Search Results (513)

Improving charge transport in the aggregated state of nanocomposites is challenging due to the large number of defects present at grain boundaries. To enhance the charge transfer and photogenerated carrier extraction of MnO_x nanofibers, a MnO_x/GO (graphene oxide) nanocomposite was prepared. The effects of GO content and bias on the optoelectronic properties were studied. Representative light sources at 405, 650, 780, 808, 980, and 1064 nm were used to examine the photoelectric signals. The results indicate that the MnO_x/GO nanocomposites have photocurrent switching behaviours from the visible region to the NIR (near-infrared) when the amount of GO added is optimised. It was also found that even with zero bias and storage of the nanocomposite sample at room temperature for over 8 years, a good photoelectric signal could still be extracted. This demonstrates that the MnO_x/GO nanocomposites present a strong built-in electric field that drives the directional motion of photogenerated carriers, avoids the photogenerated carrier recombination, and reflect a good photophysical stability. The strength of the built-in electric field is strongly affected by the component ratios of the resulting nanocomposite. The formation of the built-in electric field results from interfacial charge transfer in the nanocomposite. Modulating the charge behaviour of nanocomposites can significantly improve the physicochemical properties of materials when excited by light with different wavelengths and can be used in multidisciplinary applications. Since the recombination of photogenerated electron–hole pairs is the key bottleneck in multidisciplinary fields, this study provides a simple, low-cost method of tailoring defects at grain boundaries in the aggregated state of nanocomposites. These results can be used as a reference for multidisciplinary fields with low energy consumption. Full article

The photocatalytic performance of heterojunctions is often restricted by inferior contact interface and low charge transfer efficiency. In this work, Ti₃C₂O MXene was crafted with AgI/MoS₂ to produce a Z-scheme heterojunction (AgI/MoS₂/Ti₃C₂O). Interfacial electric fields and chemical bonds were proven to exist in the heterojunction. The interfacial electric fields supplied a powerful driving force, and the interfacial Ti-O-Mo bonds served as an atomic-level channel for synergistically expediting the vectorial transfer of photogenerated carriers. As a result, AgI/MoS₂/Ti₃C₂O exhibited significantly improved photocatalytic activity, demonstrating a high H₂O₂ production rate of 700 μmol·g⁻¹·h⁻¹ and a rapid degradation of organic pollutants. Full article

The vast majority of photocatalysts find it difficult to consistently and stably exhibit high performance due to the variability of sunlight intensity within a day, as well as the high energy consumption of artificial light sources. In this study, mechanoluminescent Sr₂MgSi₂O₇:Eu,Dy phosphors is combined with NiS@g-C₃N₄ composite to construct a ternary heterogeneous photocatalytic system, denoted as NCS. In addition to the enhanced separation efficiency of photogenerated charge carriers by the formation of a heterojunction, the introduction of Sr₂MgSi₂O₇:Eu,Dy provides an ultra-driving force for the photocatalytic reactions owing to its mechanoluminescence-induced excitation. Results show that the degradation rate of RhB increased significantly in comparison with pristine g-C₃N₄ and NiS@g-C₃N₄, indicating the obvious advantages of the ternary system for charge separation and migration. Moreover, the additional photocatalytic activity of NCS under ultrasound stimulation makes it a promising all-weather photocatalyst even in dark environments. This novel strategy opens up new horizons for the synergistic combination of light-driven and ultrasound-driven heterogeneous photocatalytic systems, and it also has important reference significance for the design and application of high-performance photocatalysts. Full article

A strong interaction between Bi³⁺ and ZnO was used to successfully sensitize ZnO nanorods with quantum dots (QDs) of Bi₂O₃ through three different strategies. Although the Bi₂O₃ QDs had similar particle size distributions, their photocatalytic performance varied significantly, prompting the investigation of factors beyond particle size. The study revealed that the photochemical method selectively deposited Bi₂O₃ QDs onto electron-rich ZnO sites, providing a favorable pathway for efficient electron–hole separation and transfer. Consequently, abundant h⁺ and ·OH radicals were generated, which effectively degraded Rhodamine B (RhB). As demonstrated in the RhB degradation experiments, the Bi₂O₃/ZnO nanorod catalyst achieved an 89.3% degradation rate within 120 min, significantly outperforming catalysts with other morphologies. The photoluminescence (PL) and time-resolved photoluminescence (TRPL) results indicated that the Bi₂O₃/ZnO heterostructure constructed an effective interface to facilitate the spatial separation of photogenerated charge carriers, which effectively prolonged their lifetime. The electron paramagnetic resonance (EPR) results confirmed that the ·OH radicals played a key role in the degradation process. Full article

Perovskite solar cells (PSCs) leverage the exceptional photoelectric properties of perovskite materials, yet interfacial energy level mismatches limit carrier extraction efficiency. In this work, energy level alignment was exploited to reduce the charge transport barrier, which can be conducive to the transmission of photo-generated carriers and reduce the probability of electron–hole recombination. We designed a dual-transition perovskite solar cell (PSC) with the structure of FTO/TiO₂/Nb₂O₅/CH₃NH₃PbI₃/MoO₃/Spiro-OMeTAD/Au by finite element analysis methods. Compared with the pristine device (FTO/TiO₂/CH₃NH₃PbI₃/Spiro-OMeTAD/Au), the open-circuit voltage of the optimized cell increases from 0.98 V to 1.06 V. Furthermore, the design of a circular platform light-trapping structure makes up for the light loss caused by the transition at the interface. The short-circuit current density of the optimized device increases from 19.81 mA/cm² to 20.36 mA/cm², and the champion device’s power conversion efficiency (PCE) reaches 17.83%, which is an 18.47% improvement over the planar device. This model provides new insight for the optimization of perovskite devices. Full article

Harnessing abundant and renewable solar energy for photocatalytic hydrogen production is a highly promising approach to sustainable energy generation. To realize the practical implementation of such systems, the development of photocatalysts that simultaneously exhibit high activity, cost-effectiveness, and long-term stability is critically important. In this study, a Cd_0.8Zn_0.2S nanowire photocatalytic system decorated with graphene (GR) was prepared by a simple hydrothermal method. The introduction of graphene increased the reaction active area of Cd_0.8Zn_0.2S, promoted the separation of photogenerated charge carriers in the semiconductor, and improved the photocatalytic performance of the Cd₀.₈Zn₀.₂S semiconductor. The results showed that Cd_0.8Zn_0.2S loaded with 5% graphene exhibited the best photocatalytic activity, with a hydrogen production rate of 1063.4 µmol·g⁻¹·h⁻¹. Characterization data revealed that the graphene cocatalyst significantly enhances electron transfer kinetics in Cd₀.₈Zn₀.₂S, thereby improving the separation efficiency of photogenerated charge carriers. This study demonstrates a rational strategy for designing high-performance, low-cost composite photocatalysts using earth-abundant cocatalysts, advancing sustainable hydrogen production. Full article

Constructing a heterojunction is considered one of the most effective strategies for enhancing photocatalytic activity. Herein, we employ Ta₃N₅ and tubular graphitic carbon nitride (TCN) to construct a Ta₃N₅/TCN van der Waals heterojunction via electrostatic self-assembly for enhanced photocatalytic H₂ production. SEM and TEM results show that Ta₃N₅ particles (~300 nm in size) are successfully anchored onto the surface of TCN. The light absorption capability of the Ta₃N₅/TCN heterojunction is between those of Ta₃N₅ and TCN. The strong interaction between Ta₃N₅ and TCN with different energy structures (Fermi levels) by van der Waals force renders the formation of an interfacial electric field to drive the separation and transfer of photogenerated charge carriers in the Ta₃N₅/TCN heterojunction, as evidenced by the photoluminescence (PL) and photoelectrochemical (PEC) characterization results. Consequently, the optimal Ta₃N₅/TCN heterojunction exhibits a remarkable H₂ production rate of 12.73 mmol g⁻¹ h⁻¹ under visible light irradiation, which is 3.3 and 16.8 times those of TCN and Ta₃N₅, respectively. Meanwhile, the cyclic experiment demonstrates excellent stability of the Ta₃N₅/TCN heterojunction upon photocatalytic reaction. Notably, the photocatalytic performance of 15-TaN/TCN outperforms the most previously reported CN-based and Ta₃N₅-based heterojunctions for H₂ production. This work provides a new avenue for the rational design of CN-based van der Waals heterojunction photocatalysts with enhanced photocatalytic activity. Full article

Nonlinear characteristics are essential for neuromorphic devices to process high-dimensional and unstructured data. However, enabling a device to realize a nonlinear response under the same stimulation condition is challenging as this involves two opposing processes: simultaneous charge accumulation and recombination. In this study, a hybrid transistor based on a mixed-halide perovskite was fabricated to achieve dynamic nonlinear changes in synaptic plasticity. The utilization of a light-induced mixed-bandgap structure within the mixed perovskite film has been demonstrated to increase the recombination paths of photogenerated carriers of the hybrid film, thereby promoting the formation of nonlinear signals in the device. The constructed heterojunction optoelectronic synaptic transistor, formed by combining a mixed-halide perovskite with a p-type semiconductor, generates dynamic nonlinear decay responses under 400 nm light pulses with an intensity as low as 0.02 mW/cm². Furthermore, it has been demonstrated that nonlinear photocurrent growth can be achieved under 650 nm light pulses. It is important to note that this novel nonlinear response is characterized by its dynamism. These improvements provide a novel method for expanding the modulation capability of optoelectronic synaptic devices for synaptic plasticity. Full article

Thylakoid-based photosynthetic biofuel cells (TBFCs) harness the inherent light-driven electron transfer pathways of photosynthesis to enable sustainable solar-to-electrical energy conversion. While TBFCs offer a unique route toward biohybrid energy systems, their practical deployment is hindered by sluggish electron transfer kinetics, unstable redox mediators, and inefficient interfacing between biological and electrode components. This review critically examines recent advances in TBFCs, with a focus on three key surface engineering strategies: (i) incorporation of nanostructured materials to enhance electrode conductivity and surface area; (ii) application of redox mediators to facilitate charge transfer between photosynthetic proteins and electrodes; and (iii) functional exploitation of individual thylakoid components, including Photosystem I (PSI) and Photosystem II (PSII), to augment photogenerated current output. By systematically evaluating current advancements, this review highlights the synergistic role of materials and biological components in advancing TBFC technology and offers insights into next generation biohybrid solar energy systems with enhanced efficiency and scalability. Full article

A three-dimensional Bi-enriched Bi₂O₃/Bi₂MoO₆ Z-scheme heterojunction photocatalyst was successfully synthesized via a facile one-step hydrothermal method for efficient phenol degradation under visible light. Structural and morphological characterizations (SEM, TEM, and XRD) confirmed the formation of a nanoflower-like architecture with a high specific surface area of 81.27 m²/g. Optical and electrochemical analyses revealed efficient charge separation and extended visible-light response. Under visible-light irradiation (λ > 420 nm), this heterojunction (Bi₂O₃:Bi₂MoO₆ = 3:7) demonstrated exceptional performance, degrading 97.06% of phenol (30 mg/L) within 60 min. XPS analysis confirmed the Z-scheme charge transfer mechanism: Photogenerated electrons in the conduction band of Bi₂O₃ (−0.59 eV) facilitated the generation of ·O₂⁻ radicals, while holes in the valence band of Bi₂MoO₆ (2.44 eV) predominantly produced ·OH radicals. This synergistic effect resulted in highly efficient mineralization and degradation of phenol. Full article

Highly efficient photocatalysts for solar energy conversion require effective charge carrier separation and rapid interfacial transport kinetics to maximize electron availability. Two-dimensional Ti₃CNT_x, a novel conductive material in the MXene family with exceptional electrical conductivity, has emerged as an ideal electron transfer mediator due to its large specific surface area and abundant active terminal groups. In this work, we strategically integrated the 2D multi-metal sulfide Cu-Zn-In-S (CZIS) with 2D Ti₃CNT_x nanosheets through physical mixture, constructing a heterostructured 2D/2D CZIS/Ti₃CNT_x composite photocatalyst for the hydrogen evolution reaction. The unique architecture significantly accelerates electron migration from CZIS to Ti₃CNT_x, while synergistically promoting the spatial separation and directional transfer of photogenerated electron–hole pairs (e⁻/h⁺). When the hydrogen evolution reaction is carried out under identical conditions, the hydrogen yield rate is 4.3 mmol g⁻¹ h⁻¹ with pristine CZIS but is improved dramatically to 14.3 mmol g⁻¹ h⁻¹ when the composite containing an adequate amount of 2D Ti₃CNT_x is used. This study offers new insight into the rational design and controllable synthesis of Ti₃CNT_x-based composite photocatalytic systems for efficient photocatalytic hydrogen production. Full article

Fabricating efficient photocatalysts that can be used in solar-to-fuel conversion and to enhance the photochemical reaction rate is essential to the current energy crisis and climate changes due to the excessive usage of nonrenewable fossil fuels. To attain high photo-to-chemical conversion efficiency, it is important to fabricate cost-effective and durable catalysts with high activity. One-dimensional cadmium sulfides (1D CdS), with higher surface area, charge carrier separation along the linear direction, and visible light harvesting properties, are promising candidates for converting solar energy to H₂, reducing CO₂ to commodity chemicals, and remediating environmental pollutants. The main disadvantage of CdS is photocorrosion due to the leaching of S²⁻ ions during the photochemical reactions, and further charge recombination rate leads to low quantum efficiency. Therefore, the implementation of core–shell heterostructured morphology, i.e., the growth of the shell on the surface of the 1D CdS, which offers unique features such as protection of CdS from photocorrosion, a tunable interface between the core CdS and shell, and photogenerated charge carrier separation via heterojunctions, provides additional active sites and enhanced visible light harvesting. Therefore, the viability of the core–shell synthesis strategy and synergetic effects offer a new way of designing photocatalysts with enhanced stability and improved charge separation in solar energy conversion systems. This review highlights some critical aspects of synthesizing 1D CdS core–shell heterostructures, underlying reaction mechanisms, and their performance in photoredox reactions. Finally, some challenges and considerations in the fabrication of 1D CdS-based core–shell nanostructures that can overcome the current barriers in industrial applications are discussed. Full article

Nanomaterials with large specific surface area (SSA) have emerged as pivotal platforms for energy storage and environmental remediation, primarily due to their enhanced active site exposure, improved mass transport capabilities, and superior interfacial reactivity. Among them, polymeric carbon nitride (g-C₃N₄) has garnered significant attention in energy and environmental applications owing to its visible-light-responsive bandgap (~2.7 eV), exceptional thermal/chemical stability, and earth-abundant composition. However, the practical performance of g-C₃N₄ is fundamentally constrained by intrinsic limitations, including its inherently low SSA (<20 m²/g via conventional thermal polymerization), rapid recombination of photogenerated carriers, and inefficient charge transfer kinetics. Notably, the theoretical SSA of g-C₃N₄ reaches 2500 m²/g, yet achieving this value remains challenging due to strong interlayer van der Waals interactions and structural collapse during synthesis. Recent advances demonstrate that state-of-the-art strategies can elevate its SSA to 50–200 m²/g. To break this surface area barrier, advanced strategies achieve SSA enhancement through three primary pathways: pre-treatment (molecular and supramolecular precursor design), in process (templating and controlled polycondensation), and post-processing (chemical exfoliation and defect engineering). This review systematically examines controllable synthesis methodologies for high-SSA g-C₃N₄, analyzing how SSA amplification intrinsically modulates band structures, extends carrier lifetimes, and boosts catalytic efficiencies. Future research should prioritize synergistic multi-stage engineering to approach the theoretical SSA limit (2500 m²/g) while preserving robust optoelectronic properties. Full article

The photocatalytic reduction of CO₂ into valuable hydrocarbons presents significant potential. In this research, a ZnO/ZnAl₂O₄ composite photocatalyst was synthesized using the hydrothermal method, resulting in a marked enhancement in CO yield—approximately three times greater than that achieved with pure ZnAl₂O₄ nanoparticles. The formation of a Z-scheme heterojunction between ZnO and ZnAl₂O₄ was observed, characterized by low interfacial charge transfer resistance, an abundance of reaction sites, and optimized charge transport pathways. Within this composite, ZnO contributes additional vacancies, thereby increasing active sites and enhancing the separation and migration of photogenerated carriers. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis indicates that ZnAl₂O₄ facilitates the formation of key intermediates, such as *COOH and HCO₃⁻, thus promoting the conversion of CO₂ to CO. This study offers valuable insights into the design of heterogeneous catalysts with diverse active components to enhance the performance of CO₂ photocatalytic reduction through synergistic effects. Full article

NiS nanoparticles were chemically deposited on the surface of g-C₃N₄, in situ, followed by high-temperature calcination to prepare x-NiS/g-C₃N₄ co-catalyst-based S-scheme heterojunction photocatalysts. Due to the intrinsic charge accumulation preference on specific crystal planes of g-C₃N₄, NiS nanoparticles selectively deposited on its surface and formed a strong interfacial contact, thereby constructing an S-scheme heterojunction with co-catalytic functionality. This structure effectively suppressesd the recombination of electron–hole pairs in the valence band, significantly enhancing the separation efficiency of photogenerated charge carriers, and thereby improving performance in photocatalytic CO₂ reduction. Compared with pure g-C₃N₄, the x-NiS/g-C₃N₄ photocatalysts exhibit superior CO₂ reduction activity. Among them, the sample with 1.0% NiS loading showed the best performance, achieving CO and CH₄ production rates of 27.34 μmol/g and 13.87 μmol/g, respectively, within 4 h. Full article