Copper Bismuth Oxide Research Articles

Unveiling the Synthesis of a Zirconium-Substituted Copper Bismuth Oxide Catalyst for Visible Light-Responsive Photocatalytic Degradation of Persistent Organic Dye

Unveiling the Synthesis of a Zirconium-Substituted Copper Bismuth Oxide Catalyst for Visible Light-Responsive Photocatalytic Degradation of Persistent Organic Dye

Uncovering the synthesis of a visible light-driven manganese-doped copper bismuth oxide catalyst for enhanced degradation of dye: Insights into the factors affecting the degradation

In recent times, effluent pollution has had an exceptionally detrimental effect on aquatic life as well as human beings. The management of wastewater has emerged as a formidable undertaking for scientists owing to the existence of organic contaminants. Herein, we synthesized the manganese-doped copper bismuth oxide (Mn0.15Cu0.85Bi2O4) through hydrothermal method and employed them for successfully eliminating complex pollutants. The assessment of the visible light-induced photocatalytic efficacy of the catalyst was performed for the degradation of methyl violet (MV). MV had a degradation of 89.68% when CuBi2O4 was used. However, the degrading rate of the Mn0.15Cu0.85Bi2O4 escalated to 99.18% in 36 min. The rate constant exhibited a rise between 0.0627 and 0.1134 min−1, confirming the effectiveness of the Mn0.15Cu0.85Bi2O4. The effectiveness of the Mn0.15Cu0.85Bi2O4 is due to its superior surface area (51.97 m2/g), which arises from the integration of Mn-ions. Additionally, examining the impact of different reaction variables revealed a substantial correlation with the elimination of MV dye. The potential reason for the deterioration of MV could be attributed to the generation of •OH and O2•− radicals, which was confirmed by radical trapping experiments. The photostability of the generated Mn0.15Cu0.85Bi2O4 catalyst exhibited remarkable characteristics. Ultimately, this study presents a technique for creating effective catalysts for treating wastewater that is both economical and practical.

Effect of Cu/Bi ratio on the photoelectrochemical performance of CuBi2O4/CuO nanocomposite films for CO2 reduction

Abstract Solar energy is free, clean, and virtually limitless; however, its conversion into a storable form presents technological challenges. One avenue towards solar energy utilization is the photoelectrochemical (PEC) reduction of CO2 to one- or two-carbon fuels, employing a semiconductor configured as an electrode. A potential material for this application is the p-type copper bismuth oxide (CuBi2O4) with a band gap capable of visible light absorption and a conduction band edge position suitable for CO2 reduction. In this study, CuBi2O4 nanocomposite films of varying Cu/Bi ratios (0.25, 0.51, 0.68, 0.94, 2.04) were prepared via an electrodeposition-spray deposition-annealing route. Where the Cu/Bi ratio exceeded the stoichiometric value of 0.5, a bilayered film composed of a copper (II) oxide (CuO) phase on top of CuBi2O4 was formed, creating a planar heterojunction between the two oxide layers. With increasing Cu/Bi ratio, the light absorption range of the films broadened due to the CuO phase. Analysis of the photocurrent-potential behavior of the films under visible-light illumination showed a 4–7-fold increase in the photocurrent from an inert electrolyte to a CO2-saturated electrolyte, confirming potential activity for CO2 reduction of the CuBi2O4/CuO films. A higher Cu/Bi ratio resulted to an improved charge separation efficiency, enhancing the photocurrent generation. However, the transient photocurrent response of the films showed a 70-80% decrease in the photocurrent after only 15 mins of testing. When tested in an electrolyte with an electron scavenger, the percent decrease was lowered to <10%, indicating that the instability of the films resulted from poor interfacial kinetics. While the CuBi2O4/CuO nanocomposite films can accomplish CO2 reduction, further strategies to improve their efficiency and stability are needed to realize practical application.

Numerical modelling of CuBi2O4 thin film solar cells with SCAPS-1D: Bridging the gap ideal and non-ideal conditions

Several simulation studies have been conducted in copper bismuth oxide (CuBi2O4) based solar cells (SCs) using SCAPS-1D simulator, demonstrating a high photoconversion efficiency (PCE) of up to 33 % under ideal conditions. The introduction of non-ideal conditions such as resistive losses, optical, and recombination losses could provide the actual performance of the SCs. In this letter, we applied all nonideal conditions to the SCs structure consisting of Mo/CuBi2O4/TiO2/ITO/Al with varied thicknesses of absorber layer of CuBi2O4 from 50 nm to 2 µm and evaluated the photovoltaic (PV) parameters and PCE of SCs. Under ideal conditions, cells exhibited a PCE of 31.23 % and 3.55 % with an absorber layer thickness of 2000 nm and 50 nm, respectively. The introduction of nonideal conditions with an absorber layer thickness of 50 nm, exhibited a drastic reduction of PCE from 3.55 to 0.46 % and other PV parameters such as open circuit voltage (Voc) from 1.19 to 1.04 V, short circuit current density (Jsc) from 4.27 to 0.77 mA/cm2, and fill factor (FF) from 69.40 to 56.42 %. The increase in thickness of the absorber layer further to 2000 nm did not improve the PCE of SCs.

Photoelectrocatalytic Reduction of Cr(VI) in Wastewater with a CuBi2O4 Thin Film Photocathode

Photoelectrocatalytic approaches show promise for contaminate removal in wastewater through redox reactions. However, the direct treatment of very low concentration heavy metals is a challenging task. Copper bismuth oxide is considered as a potential photocathode material due to its appropriate bandgap width and excellent light absorption properties. In this work, we utilize copper bismuth oxide photoelectrodes with micrometer-scale pores to achieve the efficient and complete reduction of micromolar-level hexavalent chromium(VI) in wastewater. In a continuous 180 min experiment, the reduction rate of 5 µM hexavalent chromium reached 97%, which is an order lower than the drinking standard. Such a process was facilitated by the unique hierarchical microstructure of the oxide thin film and the porous morphology. On the other hand, the structural evolution during the operation was analyzed. A surface passivation was observed, suggesting the possible long-term practical application of this material. This study serves as an important reference for the application of photoelectrocatalysis in addressing Cr(VI) pollution in wastewater, with implications for improving water quality and environmental protection.

Boosting piezo-photocatalytic activity in CuBi2O4/NaNbO3 by coupling it with PVDF for organic pollutant degradation

This work reports a piezo-photocatalytic film, which is easily synthesised and retrievable from water with an environmentally friendly composition exhibiting higher reaction kinetics for degradation of dye using polyvinylidene-fluoride (PVDF), copper bismuth oxide (CuBi2O4) and sodium niobate (NaNbO3). XRD confirmed the structure of CuBi2O4 and NaNbO3, and FTIR was used to confirm β-PVDF, while HR-SEM was used to study morphology. The prepared film displays excellent stability in piezo-photocatalytic conditions. It degrades rhodamine B (RhB) with 98 % efficiency within 30 min in piezo-photocatalysis mode and 113 times faster than CuBi2O4/NaNbO3. This enhanced performance is due to the synergistic piezocatalytic effect of PVDF and NaNbO3. Further, to understand the catalytic nature of the ultrasonic-induced piezo-photocatalytic effect for dye degradation, scavenger studies were performed to identify the radicals generation. Reusability tests revealed no loss in efficiency for five consecutive runs. The strategy outlined here can be used to treat industrial effluents containing various complex dyes.

Synthesis of Flower-Like CuBi2O4 Microspheres and Its Photocatalytic Activity

In this study, visible-light copper bismuth oxide (CuBi2O4) photocatalyst were synthesized via co-precipitation (CuBi2O4-C) and microwave-assisted methods (CuBi2O4-M). The X-ray powder diffraction (XRD) analysis reveals the presence of pure tetragonal, along with band gaps of 2.9 eV in both samples. The microwave-assisted method produced flower-like CuBi2O4 microspheres, which had a larger BET surface area and demonstrated the highest photocatalytic performance, approximately 83.4 % in the decolorization of malachite green (MG) dye under visible light. Therefore, the research suggested a facile strategy for the fast synthesis of CuBi2O4 microspheres under mild reaction conditions. The use of microwave heat treatment is a faster and more efficient way to photocatalyst materials, while also being cost-effective and energy-saving. HIGHLIGHTS The flower-like CuBi2O4 microspheres synthesized via the microwave-assisted method offer a promising approach for efficient and cost-effective photocatalysis, particularly in the degradation of malachite green dye under visible light. This study highlights the potential of microwave synthesis in enhancing the photocatalytic performance of CuBi2O4 materials GRAPHICAL ABSTRACT

Aqueous Solution-Gel Deposition of Copper-Based Photo-Electrodes for Multipurpose Photo-Electrochemical Systems

Efficient valorization of solar energy is expected to contribute significantly to a sustainable supply of energy and fuel sources, as well as the reduction of atmospheric pollution. To this end, photo-electrochemical systems show encouraging potential by converting light into chemical energy. These devices rely on semiconducting photoanodes and/or -cathodes that absorb light efficiently and generate electron-hole pairs with sufficient energy for initiating redox reactions. Several copper-based oxides exhibit appropriate band edges for both photo-electrochemical water splitting and CO2 reduction [1]. This, in combination with their bandgap values, low toxicity, and earth-abundance, has recently increased the attention for copper-based photo-electrodes for multipurpose photo-electrochemical systems. Substantial photocorrosion of CuO and Cu2O is the main issue restricting their application as functional photo-electrodes. In contrast, copper-based ternary oxides are found to be significantly less susceptible to photocorrosion. The citrate-based aqueous solution-gel method has proven to be a versatile approach for the formulation of stable aqueous metal ion precursor solutions, and the subsequent synthesis of (doped) multi-metal oxides by this method has been demonstrated numerously. [2,3] Still, due to the flexible redox chemistry of copper, the solution-gel synthesis of phase-pure copper-based ternary oxides remains challenging. This work describes the synthesis of copper-based photo-electrode materials by focusing on copper ferrite (CFO), copper tungstate (CWO), copper niobate (CNO), and copper bismuth oxide (CBO). The formulation of the respective precursor solutions is described, and their thermal decomposition is investigated. Thin-film photo-electrodes are deposited on transparent conductive substrates by spin coating. The phase purity of the resulting copper-based oxides is determined by X-ray diffraction and Raman spectroscopy. Using UV-Vis spectroscopy, the optical bandgap of the oxide semiconductors is calculated. Furthermore, the photo-electrodes are subjected to linear sweep voltammetry in dark and under illumination to evaluate their photo-electrochemical performance. [1] Wang et al. “Insights into the development of Cu-based photocathodes for carbon dioxide conversion” Green Chem. (2021) 23, 3207[2] Van den Rul et al. “Aqueous Solution-Based Synthesis of Nanostructured Metal Oxides” in “Handbook of Nanoceramics and Their Based Nanodevices” (2009) Ed. T-Y Tseng and H. S. Nalwa[3] Marchal et al. “Precursor Design Strategies for the Low-Temperature Synthesis of Functional Oxides: It’s All in the Chemistry” Chem. Eur. J. (2020) 26, 9070 This work has received funding from the Belgian federal government through the ETF project T-REX and from the VLAIO network “Flanders Innovation & Entrepreneurship” through the Catalisti Moonshot project SYN-CAT. Part of this work was financially supported by TNO in the framework of the “Energy Conversion and Storage” Early Research Program.

A response surface modeling and optimization of photocatalytic degradation of 2,4-dichlorophenol in water using hierarchical nano-assemblages of CuBi2O4 particles.

Photocatalytic degradation, as an advanced oxidation process (AOPs), offers a great advantage to target persistent organic pollutants (POPs) in water. RSM in the present study which is statistical means for optimizing processes like photocatalysis with minimum laboratory experimentation. RSM has a history of being a potent design experiment tool for creating new processes, modifying their designs, and optimizing their performances. Herein, a highly sought-after, easily preparable, visible-light active, copper bismuth oxide (CuBi2O4) is applied against a toxic emerging contaminant, 2,4-dichlorophenol (2,4-DCP) under an LED light source (viible light λ > 420nm). A simple coprecipitation method was adopted to synthesize CuBi2O4 and later analyzed with FESEM, EDX, XRD, FTIR, and spectroscopy to determine its intrinsic properties. Principally, the photocatalytic degradation investigations were based on response surface methodology (RSM), which is a commanding tool in the optimization of the processes. The 2,4-DCP concentration (pollutant loading), CuBi2O4 dosage (catalyst dosge), contact time, and pH were the chosen as dependent factors, that were optimized. However, under optimal conditions, the CuBi2O4 nanoparticle showed a remarkable photocatalytic performance of 91.6% at pH = 11.0 with a pollutant concentration of 0.5mg/L and a catalyst dose of 5mg/L within 8h. The obtained RSM model showed a satisfactory correlation between experimental and predicted values of 2,4-DCP removal, with an agreeable probability value (p) of 0.0069 and coefficient of regression (R2) of 0.990. It is therefore anticipated that the study may open up new possibilities for formulating a plan to specifically target these organic pollutants. In addition, CuBi2O4 possessed fair reusability for three-consequent cycles. Hence, the as-synthesized nanoparticles applied for photocatalysis foster a fit-for-purpose and reliable system in the decontamination of 2,4 DCP in environmental samples, and also the study highlights the efficient use of RSM for environmental remediation, particularly in AOP implementation.

Enhanced Hydrogen Evolution Reaction Performances of Ultrathin CuBi2O4 Nanoflakes

Semiconductor catalysts play a potential role for efficient electrocatalytic hydrogen production. In this work, copper bismuth oxide (CuBi2O4) nanostructures were synthesized via the coprecipitation method using two different Cu precursors: one is Cu(NO3)3·9H2O and the other is CuCl2. When using Cu(NO3)3·9H2O, the sample showed an interconnected and aggregated irregular spherical CuBi2O4 nanoparticle structure. On the other hand, the CuCl2-derived CuBi2O4 sample exhibited an interconnected ultrathin nanoflake structure. The CuBi2O4 nanoflakes displayed a higher electrochemically active surface area (160 cm2) than the CuBi2O4 nanoparticle (116 cm2). Accordingly, the CuBi2O4 nanoflakes revealed an excellent hydrogen evolution reaction performance with a low Tafel slope (117 mV/dec) and a small overpotential (384 mV at 10 mA/cm2 in 1 M KOH). These results specify that the CuBi2O4 nanoflakes are a suitable electrocatalyst material for high-performance water splitting.

Numerical Simulation of High Efficiency Environment Friendly CuBi2O4-Based Thin-Film Solar Cell Using SCAPS-1D

In this research work, a copper bismuth oxide- (CuBi2O4-) based thin-film solar cell has been proposed for the lead and toxic-free (Al/ITO/TiO2/CuBi2O4/Mo) structure simulated in SCAPS-1D software. The main aim of this work to make an ecofriendly and highly efficient thin-film solar cell. The absorber layer CuBi2O4, buffer layer TiO2, and the electron transport layer (ETL) ITO have been used in this simulation. The performance of the suggested photovoltaic devices was quantitatively evaluated using variations in thickness such as absorber, buffer, defect density, operating temperature, back contact work function, series, shunt resistances, acceptor density, and donor density. The absorber layer thickness is fixed at 2.0 μm, the buffer layer at 0.05 μm, and the electron transport layer at 0.23 μm, respectively. The CuBi2O4 absorber layer produces a solar cell efficiency of 31.21%, an open-circuit voltage ( V oc ) of 1.36 V, short-circuit current density ( J sc ) of 25.81 mA/cm2, and a fill factor (FF) of 88.77%, respectively. It is recommended that the proposed CuBi2O4-based structure can be used as a potential for thin-film solar cells that are both inexpensive and highly efficient.

Role of active area on photoelectrochemical water-splitting performance of inverse opal CuBi2O4 photocathodes

Copper bismuth oxide(CuBi2O4), a ternary metal oxide is considered as one of the best photocathodes for photoelectrochemical water splitting. However, to date, the majority of research activities have been aimed at developing photocathodes at laboratory scale (≤1 cm2 electrochemical active area) and the issues that arise with scaling up have scarcely been addressed. Herein, we demonstrate a layered self-assembly method for fabricating uniform anddifferent electrochemical active area (1–15 cm2) inverse opal structured CuBi2O4 photocathodes, intending to validate it for photoelectrochemical hydrogen evolution under solar irradiation. After scaling up, it was found that CuBi2O4 with an active area of 5 cm2 exhibits the best photocurrent density (3.24 mA/cm2 at 0.6 V vs. RHE) and Faradaic efficiency (98.06 %). The scaling-up strategy and low-cost method employed for the fabrication of photocathodes could be expanded to large-scale applications associated with the manufacturing of highly efficient photoelectrochemical hydrogen production devices.

Mechanistic insights into enhanced photocatalytic H2O2 production induced by a Z-scheme heterojunction of copper bismuth oxide and molybdenum sulfide

Photocatalytic hydrogen peroxide (H2O2) production using a Z-scheme copper bismuth oxide and molybdenum sulfide photocatalyst.

An ab initio DFT perspective on experimentally synthesized CuBi2O4.

Here we present a comprehensive density functional theory (DFT) based ab initio study of copper bismuth oxide CuBi2O4 (CBO) in combination with experimental observations. The CBO samples were prepared following both solid-state reaction (SCBO) and hydrothermal (HCBO) methods. The P4/ncc phase purity of the as-synthesized samples was corroborated by Rietveld refinement of the powdered X-ray diffraction measurements along with Generalized Gradient Approximation of Perdew-Burke-Ernzerhof (GGA-PBE) and the Hubbard interaction U corrected GGA-PBE+U relaxed crystallographic parameters. Scanning and field emission scanning electron micrographs confirmed the particle size of the SCBO and HCBO samples to be ∼250 and ∼60 nm respectively. The GGA-PBE and GGA-PBE+U derived Raman peaks are in better agreement with that of the experimentally observed ones when compared to local density approximation based results. The DFT derived phonon density of states conforms with the absorption bands in Fourier transform infrared spectra. Both structural and dynamic stability criteria of the CBO are confirmed by elastic tensor and density functional perturbation theory-based phonon band structure simulations respectively. The CBO band gap underestimation of GGA-PBE as compared to UV-vis diffuse reflectance derived 1.8 eV was eliminated by tuning the U and the Hartree-Fock exact-exchange mixing parameter αHF in GGA-PBE+U and Heyd-Scuseria-Ernzerhof (HSE06) hybrid functionals respectively. The HSE06 with αHF = 14% yields the optimum linear optical properties of CBO in terms of the dielectric function, absorption, and their derivatives as compared to that of GGA-PBE and GGA-PBE+U functionals. Our as-synthesized HCBO shows ∼70% photocatalytic efficiency in degrading methylene blue dye under 3 h optical illumination. This DFT-guided experimental approach to CBO may help to gain a better understanding of its functional properties.

Electrochemical detection of 4-nitrophenol on nanostructured CuBi2O4 with plausible mechanism supported by DFT calculations

In this report, copper bismuth oxide (CuBi2O4), a ternary oxide is used for the electrochemical detection of 4-nitrophenol (4-NP). 4-NP is an organic pollutant which is extremely toxic and hazardous to environment. Herein, CuBi2O4 nanorods are prepared hydrothermally followed by electrode fabrication using drop casting method. Structural, morphological studies of CuBi2O4 and electrochemical characterizations pertaining to its performance for electrochemical detection of 4-NP are performed. The electrode has displayed the sensitivity of 56.16 μA μΜ−1 cm−2 with limit of detection (LoD) of 0.61 μM. It displayed high selectivity against several organic and inorganic interferences. The feasibility of CuBi2O4 modified electrode for real water samples is tested and obtained good recovery values. The detailed mechanism involved in the electrochemical detection of 4-NP is proposed and validated with computational studies. Density functional theory (DFT) calculations are performed on the optimized molecules involved in the electrochemical detection of 4-NP confirming CuBi2O4 acting as electron donor while 4-NP as electron acceptor. Further, natural bond orbital (NBO) calculations of 4-NP show a charge of − 0.251 a.u. on -NO2 group and + 0.251 a.u. on the rest of the molecule indicating 4-NP undergoes facile nucleophilic attack. The electrostatic potential (ESP) mapping of 4-NP blue shaded regions justifies its favorable behavior towards nucleophilic attack. Apart from this, UV-Vis spectroscopy is used to study the catalytic reduction of 4-NP using NaBH4. This study reveals that CuBi2O4 is promising material for the electrochemical detection of 4-NP. Also, further modifications of CuBi2O4 can be explored for electrochemical sensing and catalytic performance.

Futuristic kusachiite solar cells of CuBi2O4 absorber and metal sulfide buffer Layers: Theoretical efficiency approaching 28 %

Solar cells exhibit high performance using a thin semiconducting film with superior light-harvesting ability. Though a variety of thin-film solar cells have shown promise, the quest to find cheaper and promising alternatives is necessary. Herein, this study provides evidence of the capabilities of cheap and stable copper bismuth oxide or CuBi2O4 (CBO) as an efficient light absorber for thin-film photovoltaics. Solar Cell Capacitance Simulator-1D (SCAPS-1D) software is used to optimize the performance of CBO-based kusachiite solar cells with various n-type metal sulfide (MS) buffer layers (CdS, WS2, SnS2, and ZnS). The variation in the thickness and acceptor and donor doping density of CBO light absorber and MSs buffer layers film had the highest control over power conversion efficiency (PCE) and other solar cell parameters. The effect of the work function of metal back contact and operating temperature on the performance of solar cells is also analyzed to assess the real-time application of the proposed metal sulfide and CBO-based kusachiite solar cells. The solar cell device structure of ITO/WS2/CBO/Au optimized in terms of thickness and doping density has shown a theoretical PCE of 22.84 %.

Copper ternary oxides as photocathodes for solar-driven CO2reduction

AbstractThe sun’s energy, though free and virtually limitless, is a largely unexploited resource, as its conversion into a storable form presents several technological challenges. A promising way of capturing and storing solar energy is in the form of “solar fuels,” in a process termed artificial photosynthesis. In a photoelectrochemical (PEC) system, the reduction of CO2to carbon-based fuels is driven on the surface of an illuminated semiconductor electrode. Through the decades, many different classes of semiconducting materials have been studied for this purpose, to varying successes. Because of their cheap and abundant nature, semiconducting transition metal oxides are good candidates to realize this technology in an economic scale and have thus attracted considerable research attention. In this review article, the progress achieved with a specific class of metal oxides, namely, the copper ternary oxides such as copper iron oxide and copper bismuth oxide, for PEC CO2reduction is examined. Although there have been significant advances in terms of strategies to improve the efficiency and stability of these materials, further studies are warranted to address the many challenges to PEC CO2reduction and solar fuel production.

22% efficient Kusachiite solar cells of CuBi2O4 light harvester and ABO3 buffer layers: A theoretical analysis

Thin film solar cells have gained tremendous interest due to their easy processing and packaging at low costs, but most of them suffer from long-term stability. Therefore, in the quest to find a novel thin film harvester with both high efficiency and long-term stability, the capabilities of cheap and stable copper bismuth oxide or CuBi2O4 (CBO) are comprehensively investigated as an efficient light harvester. Solar Cell Capacitance Simulator-1D (SCAPS-1D) software is used to optimize the performance of CBO-based kusachiite solar cells with various n-type ABO3 perovskite oxide (PO) buffer layers (such as SrTiO3, BaTiO3, SrSnO3, and BaSnO3). The variation in the thickness, doping density, and defect density of the CBO light absorber showed the utmost control over power conversion efficiency (PCE) and other solar cell parameters. The effect of the work function of metal back contact and operating temperature on the performance of solar cells is also analyzed to assess the real-time application of the proposed PO buffer and CBO light harvester based kusachiite solar cells. Among all investigated solar cell device structures, ITO/SrSnO3/CBO/Au optimized in terms of thickness and doping density has shown a theoretical PCE of 22.19%.

Copper oxide clusters modified by bismuth single atoms to catalyze CO oxidation

Supported single atom and cluster catalysts have received an extensive attention in all kind of heterogeneous catalytic reactions due to their unique physical and chemical properties. In this work, we prepared silica-supported copper-bismuth oxide catalysts via incipient-wetness impregnation method. This Bi-doped catalyst exhibits an excellent performance in carbon monoxide oxidation with a reaction rate at 0.6 μmolCO·gcat−1·s −1 at 170 °C, which is about ten times of that for pure copper-silica catalyst. Furthermore, we found a unique active site structure: Bi single atom anchored on the surface of CuOx cluster via Bi−O−Cu structure with the help of comprehensive characterization method, especially aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and extend X-ray absorption fine structure (EXAFS) fitting result. On one hand, the Bi−O−Cu structure can significantly enhance the anti-sintering ability of copper species and provide more available Cu active site with similar apparent activation energy (~40 kJ·mol−1). On another hand, this structure not only increases surface active oxygen species confirmed by CO−temperature programmed reduction (CO−TPR), but also significantly strengthens the adsorption of CO molecule by CO−temperature programmed desorption (CO−TPD) and in-situ Diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) to promote the activity of CO oxidation. This work may provide a new guideline to synthesize high active atomic-scale catalysts for different redox reactions.

Operational Spectroelectrochemical Investigation on the Interfacial Charge Dynamics of Copper Bismuth Oxide Based Photocathode

Copper bismuth oxide (CBO) is an emerging photocathode in photoelectrochemical (PEC) water splitting but exhibits limited performance due to the severe recombination of photogenerated charges at the semiconductor-liquid junction (SCLJ). For the first time, a set of operational spectroelectrochemical experiments including electrochemical impedance spectroscopy (EIS), transient photocurrent spectroscopy (TPS), and intensity-modulated photocurrent/voltage spectroscopy (IMVS, IMPS) are designed to investigate the charge dynamics at the SCLJ. It is indicated that there are dense surface states above the valence band of CBO, inducing the "Fermi level pinning" (FLP) effect at the SCLJ. The kinetic parameters speculated by IMVS and IMPS indicate the charge transfer efficiency of below 10% with even a bias of ∼0.7 V applied. TPS confirms the sluggish dynamics because of the charging behavior of the surface states. It is expected that this work would provide new connotations of charge dynamics at the SCLJ for the further optimization of CBO-based PEC systems.