization was applied to determine the crystal structure of the particles of PtAu/3D carbon and Pt/3D carbon. The XRD patterns of PtAu/3D carbon and Pt/3D carbon are shown in Figure 2. For the Pt/3D carbon sample, the characteristic peaks at about 40°, 46°, and 67° were ascribed to the crystal faces of Pt(111), Pt(200), and Pt(220) (NO. 04-0802). The XRD diffraction angle of Au metal is lower than Pt metal at the same crystal faces [39]. For the PtAu/3D carbon sample, the diffraction angle corresponding to the characteristic peak position decreased. Meanwhile, the individual characteristic peaks assigned to Pt and Au metals could not be observed, indicating that Pt and Au in PtAu/3D carbon exist in the form of an alloy.
TEM was conducted to demonstrate the inner structure of PtAu/ZSBA and detect the sizes of PtAu NPs. The TEM results illustrate that there were few clear PtAu nanoparticles supported on the surface of the PtAu/ZSBA synthesized at 100 °C without calcinations (Figure 3A), revealing that the Pt and Au species were atomically distributed on the surface and inner framework of the ZSBA. After calcination, images of the PtAu/carbon ZSBA (Figure 3B) and Pt/carbon ZSBA (Figure 3C) show that the PtAu and Pt nanoparticles were highly distributed on the surface and framework of SBA-15, with an average size of 2.5 nm and size distributed from 2.0 nm to 3.0 nm, except for a few nanosized PtAu and Pt NPs (about 4.0 nm) dispersed on the surface of the ZSBA. The PtAu/carbon ZSBA was treated with 2M of NaOH to obtain PtAu/3D carbon. Thus, the PtAu nanoclusters were effectively incorporated into the three-dimension carbon material and the obtained catalysts had high stability.
TEM images and the corresponding sub-nanosized PtAu particle distribution of PtAu/3D carbon are listed in Figure 3D–F. PtAu nanoparticles were highly distributed in the surface and inner framework of the 3D carbon, with an average diameter of 2.6 nm and size distribution from 1.8 nm to 3.3 nm. Meanwhile, the composition distributions of C, Pt and Au over PtAu/3D carbon were determined via EDX elemental mapping analysis. The mapping results of Pt and Au clarify that Pt and Au elements exist in PtAu/3D carbon and are uniformly distributed, demonstrating that the sub-nanoparticles in Figure 3D are PtAu alloy nanoparticles encapsulated in the 3D carbon materials. The molar ratio of Pt/Au for the PtAu/3D carbon catalyst, measured via ICP-AES, was 3.8/1.0. Similarly, the TEM images and corresponding sub-nanosized PtAu particle distribution of Pt/3D carbon are shown in Figure 3J–L, revealing that the Pt nanoparticles were uniformly distributed. Additionally, the sizes of the Pt nanoparticles were distributed from 1.5 nm to 3.0 nm, with an average size of 2.3 nm, which is smaller than that of the PtAu nanoparticles.
The catalytic performances of the as-prepared PtAu/3D carbon NCs were evaluated by using methanol electro-oxidation as the probe reaction. The effects of the structural composition of PtAu/3D carbon NCs on their electro-catalytic properties was investigated in detail. Commercial Pt/carbon was selected as the reference and measured under the same conditions. The cyclic voltammograms (CVs) of methanol oxidation on PtAu/3D carbon and commercial Pt/carbon catalyst are listed in Figure 4A. It can be seen from Figure 4B that the activity of methanol electro-oxidation for the Pt/3D carbon catalyst was the highest among the three catalysts at the beginning. However, as the evaluation time became higher than 200 s, the activity of the Pt/3D carbon catalyst decreased sharply. Too-high initial activity may form more oxide attached to the electrode surface of the Pt/3D carbon catalyst, causing its poisoning and deactivation. Noticeably, the activity of the PtAu/3D carbon catalyst was lower than the Pt/3D carbon catalyst at the beginning, after which the reaction activity increased, which should be due to the fact that the introduction of Au into a Pt catalyst can increase the stability of the catalyst. The specific current density (Js) was normalized to the electrochemically active surface area (ECSA). The current densities of the methanol electro-oxidation reaction were 5.82, 2.49, and 2.96 mA cm−2 for PtAu/3D carbon, Pt/3D carbon, and commercial Pt/C, respectively. The electro-oxidation current density of PtAu/3D carbon was almost 2.3 times greater than that of Pt/3D carbon and 1.9 times that of commercial Pt/C. It is obvious that PtAu/3D carbon exhibits higher specific activity compared with other catalysts. To further evaluate the stability of these catalysts, i-t curves were carried out for 1000 s (Figure 4B). In addition, the peak potentials of PtAu/3D carbon, Pt/3D carbon, and Pt/C were 0.81, 0.86, and 0.79 V (vs. RHE), respectively. It can be seen from the peak position results that, compared with pure Pt catalyst, the peak potential of PtAu catalyst shifts to a lower position after adding Au species. Combined with the EDS-mapping results, this shows that the formation of Pt and Au alloys promotes the methanol electro-oxidation activity of Pt. PtAu/3D carbon and Pt/3D carbon demonstrated superior stability during electrochemical measurements compared with benchmark Pt/C.
To further evaluate the electrocatalytic activities of these catalysts, the electrocatalytic HER activities of PtAu/3D carbon in 0.1M NaOH solution were also investigated. The commercial Pt/C was selected as a reference. Figure 5A lists the HER polarization curves of the as-synthesized catalysts. Based on the above results, PtAu/3D carbon and Pt/3D carbon catalysts exhibit similar onset potential to the commercial Pt/C. The Tafel slope, which can clarify the rate-limiting step of the hydrogen evolution reaction, is considered an inherent property to electrocatalysts. Under specific conditions, a slope of 120 mV dec−1 can exist if the Volmer reaction is the rate-limiting step of the hydrogen evolution reaction. Meanwhile, if the Heyrovsky or Tafel reaction are supposed as the rate-limiting step of the hydrogen evolution reaction, the Tafel slope is 40 or 30 mV dec−1. In the case of a complete hydrogen evolution reaction, either Volmer–Tafel or Volmer–Heyrovsky reaction steps should be used to generate H2. Figure 5B shows the linear portions of the Tafel plots according to the Tafel equation (ƞ = blogj + a, where j is the current density and b is the Tafel slope). The Tafel slopes of the PtAu/3D carbon, Pt/3D carbon, and commercial Pt/C were approximately 112, 124, and 106 mV dec−1, respectively. The above results demonstrate that the electrochemical desorption (Heyrovsky reaction) is the rate-limiting step in the hydrogen evolution reaction of the as-synthesized catalysts.
The methanol electro-oxidation reaction performances in other the other reported literature are listed in Table 1. As shown in Figure 4, the PtAu/3D carbon sample shows the highest specific activity of 5.86 mA/cm2, which is higher than the other two catalysts. The methanol electro-oxidation reaction-specific activities of the reported catalysts ranged from 0.70 to 5.22 mA/cm2. Therefore, the PtAu/3D carbon sample shows higher methanol electro-oxidation reaction performances than the other reported catalysts.

3. Experimental Section

3.1. Catalyst Synthesis

The chemical materials used for preparing the catalysts included NaOH (Aladdin, AR, 99.9%), NaAlO2 (Macklin, AR), tetrapropylammonium bromide (TPABr) (Aladdin, 98%), colloidal silica (Macklin, China, SiO2: 40 wt%), (3-mercaptopropyl)-trimethoxysilane ((Macklin, China, 97%), H2PtCl6 (Macklin, China, 99.995%), HAuCl4 (Meryer, China, 48–50%), HCl (Aladdin, China, 36–38%), and tetraethyl orthosilicate (TEOS) (Sigma-Aldrich, China, 98%).
The synthesis process of PtAu/3D carbon is illustrated in Scheme 1a–f. The PtAu/ZSM-5 seeds were prepared according to the following steps. First, 0.3 g of NaOH and 0.13 g of NaAlO2 were added to 10 g of deionized H2O. Then, 0.08 g of ZSM-5 nanoseeds, 1.4 g of TPABr, and 7.5 g of colloidal silica (40 wt%) were added to the above solution to form solution I. Next, 0.10 g of (3-mercaptopropyl)-trimethoxysilane and 0.13 g of NaOH were mixed with 1.9 mL H2PtCl6 (100 mmol/L) and 0.48 mL HAuCl4 (100 mmol/L) to form solution II. Afterwards, solution II was slowly added to solution I. The resulting solution was stirred for 3 h to form a homogeneous solution and then aged at 443 K for 4.5 h. The obtained PtAu/ZSM-5 seeds were used to further synthesize PtAu/3D carbon. Typically, 2.00 g of P123 was added in 65 mL of HCl (2 mol/L) under 35 °C, and 4.28 g of TEOS solution and 4.8 g of PtAu/ZSM-5 seed were dropped in the above mixture and stirred for another 24 h. The final mixture was kept at 373 K for 24 h and denoted as PtAu/ZSBA. The PtAu/ZSBA sample was dried at 100 °C for 12 h and then calcinated at 800 °C under N2. The final product PtAu/3D carbon was obtained by removing the ZSBA of PtAu/ZSBA using NaOH (2 M) solution. The synthetic process of Pt/3D carbon is similar to PtAu/3D carbon aside from the addition of HAuCl4. According to the inductively coupled plasma (ICP) measurement result, the Pt and Au masses in the composite were 8.4% and 2.1%, respectively. The Pt and Au loading masses on the electrode were 0.496 μg and 0.122 μg, respectively.
As displayed in Scheme 1, PtAu/3D carbon was synthesized according to the following steps. First, PtAu/ZSM-5 seeds were synthesized via the mercaptosilane-assisted preparation method [50]. During the synthetic process, the mercapto group of (3-mercaptopropyl)trimethoxysilane possesses strong interaction with PtAu ions, resulting in the formation of stable metal–sulfur adducts, which can limit the formation of metal hydroxide nanoparticles (Scheme 1a). Moreover, the alkoxysilane moiety of the ligands after hydrolysis can form Si-O-Si or Si-O-Al bonds with the TEOS and NaAlO2 precursors in the synthesis process of ZSM-5 zeolite. Then, the PtAu atoms were confined in the pores of the ZSM-5 nanoseeds in the further hydrothermal synthetic process (Scheme 1b). Afterwards, PtAu/ZSBA porous catalysts were synthesized by using TEOS and PtAu/ZSM-5 nanoseeds as silicon and aluminum sources and P123 (EO20PO70EO20) as the structure-directing reagent (Scheme 1c). The PtAu/ZSM-5 nanoseeds were confined into the framework of the PtAu/ZSBA porous material in the formation process of mesostructures, subject to the orientation effect of the surfactant (Scheme 1d). Then, the sample was calcined under N2 at 800 °C to obtain PtAu/carbon ZSBA (Scheme 1e). Additionally, the PtAu/carbon ZSBA was treated with 2 M of NaOH to obtain PtAu/3D carbon (Scheme 1f). Thus, the PtAu nanoparticles were effectively encapsulated into the three-dimensional carbon material, and the final catalysts exhibited high stability. Conventional Pt/C was used for the reference catalysts [51].

3.2. Catalyst Characterization

The XRD patterns of PtAu/ZSBA and PtAu/3D carbon were obtained using a Bruker D8 Advance Powder diffractometer using Cu Ka radiation with a detected angle from 20° to 80°.
The catalyst sizes and morphologies of PtAu/ZSBA and PtAu/3D carbon were detected using scanning electron microscopy (SEM-SU8010) at 20 kV. Before performing the measurement, all samples were coated with gold.
Transmission electron microscope (TEM) images were detected using a Tecnai F20 instrument that was equipped with a field emission source at an accelerating voltage of 200 Kv.
The loading of Pt and Au on 3D carbon was obtained via inductively coupled plasma atomic emission spectroscopy (ICP-AES).

3.3. Electrochemical Measurements

The as-synthesized PtAu/3D carbon or Pt/3D carbon catalysts (1 mg) were added in aqueous ethanol solution (1 mL), and a 6 μL solution containing 6 μg of catalyst was dropped on the surface of a GC electrode. Then, 0.5 μL of 0.5 wt% Nafion solution was dropped onto the catalyst surface. For reference, the solution concentration of benchmark Pt/C was the same as that of as-synthesized PtAu/3D carbon. A three-electrode cell was selected for this electrochemical measurement. A glassy carbon (GC) electrode was selected as the working electrode, a saturated calomel electrode (SCE) as the reference electrode, and a Pt gauze as the counter electrode. The electrochemical measurements of the methanol electro-oxidation reaction (MOR) are described as follows: Cyclic voltammetry (CV) measurements were performed in a fresh N2-saturated NaOH solution (0.1 M) with potential ranging from 0 to 1.2 V (vs. RHE) with a scan rate of 50 mV s−1. Afterwards, CV scans were conducted in 0.1 M NaOH + 1 M CH3OH with a scan rate of 50 mV s−1. In the case of hydrogen evolution reaction (HER), the electrolyte was 0.1 M NaOH solution saturated with N2 for 30 min before the linear sweep voltammetry (LSV) measurement.

4. Conclusions

This research reports a strategy for preparing a new catalyst consisting of sub-nanosized PtAu particles within porous carbon with three dimensions by using a mercaptosilane-assisted synthesis technique. This method can effectively control the size of the PtAu particles and avoid the use of an additional carbon precursor. The as-synthesized three-dimensional carbon material possesses excellent properties compared to other carbon materials. Moreover, the PtAu particles on carbon (PtAu/3D carbon) possessed superior electrocatalytic performances in methanol oxidation and the hydrogen evolution reaction compared to Pt/3D carbon and the commercial Pt black catalyst. Specifically, the methanol peak current density of PtAu/3D carbon is almost 2.3 times higher than that of Pt/3D carbon and 1.9 times higher than that of commercial Pt/C. The Tafel slopes of PtAu/3D carbon, Pt/3D carbon, and commercial Pt/C were approximately 112, 124, and 106 mV dec−1, respectively, demonstrating that electrochemical desorption is the rate-limiting step in the hydrogen evolution reaction of the as-synthesized catalysts. PtAu/3D carbon reduces the cost of Pt catalysts and enhances the electrocatalytic activities of Pt catalysts. This work provides useful information for the design of novel supported noble metal alloy nanocatalysts for highly efficient electrocatalysis.

Author Contributions

Conceptualization, X.Z. and Z.C.; methodology, X.Z. and Z.C.; software, X.Z.; validation, X.Z. and Z.C.; formal analysis, X.Z. and Z.C.; investigation, X.Z. and Z.C.; resources, X.Z. and Z.C.; data curation, Z.C.; writing—original draft preparation, Z.C.; writing—review and editing, Z.C.; visualization, X.Z.; All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

All data used during the study appear in this article.

Acknowledgments

This work was financially supported by the Open Research Fund of State Key Laboratory of Coking Coal Exploitation and Comprehensive Utilization, China Pingmei Shenma Group, Grant NO. 41040220171106-5.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Lim, H.; Nagaura, T.; Kim, M.; Kani, K.; Kim, J.; Bando, Y.; Alshehri, S.M.; Ahamad, T.; You, J.; Na, J.; et al. Electrochemical preparation system for unique mesoporous hemisphere gold nanoparticles using block copolymer micelles. RSC Adv. 2020, 10, 8309–8313. [Google Scholar] [CrossRef] [PubMed]
  2. Lim, H.; Kani, K.; Henzie, J.; Nagaura, T.; Nugraha, A.S.; Iqbal, M.; Ok, Y.S.; Hossain, S.A.; Bando, Y.; Wu, K.C.W.; et al. A universal approach for the synthesis of mesoporous gold, palladium and platinum films for applications in electrocatalysis. Nat. Protoc. 2020, 15, 2980–3008. [Google Scholar] [CrossRef] [PubMed]
  3. Borges, L.R.; Lopez-Castillo, A.; Meira, D.; Gallo, J.; Zanchet, D.; Bueno, J. Effect of the Pt precursor and loading on the structural parameters and catalytic properties of Pt/Al2O3. ChemCatChem 2019, 11, 3064. [Google Scholar] [CrossRef]
  4. Deng, S.; Liu, C.; Zhang, Y.; Ji, Y.; Mei, B.; Yao, Z.; Lin, S. Large-Scale Preparation of Ultrathin Bimetallic Nickel Iron Sulfides Branch Nanoflake Arrays for Enhanced Hydrogen Evolution Reaction. Catalysts 2023, 13, 174. [Google Scholar] [CrossRef]
  5. Zhang, N.; Yang, Z.; Liu, W.; Zhang, F.; Yan, H. Novel Bifunctional Nitrogen Doped MoS2/COF-C4N Vertical Heterostructures for Electrocatalytic HER and OER. Catalysts 2023, 13, 90. [Google Scholar] [CrossRef]
  6. Mohammed-Ibrahim, J.; Sun, X. Recent progress on earth abundant electrocatalysts for hydrogen evolution reaction (HER) in alkaline medium to achieve efficient water splitting—A review. J. Energy Chem. 2018, 34, 111–160. [Google Scholar] [CrossRef]
  7. Ometto, F.B.; Paganin, V.A.; Hammer, P.; Ticianelli, E.A. Effects of Metal–Support Interaction in the Electrocatalysis of the Hydrogen Evolution Reaction of the Metal-Decorated Titanium Dioxide Supported Carbon. Catalysts 2022, 13, 22. [Google Scholar] [CrossRef]
  8. Shinde, N.M.; Raut, S.D.; Ghule, B.G.; Deokate, R.J.; Narwade, S.H.; Mane, R.S.; Xia, Q.; Pak, J.J.; Kim, J.-S. Hydrogen Evolution Reaction Activities of Room-Temperature Self-Grown Glycerol-Assisted Nickel Chloride Nanostructures. Catalysts 2023, 13, 177. [Google Scholar] [CrossRef]
  9. Avani, A.; Anila, E. Recent advances of MoO3 based materials in energy catalysis: Applications in hydrogen evolution and oxygen evolution reactions. Int. J. Hydrogen Energy 2022, 47, 20475–20493. [Google Scholar] [CrossRef]
  10. Popczun, E.J.; McKone, J.R.; Read, C.G.; Biacchi, A.J.; Wiltrout, A.M.; Lewis, N.S.; Schaak, R.E. Nanostructured Nickel Phosphide as an Electrocatalyst for the Hydrogen Evolution Reaction. J. Am. Chem. Soc. 2013, 135, 9267–9270. [Google Scholar] [CrossRef]
  11. Hu, X.; Brunschwig, B.S.; Peters, J.C. Electrocatalytic Hydrogen Evolution at Low Overpotentials by Cobalt Macrocyclic Glyoxime and Tetraimine Complexes. J. Am. Chem. Soc. 2007, 129, 8988–8998. [Google Scholar] [CrossRef]
  12. Andreiadis, E.S.; Jacques, P.; Tran, P.; Leyris, A.; Chavarot-Kerlidou, M.; Jousselme, B.; Matheron, M.; Pécaut, J.; Palacin, S.; Fontecave, M. Molecular engineering of a cobalt-based electrocatalytic nanomaterial for H(2) evolution under fully aqueous con-ditions. Nat. Chem. 2012, 5, 48. [Google Scholar]
  13. Voiry, D.; Yamaguchi, H.; Li, J.; Silva, R.; Alves, D.C.; Fujita, T.; Chen, M.; Asefa, T.; Shenoy, V.B.; Eda, G.; et al. Enhanced Catalytic Activity in Strained Chemically Exfoliated WS2 Nanosheets for Hydrogen Evolution. Nat. Mater. 2013, 12, 850. [Google Scholar] [CrossRef] [PubMed]
  14. Voiry, D.; Salehi, M.; Silva, R.; Fujita, T.; Chen, M.; Asefa, T.; Shenoy, V.B.; Eda, G.; Chhowalla, M. Conducting MoS2 Nanosheets as Catalysts for Hydrogen Evolution Reaction. Nano Lett. 2013, 13, 6222–6227. [Google Scholar] [CrossRef]
  15. Xie, J.; Zhang, J.; Li, S.; Grote, F.; Zhang, X.; Zhang, H.; Wang, R.; Lei, Y.; Pan, B.; Xie, Y. Correction to Controllable Disorder En-gineering in Oxygen-Incorporated MoS2 Ultrathin Nanosheets for Efficient Hydrogen Evolution. J. Am. Chem. Soc. 2013, 135, 17881. [Google Scholar] [CrossRef] [PubMed]
  16. Li, W.; Weng, B.; Sun, X.; Cai, B.; Hübner, R.; Luo, Y.; Du, R. A Decade of Electrocatalysis with Metal Aerogels: A Perspective. Catalysts 2023, 13, 167. [Google Scholar] [CrossRef]
  17. Vernigor, I.; Bogdanovskaya, V.; Radina, M.; Andreev, V.; Grafov, O. PtM/CNT (M = Mo, Ni, CoCr) Electrocatalysts with Reduced Platinum Content for Anodic Hydrogen Oxidation and Cathodic Oxygen Reduction in Alkaline Electrolytes. Catalysts 2023, 13, 161. [Google Scholar] [CrossRef]
  18. Zhang, C.; Sang, Y.; Peng, Z.; Sang, Y.; Peng, Z. Size-Dependent Oxygen Reduction Property of Octahedral Pt-Ni Nano-particle Electrocatalysts. J. Mater. Chem. A 2014, 2, 19778. [Google Scholar] [CrossRef]
  19. Wu, J.; Qi, L.; You, H.; Gross, A.; Li, J.; Yang, H. Icosahedral Platinum Alloy Nanocrystals with Enhanced Electrocatalytic Activities. J. Am. Chem. Soc. 2012, 134, 11880–11883. [Google Scholar] [CrossRef]
  20. Carpenter, M.K.; Moylan, T.; Kukreja, R.; Atwan, M.; Tessema, M. Solvothermal synthesis of platinum alloy nano-particles for oxygen reduction electrocatalysis. J. Am. Chem. Soc. 2012, 134, 11. [Google Scholar] [CrossRef]
  21. Kwon, S.Y.; Blum, J.D.; Chirby, M.A.; Chesney, E.J. Application of mercury isotopes for tracing trophic transfer and internal distribution of mercury in marine fish feeding experiments. Environ. Toxicol. Chem. 2013, 32, 2322–2330. [Google Scholar] [CrossRef] [PubMed]
  22. Lalonde, M.; Bury, W.; Karagiaridi, O.; Brown, Z.; Hupp, J.T.; Farha, O.K. Transmetalation: Routes to metal exchange within metal–organic frameworks. J. Mater. Chem. A 2013, 1, 5453. [Google Scholar] [CrossRef]
  23. Ertl, G. Reactions at Surfaces: From Atoms to Complexity (Nobel Lecture). Angew. Chem. 2008, 47, 3524. [Google Scholar] [CrossRef] [PubMed]
  24. Hutchings, G.J.; Kiely, C. Strategies for the Synthesis of Supported Gold Palladium Nanoparticles with Controlled Morphology and Composition. Acc. Chem. Res. 2013, 46, 1759–1772. [Google Scholar] [CrossRef] [PubMed]
  25. Zhang, F.; Zhang, S.; Pollack, S.; Li, R.; Gonzalez, A.; Fan, J.; Zou, J.; Leininger, S.; Pavía-Sanders, A.; Johnson, R. Improving paclitaxel delivery: In vitro and in vivo characterization of PEGylated polyphosphoester-based nanocarriers. J. Am. Chem. Soc. 2015, 137, 2056. [Google Scholar] [CrossRef]
  26. Turner, M.; Golovko, V.B.; Vaughan, O.P.H.; Abdulkin, P.; Berenguer-Murcia, A.; Tikhov, M.S.; Johnson, B.F.G.; Lambert, R.M. Selective oxidation with dioxygen by gold nanoparticle catalysts derived from 55-atom clusters. Nature 2008, 454, 981–983. [Google Scholar] [CrossRef]
  27. Huang, J.; Akita, T.; Faye, J.; Fujitani, T.; Takei, T.; Haruta, M. Propene Epoxidation with Dioxygen Catalyzed by Gold Clusters. Angew. Chem. Int. Ed. 2009, 48, 7862–7866. [Google Scholar] [CrossRef] [PubMed]
  28. Tsunoyama, H.; Sakurai, H.; Negishi, Y.; Tsukuda, T. Size-Specific Catalytic Activity of Polymer-Stabilized Gold Nanoclusters for Aerobic Alcohol Oxidation in Water. J. Am. Chem. Soc. 2005, 127, 9374–9375. [Google Scholar] [CrossRef]
  29. Haruta, M. Nanoparticulate Gold Catalysts for Low-Temperature CO Oxidation. Cheminform 2004, 7, 163. [Google Scholar] [CrossRef]
  30. Niu, Z.; Li, Y. Removal and Utilization of Capping Agents in Nanocatalysis. Chem. Mater. 2013, 26, 72–83. [Google Scholar] [CrossRef]
  31. Li, X.; Wang, H.; Robinson, J.T.; Sanchez, H.; Diankov, G.; Dai, H. Simultaneous Nitrogen Doping and Reduction of Graphene Oxide. J. Am. Chem. Soc. 2009, 131, 15939–15944. [Google Scholar] [CrossRef]
  32. Li, B.; Hao, Y.; Shao, X.; Tang, H.; Wang, T.; Zhu, J.; Yan, S. Synthesis of hierarchically porous metal oxides and Au/TiO2 nano-hybrids for photodegradation of organic dye and catalytic reduction of 4-nitrophenol. J. Catal. 2015, 329, 368. [Google Scholar] [CrossRef]
  33. Li, C.-Y.; Fan, F.; Yin, B.; Chen, L.; Ganguly, T.; Tian, Z. Au+-cetyltrimethylammonium bromide solution: A novel precursor for seed-mediated growth of gold nanoparticles in aqueous solution. Nano Res. 2012, 6, 29–37. [Google Scholar] [CrossRef]
  34. Hu, H.; Guan, B.; Xia, B.; Lou, X. Designed Formation of Co3O4/NiCo2O4 Double-Shelled Nanocages with Enhanced Pseu-docapacitive and Electrocatalytic Properties. J. Am. Chem. Soc. 2015, 137, 5590. [Google Scholar] [CrossRef]
  35. Li, Q.; Zhang, Y.; Chen, G.; Fan, J.; Lan, H.; Yang, Y. Ultra-low-gold loading Au/CeO2 catalysts for ambient temperature CO oxidation: Effect of preparation conditions on surface composition and activity. J. Catal. 2010, 273, 167–176. [Google Scholar] [CrossRef]
  36. Li, T.; Duan, A.; Zhao, Z.; Liu, B.; Jiang, G.; Liu, J.; Wei, Y.; Pan, H. Synthesis of ordered hierarchically porous L-SBA-15 material and its hydro-upgrading performance for FCC gasoline. Fuel 2013, 117, 974–980. [Google Scholar] [CrossRef]
  37. Li, W.; Deng, Y.; Wu, Z.; Qian, X.; Yang, J.; Wang, Y.; Gu, D.; Zhang, F.; Tu, B.; Zhao, D. Hydrothermal Etching Assisted Crystal-lization: A Facile Route to Functional Yolk-Shell Titanate Microspheres with Ultrathin Nanosheets-Assembled Double Shells. J. Am. Chem. Soc. 2011, 133, 15830. [Google Scholar] [CrossRef] [PubMed]
  38. Li, W.; Wu, Z.; Wang, J.; Elzatahry, A.; Zhao, D. A Perspective on Mesoporous TiO2 Materials. Chem. Mater. 2013, 26, 287. [Google Scholar] [CrossRef]
  39. Du, C.; Gao, X.; Zhuang, Z.; Cheng, C.; Zheng, F.; Li, X.; Chen, W. Epitaxial growth of zigzag PtAu alloy surface on Au nano-pentagrams with enhanced Pt utilization and electrocatalytic performance toward ethanol oxidation reaction. Electrochim. Acta 2017, 238, 263–268. [Google Scholar] [CrossRef]
  40. Xu, X.; Zhang, X.; Sun, H.; Yang, Y.; Dai, X.; Gao, J.; Li, X.; Zhang, P.; Wang, H.-H.; Yu, N.-F.; et al. Synthesis of Pt-Ni Alloy Nanocrystals with High-Index Facets and Enhanced Electrocatalytic Properties. Angew. Chem. 2014, 126, 12730–12735. [Google Scholar] [CrossRef]
  41. Tang, M.; Luo, S.; Wang, K.; Du, H.; Sriphathoorat, R.; Shen, P. Simultaneous formation of trimetallic Pt-Ni-Cu excavated rhombic dodecahedrons with enhanced catalytic performance for the methanol oxidation reaction. Nano Res. 2018, 11, 4786–4795. [Google Scholar] [CrossRef]
  42. Ding, J.; Bu, L.; Guo, S.; Zhao, Z.; Zhu, E.; Huang, Y.; Huang, X. Morphology and Phase Controlled Construction of Pt–Ni Nanostructures for Efficient Electrocatalysis. Nano Lett. 2016, 16, 2762–2767. [Google Scholar] [CrossRef] [PubMed]
  43. Kuang, Y.; Cai, Z.; Zhang, Y.; He, D.; Yan, X.; Bi, Y.; Li, Y.; Li, Z.; Sun, X. Ultrathin Dendritic Pt3Cu Triangular Pyramid Caps with Enhanced Electrocatalytic Activity. ACS Appl. Mater. Interfaces 2014, 6, 17748–17752. [Google Scholar] [CrossRef]
  44. Xue, S.; Deng, W.; Yang, F.; Yang, J.; Amiinu, I.S.; He, D.; Tang, H.; Mu, S. Hexapod PtRuCu Nanocrystalline Alloy for Highly Efficient and Stable Methanol Oxidation. ACS Catal. 2018, 8, 7578–7584. [Google Scholar] [CrossRef]
  45. Huang, L.; Zhang, X.; Han, Y.; Wang, Q.; Fang, Y.; Dong, S. High-Index Facets Bounded Platinum–Lead Concave Nanocubes with Enhanced Electrocatalytic Properties. Chem. Mater. 2017, 29, 4557–4562. [Google Scholar] [CrossRef]
  46. Du, H.; Luo, S.; Wang, K.; Tang, M.; Sriphathoorat, R.; Jin, Y.; Shen, P.K. High-Quality and Deeply Excavated Pt3Co Nanocubes as Efficient Catalysts for Liquid Fuel Electrooxidation. Chem. Mater. 2017, 29, 9613–9617. [Google Scholar] [CrossRef]
  47. Zhang, N.; Bu, L.; Guo, S.; Guo, J.; Huang, X. Screw Thread-Like Platinum–Copper Nanowires Bounded with High-Index Facets for Efficient Electrocatalysis. Nano Lett. 2016, 16, 5037–5043. [Google Scholar] [CrossRef]
  48. Huang, L.; Zhang, X.; Wang, Q.; Han, Y.; Fang, Y.; Dong, S. Shape-Control of Pt–Ru Nanocrystals: Tuning Surface Structure for Enhanced Electrocatalytic Methanol Oxidation. J. Am. Chem. Soc. 2018, 140, 1142–1147. [Google Scholar] [CrossRef]
  49. Cao, Y.; Yang, Y.; Shan, Y.; Huang, Z. One-Pot and Facile Fabrication of Hierarchical Branched Pt–Cu Nanoparticles as Excellent Electrocatalysts for Direct Methanol Fuel Cells. ACS Appl. Mater. Interfaces 2016, 8, 5998–6003. [Google Scholar] [CrossRef]
  50. Liu, J.; Qiao, S.Z.; Hartono, S.B.; Lu, G.Q.M. Monodisperse Yolk-Shell Nanoparticles with a Hierarchical Porous Structure for Delivery Vehicles and Nanoreactors. Angew. Chem. Int. Ed. 2010, 49, 4981–4985. [Google Scholar] [CrossRef]
  51. Pazmiño, J.H.; Miller, J.T.; Mulla, S.S.; Delgass, W.N.; Ribeiro, F.H. Kinetic studies of the stability of Pt for NO oxidation: Effect of sulfur and long-term aging. J. Catal. 2011, 282, 13–24. [Google Scholar] [CrossRef]
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Figure 1. The SEM images of the materials, PtAu/carbon ZSBA (A) and Pt/carbon ZSBA (B) after calcination; PtAu/3D carbon (C,D) and Pt/3D carbon (E,F) after SiO2 leaching.
Figure 1. The SEM images of the materials, PtAu/carbon ZSBA (A) and Pt/carbon ZSBA (B) after calcination; PtAu/3D carbon (C,D) and Pt/3D carbon (E,F) after SiO2 leaching.
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Figure 2. XRD patterns of PtAu/3D carbon and Pt/3D carbon.
Figure 2. XRD patterns of PtAu/3D carbon and Pt/3D carbon.
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Figure 3. TEM image of PtAu/ZSBA (A) without calcination. TEM images of PtAu/carbon ZSBA (B) and Pt/carbon ZSBA (C) after calcination. TEM images and corresponding sub-nanosized PtAu particle distribution of PtAu/3D carbon (D,E). HAADF-STEM and EDX elemental mapping images of PtAu/3D carbon (F–I). TEM images and corresponding sub-nanosized Pt particle distribution of Pt/3D carbon (J–L).
Figure 3. TEM image of PtAu/ZSBA (A) without calcination. TEM images of PtAu/carbon ZSBA (B) and Pt/carbon ZSBA (C) after calcination. TEM images and corresponding sub-nanosized PtAu particle distribution of PtAu/3D carbon (D,E). HAADF-STEM and EDX elemental mapping images of PtAu/3D carbon (F–I). TEM images and corresponding sub-nanosized Pt particle distribution of Pt/3D carbon (J–L).
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Figure 4. (A) Cyclic voltammograms and (B) i–t curves (at 0.7 V vs. RHE) of PtAu/3D carbon and commercial Pt/C in 0.1M NaOH + 1M CH3OH solution with a scan rate of 50 mV s−1.
Figure 4. (A) Cyclic voltammograms and (B) i–t curves (at 0.7 V vs. RHE) of PtAu/3D carbon and commercial Pt/C in 0.1M NaOH + 1M CH3OH solution with a scan rate of 50 mV s−1.
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Figure 5. (A) the polarization curves and (B) corresponding Tafel plots of PtAu/3D carbon, Pt/3D carbon, and commercial Pt/C.
Figure 5. (A) the polarization curves and (B) corresponding Tafel plots of PtAu/3D carbon, Pt/3D carbon, and commercial Pt/C.
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Scheme 1. Schematic illustration of the preparation for PtAu/3D carbon material (M denotes PtAu).
Scheme 1. Schematic illustration of the preparation for PtAu/3D carbon material (M denotes PtAu).
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Table 1. Methanol electro-oxidation reaction performances in the other reported literature.
Table 1. Methanol electro-oxidation reaction performances in the other reported literature.
CatalystsMethanol Electro-Oxidation ReactionReferences
Specific Activities
(mA/cm2)		Mass Activities
(mA/μgPt)
PtNi CNC1.86-[40]
PtNi nanocube1.40-
PtNi HOH1.71-
Pt-Ni-Cu ERDs3.882.39[41]
Pt-Cu ERDs2.61.51
Pt-Ni-Cu SRDs2.450.81
THH Pt−Ni NFs0.842.19[42]
RDH Pt−Ni NFs1.041.90
Pt3Cu0.72.1[43]
PtRuCu5.221.35[44]
PtPb CNCs2.090.97[45]
Pt3Co DENC3.4-[46]
Pt-Cu NWs3.311.56[47]
PtRu NRs1.160.82[48]
Pt-Cu HBNDs1.260.7[49]
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Zhang, X.; Cao, Z. Synthesis of PtAu Alloy Nanocrystals Supported on Three-Dimensional Carbon with Enhanced Electrocatalytic Properties. Catalysts 2023, 13, 464. https://doi.org/10.3390/catal13030464

AMA Style

Zhang X, Cao Z. Synthesis of PtAu Alloy Nanocrystals Supported on Three-Dimensional Carbon with Enhanced Electrocatalytic Properties. Catalysts. 2023; 13(3):464. https://doi.org/10.3390/catal13030464

Chicago/Turabian Style

Zhang, Xia, and Zhengkai Cao. 2023. "Synthesis of PtAu Alloy Nanocrystals Supported on Three-Dimensional Carbon with Enhanced Electrocatalytic Properties" Catalysts 13, no. 3: 464. https://doi.org/10.3390/catal13030464

APA Style

Zhang, X., & Cao, Z. (2023). Synthesis of PtAu Alloy Nanocrystals Supported on Three-Dimensional Carbon with Enhanced Electrocatalytic Properties. Catalysts, 13(3), 464. https://doi.org/10.3390/catal13030464

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