Photoelectrocatalytic Research Articles

3D-TNAs/N-TiO2 photoanode assisted heterogeneous electro-Fenton with a novel Fe-MOFs@CF cathode for efficient synergetic oxidation of organic contaminants

Photoelectro-catalysis (PEC) and heterogeneous electro-Fenton (HEF) reactions are two frontier research fields for real effluent treatments. In the present work, a synergetic system with integration of both PEC and HEF has been developed for pollutant removal. PEC process with lower external bias results in the efficient separation of photogenerated hole and electrons, which can also modulate the HEF catalytic performance at the counter electrode, and in other cases the active HEF reaction can in turn affect the intrinsic activity of PEC. In this system, three dimensional TiO2 nanotube arrays coupled with nitrogen doped TiO2 nanoparticles (3D-TNAs/N-TiO2) was prepared as photoanode for solar light-driven PEC process while NH2-MIL-101 loaded on carbon felt (Fe-MOFs@CF) have been used as the cathode for HEF reaction. The performances of the synergetic system showed much higher degradation efficiency, which were evaluated by degrading typical organic containments in water (with the best of∼95 % in 5 min with 2*3 cm2 electrode area). The reaction rate in the coupling system were ∼7.25 and 1.18 times higher than single PEC or HEF with a wide pH applied range, well recycled and good stability for further application in water purification.

Solar enhanced oxygen evolution reaction with transition metal telluride.

The photo-enhanced electrocatalytic method of oxygen evolution reaction (OER) shows promise for enhancing the effectiveness of clear energy generation through water splitting by using renewable and sustainable source of energy. However, despite benefits of photoelectrocatalytic (PEC) water splitting, its uses are constrained by its low efficiency as a result of charge carrier recombination, a large overpotential, and sluggish reaction kinetics. Here, we illustrate that Nickel telluride (NiTe) synthesized by hydrothermal methods can function as an extremely effective photo-coupled electrochemical oxygen evolution reaction (POER) catalyst. In this study, NiTe was synthesized by hydrothermal method at 145°C within just an hour of reaction time. In dark conditions, the NiTe deposited on carbon cloth substrate shows a small oxygen evolution reaction overpotential (261mV) at a current density of 10mA cm-2, a reduced Tafel slope (65.4mV dec-1), and negligible activity decay after 12h of chronoamperometry. By virtue of its enhanced photo response, excellent light harvesting ability, and increased interfacial kinetics of charge separation, the NiTe electrode under simulated solar illumination displays exceptional photoelectrochemical performance exhibiting overpotential of 165mV at current density of 10mA cm-2, which is about 96mV less than on dark conditions. In addition, Density Functional Theory investigations have been carried out on the NiTe surface, the results of which demonstrated a greater adsorption energy for intermediate -OH on the catalyst site. Since the -OH adsorption on the catalyst site correlates to catalyst activation, it indicates the facile electrocatalytic activity of NiTe owing to favorable catalyst activation. DFT calculations also revealed the facile charge density redistribution following intermediate -OH adsorption on the NiTe surface. This work demonstrates that arrays of NiTe elongated nanostructure are a promising option for both electrochemical and photoelectrocatalytic water oxidation and offers broad suggestions for developing effective PEC devices.

Four-in-one multifunctional self-driven photoelectrocatalytic system for water purification: Organics degradation, U(VI) reduction, electricity generation and disinfection against bacteria

This study addresses the energy-intensive nature of conventional wastewater treatment processes and proposes a solution through the development of a green, low-energy, and multifunctional wastewater treatment technology. The research focuses on a multifunctional self-driven photoelectrocatalytic (PEC) system, exploring its four-in-one applications in eliminating organic pollutants, reducing U(VI), generating electrical energy, and disinfecting pathogenic microorganisms. A TiO2-decorated carbon felt (CF@TiO2) cathode is synthesized to enhance interfacial charge transfer, with TiO2 coating improving surface binding sites (edge TiO and adsorbed -OH) for UO22+ adsorption and reduction. The self-driven PEC system, illuminated solely with simulated sunlight, exhibits remarkable efficiency in removing nearly 100 % of uranium within 0.5 h and simultaneously degrading 99.9 % of sulfamethoxazole (SMX) within 1.5 h, all while generating a maximum power output density (Pmax) of approximately 1065 μW·cm−2. The system demonstrates significant anti-interference properties across a wide pH range and coexisting ions. Moreover, 49.4 % of the fixed uranium on the cathode is reduced into U(IV) species, limiting its migration. The self-driven PEC system also excels in detoxifying various toxic organic compounds, including tetracycline, chlortetracycline, and oxytetracycline, and exhibits exceptional sterilization ability by disinfecting nearly 100 % of Escherichia coli within 0.5 h. This work presents an energy-saving, sustainable, and easily recyclable wastewater purification system with four-in-one capabilities, relying solely on sunlight for operation.

Enhanced ammonia oxidation by a photoelectrocatalysis‑chlorine system: The role of ClO• and free chlorine

The decomposition of ammonia-N to environmental-friendly N2 remains a fundamental problem for water treatment. We proposed a way to selectively and efficiently oxidize ammonia to N2 through an integrated photoeletrocatalysis‑chlorine reactions (PECCl) system based on a bifunctional TiO2 nanotube photoanode. The ·OH and HClO can be simultaneously generated on the TiO2 nanotube photoanode in this system, which can in situ form ClO· for efficient ammonia removal. Compared with electrochemical‑chlorine (EC-Cl), photocatalysis‑chlorine (PC-Cl) and photoelectrocatalysis (PEC) systems, the PEC-Cl system exhibited much higher electrocatalytic activity due to the synergetic effect of photoelectrocatalyst and electrocatalyst in bifunctional TiO2 nanotube electrode. The removal efficiency of ammonia-N and total-N reached 100.0 % and 93.3 % at 0.3 V (vs Ag/AgCl) in the PEC-Cl system. Moreover, the system was efficient under various pH conditions. The reactions between ClO−/ClO· and the N-containing intermediates contributed to the high performance of the system, which expanded the reactions from the electrode surface to the electrolyte. Furthermore, radical scavenging and free chlorine determination experiments confirmed that ClO· and free chlorine were the main active species that enabled the ammonia oxidation. This study presents new understanding on the role of active species for ammonia removal in wastewater.

Novel photoelectrocatalytic system of oxygen vacancy-rich black TiO2-x nanocones photoanode and natural air diffusion cathode for efficient water purification and simultaneous H2O2 production

Photoelectrocatalytic (PEC) system harnesses solar energy for chemical reactions, representing a highly promising renewable energy-based technology for water purification. Herein, we design a novel separated PEC system that integrates water purification on an oxygen vacancy-rich black TiO2 nanocones (b-TiO2-x) photoanode with two-electron O2 reduction reaction for H2O2 production on a natural air diffusion cathode. This integration benefits from thermodynamic advantages, synergy effects and enhanced •OH production, thus exhibiting superior water purification (98.32%, 0.064 min−1) and H2O2 production (6.83 μmol/h/cm2) at ultra-low applied cell voltage of 0.5 V, with the energy consumption of only 0.034 kWh/m3 wastewater treated, where the simultaneous production of value-added H2O2 could fully compensate for the electric cost of the system. Notably, even under real sunlight irradiation, this system achieves efficient water purification and H2O2 production without additional energy consumption, offering a cost-effective and environmental-benign strategy for the dual purpose of water purification and resourcization.

Preparation of Ti4O7/h‐BN self‐supported ceramic photoelectrode and its photoelectrocatalytic performance for water purification

AbstractThe construction of high‐efficiency self‐supported ceramic photoelectrode based on ideal semiconductor materials is essential for achieving effective degradation of pollutants by photoelectrocatalysis (PEC) technology. Herein, a Ti4O7/h‐BN composite ceramic photoelectrode with a unique microstructure was fabricated by a step‐by‐step calcination process and used in PEC water pollution remediation. The PEC activity of Ti4O7 ceramic photoelectrode could be enhanced by introducing hexagonal boron nitride (h‐BN) nanoparticles on the surface. The most optimized Ti4O7/h‐BN photoelectrode exhibited the decolorization rate of active brilliant blue KN‐R at about 97.79% in 30 min. The PEC activities could remain stable during five degradation cycles. The excellent photoelectrocatalytic performance of Ti4O7/h‐BN ceramic photoelectrode could be attributed to the low Tafel slope, low charge transfer resistance, large electrochemical active area, and excellent photo‐generated carrier separation efficiency. A type‐II heterojunction was formed between the Ti4O7 and h‐BN, which caused more effective carrier separation and enhanced the generation of dominant active species •O2− and h+. This work provided a mature synthesis strategy of Ti4O7/h‐BN self‐supported ceramic photoelectrodes with excellent practical application prospects to achieve superior PEC performance for water purification.

Carbon cloth supported black phosphorus-FeMoO4 composites for peroxymonosulfate-assisted photoelectrocatalytic degradation of tetracycline hydrochloride

This research utilized the solvothermal technique to prepare carbon cloth supported black phosphorus-FeMoO4 (CC-BP-FMO) composites, which were used for the degradation of tetracycline hydrochloride (TC-HCl) through the peroxymonosulfate (PMS)-assisted photoelectrocatalysis (PEC) route. Several characterization techniques were employed to systematically examine the morphology, elemental composition, crystal and molecule structures, magnetism properties, bonding states, energy band structure, separation efficiency of photo-induced carriers, electrochemical behaviors, reactive species, and intermediate products of TC-HCl degradation. The experimental results demonstrated that the performance of PMS-assisted PEC TC-HCl degradation by the CC-BP-FMO composites was significantly improved in comparison with photocatalysis, electrocatalysis, PMS activation, and PEC. The CC-BP-FMO composites with more exposed BP-FMO catalysts exhibited the ability to be reused for PMS-assisted PEC degradation of TC-HCl, with a large k value of 0.21 min−1 and a high degradation rate of 97% after the fourth cycle. The remarkable PMS-assisted PEC property of the CC-BP-FMO composites was mainly attributed to the swift separation of photo-induced charge carriers, which hastened the creation of reactive radicals. Five possible catalytic reaction pathways existed in the CC-BP-FMO composites towards TC-HCl degradation under the PMS-assisted PEC condition. Importantly, the photo-generated electrons and [Formula: see text] radicals were advantageous for the redox reaction of Fe+2/Fe+3 and Mo+4/Mo+6. The oxygen vacancies caused by P and Mo in the BP-FMO heterojunction could suppress the carrier recombination. The degradation of TC-HCl involved the participation of oxygen vacancy, [Formula: see text], [Formula: see text], and ∙OH radicals, and 1O2 nonradicals. The CC-BP-FMO composites have the potential application for treating wastewater containing organic pollutants.

Two-Dimensional Layered Heterojunctions for Photoelectrocatalysis.

Two-dimensional (2D) layered nanomaterial heterostructures, arising from the combination of 2D materials with other low-dimensional species, feature a large surface area to volume ratio, which provides a high density of active sites for catalytic applications and for (photo)electrocatalysis (PEC). Meanwhile, their electronic band structure and high electrical conductivity enable efficient charge transfer (CT) between the active material and the substrate, which is essential for catalytic activity. In recent years, researchers have demonstrated the potential of a range of 2D material interfaces, such as graphene, graphitic carbon nitride (g-C3N4), metal chalcogenides (MCs), and MXenes, for (photo)electrocatalytic applications. For instance, MCs such as MoS2 and WS2 have shown excellent catalytic activity for hydrogen evolution, while graphene and MXenes have been used for the reduction of carbon dioxide to higher value chemicals. However, despite their great potential, there are still major challenges that need to be addressed to fully realize the potential of 2D materials for PEC. For example, their stability under harsh reaction conditions, as well as their scalability for large-scale production are important factors to be considered. Generating heterojunctions (HJs) by combining 2D layered structures with other nanomaterials is a promising method to improve the photoelectrocatalytic properties of the former. In this review, we inspect thoroughly the recent literature, to demonstrate the significant potential that arises from utilizing 2D layered heterostructures in PEC processes across a broad spectrum of applications, from energy conversion and storage to environmental remediation. With the ongoing research and development, it is likely that the potential of these materials will be fully expressed in the near future.

Novel Fenton-like system based on bifunctional MgO/g-C3N4 S-scheme heterojunction photoanode for efficient tetracycline degradation

A novel photoelectrocatalytic (PEC) system consisting of S-scheme MgO/g-C3N4 photoanode and modified carbon felt (MCF) cathode was designed for efficient degradation of tetracycline, in which photoanode had both efficient photocatalytic performance and activation of H2O2 produced by the MCF cathode. After 30 min of LED irradiation, the PEC system could completely remove tetracycline at cathodic bias of −0.5 V (vs. Ag/AgCl), and the degradation rate constants were 5.3 and 1.5 times that of electrocatalysis and photocatalysis. The charge transfer mechanism of S-scheme MgO/g-C3N4 was verified by experimental studies and DFT calculations. Mg-N coordination was the key to activate H2O2 to produce singlet oxygen (1O2) and hydroxyl radicals (•OH). The PEC system had excellent degradation performance at pH ranges 4–10, which solved the bottleneck that Fenton system is effective at narrow pH range. This study provides new ideas for preparation of bifunctional photoanodes and new insights into the PEC process.

Is photoelectrocatalysis an efficient process to degrade endocrine disruptors chemicals?

Endocrine disruptors chemicals (EDCs) pose significant health risks, including cancer, behavioral disorders, and infertility. In this study, we employed the photoelectrocatalysis (PEC) technique with optimized tungsten oxide (WO3) nanostructures as a photoanode to degrade three diverse EDCs: methiocarb, dimethyl phthalate, and 4-tert-butylphenol. PEC degradation tests were carried out for individual contaminants and a mixture of them, assessing efficiency across different EDC families. Ultra High-Performance Liquid Chromatography and Mass Spectrometry was used to control the course of the experiments. For individual solutions, 4-tert-butylphenol and methiocarb were 100% degraded at 1 hour of PEC degradation. Among the tested EDCs, dimethyl phthalate showed the highest resistance to degradation when treated individually. However, when assessed in a mixture with the other EDCs, the degradation efficiency of dimethyl phthalate increased compared to its individual treatment. Furthermore, four degradation intermediates were identified for each contaminant. Finally, toxicity tests revealed that the initial solution was more toxic than the samples treated for all the contaminants tested, except for the phthalate.

Sulfur poisoning-resistant TiO2/Cu-doped ZnIn2S4 photoanode for achieving efficient sulfur oxidation

Ternary ZnIn2S4 is a layered metal sulfide and suitable for catalyzing H2S-containing industrial waste streams due to its excellent light absorption in the visible region. However, imperfect electrical conductivity and slow surface reaction lead to severe internal intrinsic charge recombination. For this reason, we modify pristine ZnIn2S4 by synergistic coordination of heterojunction and doping. The TiO2/0.6 ml Cu2+-ZIS sample achieves a photocurrent density of 2.87 mA/cm2, which is 8.2 times higher than that of pure ZnIn2S4. Investigation of the surface states (SS) shows that the improved performance results from an increase in the density of available surface states as well as the consistency of the surface state center potential with the S/H2S oxidation potential. This is the new attempt to analyze the photoelectrocatalytic (PEC) behavior of the sulfur oxidation reaction using surface state theory. The results of catalytic product resolution and data from theoretical calculations indicate that the timely desorption of polysulfide ions at Cu2+ sites and the solubility of the only oxidation product (S2O32-), are the reasons for maintaining high performance after 4 h stability testing. This study not only gives a new reference for the modification strategy of ZnIn2S4 but also a new solution for catalyst S poisoning.

Constructing core-shell structured Co3O4–MnWO4 composite photoelectrode with superior PEC water purification performance

Semiconductor photoelectrocatalytic (PEC) technology is one of the most effective methods for removing organic pollutants from wastewater in advanced oxidation processes(AOPs). The selection of suitable semiconductor materials as photoanodes is a crucial factor for achieving superior PEC performance. Here, a core-shell structured Co3O4–MnWO4 architecture is created by enveloping MnWO4 nanoparticles onto the surface of Co3O4 nanowires through a two-step hydrothermal process. The optimized Co3O4–MnWO4-5 photoelectrode showed superior PEC degradation efficiency for KN-R (∼91.2% in 2 h) and durable stability (the accelerated lifetime reached ∼9100 s at a current density of 50 mA cm−2). Three actual wastewaters were also collected to verify the practical applicability of the photoelectrode.The energy consumption was measured at 4.48 kWhm−3, with a COD removal efficiency of 83% and a decolorization rate of 98%. These results demonstrate the excellent performance and promising application of the photoelectrode. The enhancement of PEC performance for the core-shell structured Co3O4–MnWO4 architecture can be attributed to the suitable energy band structure of the Co3O4–MnWO4 composite, higher OEP, larger electrochemical active surface area, accelerated transport of interface carriers, and lower charge transfer resistance. The energy band structure of the Co3O4–MnWO4 composite showed a strong redox ability to induce electrons/holes (e−/h+), which enhances the generation of intermediate active species (hydroxyl radical ·OH and superoxide radicals ·O2-). Therefore, the rationally designed core-shell structured Co3O4–MnWO4 architecture exhibited excellent practical applicability in the degradation of organic pollutants.

LDH/MXene Synergistic Carrier Separation Effects to Improve the Photoelectric Catalytic Activities of Bi2WO6 Nanosheet Arrays.

Photoelectric catalysis is a green and efficient way to degrade pollutants, which has been paid more and more attention by researchers. Among them, Bi2WO3 has been proved to have excellent photocatalytic oxidation activity on its {001} facets. In this study, {001}-oriented facets with high exposure were successfully integrated into Bi2WO6 nanoplate arrays (Bi2WO6 NAs) to create a photoelectrode. This structure was grown in situ on an indium tin oxide (ITO) substrate. To promote photogenerated carrier separation efficiency and reduce agglomeration of Bi2WO6 photocatalysts, the electrochemical deposition of NiFe-layered double hydroxide (NiFe-LDH) and Ti3C2 (MXene) were introduced in this research to synergistically catalyze pollutant degradation. Morphology, spectral characterization, and electrochemical analysis jointly confirmed that the outstanding performance of hole capture behavior with LDH and electron conduction properties with MXene were the main reasons for the improvement in catalytic activity of the photoelectrode. Taking bisphenol A (BPA) as the model pollutant, the rate constant k of the NiFe-LDH/Ti3C2/Bi2WO6 NAs photoelectrode reaches 0.00196 min-1 under photoelectrocatalytic (PEC) conditions, which is 4.5 times that of the pure Bi2WO6 NAs photoelectrode. This work provides a new way to improve the reaction kinetics of the PEC degradation of pollutants.

Robust photoelectrocatalytic degradation of antibiotics by organic-inorganic PDISA/Bi2WO6 S-scheme heterojunction membrane

Ensuring the stability of the photoelectrode is paramount for optimal photoelectrocatalysis performance. In this investigation, a hybrid nanofiber film, incorporating the π-π conjugated self-assembly of perylene diimide monomers (PDISA) with Bi2WO6 (PDISA/Bi2WO6), was fabricated through the electrospinning process. Subsequently, this flexible electrospun film was pressed onto a Ni mesh to create a robust PDISA/Bi2WO6 electrode membrane. Results from photoelectrocatalytic studies reveal that the devised PDISA/Bi2WO6 photoanode significantly enhances the photoelectrocatalytic degradation efficiency of tetracycline (TC) and ciprofloxacin (CIP). Specifically, the apparent rate constants for the photoelectrocatalytic degradation of TC by 30%PDISA/Bi2WO6, compared to pristine PDISA and Bi2WO6, are elevated by 1.9 and 2.0 times, respectively. Moreover, the reaction rates of the photoelectrocatalytic (PEC) process surpass those of photocatalysis (PC) and electrocatalysis (EC) by 1.9 times and 8.0 times, respectively. Impressively, even after five cycles of PEC degradation of TC, the photoelectrode maintains 98.4% of its initial degradation rate, indicating its exceptional stability. These improvements in degradation efficiency and stability are attributed to the creation of the PDISA/Bi2WO6 S-scheme heterojunction membrane photoanode and the synergistic effects of photoelectrocatalysis.

Interface-engineered dual Z-scheme of BiVO4/NH2-MIL-125(Ti)/POF photoanode with enhanced photoelectrochemical performance

The key factors that restrain the decomposition activity of photoelectrocatalysis (PEC) are poor redox ability and low charge separation rate. In this work, the dual Z-scheme BiVO4/NH2-MIL-125(Ti)/POF (BiVO4/NM125(Ti)/POF) heterojunctions were successfully established for visible-light driven PEC degradation of phenol. As expected, the optimum BiVO4/NM125(Ti)/POF photoanode exhibited outstanding PEC performance with near-total degradation of phenol within 2 h of illumination. The evaluated activity was assigned to high charge transfer rate and dual Z-scheme heterostructures with double electron transport channels. The fabrication of dual Z-scheme heterojunctions improved a more efficient separation of photo-induced charge carriers while holding a higher redox ability to generate more reactive oxygen species (ROS) such as O2•− and •OH to decompose organic pollutants. In addition, excellent chemical stability and recyclability were also achieved after five times cycles, and the degradation pathway of phenol was also put forward. Finally, the quantitative structure-activity relationship (QSAR) was applied to forecast phenol and its degradation products toxicity. This research gives novel insights into establishing highly effective photoanode with promising applications for organic contaminants degradation, and offers in-depth understanding of charge separation and migration in PEC process.

A sustainable activated carbon fiber/TiO2 cathode for the photoelectro-Fenton treatment of pharmaceutical pollutant enalapril

In this work, a TiO2-decorated electrode was fabricated by dip coating activated carbon fibers (ACF) with TiO2, which were then used as a cathode for the photoelectro-Fenton (PEF) treatment of the pharmaceutical enalapril, an angiotensin-converting enzyme inhibitor that has been detected in several waterways. The TiO2 coating was found to principally improve the electrocatalytic properties of ACF for H2O2 production via the 2-e- O2 reduction, in turn increasing enalapril degradation by PEF. The effect of the current density on the mineralization of enalapril was evaluated and the highest TOC removal yield (80.5% in 3 h) was obtained at 8.33 mA cm−2, in the presence of 0.5 mmol L−1 of Fe2+ catalyst. Under those conditions, enalapril was totally removed within the first 10 min of treatment with a rate constant k = 0.472 min−1. In contrast, uncoated ACF only achieved 60% of TOC removal in 3 h at 8.33 mA cm−2. A degradation pathway for enalapril mineralization is proposed, based on the degradation by-products identified during treatment. Overall, the results demonstrate the promises of TiO2 cathodes for PEF, a strategy that has often been overlooked in favor of photoelectrocatalysis (PEC) based on TiO2-modified photoanodes.

Density‐Functional Theory Studies on Photocatalysis and Photoelectrocatalysis: Challenges and Opportunities

Density‐functional theory (DFT) is pivotal in the advancement of photocatalysis and photoelectrocatalysis. Its capability to explore electronic structures of materials contributes significantly to clarifying the mechanisms of photocatalytic (PC) and photoelectrocatalytic (PEC) processes. DFT calculations enable a deeper understanding of how these processes work at a molecular level, which is essential for designing versatile photocatalysts and photoelectrodes and optimizing reaction pathways. In this perspective, key PC and PEC applications, such as H2 production, CO2 reduction, dye degradation, and N2 reduction, where DFT is instrumental in optimizing materials designs and reaction pathways, are highlighted. Exploration on the synergy between experimental research and DFT calculations is highlighted, which is crucial for the development of efficient and environmentally friendly energy solutions. The discussion further extends to challenges and future directions, emphasizing the need for incorporating factors, including discrepancy in scale, light illumination, electrolyte presence, and applied bias, into DFT calculations, to achieve a more comprehensive understanding of PC and PEC systems. In this perspective, it is aimed to provide a holistic view of the current state and potential advancements in photocatalyst and photoelectrode modeling, thereby guiding future research toward more effective and sustainable energy and chemical production processes in PC and PEC systems.

Rod-like BiVO4 with two-phase structure to boost photoelectrocatalytic degradation activity for tetracycline via the p-n junction

Bismuth vanadate (BiVO4) as a potential photoanode is widely applied in photoelectrocatalytic (PEC) degradation flied. However, it is inhibited due to easy recombination of the photogenerated carries. Herein, rod-like morphology BiVO4 with monoclinic and tetragonal phase structure (R-BVO) are prepared using hydrothermal approach. Density functional theory (DFT) calculation confirms that the build-in electron field is constituted at contact interface of two-phase structure. Benefiting from the one-dimensional conduction of rod like morphology and the p-n junction formed by two-phase structure, R-BVO indicates outstanding photocurrent, the applied bias photo-to-current efficiency (ABPE) and the incident photoelectron conversion efficiency (IPCE). Compared with the single phase structure particle BiVO4 (P-BVO), the PEC degradation rate for TC of R-BVO is 96.4 %, which is 1.4 times of P-BVO. Equally importantly, the Ni foam is used as conducting substrate owing to its low cost and practicability, moreover, it is not only easy to determine catalyst dosage, but also ensures the tight contact between active substance and substrate, preventing the catalyst from peeling off in reaction. This study puts forward an adventurous strategy for designing effective photoanode materials.

Precise Lattice‐Strain Modulation of Hematite Enabled by Gradient Doping of Mn for Enhanced Photoelectrocatalytic Oxidative C─C Bond Scission

The high‐value utilization of biomass feedstock is fascinating but limited by efficient C─H activation to break C─C bonds. Herein, F‐Fe2O3‐Mn photoanodes with modulable compressive strain are fabricated by gradient infusion of Mn into F‐doped hematite (F‐Fe2O3), which is illustrated to be highly efficient for oxidative C─C bond cleavage of various bio‐based 1,2‐diols to produce benzoic acids or aromatic ketones (94.5–97.2% yields) in photoelectrocatalytic (PEC) device, coupling with a high H2 production of 1180 μmol cm−2 (≈96% yield). The gradient doping of Mn species into the photoelectrode bulk results in improved photoexcited carriers separation and transfer efficiency of the photoelectrode (3.41 mA cm−2). On the other hand, the lattice distortion induced by Mn doping also leads to a strain effect on F─Fe2O3─Mn, which can precisely modulate the photoelectrode electronic structure. Control experiments, in situ characterization, and theoretical calculations elaborate that compressive strain is capable of adjusting the position of the d‐band center to facilitate C─H activation, remarkably enabling PEC oxidative C─C bond breaking of 1,2‐diol and the desorption of the oxidized product. This “one‐stone‐two‐bird” strategy presents a straightforward protocol for efficiently breaking C─C bonds in organic and biomass transformations via PEC oxidation.

Investigating the interfacial charge transfer between electrodeposited BiVO4 and pulsed laser-deposited Co3O4 p-n junction photoanode in photoelectrocatalytic water splitting

The formation of a p-n junction consisting small-sized, and homogeneous material over the porous semiconductor is an effective strategy for improved photoelectrocatalytic (PEC) water oxidation. Here, the facile pulsed laser deposition (PLD) method was used to load small-sized Co3O4 on BiVO4. The BiVO4/Co3O4 (30 s) photoanode exhibits a higher photocurrent density of 4.66 mA cm−2 @ +1.23 VRHE which is ∼ 4-fold higher than pristine BiVO4. This improved PEC performance is due to the availability of more active sites, improved charge separation, rapid interfacial charge transfer process, higher injection ability, and higher water oxidation kinetics. The higher open circuit voltage (VOC) of BiVO4/Co3O4 offers the greater driving force for charge separation. On the other hand, the density functional theory (DFT) investigations were carried out for further understanding of the facile interfacial charge transfer process. The electrostatic plots from the DFT studies reveals that Co3O4 has a deeper potential than BiVO4 and this potential difference can induce a strong internal electric field across the junction which promotes facile charge transfer from BiVO4 to Co3O4 until equilibration. Under illumination, BiVO4 and Co3O4 act electron acceptor and hole acceptor, respectively. Hence, the hole accumulated water oxidation is taken place in the valence band maximum (VBM) of Co3O4 for an enhanced PEC performance of the p-n junction photoanode.