Photo-generated Charge Research Articles

Low-valence platinum single atoms in sulfur-containing covalent organic frameworks for photocatalytic hydrogen evolution

This study focuses on optimizing catalytic activity in photocatalytic hydrogen evolution reaction by precisely designing and modulating the electronic structure of metal single atoms. The catalyst, denoted as PtSA@S-TFPT, integrates low-valence platinum single atoms into sulfur-containing covalent organic frameworks. The robust asymmetric four-coordination between sulfur and platinum within the framework enables a high platinum loading of 12.1 wt%, resulting in efficient photocatalytic hydrogen production activity of 11.4 mmol g−1 h−1 and stable performance under visible light. These outcomes are attributed to a reduced hydrogen desorption barrier and enhanced photogenerated charge separation, as indicated by density functional theory calculations and dynamic carrier analysis. This work challenges traditional notions and opens an avenue for developing low-valence metal single atom-loaded covalent organic framework catalysts to advance photocatalytic hydrogen evolution.

SnS2-supported MAPbI3 composites for effective photocatalytic hydrogen evolution

Metal halide perovskites have demonstrated encouraging photocatalytic potential due to their favorable photoelectric properties. However, severe carrier recombination greatly affects their catalytic performance. Here, we introduced cocatalyst SnS2 to synthesize novel SnS2/MAPbI3 composites via the electrostatic coupling method, which presented excellent hydrogen production performance. The hydrogen production rate of 5 % SnS2/MAPbI3 (5 wt% SnS2/MAPbI3) reached 445.96 μmol·g−1·h−1, about 325-fold increase compared to pure MAPbI3 (1.37 μmol·g−1·h−1). The 16 h cycle stability test proved its stability and effectiveness. Detailed experimental characterizations and analysis indicate that the cocatalyst SnS2 reduces the surface overpotential and facilitates electron transport and efficiently separates photogenerated charge carriers. This work provides new insights into effective photocatalysts based on MAPbI3.

UV-promoted carrier transfer regulation of PbS quantum dots modified ZnO for ultra-high response detection of ppb-level triethylamine

Triethylamine (TEA) is internationally recognized as a common industrial waste gas, necessitating the urgent development of gas sensors with high selectivity and sensitivity. Here, the gas sensor derived from ZIF-L modified with PbS quantum dots (QDs) was designed and prepared. The photo-generated charge under UV light interacts with the adsorbed oxygen on the ZnO/PbS surface, resulting in the formation of alternating cycles. The p-n nano heterojunction created at the ZnO/PbS interface facilitates rapid carrier transfer. Therefore, the ZnO/PbS-0.2 sensor exhibits a response to TEA under UV light is as high as 13,600 (Ra/Rg), which is 5 times greater than that of ZnO, and 16 times higher than that of ZnO/PbS-0.2 sensor in darkness. Moreover, the response of ZnO/PbS-0.2 to TEA under UV light is at least 8 times that of the other 7 types of volatile organic compounds (VOCs). In addition, the detection limits of ZnO/PbS-0.2 under UV light are as low as 198 ppb, far below the internationally emission limit value (1 ppm). The ppb-level detection, super-high responsiveness, and outstanding selectivity of ZnO/PbS-0.2 sensor are result from the synergistic effect of the p-n nano heterojunction at the PbS-ZnO interface and abundant photo-generated charge carriers generated under UV light.

A general strategy for enhancing the performance of Ga2O3-based self-powered solar-blind photodetectors through band structure engineering

Abstract The spectral response of Ga2O3 almost perfectly covers the 200~280 nm solar-blind ultraviolet wavelength range, making it an ideal semiconductor material for fabricating solar-blind ultraviolet photodetectors. However, due to the considerably deep valence band energy of Ga2O3 the construction of heterojunctions typically induces a significant valence band offset (EV). Herein, we present a band engineering approach to improve the performance of Ga2O3 bases photodetectors. This pronounced valence band barrier can strongly influence the transport of photo-generated charge carriers, especially the extraction of holes in the depletion region. By introducing nitrogen (N) during the growth process, we elevated the valence band of Ga2O3 by 0.43 eV. The organic high-molecular-weight material of PEDOT:PSS has been utilized in conjunction with Ga2O3 to construct heterojunction photodetectors. The photodetectors exhibit excellent self-powered characteristics, with responsivity, detectivity, and response time being nearly ten times higher than those of Ga2O3 photodetectors before band structure modulation. The investigation into modulating the band structure of Ga2O3 carried out in this study will lay the theoretical foundation and provide technical solutions for developing satisfactory self-powered photodetectors.

In situ construction of η-Fe2O3/g-C3N4 Z-scheme heterojunction on nickel foam with efficient interfacial charge transport for enhanced photodegradation of Rhodamine B

The design of efficient, low cost and recyclable photocatalyst is of great significance for disposing organic wastewater. In this work, η-Fe2O3/g-C3N4 heterostructure was constructed by in-situ cyclic voltammetry codeposition and calcination on nickel foam (NF). The microstructural and morphological characterization of the sample confirmed that spherical η-Fe2O3/g-C3N4 nanocomposites were co-deposited on three-dimensional porous NF to form Fe2O3/g-C3N4/NF photoelectrode under 50 cycles of 50 mV/s electric field. The removal rate of as-prepared η-Fe2O3/g-C3N4/NF photoelectrode for 10 mg·L−1 Rhodamine B solution reaches 95.2 % in 1h, which is 5.6 times of g-C3N4/NF and 5.3 times of η-Fe2O3/NF, respectively. According to the electrochemical test results, the enhanced photocatalytic activity of η-Fe2O3/g-C3N4/NF was principally due to efficient photogenerated charge separation and transfer ability of the photoelectrode. The results of active species capture experiments indicate that superoxide radical, hydroxyl radical and hole almost equivalently participated in photodegradation of η-Fe2O3/g-C3N4/NF, and its possible photodegradation mechanism was proposed on the basis of Z-scheme charge transport path. The η-Fe2O3/g-C3N4/NF nanocomposites would be expected to become a promising photoelectrode for large-scale applications.

Boosting Fill Factor of Semitransparent Donor‐Poor Organic Solar Cells for the Best Light Utilization Efficiency

AbstractReducing the content of light‐absorbing material in the active layer of semitransparent organic solar cells (ST‐OSCs) enhances the average visible transmittance (AVT) but sacrifices the power conversion efficiency (PCE). This dilemma is a key challenge to ST‐OSCs. Here trityl tetrakis(pentafluorophenyl) borate (TrTPFB)‐doping of the polymer donor at a suboptimal donor:acceptor (D:A) ratio is reported as an approach to enhance the light utilization efficiency (LUE) via boosting the fill factor (FF). The suboptimal D:A ratio results in not only a less efficient hole transporting network but also a narrower charge photogeneration profile. The latter widens the flat‐band region. These deteriorations make charge diffusion a crucial factor for compensating charge collection. TrTPFB‐doping mainly helps elongate the charge diffusion length to alleviate severe bimolecular recombination. As a result, the FF boosts from 65.1% to 72.2% in the film AVT increased device, which is comparable to that of the bulk heterojunction device with the optimal D:A ratio. The best LUE of 3.51% is achieved in the TrTPFB‐doped ST‐OSCs based on a ternary material combination; moreover, an LUE of 5.18% is predicted after proper optical optimization. The ST‐OSC showcases a greenhouse rooftop, which outperforms the glass one for the wheat plant.

Toward Efficient Utilization of Photogenerated Charge Carriers in Photoelectrochemical Systems: Engineering Strategies from the Atomic Level to Configuration.

Photoelectrochemical (PEC) systems are essential for solar energy conversion, addressing critical energy and environmental issues. However, the low efficiency in utilizing photogenerated charge carriers significantly limits overall energy conversion. Consequently, there is a growing focus on developing strategies to enhance photoelectrode performance. This review systematically explores recent advancements in PEC system modifications, spanning from atomic and nanoscopic levels to configuration engineering. We delve into the relationships between PEC structures, intrinsic properties, kinetics of photogenerated charge carriers, and their utilization. Additionally, we propose future directions and perspectives for developing more efficient PEC systems, offering valuable insights into potential innovations in the field.

Comparison of different α-Fe2O3 sources in the enhancement of ZnO photocatalytic activity during the degradation of a mixture of endocrine-disruptors

α-Fe2O3/ZnO composites were synthesized using MOF235(Fe), NH2–MOF235(Fe), and FeOOH as α-Fe2O3 precursors via microwave-assisted precipitation and post-calcination at 450 °C. Thermogravimetric analyses (TGA), X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), N2 physisorption analysis, scanning electron microscopy using a fully integrated EDS detector (SEM–EDS), X-ray photoelectron spectroscopy (XPS), and electrochemical experiments were employed to characterize the prepared materials. The coupling of MOF235(Fe)-, NH2–MOF235(Fe)-, and FeOOH-derived α-Fe2O3 into ZnO increased the specific surface area values and light absorption in the visible region of ZnO. The NH2–MOF235(Fe)-derived α-Fe2O3/ZnO allowed enhanced photogenerated charge separation with retarded e−/h+ recombination rate and reduced charge-transfer resistance, promoting superior photocatalytic activity. The photocatalytic activity of α-Fe2O3/ZnO composites was evaluated in the degradation of bisphenol A, 4-tert-butylphenol, and 4-tert-octylphenol mixture solution at pH 7.0 under simulated solar light using 0.5 g L−1 catalyst loading. The mineralization percentages of endocrine-disrupting compounds (EDCs) of 36.76%, 42.25%, and 19.92% occurred in 330 min (600 kJ m−2 of accumulated energy) for MOF235(Fe)-, NH2–MOF235(Fe)-, and FeOOH-derived α-Fe2O3/ZnO, respectively. The QSAR approach using the ECOSAR program to evaluate the acute toxicity of the by-products generated with the NH2–MOF235(Fe)_α-Fe2O3/ZnO photocatalyst showed that the effluent was nontoxic for the three target trophic models (fish, Daphnia, and green algae). This result was consistent with those of the Vibrio fischeri bioluminescence inhibition assay, where the effluents using NH2–MOF235(Fe)_α-Fe2O3/ZnO were classified as nontoxic. Thus, NH2–MOF235(Fe) can be successfully used as an α-Fe2O3 precursor to generate an α-Fe2O3/ZnO composite, which is a promising material for removing EDCs from aqueous solutions.

Solvothermal synthesized mesoporous BiOCl nano-ellipsoids with oxygen vacancies for photocatalytic degradation of low density polyethylene (LDPE) plastic

This study explores mesoporous BiOCl nanoparticles as a promising photocatalyst for low-density polyethylene (LDPE) degradation under visible light for the first time. A solvothermal synthesis yields BiOCl nanoparticles with a high ratio of exposed {010} facets and abundant oxygen vacancies (OVs). These properties, along with the co-existence of Bi³-x and Bi³⁺x defect states, promote a tailored surface chemistry with high surface-bound hydroxyl groups. These properties optimize light absorption by inducing favorable surface states, leading to a red shift in the light absorption edge for efficient utilization of visible light. Additionally, OVs suppress the recombination of photo-generated charge carriers and enhance their transfer rate. Furthermore, the free-standing LDPE/BiOCl nanocomposite films of 50μm, prepared via solution casting technique with varying BiOCl weight percentages (3, 5, and 7 wt.%), exhibit remarkable photocatalytic activity. The analysis of photodegraded LDPE confirms the presence of carbonyl groups (C.I.= 86%), cracks, pores, and hydroxyl radicals (•OH), alongside reduced thermal stability and band gap changes. Through meticulous analysis of the results obtained, we have ascertained that the optimal photocatalytic degradation of LDPE is achieved by incorporating up to 5 wt.% of BiOCl.

Balancing the Charge Separation and Surface Reaction Dynamics in Twin-Interface Photocatalysts for Solar-to-Hydrogen Production.

Solar-driven photocatalytic green hydrogen (H2) evolution reaction presents a promising route toward solar-to-chemical fuel conversion. However, its efficiency has been hindered by the desynchronization of fast photogenerated charge carriers and slow surface reaction kinetics. This work introduces a paradigm shift in photocatalyst design by focusing on the synchronization of charge transport and surface reactions through the use of twin structures as a unique platform. With CdS twin structure (CdS-T) as a model, the role of twin boundaries in modulating surface reactions and facilitating charge migration is systematically investigated. Utilizing transient absorption (TA) and time-resolved infrared (TRIR) spectroscopies, it is revealed that CdS-T achieves charge separation on a picosecond timescale and, importantly, the surface reaction at the twin boundary with the involvement of holes also occurs within 100ps to 3ns. This synchronization of charge donation and surface regeneration significantly enhances the hydrogen evolution process. Accordingly, CdS-T exhibits superior activity for visible light photocatalytic H2 production, withthe H2 production rate of 55.61mmol h-1 g-1 and remarkable stability (>30h), outperforming pristine CdS significantly. This study underscores the transformative potential of twin structures in photocatalysis, offering a new avenue to synchronize charge transport and surface reactions.

Novel Inorganic-Organic Dual-Photosensitizing Dinuclear-Metal Self-Assembly System for Efficient Artificial Photosynthesis without Sacrificial Electron Donors.

Owing to the unique synergistic effect, dinuclear-metal-molecule-catalysts (DMCs) show excellent performance in catalytic fields. However, for overall photocatalytic CO2 reaction (CO2RR), it is still a challenge to construct well-matched photosensitizer (PS) components for DMCs-based photocatalysts. Inorganic-quantum-dot PS possesses capacities of multiple exciton generation and catalyzing water oxidation but is incompatible with DMCs. In contrast, organic PS can be covalently linked with DMCs but inescapable of using sacrificial electron donors. For overall photocatalytic CO2RR, organic-inorganic dual-photosensitizing system might be a promising candidate. Herein, we employed covalent-linking and electrostatic-driven approaches to construct the self-assembly of pyrene-sensitized Co2L DMCs (Py-Co2L) and perovskite (PVK) quantum dots, i.e., PVK@[Py-Co2L]. Using H2O as an electron donor, PVK@[Py-Co2L] realized 105.24 μmol ⋅ g-1⋅h-1 CO yield in photocatalytic CO2RR, much higher than PVK (15.44 μmol ⋅ g-1⋅h-1) and PVK@Co2L (32.30 μmol ⋅ g-1 ⋅ h-1), ascribing to the efficient photogenerated charge separation and transfer. The experimental results and theoretical investigations demonstrated that the pyrene linked on Co2L boosted the electron delivery from PVK to DMCs. Besides, this strategy could also be extended to the photocatalytic H2 evolution coupled with alcohol oxidation. As a proof-of-concept, our work lightens the integration of DMCs, organic and inorganic PS components, promoting the development of photocatalysis without sacrificial electron donors.

Novel Inorganic‐Organic Dual‐Photosensitizing Dinuclear‐Metal Self‐Assembly System for Efficient Artificial Photosynthesis without Sacrificial Electron Donors

AbstractOwing to the unique synergistic effect, dinuclear‐metal‐molecule‐catalysts (DMCs) show excellent performance in catalytic fields. However, for overall photocatalytic CO2 reaction (CO2RR), it is still a challenge to construct well‐matched photosensitizer (PS) components for DMCs‐based photocatalysts. Inorganic‐quantum‐dot PS possesses capacities of multiple exciton generation and catalyzing water oxidation but is incompatible with DMCs. In contrast, organic PS can be covalently linked with DMCs but inescapable of using sacrificial electron donors. For overall photocatalytic CO2RR, organic–inorganic dual‐photosensitizing system might be a promising candidate. Herein, we employed covalent‐linking and electrostatic‐driven approaches to construct the self‐assembly of pyrene‐sensitized Co2L DMCs (Py‐Co2L) and perovskite (PVK) quantum dots, i.e., PVK@[Py‐Co2L]. Using H2O as an electron donor, PVK@[Py‐Co2L] realized 105.24 μmol ⋅ g−1⋅h−1 CO yield in photocatalytic CO2RR, much higher than PVK (15.44 μmol ⋅ g−1⋅h−1) and PVK@Co2L (32.30 μmol ⋅ g−1 ⋅ h−1), ascribing to the efficient photogenerated charge separation and transfer. The experimental results and theoretical investigations demonstrated that the pyrene linked on Co2L boosted the electron delivery from PVK to DMCs. Besides, this strategy could also be extended to the photocatalytic H2 evolution coupled with alcohol oxidation. As a proof‐of‐concept, our work lightens the integration of DMCs, organic and inorganic PS components, promoting the development of photocatalysis without sacrificial electron donors.

Recent Progress in External-field EnhancedPhoto-Electrochemistry.

The ever-growing demands for energy supply have put great stress on environment protections. Photo-electrochemistry (PEC) is a repaid developing technique which can directly transform solar energy into chemical compounds and have been regarded as a promising strategy to solve the energy and environmental problems. However, the biggest restriction is the fast recombination of photo-generated charge carriers which greatly limits the PEC efficiency. In recent years, introducing external-field into PEC system have been proved to be a powerful method to enhance the PEC performance and attracted more and more attentions. In this review, we summarized the remarkable progresses in external-field enhanced PEC reactions including mechanical stress field, thermal field, electrical field, magnetic field and muti-field coupling. The enhancing principles of different external-fields have also been systemically discussed. Furthermore, the challenges and outlook of the external-field enhanced PEC reactions are presented.

Development and Performance of ZnO/MoS2 Gas Sensors for NO2 Monitoring and Protection in Library Environments

The presence of harmful oxidizing gases accelerates the oxidation of cellulose fibers in paper, resulting in reduced strength and fading ink. Therefore, the development of highly sensitive NO2 gas sensors for monitoring and protecting books holds significant practical value. In this manuscript, ZnO/MoS2 composites were synthesized using sodium molybdate and thiourea as raw materials through a hydrothermal method. The morphology and microstructure were characterized by X-ray diffraction analysis (XRD), energy dispersive spectroscopy (EDS), field emission scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The ZnO/MoS2 composite exhibited a flower-like structure, with ZnO nanoparticles uniformly attached to the surface of MoS2, demonstrating advantages such as high specific surface area and good uniformity. The gas sensitivity of the ZnO/MoS2 nanocomposites reached its peak at 260 °C, with a sensitivity value around 3.5, which represents an improvement compared to pure ZnO, while also enhancing sensitivity. The resistance of the ZnO/MoS2 gas sensor remained relatively stable in air, exhibiting short response times during transitions between air and NO2 environments while consistently returning to a stable state. In addition to increasing adsorption capacity and improving light utilization efficiency, the formation of hetero-junctions at the ZnO-MoS2 interface creates an internal electric field that effectively promotes the rapid separation of photo-generated charge carriers within ZnO, thereby extending carrier lifetime.

High Charge Carrier Mobility in Porphyrin Nanoribbons.

Polydisperse edge-fused nickel(II) porphyrin nanoribbons have been synthesized by Yamamoto coupling followed by gold(III)-mediated fusion, with average degrees of polymerization of up to 37 repeat units (length 31 nm). Time-resolved optical-pump terahertz spectroscopy measurements indicate that photo-generated charge carriers have dc mobilities of up to 205 cm2 V-1 s-1 in these nanoribbons, exceeding the values previously reported for most other types of nanoribbon or π-conjugated polymer.

Improvement of Photocatalytic CO2 Reduction with Conjugated Organic Polymers by Rational Modulation of Donor, Acceptor and Bonding Method.

The use of metal-free catalysts to convert CO2 into valuable chemicals is very challenging. Here, we synthesized a conjugated organic polymer (TpTf-1) featuring 2,4,6-Triphenyl-1,3,5-Triazine as the acceptor unit, triphenylamine as the donor unit, and vinylidene bond as the linkage. The local structure of donor-acceptor (D-A) forms an intramolecular electric field that can promote the separation of photogenerated electrons and charges, meanwhile, the vinylidene bond can further change the charge distribution to promote exciton dissociation. Without the use of photosensitizers, the TpTf-1 exhibits outstanding selectivity of CO of up to 91.96 %, with a production rate of 45.2 μmol g-1 h-1 at visible light, which is 3.4-fold than TaTf-1 with the same D-A structure but linking in imine bond and is 2.8-fold than TpTf-2 linking in vinylidene bond but with a different donor unit. Moreover, TpTf-1 has a CO production rate of up to 117.3 μmol g-1 h-1 under full wavelength light irradiation.

Hole Polaron-Mediated Suppression of Electron-Hole Recombination Triggers Efficient Photocatalytic Nitrogen Fixation.

In the pursuit of successful photocatalytic transformations, challenges persist due to limitations in charge carrier utilization and transfer efficiency, which stemming from rapid recombination. Overcoming these limitations necessitates the exploration of novel mechanisms that enhance the effective separation of photogenerated electron-hole pairs. Herein, deviating from the conventional approach of enhancing carrier migration to separate photogenerated charges and extend their lifetime, the proposal is to directly prevent the recombination of photogenerated electrons and holes by forming hole polarons. Specifically, disordered pores are introduced on the surface of KTaO3 ultrathin sheets, and the clear-cut evidences in electron paramagnetic resonance, photoluminescence, and ultrafast spectroscopy unambiguously confirm the enhanced carrier-phonon coupling, which results in the formation of hole polarons to impede the recombination of photogenerated electron-hole pairs. Taking the challenging nitrogen oxidation reaction as an example, it is found that the hole polarons in atomic-disordered pore KTaO3 ultrathin nanosheets trigger outstanding photo-oxidation performance of nitrogen (N2)to nitrate, with a nitrate-producing rate of 2.1 mg g-1 h-1. This scenario is undoubtedly applicable to a wide variety of photocatalytic reactions due to the common challenge of charge carrier recombination in all photocatalytic processes, manifesting broad implications for promoting photocatalysis performance.

Constructing asymmetric dual active sites of Ag single atoms and nitrogen defects on carbon nitride for enhanced photocatalytic H2O2 production

Photosynthesis of hydrogen peroxide (H2O2) from H2O and O2 is considered to be a promising approach. However, limited to the rapid recombination of photo-generated carriers and sluggish kinetics of O2 reduction to H2O2, it is a challenge for polymeric photocatalysts to achieve efficient photocatalytic H2O2 production. Herein, Ag single atoms and nitrogen defects decorated carbon nitride (Ag@MCT) are constructed through self-assembly and pyrolysis methods. The optimized photocatalyst displays exceptional performance in pure water, with an H2O2 production rate of as high as 528.4 μmol g-1 h-1 and an apparent quantum yield for H2O2 production of 4.5% at 420 nm. Experimental and theoretical results reveal that the Ag atomic sites act as electron mediators that promote the capture and transfer of photo-generated charge carriers, while nitrogen defects as electron collectors and reaction sites to enhance the adsorption and activation of O2, accelerating reduction kinetics from O2 to H2O2. This work presents a reliable strategy to design excellent photocatalysts by rationally modulating electronic structures and active sites for accelerating photo-generated charge carriers transfer and surface reaction kinetics.

Boosted photocatalytic degradation performance of TiO2 with enriched oxygen vacancies

In this study, TiO2 with abundant oxygen vacancies (OVs) was prepared through a hydrothermal method in the presence of polyphenylsulphone (PPSU). Introduction of PPSU results in enriched OVs within TiO2 and boosted the level of ∙O2-, dramatically ameliorating photogenerated charges separation efficiency and elevating photocatalytic activity. Compared with the reference TiO2, PPSU-TiO2 exhibits enhance activity in photocatalytic degradation of rhodamine B (RhB) and tetracycline (TC). Analysis reveals that ∙O2- serves as the primary active free radicals in RhB degradation by PPSU-TiO2. Furthermore, PPSU-TiO2 maintains high activity over seven successive cycles, demonstrating excellent stability. Therefore, adding PPSU into the synthesis system of TiO2 is proved to be an effective strategy to enhance photocatalytic performance.

Anchoring AuCu alloy nanoparticles on TiO2 nanosheets: Exploiting synergistic effects and directed electron transfer for enhanced photocatalytic H2 evolution

AuCu/TiO2 composite photocatalysts were prepared by anchoring AuCu nanoparticles (NPs) on TiO2 nanosheets using a simple photoreduction method. Visible diffuse reflectance spectra indicated that the AuCu/TiO2 significantly enhanced light absorption in the visible region. Through photoluminescence spectroscopy and steady-state surface photovoltage experiments, AuCu/TiO2 exhibits an excellent photogenerated electron transfer rate. In addition, photoelectrochemical experiments showed that AuCu/TiO2 had a high photogenerated charge separation efficiency. AuCu/TiO2 (1.0 wt%) exhibited the best performance, under full spectrum, the hydrogen evolution rate is 33.94 mmol g−1 h−1, which is 1.59 times and 1.66 times higher than that of single metal Au/TiO2 (1.0 wt%) (21.28 mmol g−1 h−1) and Cu/TiO2 (1.0 wt%) (20.42 mmol g−1 h−1), respectively. The results showed that AuCu NPs greatly enhanced the photocatalytic performance of the composite photocatalysts.