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Metal halide perovskites have brought about a disruptive shift in the field of third-generation photovoltaics. Their potential as remarkably efficient solar cell absorbers was first demonstrated in the beginning of the 2010s. However, right from their inception, persistent challenges have impeded the smooth adoption of this technology in the industry. These challenges encompass issues such as the lack of reproducibility in fabrication, limited mid- and long-term stability, and concerns over toxicity. Despite achieving record efficiencies that have outperformed even well-established technologies, such as polycrystalline silicon, these hurdles have hindered the seamless transition of this technology into industrial applications. In this Perspective, we discuss which of these challenges are rooted in the unique dual nature of metal halide perovskites, which simultaneously function as electronic and ionic semiconductors. This duality results in the intermingling of processes occurring at vastly different timescales, still complicating both their comprehensive investigation and the development of robust and dependable devices. Our discussion here undertakes a critical analysis of the field, addressing the current status of knowledge for devices based on halide perovskites in view of electronic and ionic conduction, the underlying models, and the challenges encountered when these devices are optoelectronically characterized. We place a distinct emphasis on the positive contributions that this area of research has not only made to the advancement of photovoltaics but also to the broader progress of solid-state physics and photoelectrochemistry. [ABSTRACT FROM AUTHOR]

Photocatalytic water splitting for green hydrogen production is hindered by the sluggish kinetics of oxygen evolution reaction (OER). Loading a co-catalyst is essential for accelerating the kinetics, but the detailed reaction mechanism and role of the co-catalyst are still obscure. Here, we focus on cobalt oxide (CoOx) loaded on bismuth vanadate (BiVO4) to investigate the impact of CoOx on the OER mechanism. We employ photoelectrochemical impedance spectroscopy and simultaneous measurements of photoinduced absorption and photocurrent. The reduction of V5+ in BiVO4 promotes the formation of a surface state on CoOx that plays a crucial role in the OER. The third-order reaction rate with respect to photohole charge density indicates that reaction intermediate species accumulate in the surface state through a three-electron oxidation process prior to the rate-determining step. Increasing the excitation light intensity onto the CoOx-loaded anode improves the photoconversion efficiency significantly, suggesting that the OER reaction at dual sites in an amorphous CoOx(OH)y layer dominates over single sites. Therefore, CoOx is directly involved in the OER by providing effective reaction sites, stabilizing reaction intermediates, and improving the charge transfer rate. These insights help advance our understanding of co-catalyst-assisted OER to achieve efficient water splitting. [ABSTRACT FROM AUTHOR]

This study focuses on the potentiostatic electrodeposition of copper indium and cadmium sulfide (CuS, In 2 S 3 , and CdS) thin films on copper substrates, aiming to develop efficient electrocatalysts for the electrochemical reduction of CO 2 and sustainable hydrogen generation. Utilizing Cu Kα radiation for X-ray diffraction (XRD) analysis, the crystal structures of the electrodeposited films were confirmed, revealing well-defined crystalline phases. The films exhibited average particle sizes of 55.99 nm for CuS, 50.37 nm for In 2 S 3 , and 63.51 nm for CdS. Cyclic voltammetry and chronoamperometry were employed to optimize the deposition parameters, ensuring efficient nucleation and growth of the metal sulfide films. The electrochemical performance of the synthesized electrocatalysts was rigorously tested, demonstrating their potential for CO 2 reduction under optimized conditions with the highest efficiency for CdS electrodes. Additionally, the electrodeposited CuS and CdS are of the p-type, and In 2 S 3 is of the n-type semiconductor were studied and verified by the Mott–Schottky test. CuS, In 2 S 3 , and CdS were found to have donor and acceptor concentrations (N D) of 1.68 × 106, 1.44 × 105, and 8.9 × 105 cm3, respectively. The photoelectrochemical measurements of the electrodeposited metal sulfides were studied at ambient temperature and under illumination, providing higher photocurrent responses for CdS and demonstrating its strong potential as a photoelectrode material for CO 2 reduction. This work underscores the significance of facile electrochemical synthesis methods in developing cost-effective and scalable electrocatalysts, paving the way for their integration into photoelectrochemical systems for green energy applications. [Display omitted] • Potentiostatic electrodeposition was used for CuS, In 2 S 3 , and CdS thin films. • XRD confirms high crystal phase purity and well-defined crystallinity. • Average particle sizes: CuS 55.99 nm, In 2 S 3 50.37 nm, CdS 63.51 nm. • CdS demonstrates the highest efficiency in electrocatalytic performance. • The study supports scalable, eco-friendly methods for CO 2 and H 2 applications. [ABSTRACT FROM AUTHOR]

BiVO4 faces significant challenges for widespread application in photoelectrochemical (PEC) water oxidation due to its poor hole transport ability, high surface defect density, and sluggish water oxidation reaction kinetics. Employing interfacial engineering to assist in energy level modulation is an effective strategy to address these challenges. Herein, a CuCrO2 hole transport layer (HTL) is coupled and further grew NiCo‐MOF in situ to prepare a NiCo‐MOF‐CuCrO2‐BiVO4 composite photoanode. The novel composite photoanode not only achieves a photocurrent density of 5.75 mA cm−2 at 1.23 V versus a reversible hydrogen electrode (vs RHE) but also maintains stable operation for over 24 h. Comprehensive physicochemical characterization and density‐functional theory calculations confirm that the built‐in electric field generated by the p–n heterojunction formed between the CuCrO2 HTL and BiVO4 photoanode enhances the hole transport ability. Moreover, the NiCo‐MOF chelated on the photoanode surface not only passivates the surface defect states but also accelerates the kinetics of the water oxidation reaction. Under the synergistic effect of dual modification, the PEC water oxidation performance of the BiVO4 photoanode is dramatically improved. This pioneering work presents a MOF/HTL/BiVO4 configuration that provides a blueprint for the future development of integrated photoanodes for efficient solar energy conversion. [ABSTRACT FROM AUTHOR]

Green hydrogen production using particulate photocatalyst materials has attracted much attention in recent years because this process could potentially lead to inexpensive and scalable solar‐to‐chemical energy conversion systems. Although the development of efficient particulate photocatalysts enabling one‐step overall water splitting (OWS) with solar‐to‐hydrogen efficiencies in excess of 10 % remains challenging, promising photocatalyst candidates exhibiting OWS activity have been demonstrated. This review provides a comprehensive introduction to the solar‐to‐hydrogen energy conversion process of semiconductor photocatalyst materials and highlights recent advances in photocatalytic OWS via both one‐step and two‐step photoexcitation processes. The review also covers recent developments in the photocatalytic OWS of SrTiO3, including the establishment of large‐scale photocatalytic systems, interfacial design using cocatalysts to enhance water splitting activity, and its photoelectrochemical (PEC) properties at the electrified solid/liquid interface. In addition, there is a special focus on visible‐light‐absorbing oxynitride and oxysulfide particulate photocatalysts with absorption edges near 600 nm. Methods for photocatalyst preparation and surface modification, as well as PEC properties, are also discussed. The semiconductor properties of particulate photocatalysts obtained from photoelectroanalytical evaluations using particulate photoelectrodes are evaluated. This review is intended to provide guidelines for the future development of particulate photocatalysts capable of efficient and stable OWS. [ABSTRACT FROM AUTHOR]

The modification of ZnO, such as transforming it from 1‐D to 3‐D nanostructures or compositing it with carbon‐based materials, has been extensively explored to enhance light energy harvesting and reduce electron‐hole recombination‐key limitations of ZnO. Herein, the effect of different composite materials, specifically nitrogen‐doped carbon quantum dots (N‐CQDs) and nitrogen, sulfur‐doped carbon quantum dots (N,S‐CQDs), on ZnO's morphology and photocurrent response was studied. Various morphologies were synthesized on conductive glass substrate using a one‐pot hydrothermal method, including flower‐like structure for ZnO/N‐CQDs (∼d = 0.9 µm) and multilayered microspheres for ZnO/N,S‐CQDs (∼d = 1.1 µm). The inclusion of sulfur atoms in the composite resulted in a reduced bandgap value from 3.22 to 3.11 eV, along with enhanced light absorption efficiency and improved separation of photogenerated electron‐hole pairs. Furthermore, the crystallinity of ZnO/N,S‐CQDs was significantly enhanced compared to ZnO without sulfur doping. These improvements were reflected in the photoelectrochemical (PEC) measurements, where ZnO/N,S‐CQDs showed a current density of 21.8 µA/cm2 at 0.5 V (vs. Ag/AgCl), which is 5.5 times higher than that of ZnO/N‐CQDs (4.0 µA/cm2). These findings demonstrate that sulfur doping improves photocatalytic efficiency, making 3D ZnO/N,S‐CQDs a promising candidate for various UV‐driven PEC applications. [ABSTRACT FROM AUTHOR]

Hydrogen fuel produced from water splitting using sunlight remains one of the cleanest and most sustainable energy sources. However, photoelectrochemical hydrogen production faces several challenges, including poor sunlight absorption, deficient charge carrier lifetime and transfer rates, and very sluggish kinetics of the water oxidation half‐reaction. To address these challenges, researchers have concentrated on enhancing the efficiency of photoelectrochemical water splitting. A critical factor in this enhancement is a deeper understanding of the fundamental processes involved in photoabsorption and the subsequent oxidation evolution reaction. The advent of ultrafast lasers has enabled the detailed tracking of charge carriers within materials after sunlight absorption, including their separation and migration to the surface for water oxidation. Ultrafast transient absorption spectroscopy is a powerful technique that allows real‐time observation of the behavior of excited states and charge carriers on femtosecond to nanosecond timescales. Recent studies utilizing ultrafast transient absorption spectroscopy are explored to investigate the dynamics of charge carriers in photoelectrochemical water splitting, providing insights into the mechanisms that lead to the design of enhanced photoanodes with improved efficiency. [ABSTRACT FROM AUTHOR]

Recently, increasing attention has been paid to exploring the unique characteristics of newly emerged organic photoelectrochemical transistors (OPECT) for biological application and neuromorphic engineering due to their effectiveness for light‐driven ionic regulation of channels interfaced with rich biochemical reactions. The observation of interesting signaling reversion is reported—the realization of dual‐directional signaling with enhanced signal resolution—enabled by porous coordination networks (PCN)‐134(Fe) in the presence of varying H2O2 concentrations, which is totally different from exiting unidirectional signaling in OPECT. The underlying mechanism of such behavior is attributed to the change in the polarity of the gate photocurrent and is explained from the perspective of potential distribution. The practical application of this device is then studied by detecting the phorbol myristate acetate (PMA)‐induced secretion of H2O2 from three kinds of human breast cells. This study features the realization of dual‐directional signaling, which is expected to catalyze a new category of OPECT operation with unknown possibilities. [ABSTRACT FROM AUTHOR]

Allotropy structures may induce different electronic and optical properties, which implies that one can acquire novel performance by screening its allotropy structures. Here, we demonstrate that two In 2 S 3 allotropy monolayers with excellent photocatalytic performance for water splitting to produce hydrogen are screened from 1038 In 2 S 3 allotropy monolayers. The phonon dispersions are calculated for 39 allotropes with the lowest formation energies, which confirms that 16 allotropes have dynamic stability, including the only one reported in the literature. The results of overpotentials of band edges demonstrate that 8 allotropes match the potential requirements of overall water splitting. The thermodynamic stability of these allotropes is further confirmed for the obtained allotropes. Then, two allotropes with maximum solar-to-hydrogen efficiency of 17.78% and 29.32% are screened. The Gibbs free energy with the solvent effect indicates that one allotrope can proceed photocatalytic hydrogen/oxygen evolution reactions spontaneously. Therefore, the newfound In 2 S 3 allotropy monolayers have potential applications in photocatalytic overall water splitting for hydrogen generation. [Display omitted] • 8 In 2 S 3 monolayers for photocatalytic HER/OER are screened from 1038 allotropes. • The maximum η STH ′ of 29.32% is attributed to the In 2 S 3 -VIII monolayer. • Photocatalytic HER/OER can spontaneously proceed with In 2 S 3 -VI/VIII monolayers. • η STH ′ of In 2 S 3 -VI monolayer can be boosted from 17.78% to 30.16% by adjusting pH. [ABSTRACT FROM AUTHOR]

The self-doping of oxygen vacancy and Ti3+ by electrochemical reduction (ER) method has been proved to be an effective means to improve the PEC performance of TiO2. However, the effect of the surface structure on ER treatment remains ambiguous. In this work, three kinds of nanostructured rutile TiO2 (nanowire arrays (TNWs), etched nanowire arrays (E-TNWs) and nanorod arrays (TNRs)) were reduced electrochemically to explore the factors influencing the ER process of rutile TiO2. The experimental results show that alkaline environment (1 M NaOH) is more conducive to the occurrence of ER reaction. And the reduced three kinds of nanostructured TiO2 photoanodes show a significantly higher photocurrent density of about 1.46, 1.65 and 1.45 mA cm−2 at 1.23 V vs. relative hydrogen electrode (RHE), respectively, which are 15, 16 and 1.1 times that of pristine TiO2. The different degrees of photocurrent density enhancement can be ascribed to the different degrees of electrochemical reduction of TiO2 with different crystallinity and exposed crystal facets as well as specific surface area. This study provides new insights into the mechanism of electrochemical reduction method. [ABSTRACT FROM AUTHOR]

The self-doping of oxygen vacancy and Ti3+ by electrochemical reduction (ER) method has been proved to be an effective means to improve the PEC performance of TiO2. However, the effect of the surface structure on ER treatment remains ambiguous. In this work, three kinds of nanostructured rutile TiO2 (nanowire arrays (TNWs), etched nanowire arrays (E-TNWs) and nanorod arrays (TNRs)) were reduced electrochemically to explore the factors influencing the ER process of rutile TiO2. The experimental results show that alkaline environment (1 M NaOH) is more conducive to the occurrence of ER reaction. And the reduced three kinds of nanostructured TiO2 photoanodes show a significantly higher photocurrent density of about 1.46, 1.65 and 1.45 mA cm−2 at 1.23 V vs. relative hydrogen electrode (RHE), respectively, which are 15, 16 and 1.1 times that of pristine TiO2. The different degrees of photocurrent density enhancement can be ascribed to the different degrees of electrochemical reduction of TiO2 with different crystallinity and exposed crystal facets as well as specific surface area. This study provides new insights into the mechanism of electrochemical reduction method. [ABSTRACT FROM AUTHOR]

Surface engineering of BiVO4 photoanodes is effective and feasible for photoelectrochemical (PEC) water splitting. To achieve superior PEC performance, however, more than one surface engineering method is usually indispensable, for which a positive synergistic effect is vital and thus highly desired. Herein, it is reported that the incorporation of borate moieties into ultrathin p‐type NiOx catalysts can induce the reconfiguration of surface catalytic sites to form new highly active species, in addition to enhanced fast charge separation and transfer. The photocurrent density of BiVO4 photoanodes is enhanced from 1.49 to 5.76 mA cm−2 at 1.23 V versus reversible hydrogen electrode (RHE) under AM 1.5G illumination, which is achieved by successive modifications of NiOx and borate moieties. It is found that BO3 groups anchored to Ni atoms by replacing the surface hydroxyl sites of NiOx catalysts not only increase the relative ratio of Ni3+ species to facilitate charge transfer but also provide efficient active sites for H2O molecule adsorption and oxidation reactions. This work demonstrates the positive synergistic effect of these two surface engineering methods and provides an effective pathway to construct highly efficient and stable photoanodes for PEC water splitting. [ABSTRACT FROM AUTHOR]

Photoelectrochemical solar to hydrogen production is a promising way to achieve carbon neutrality, but severe charge recombination in photoanodes limits the conversion efficiency. Herein, Au nanoparticles and Co(OH)x co‐sensitized bismuth vanadate (BiVO4) to construct AuCo(OH)x/BiVO4 photoanode for significantly enhancing the performance of photoelectrochemical water splitting. This process significantly improves the bulk charge carrier separation efficiency, the surface kinetics of water oxidation, and the electron density of BiVO4 photoanode through Au surface plasmon resonance (SPR) and Co(OH)x oxygen evolution catalysts effect. Additionally, the enhancement of the *O and the *OOH generation accelerate the oxygen evolution reaction kinetics. Consequently, the constructed AuCo(OH)x/BiVO4 photoanode demonstrates an excellent photocurrent of 6.2 mA cm−2 at 1.23 V versus reversible hydrogen electrode and a stable continuous output within 42 h. This work contributes to developing high‐efficiency and high‐stability photoanodes for solar H2 production through SPR effect and oxygen evolution catalysts. [ABSTRACT FROM AUTHOR]

Limited charge transfer and slow oxygen evolution (OER) kinetics significantly impede the practical realization of photoanodes for photoelectrochemical (PEC) water splitting. Here, pn-type-Fe 2 O 3 homojunction photoanode catalysts with P active sites are designed by doping phosphorus (P) into outer lattice of n-type Fe 2 O 3 nanorods (pn-P-Fe 2 O 3). The optimized pn-P-Fe 2 O 3 photoanode shows the maximum photocurrent density of 2.61 mA/cm2 at 1.23 V RHE , and the value is 6.4 times greater than that of pristine Fe 2 O 3. Experimental and theoretical results clearly show that the P–N homogeneous junctions constructed in Fe 2 O 3 through P-doping increase active sites for H 2 O adsorption and activation, reduce OER reaction energy barrier, and promote effective separation of photogenerated electron-hole pairs and water splitting kinetics. This not only makes the photoelectric water decomposition performance outstanding, but also produces excellent durability. This work provides a novel simple and environmentally friendly strategy for designing effective photoanodes for PEC water splitting. • The homojunction photoanode catalyst with P active sites is designed by P doping. • The photocurrent density of pn-P-Fe 2 O 3 is 6.4 times higher than pristine Fe 2 O 3. • P active sites and the P–N homojunction reduce the energy barrier of OER. [ABSTRACT FROM AUTHOR]

CuBi 2 O 4 exhibits a high onset potential and theoretically high photocurrent density due to its well-matched bandgap for solar water splitting. However, factors such as low charge carrier mobility and severe charge recombination prevent CuBi 2 O 4 from reaching its ideal photoelectrochemical performance, while photocorrosion of the Cu element severely compromises its stability. Herein, a convenient and low-cost chemical bath deposition method has been employed to combine carbon quantum dots (CQDs) with Ni(OH) 2 , resulting in the preparation of a conformal CQD@Ni(OH) 2 layer-coated CuBi₂O₄/CuO heterojunction photocathode. Under AM 1.5G illumination, CuBi 2 O 4 /CuO/CQD@Ni(OH) 2 illustrates a photocurrent density of −1.36 mA cm−2, which is 2.12 times higher than that of CuBi 2 O 4 /CuO. More importantly, the conformal coating of CQD@Ni(OH) 2 effectively prevents photocorrosion induced by oxidation-reduction reactions of Cu2+/Cu. At 0.3 V RHE , the photocurrent of CuBi 2 O 4 /CuO/CQD@Ni(OH) 2 remains at 76.4% after 10000 s of chopped light illumination, significantly outperforming the 48.9% retention observed for CuBi 2 O 4 /CuO photocathode after 3600 s of chopped light illumination. This work demonstrates that the CQDs and Ni(OH) 2 are good candidates for the photoelectrode overlayer with significant synergetic effects. • CQD@Ni(OH) 2 is conformally coated on the CuBi 2 O 4 /CuO photocathode via a chemical bath deposition. • This composite photocathode exhibits a 2.12-folds photocurrent and good anti-photocorrosion. • CQDs and Ni(OH) 2 synergistically serve as charge transporter and cocatalyst, respectively. [ABSTRACT FROM AUTHOR]

The process of transforming solar power into hydrogen fuel through photoelectrochemical water splitting is a highly viable strategy for producing hydrogen in an environmentally friendly and sustainable manner, offering a long-term solution to the worldwide energy crisis. Therefore, the need for high-performance photoelectrodes is critical for optimizing the transformation of solar energy into hydrogen fuel. Herein, a simple citrate sol-gel technique was employed to fabricate magnesium iron oxide (MgFeO 3) for its potential use in photoelectrochemical water splitting. A detailed analysis was undertaken using techniques such as XRD, FESEM, XPS, PL, EDX, and UV–Vis spectrophotometry to uncover the fundamental physicochemical and optoelectronic aspects of the MgFeO 3 perovskite material. The MgFeO 3 photoelectrode manifests superior PEC characteristics as evidenced by the optimal photocurrent density of 4.5 mA cm−2 achieved at a potential of 1.2 V vs. RHE, and a commendable solar-to-hydrogen conversion efficiency of 0.97%. EIS studies provided evidence of improved charge transfer kinetics and decreased recombination rates in the MgFeO 3 photoelectrode. In addition, extended reliability evaluations utilizing chronoamperometry verified consistent operation for 10 h at a photocurrent density of 3.5 mA cm−2, demonstrating the long-term durability of MgFeO 3 in PEC water splitting. These results emphasize the considerable promise of MgFeO 3 perovskite as a proficient and robust photoelectrode substance for PEC water-splitting applications. [Display omitted] • Developed MgFeO 3 perovskite nanostructures using a facile citrate sol-gel method. • High photocurrent density of 9.1 mA cm⁻2 at 1.2 V vs. RHE under visible light irradiation. • Demonstrated a solar-to-hydrogen conversion efficiency of 0.97% that showcase the material's efficiency. • MgFeO 3 material exhibited outstanding long-term stability under prolonged visible light exposure. [ABSTRACT FROM AUTHOR]

The development of an ideal photoanode that exhibits broad light absorption, efficient photogenerated carrier separation, and superior transmission efficiency remains a pivotal challenge in enhancing the sluggish photoelectrochemical (PEC) water splitting reaction. Here, we present an efficacious strategy to bolster the PEC performance of oxygen evolution by fabricating a BiVO 4 /BiOBr heterojunction through a combined electrochemical deposition-calcination approach and the successive ionic layer adsorption and reaction (SILAR) method. The band structure of BiOBr is optimally aligned with BiVO 4 , enabling the heterojunction to significantly enhance the separation efficiency of photogenerated charges and accelerate the kinetics of PEC water oxidation. Under simulated sunlight irradiation, the BiVO 4 /BiOBr heterojunction exhibits a remarkable photocurrent density of 2.69 mA/cm2 at 1.23 V vs. reversible hydrogen electrode (RHE), surpassing the performance of bare BiVO 4 film (0.46 mA/cm2 at 1.23 V vs. RHE) and demonstrating exceptional stability. This work offers novel insights into the rational design and fabrication of solar-driven PEC water splitting photoanodes. [Display omitted] • A type-II heterojunction was constructed between BiVO 4 and BiOBr. • Heterojunction promotes the transmission of photogenerated charge in and on the surface of photoanode bulk phase. • Heterojunction improves the optical absorption range and enhances the photogenerated charge separation. [ABSTRACT FROM AUTHOR]

Photocatalytic water splitting represents a leading approach to harness the abundant solar energy, producing hydrogen as a clean and sustainable energy carrier. Zinc indium sulfide (ZIS) emerges as one of the most captivating candidates attributed to its unique physicochemical and photophysical properties, attracting much interest and holding significant promise in this domain. To develop a highly efficient ZIS-based photocatalytic system for green energy production, it is paramount to comprehensively understand the strengths and limitations of ZIS, particularly within the framework of solar-driven water splitting. This review elucidates the three sequential steps that govern the overall efficiency of ZIS with a sharp focus on the mechanisms and inherent drawbacks associated with each phase, including commonly overlooked aspects such as the jeopardising photocorrosion issue, the neglected oxidative counter surface reaction kinetics in overall water splitting, the sluggish photocarrier dynamics and the undesired side redox reactions. Multifarious material design strategies are discussed to specifically mitigate the formidable limitations and bottleneck issues. This review concludes with the current state of ZIS-based photocatalytic water splitting systems, followed by personal perspectives aimed at elevating the field to practical consideration for future endeavours towards sustainable hydrogen production through solar-driven water splitting. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) water splitting by TiO 2 photoanode for clean hydrogen production is limited by the poor charge separation and inert oxygen evolution reaction (OER) kinetics issues for now. In this work, a band-matched heterophase homojunction (TiO x /N–TiO 2) by amorphous TiO x and N-doped TiO 2 nanotube arrays is constructed by two-step anodic oxidation and impregnation. The photocurrent density of TiO x /N–TiO 2 reaches 0.69 mA/cm2 at 1.23 V vs. RHE, which is 1.86 folds than bare TiO 2. The enhanced charge carriers' injection/separation efficiency, smaller Tafel slope (37.79 mF dec−1) and larger electrochemical active surface area (ECSA) (1.98 mF cm−2) of TiO x /N–TiO 2 indicate that N doping and heterophase homojunction with amorphous TiO x effectively facilitate the surface OER kinetics and charge carriers' transportation. TiO x /N–TiO 2 is annealed with a transformation of the surface amorphous TiO x layer into anatase TiO 2 (a-TiO x /N–TiO 2) to study the role of amorphous TiO 2 in PEC water splitting. The photocurrent density and applied bias photon-to-current efficiency (ABPE) for a-TiO x /N–TiO 2 decrease, even lower than the pristine TiO 2. This is due to the reduction of surface oxygen vacancies, which causes the slowdown of OER kinetics and the weakening of charge carrier transportation ability. That is favorable for a better understanding of the OER kinetics and charge carriers' transportation enhancement mechanism by the surficial modification on the semiconductor during the PEC water splitting. A band-matched heterophase homojunction (TiO x /N–TiO 2) by amorphous TiO x and N-doped TiO 2 nanotube arrays is constructed. The increased charge carriers' injection/separation efficiency, smaller Tafel slope and larger electrochemically active surface area of TiO x /N–TiO 2 indicate N doping and heterophase homojunction with amorphous TiO x enhance the surface OER kinetics and charge carriers' transportation. TiO x /N–TiO 2 is annealed with a transformation of the surface amorphous TiO x layer into anatase TiO 2 (a-TiO x /N–TiO 2) to study the role of amorphous TiO x. The photocurrent density and applied bias photon-to-current efficiency (ABPE) for a-TiO x /N–TiO 2 decrease, even lower than the pristine TiO 2. This is due to the reduction of surface oxygen vacancies, which causes the slowdown of OER kinetics and the weakening of charge carrier transportation ability. [Display omitted] • TiO x /N–TiO 2 heterophase homojunction system with suitable band alignment is constructed. • The charge carriers' transportation is improved by N doping and TiO x /N–TiO 2 heterophase homojunction. • Amorphous TiO x heterophase homojunction is favorable for oxygen evolution reaction kinetics acceleration. • The PEC performance decrease by the amorphous TiO x disappearance further reveals the mechanism of OER kinetics enhancement. [ABSTRACT FROM AUTHOR]

A novel mixed metal oxide of CuNiO x has been successfully obtained via electrosynthesis and thermal conversion of a Hofmann-type MOF Cu(pz) 2 [Ni(CN) 4 ] (pz = pyrazine). CuNiO x has demonstrated a significant enhancement in light absorption within a visible light range, leading to an impressive increase in photocurrent density and photocatalytic activity during light irradiation compared to CuO. The exceptional photoelectrochemical properties of the photocathodes of CuNiO x have been studied using multiple photoelectrochemical instrumental techniques, which proved the electrodes were stable over the whole water photolysis. The coupling of two metal centers has explained their outstanding performance. • A novel CuNiO x photocathode derived from Hofmann-type MOF was prepared. • CuNiO x shows significant improvement in photocatalytic activity towards H 2 production. • CuNiO x outperforms CuO in hydrogen evolution due to Cu-Ni synergy. • Spectroscopic studies highlight CuO and NiO roles in charge separation. [ABSTRACT FROM AUTHOR]

Photoanodes with ample visible-light absorption and efficient photogenerated charge carrier dynamics expedite the actualization of high-efficiency photoelectrochemical water splitting (PEC-WS). Herein, we fabricated the heterojunction nanostructures of In2S3/MoS2 on indium-doped tin oxide glass substrates by indium sputtering and sulfurization, followed by the metal–organic chemical vapor deposition of 2D MoS2 nanosheets (NSs). The photocurrent density of In2S3/MoS2 was substantially enhanced and higher than those of pristine In2S3 and MoS2 NSs. This improvement is due to the MoS2 NSs extending the visible-light absorption range and the type-II heterojunction enhancing the separation and transfer of photogenerated electron–hole pairs. This work offers a promising avenue toward the development of an efficient photoanode for solar-driven PEC-WS. [ABSTRACT FROM AUTHOR]

Electronic structure regulation is a prevailing approach to modifying the electrocatalysts in the oxygen evolution reaction (OER), yet its impact on the co‐catalysts modified photoanodes remains uncertain. Herein, B‐modified NiFe‐LDH (NiFeB‐hydx) co‐catalyst in situ is immobilized onto Ti‐Fe2O3 and emphasizes the effect of lower‐valence Ni (Ni2‐δ) in the photoelectrochemical (PEC) process. A flexible adjustment in the oxidation state of Ni from +2 to 0 by manipulating the Ni content and the corresponding B quantity is achieved. Interestingly, the Ni0 significantly reduces the onset potential low to 0.53 VRHE, albeit leading to wasted holes due to incomplete redox transition. An optimal amount of Ni2‐δ effectively facilitates the redox transition of Ni and achieves a delicate balance between hole extraction and consumption, substantially enhancing the PEC performance. Density functional theory calculations verifies the electron enrichment of Ni and the corresponding benefits for enhancing OER. Furthermore, introducing FeOOH as a hole transfer layer on Ti‐Fe2O3 induces a pronounced band bending effect, remarkably promoting the meticulously engineered NiFeB‐hydx/FeOOH/Ti‐Fe2O3 photoanode to a photocurrent density of 3.29 mA cm−2 at 1.23 VRHE. NiFeB‐hydx/FeOOH can be universally applied to the BiVO4 photoanode, resulting in doubled photocurrent density (4.8 mA cm−2 at 1.23 VRHE). [ABSTRACT FROM AUTHOR]

Crafting an inorganic semiconductor heterojunction with defect engineering and morphology modulation is a strategic approach to produce clean energy by the highly efficient light-driven splitting of water. In this paper, a novel Z-scheme sulfur-vacancy containing Zn 3 In 2 S 6 (Vs-Zn 3 In 2 S 6) nanosheets/In 2 O 3 hollow hexagonal prisms heterostructrue (Vs-ZIS6INO) was firstly constructed by an oil bath method, in which Vs-Zn 3 In 2 S 6 nanosheets grew on the surfaces of In 2 O 3 hollow hexagonal prisms to form a hollow core–shell structure. The obtained Vs-ZIS6INO heterostructrue exhibited much enhanced activity of the production of H 2 and H 2 O 2 by the light-driven water splitting. In particular, under visible light irradiation (λ > 420 nm), the rate of generation of H 2 of Vs-ZIS6INO sample containing 30 wt% Vs-Zn 3 In 2 S 6 (30Vs-ZIS6INO) could reach 3721 μmol g–1h−1, which was 87 and 6 times higher than those of Zn 3 In 2 S 6 (43 μmol g–1h−1) and Vs-Zn 3 In 2 S 6 (586 μmol g–1h−1), respectively. Meanwhile, 30Vs-ZIS6INO could exhibit the rate of H 2 O 2 production of 483 μmol g–1h−1 through the dual pathways of indirect 2e– oxygen reduction (ORR) and water oxidation (WOR) without adding any sacrifice agents, far exceeding In 2 O 3 (7 μmol g–1h−1) and Vs-Zn 3 In 2 S 6 (58 μmol g–1h−1). The excellent photocatalytic activities of H 2 and H 2 O 2 generations of Vs-ZIS6INO sample might result from the synergistic effect of the sulfur vacancy, hollow core–shell structure, and Z-scheme heterostructure, which accelerated the electron delocalization, enhanced the absorption and conversion of solar energy, reduced the carrier diffusion distance, and ensured high REDOX ability. In addition, the possible photocatalytic mechanisms for the production of H 2 and H 2 O 2 were discussed in detail. This study provided a new idea and reference for constructing the novel and efficient inorganic semiconductor heterostructures by coordinating vacancy defect and morphology design to adequately utilize water splitting for the production of clean energy. [ABSTRACT FROM AUTHOR]

Photoelectrochemical water splitting offers a promising approach for carbon neutrality, but its commercial prospects are still hampered by a lack of efficient and stable photoelectrodes with earth‐abundant materials. Here, we report a strategy to construct an efficient photoanode with a coaxial nanobelt structure, comprising a buried‐ZrS3/ZrOS n−p junction, for photoelectrochemical water splitting. The p‐type ZrOS layer, formed on the surface of the n‐type ZrS3 nanobelt through a pulsed‐ozone‐treatment method, acts as a hole collection layer for hole extraction and a protective layer to shield the photoanode from photocorrosion. The resulting ZrS3/ZrOS photoanode exhibits light harvesting with good photo‐to‐current efficiencies across the whole visible region to over 650 nm. By further employing NiOOH/FeOOH as the oxygen evolution reaction cocatalyst, the ZrS3/ZrOS/NiOOH/FeOOH photoanode yields a photocurrent density of ~9.3 mA cm−2 at 1.23 V versus the reversible hydrogen electrode with an applied bias photon‐to‐current efficiency of ~3.2 % under simulated sunlight irradiation in an alkaline solution (pH=13.6). The conformal ZrOS layer enables ZrS3/ZrOS/NiOOH/FeOOH photoanode operation over 1000 hours in an alkaline solution without obvious performance degradation. This study, offering a promising approach to fabricate efficient and durable photoelectrodes with earth‐abundant materials, advances the frontiers of photoelectrochemical water splitting. [ABSTRACT FROM AUTHOR]

Transconductance (gm) is one important figure of merit for benchmarking organic electrochemical transistor (OECT) biosensors, which nevertheless experiences undesired fluctuation instead of keep constant during the target detection of varied concentrations. Light‐matter interplay is recently shown as a potential way to regulate the OECT characteristics, e.g. maximum gm at zero gate bias is achieved. In this work, the challenge of unstable gm is addressed by using a unique metal‐organic framework (MOF)‐derived hollow tube indium sulfide (m‐In2S3) as the photogate. Interestingly, the light irradiation on m‐In2S3 generate a straight transfer curve, leading to a stable gm that is desirable for biological application. Exemplifying by an aptasening, such a device is then tested for protein quantification with a stable sensitivity during the detection. This work features the feasibility of light‐matter interplay to achieve a stable gm in organic electronics. [ABSTRACT FROM AUTHOR]

Photoelectrochemistry (PEC) is burgeoning as an innovative solution to organic synthesis. However, the current PEC systems suffer from limited reaction types and unsatisfactory performances. Herein, we employ efficient BiVO4 photoanodes with tailored deposition layers for customizing two PEC approaches toward C−N and C−P bond formation. Our process proceeds under mild reaction conditions, deploying easily available substrates and ultra‐low potentials. Beyond photocatalysis and electrocatalysis, customized PEC offers high efficiency, good functional group tolerance, and substantial applicability for decorating drug molecules, highlighting its promising potential to enrich the synthetic toolbox for broader organic chemistry of practical applications. [ABSTRACT FROM AUTHOR]

The study investigated the influence of catalyst concentration, co-catalyst loading ratio, sacrificial agent concentration, irradiation time, irradiation intensity and different pretreatments of sacrificial agent on hydrogen production, using multistage porous Pd/TiO 2 as the catalyst and kelp as the sacrificial agent. The morphological and structural changes in the catalyst, sacrificial agent, and their mixtures before and after the photocatalysis were analyzed using Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and ultraviolet–visible (UV–vis) spectroscopy. Based upon single-factor experiments, it was confirmed that mannitol was the primary substance acting as a sacrificial agent in kelp. Orthogonal experiments were conducted to determine the optimum conditions for hydrogen production with a reaction liquid volume of 100 mL. The highest hydrogen production efficiency was achieved for the following conditions: kelp sacrificial agent's concentration of 1.5 g/L; concentration of multistage porous Pd/TiO 2 catalyst of 3.5 g/L; Pd loading ratio of 1 wt%. Under these conditions, hydrogen production reached the value of 121.1 μmol in 4 h. Under the same conditions, replacing the kelp sacrificial agent with kelp treated with 4% alkali, resulted in a corresponding hydrogen production of 141.0 μmol in 4 h. Compared to other common biomass sacrificial agents, the use of kelp as a sacrificial agent for photocatalytic water splitting demonstrates superior hydrogen production performance. • Kelp is a suitable sacrificial agent for photocatalytic hydrogen production. • Synthesizes multistage porous Pd/TiO 2 for improved hydrogen production. • The primary substance acting as a sacrificial agent in kelp is mannitol. • Alkaline pretreatment optimizes kelp for photocatalytic hydrogen production. [ABSTRACT FROM AUTHOR]

A single thin MnCr2O4 spinel layer was synthesized on a Ni–25Cr–1.5Mn alloy by a fine control of oxygen partial pressure using the Rhines-pack method, a technique that utilized an appropriate buffering powder mixture. The spinel was characterized using X-Ray diffraction, Raman spectroscopy and photoelectrochemistry. The cubic spinel MnCr2O4 was formed under the oxygen partial pressure close to 5 × 10–21 atm at 1050 °C controlled by the buffering Ni–25Cr/Cr2O3 powder mixture. Raman MnCr2O4 spectrum is characterized by five vibrational modes, whereas photoelectrochemical characterization revealed the MnCr2O4 band gap measurement at 3.7 eV with an n-type conductivity. [ABSTRACT FROM AUTHOR]

This work systematically investigated the influence of fabrication parameters on photoelectrodes of a biphasic indium oxide polymorph (In2O3) with cubic (c-) and rhombohedral (rh-) phase contents of 72 and 28%, respectively, deposited on the surface of conductive fluorine-doped tin oxide (FTO) glass. The study examined the effects of varying the concentration of c/rh-In2O3 suspension, the composition of the dispersion medium, the number of cycles, and the mode of suspension application onto FTO glass. Linear voltammetry, chronoamperometry, and impedance spectroscopy in the illumination mode were used to demonstrate that the photoelectrode made with a suspension based on isopropyl alcohol at an c/rh-In2O3 concentration of 100 g/L exhibited the highest photocurrent density and the lowest charge transfer resistance in an aqueous electrolyte solution of 0.5 M Na2SO4 + 0.25 M Na2SO3. It has been shown that the optimal approach was to apply three layers using a multistage application mode. The results obtained can be used as a basis for the development of optimization protocols for the photoelectrodes based on oxide-containing systems and photoelectrochemical devices based on c/rh-In2O3 material. [ABSTRACT FROM AUTHOR]

Polymeric carbon nitride (CN) has emerged as a promising photoanodic material in water‐splitting photoelectrochemical cells (PEC). However, the current deposition methods of CN layers on substrates usually include a long heating process at 500−550 °C, which might cause sublimation or decomposition of the CN monomers and destruction of the substrate, leading to a nonuniform CN film. Herein, a simple, fast, and scalable energy‐economic procedure to synthesize homogenous CN films is introduced. The predesigned CN monomers film is subjected for several minutes to higher temperatures than the standard calcination procedure. The short heating process allows the formation of a uniform CN layer, with excellent contact with the substrate and good activity as a photoanode in PEC. The optimal CN photoanode reaches photocurrent densities of ≈200 μA cm−2 at 1.23 versus reversible hydrogen electrode in neutral and acidic solutions and 120 μA cm−2 in a basic solution. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) water splitting is a promising technology for green hydrogen production. However, severe charge recombination in the photoelectrode materials is one of the key obstacles to achieving high performance. Herein, a BiVO₄ photoanode with lattice strain (Str‐BVO) is constructed by generating Bi vacancies to promote charge separation in the bulk. The optimized Str‐BVO photoanode achieves a photocurrent density of 6.20 mA cm⁻2 at 1.23 V versus the reversible hydrogen electrode under AM 1.5 G illumination, with an impressive charge separation efficiency close to 100%. Systematical experiments and density functional theory reveal that the surface Bi vacancies induced strain causes the distortion of a small number of VO4 tetrahedra, which increases the antibonding state energy of most normal VO4 tetrahedra and creates more electronic vacancy states, thereby significantly promoting electron–hole separation. By surface loading with a FeNiOx co‐catalyst, the photoanode exhibits excellent PEC water‐splitting performance and stability. [ABSTRACT FROM AUTHOR]

[Display omitted] Photoelectrochemical (PEC) water splitting is an effective and sustainable method for solar energy harvesting. However, the technology is still far away from practical application because of the high cost and low efficiency. Here, we report a low-cost, stable and high-performing industrial-Si-based photoanode (n -Indus-Si/Co -2mA-xs) that is fabricated by simple electrodeposition. Systematic characterizations such as scanning electron microscopy, X-ray photoelectron spectroscopy have been employed to characterize and understand the working mechanisms of this photoanode. The uniform and adherent dispersion of co-catalyst particles result in high built-in electric field, reduced charge transfer resistance, and abundant active sites. The core–shell structure of co-catalyst particles is formed after the activation process. The reconstructed morphology and modified chemical states of the surface co-catalyst particles improve the separation and transfer of charges, and the reaction kinetics for water oxidation greatly. Our work demonstrates that large-scale PEC water splitting can be achieved by engineering the industrial-Si-based photoelectrode, which shall guide the development of solar energy conversion in the industry. [ABSTRACT FROM AUTHOR]

Cyanobacteria play a crucial role in global carbon and nitrogen cycles through photosynthesis, making them valuable subjects for understanding the factors influencing their light utilization efficiency. Photosynthetic microorganisms offer a promising avenue for sustainable energy conversion in the field of photovoltaics. It was demonstrated before that application of an external electric field to the microbial biofilm or cell improves electron transfer kinetics and, consequently, efficiency of power generation. We have integrated live cyanobacterial cultures into photovoltaic devices by embedding Limnospira indica PCC 8005 cyanobacteria in agar and PEDOT:PSS matrices on the surface of boron-doped diamond electrodes. We have subjected them to varying external polarizations while simultaneously measuring current response and photosynthetic performance. For the latter, we employed Pulse-Amplitude-Modulation (PAM) fluorometry as a non-invasive and real-time monitoring tool. Our study demonstrates an improved light utilization efficiency for L. indica PCC 8005 when immobilized in a conductive matrix, particularly so for low-intensity light. Simultaneously, the impact of electrical polarization as an environmental factor influencing the photosynthetic apparatus diminishes as matrix conductivity increases. This results in only a slight decrease in light utilization efficiency for the illuminated sample compared to the dark-adapted state. [ABSTRACT FROM AUTHOR]

Electricity-driven water splitting to produce hydrogen is one of the most efficient ways to alleviate energy crisis and environmental pollution problems, in which the anodic oxygen evolution reaction (OER) is the key half-reaction of performance-limiting in water splitting. Given the complicated reaction process and surface reconstruction of the involved catalysts under actual working conditions, unraveling the real active sites, probing multiple reaction intermediates and clarifying catalytic pathways through in-situ characterization techniques and theoretical calculations are essential. In this review, we summarize the recent advancements in understanding the catalytic process, unlocking the water oxidation active phase and elucidating catalytic mechanism of water oxidation by various in-situ characterization techniques. Firstly, we introduce conventionally proposed traditional catalytic mechanisms and novel evolutionary mechanisms of OER, and highlight the significance of optimal catalytic pathways and intrinsic stability. Next, we provide a comprehensive overview of the fundamental working principles, different detection modes, applicable scenarios, and limitations associated with the in-situ characterization techniques. Further, we exemplified the in-situ studies and discussed phase transition detection, visualization of speciation evolution, electronic structure tracking, observation of reaction active intermediates, and monitoring of catalytic products, as well as establishing catalytic structure--activity relationships and catalytic mechanism. Finally, the key challenges and future perspectives for demystifying the water oxidation process are briefly proposed. [ABSTRACT FROM AUTHOR]

Bismuth vanadate (BVO) ranks among the most promising photoanodes for photoelectrochemical (PEC) water splitting. Nonetheless, slow charge separation and transport, besides the sluggish water oxidation kinetics, are key barriers to its photoefficiency. Here, we present a co‐doping strategy that significantly improves the charge separation performance of BVO photoanodes. We found that, under standard one sun illumination, the Fe−N co‐doped BVO photoanode (Fe−N−BVO) by N‐coordinated Fe precursor reaches a record photocurrent density of 7.01 mA cm−2 at 1.23 V vs RHE after modified a surface co‐catalyst (FeNiOOH), and exhibits an outstanding stability. By contrast, much lower photocurrent density is obtained for the N‐doped, Fe‐doped and Fe/N‐doped BVO photoanode with separated N and Fe precursors. The detailed experimental characterizations show that the high activity of the Fe−N co‐doped BVO photoanode is attributed to the enhanced photo‐induced bulk charge separation, as well as the accelerated surface water oxidation kinetics. XPS, EXAFS and DFT calculations clearly show that, instead of formation of deep trapping state in the individually doped BVO, the co‐doping of Fe−N into BVO generates Fe‐based electronic states just below the bottom of conduction band and N‐derived states just above the top of valence band. Such modulations in electronic structure enable the efficient trap of the electrons and holes to enhance the separation of photo‐induced carriers, but hinder the charge recombination originated from the deep trapping sites. [ABSTRACT FROM AUTHOR]

The influence of the ion transfer on photoinduced electron transfer (ET) reactions was studied on the surface of hyperbranched semiconducting BiVO4 particles spontaneously adsorbed at the liquid‐liquid (L/L) interface between an aqueous LiCl solution and bis(triphenylphosphoranylidene) ammonium tetrakis(pentaflurophenyl)borate (BATB) in 1,2‐dichlorethane. The organic electrolyte was supplemented with [Co(bpy)3](PF6)3 to accept photoexcited electrons from BiVO4 under formation of the corresponding Co(II) complex. The L/L interface was stabilized at the orifice of a micropipette (MP) and allowed to record ion transfer cyclic voltammetry (ITCV) by applying a Galvani potential difference Δowϕ ${{\rm{\Delta }}_o^w \varphi }$ between two reference electrodes in the electrolyte solutions with intermittent illumination by visible light (λ>420 nm). The photogenerated holes caused oxidation of water to O2. Co(II) and O2 were detected at constant Δowϕ ${{\rm{\Delta }}_o^w \varphi }$ at an amperometric microelectrode (ME) facing the orifice of the MP in either the organic or the aqueous electrolyte. The overall current exhibits a photocurrent only in the Δowϕ ${{\rm{\Delta }}_o^w \varphi }$ ‐range, in which the IT of PF6− is kinetically limited. The amperometric detection of photogenerated products followed the same pattern as the photocurrent in the total current. [ABSTRACT FROM AUTHOR]

The oxidation of alcohols to the corresponding carbonyl derivatives has been realized under photoelectrochemical conditions in the presence of tetrabutylammonium decatungstate (TBADT) as the homogeneous photocatalyst. The protocol can be applied to both primary and secondary, benzylic and aliphatic alcohols. The desired products are obtained selectively, skipping the need for purposely added chemical oxidants. An in‐depth study of photoelectrochemical conditions revealed that the protocol works best under amperostatic conditions in an undivided electrochemical cell irradiated with a 390 nm LED lamp. The comparison with analogous electrochemical and chemical oxidant‐promoted photocatalytic transformations demonstrates the superior efficiency and selectivity of the hereby reported photoelectrochemical conditions. [ABSTRACT FROM AUTHOR]

For photoelectrocatalytic cells, a limitation exists in finding appropriate photoelectrode configurations that couple efficient extraction of high‐energy electrons from absorbed photons and selective catalysis. Here we report an organic p‐n junction approach to fabricate molecular photoelectrodes for conversion of solar energy and nitrate into valuable ammonia product. Solar irradiation of the photoelectrode generates charge‐separated states with electrons and holes spatially separated at the n‐type and p‐type components, as revealed by surface photovoltage mapping, at a quantum yield of 90 %. The high‐flux photogenerated electrons are rapidly transferred to the catalyst for solar ammonia production from nitrate reduction at an external quantum efficiency (EQE) and an internal quantum efficiency (IQE) of 57 % and 86 %, respectively. Time‐resolved spectroscopic studies reveal that the large IQE originates from the combined high efficiencies for photoelectron generation, catalyst activation and dark catalysis. In a flow‐cell setup coupled with a silicon solar cell, the photoelectrode without bias generates photocurrent of 57 mA cm−2 and ammonia at an EQE of 52 %. [ABSTRACT FROM AUTHOR]

Red phosphorus (RP), as a talented semiconductor, is widely employed in the field of photocatalysis owing to its superior stability and optical properties. However, RP's inherent poor conductivity and rapid carriers’ recombination significantly impede its efficient photoelectrochemical (PEC) applications. Herein, non‐homogeneous porous RP particles (NPRPs) are prepared via a ball milling‐assisted hydrothermal strategy, which provides more chemical reaction sites and fast carriers transportation rates for sensitive PEC sensing. Experiments and computational findings reveal that NPRPs incorporating oxygen doping possess staggered energy band structures along with potential driving forces, which synergistically promote the separation and migration of carriers. Furthermore, carbon nanotubes are introduced to bridge the NPRPs for constructing a conductive network, and a uniform and fully‐integrated photoelectrode array is custom‐made in batches through zonal template‐filtration. As an illustration, aptamer‐mediated PEC sensors for trace amoxicillin (AMO, an artificial antibiotic) in various samples exhibit ultra‐high sensitivity (0.43 nm) and robust selectivity. Such a PEC aptasensing prototype based on NPRPs arrays, with tunable detection throughput, holds great potential for rapid and on‐site screening of massive specimens. More meaningfully, this study offers an innovative paradigm for elemental semiconductors to efficiently transport carriers in the photoelectrocatalytic applications. [ABSTRACT FROM AUTHOR]

The organic photoelectrochemical transistor (OPECT) biosensing relies solely on a singular signal readout inherently, which restrains the precision and dependability nestled within pertinent biological measurements. Herein, a high‐precision magnetic assisted OPECT and smartphone colorimetric (SCL) dual‐mode biosensing platform is first established for detecting harmful algal toxin okadaic acid (OA) by biocatalytic reaction. MXene@SnO2‐Ce‐MOF (MXSnO/Ce‐MOF) Z‐scheme heterojunctions with abundant oxygen vacancies are prepared as photoactive materials. Initially, in the presence of OA, the coupling of trigger DNA (tDNA) to magnetic beads (MBs) via anchor DNA (aDNA) is released through the interaction of the target analyte with the aptamer. Subsequently, the carried tDNA triggers HCR between the two hairpin sequences, producing long double helix chains to capture glucose oxidase (GOx). The obtained GOx supernatant catalyzes glucose to produce H2O2, which can oxidize Ce‐MOF, leading to the alteration of electrode color and a significant decrease in the overall photocurrent of MXSnO/Ce‐MOF. Crucially, the novel OPECT‐SCL biosensor exhibits excellent sensitivity and precision, boasting detection thresholds as low as 42.9 pM and 1.2 nM, respectively, and accomplishes the automated detection of OA within real samples. The proposed OPECT‐SCL dual‐signal measurement model constitutes a sensitive, portable, and precise platform for the quantification of marine toxins. [ABSTRACT FROM AUTHOR]

α-Fe 2 O 3 attracted great attention as a promising photoanode candidate for photoelectrochemical (PEC) H 2 O spitting. In this paper, one dimensional (1D) α-Fe 2 O 3 nanorods coupled 2D porous In 2 O 3 nanosheet assemblies were designed to construct a S-scheme α-Fe 2 O 3 /In 2 O 3 heterojunction photoanode. The unique porous In 2 O 3 nanosheet assemblies are conductive to improve light-harvesting efficiency and provide more active sites. An internal electric field induced at the α-Fe 2 O 3 /In 2 O 3 heterojunction interface could promote interfacial charge separation and transfer, enhancing redox kinetics. The as-obtained 2D/1D In 2 O 3 /α-Fe 2 O 3 photoanode achieved a stable photocurrent density of 2.2 mA cm−2 at 1.23 V (vs. RHE). It is 6.3 times higher than that of the α-Fe 2 O 3 component, and got a max applied bias photo-to-current efficiency (ABPE) of 0.28%, which is about 5.8 times that of bare α-Fe 2 O 3 at 1.01 V. The work provides a promising strategy to construct high-performance S-scheme heterostructure photoanodes, featuring the role of surface and interface science in sustainable energy. [Display omitted] • 1D α-Fe 2 O 3 nanorods coupled 3D porous In 2 O 3 nanosheet assemblies were constructed. • In 2 O 3 nanosheets modified on α-Fe 2 O 3 nanorods could promote interfacial charge separation and transfer. • α-Fe 2 O 3 /In 2 O 3 photoanode achieved 2.2 mA cm−2 at 1.23 V (vs. RHE) and ABPE of 0.28% at 1.01 V. • The photoanode follows a S-scheme mechanism for enhanced photoelectrochemical activity. [ABSTRACT FROM AUTHOR]

Magnetic field-assisted method has been proved as an effective method to improve oxygen evolution reaction performance (OER) of water splitting, however, the essential reason for the improvement of OER performance still remains unclear. Herein, Ni 1- x Zn x Fe 2 O 4 ferrites were prepared by the combination of hydrothermal and calcination method, the magnetic properties, oxygen evolution reaction performance and the effect of applied magnetic field on OER performance were studied and discussed according to the magnetic properties and ion site situation. The magnetic field effect depended on the applied magnetic field strength and the magnetic magnetization density of catalysts, it was attributed to changes of electron state and redistribution of ions in the spinel structure. The overpotential decreased by approximately 50 mV and its double layer capacitance increased about 60 % at 125 mT applied magnetic field. The results provided a newness research view for the domain of electrochemistry. [ABSTRACT FROM AUTHOR]

The unsatisfied visible light harvesting, slow charge separation, and limited practical surface area of carbon nitride (CN) constrain its performance in photocatalytic water splitting and environmental remediation. Herein, the thermal vapor‐assisted π‐conjugation modification of CN by grafting with p‐aminophenoxy groups was developed to tune the photophysical properties of CN to enhance its photocatalytic activity. Besides extending the light absorption, the surface modification constructed a nanojunction across the depth direction, which leads to facilitated charge separation and transfer. In addition, the thermal vapor modification process thermally etches and trims the pristine CN to be a highly holey structure, resulting to >10 times increase in specific surface area. Photocatalysis results showed that the obtained modified CN yielded hydrogen from photocatalytic water splitting at a rate of 7.82 mmol/g/h, over 7‐folds as that of pristine CN, with a quantum yield of 3.28% at 400 nm. The π‐conjugation modified CN also demonstrated enhanced photocatalytic environmental remediation application, exemplified by much faster photodegradation of tetracycline hydrochloride. This work provides the thermal vapor surface chemical modification of CN as a promising integrated pathway of multiple favorable photophysical properties toward efficient photocatalysis application. [ABSTRACT FROM AUTHOR]

[Display omitted] • An electrocatalyst based on the Pt-MoO 3 /NiMoO 4 NRs has been fabricated for industrial-grade water splitting. • The electrolyzer using Pt-MoO 3 /NiMoO 4 NRs electrodes only required 1.55 V to achieve 10 mA cm−2. • Density functional theory calculations proved that the good synergy of the MoO 3 /NiMoO 4 and Pt benefited their catalytic performance. A new catalyst has been developed that utilizes molybdenum oxide (MoO 3)/nickel molybdenum oxide (NiMoO 4) heterostructured nanorods coupled with Pt ultrafine nanoparticles for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) toward industrial-grade water splitting. This catalyst has been synthesized using a versatile approach and has shown to perform better than noble-metals catalysts, such as Pt/C and RuO 2 , at industrial-grade current level (≥1000 mA·cm−2). When used simultaneously as a cathode and anode, the proposed material yields 10 mA·cm−2 at a remarkably small cell voltage of 1.55 V and has shown extraordinary durability for over 50 h. Density functional theory (DFT) calculations have proved that the combination of MoO 3 and NiMoO 4 creates a metallic heterostructure with outstanding charge transfer ability. The DFT calculations have also shown that the excellent chemical coupling effect between the MoO 3 /NiMoO 4 and Pt synergistically optimize the charge transfer capability and Gibbs free energies of intermediate species, leading to remarkably speeding up the reaction kinetics of water electrolysis. [ABSTRACT FROM AUTHOR]

In this study, a coating of strontium ferrite oxide (SFO), Sr 3 Fe 2 O 7, on TiO 2 demonstrated an enhancement in photoelectrochemical cell (PEC) performance. Pure TiO 2 and SFO decorated TiO 2 (SFO/TiO 2) were synthesized using the hydrothermal method. The concentration of SFO precursor in this study varied between 0.5, 1.0, and 1.5 mmol. Most of the optimized SFO concentration showed the better Applied Bias Photon-to-current Efficiency than the pure TiO 2. The structure, chemistry, and surface morphology of TiO 2 and SFO/TiO 2 materials were investigated using several techniques, including X-ray diffraction, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The UV–visible spectra revealed that SFO was able to reduce the energy band gap of pristine TiO 2 from 3.09 to 2.55 eV. The photoluminescence spectroscopy displayed that almost SFO/TiO 2 materials exhibited the lower recombination time than the pristine TiO 2. Moreover, 1.0 mmol of SFO/TiO 2 exhibited the highest photocurrent density, at approximately 12.5 μA/cm2, which was 12 times greater than pure TiO 2. The Mott-Schottky analysis revealed the energy band edge of SFO and the TiO 2 was well alignment. Therefore, SFO plays a crucial role in improving the photo-absorption efficiency of PEC cell. The enhanced PEC performance was achievable due to the materials' tailored light response. [Display omitted] • TiO 2 and SFO/TiO 2 growth on the FTO were synthesized using the hydrothermal method. • SFO decorations enhance the visible light absorption of TiO 2. • The highest current density of SFO/TiO 2 was improved by 12 times. • SFO leads to higher internal resistance compared to the pristine TiO 2. [ABSTRACT FROM AUTHOR]

Recently, tungsten oxide (WO 3) and bismuth vanadate (BiVO 4) have been considered as an intriguing combination for constructing a heterojunction for efficient photoelectrochemical (PEC) applications. Herein, we report the preparation of ternary WO 3 /BiVO 4 /NiCo layered double hydroxide (LDH) photoanodes for boosting photogenerated carrier transport and promotion of catalytic activity. WO 3 /BiVO 4 heterostructures were synthesized by a hydrothermal process of WO 3 nanoplates on a fluorine-doped tin oxide (FTO) glass substrate, followed by spin-coating for BiVO 4 materials. We investigated the effect of a NiCo LDH catalyst on PEC performance by controlling the growth temperatures of the NiCo LDH via hydrothermal synthesis. Moreover, the X-ray diffraction (XRD), Fourier‒transform infrared (FTIR) and X‒ray photoelectron spectroscopy (XPS) analyses revealed that the WO 3 /BiVO 4 heterojunction was retained after the NiCo LDH growth process regardless of synthesis temperatures. The PEC results verified that the WO 3 /BiVO 4 heterostructure with the optimized NiCo LDH catalyst (WBN60) possessed the best photocurrent density of 3.2 mA/cm2 at 1.23 V vs. reversible hydrogen electrode (RHE), which created improved charge separation and surface oxidation kinetics of photogenerated carriers. Consequentially, the smallest charge transfer resistance and recombination rate were achieved in the WBN60 electrode compared to others, indicating a much lower photoelectrode‒electrolyte interfacial resistance and the enhancement of photogenerated carrier transport by suppressing recombination. [ABSTRACT FROM AUTHOR]

Sp2‐carbon (sp2‐c) covalent organic frameworks (COFs), featuring distinctive π‐conjugated network structures, facilitate the migration of photo‐generated carriers, rendering them exceptionally appealing for applications in photoelectrochemical water splitting. However, owing to the powdery nature of COFs, leaving anchor the sp2‐c COFs powder tightly onto a conductive substrate challenging. Here, we propose a method for preparing photoactive substance‐conductive substrate integrated photocathodes through copper surface‐mediated knoevenagel polycondensation (Cu‐SMKP), this approach results in a uniform and stable sp2‐c COF film, directly grown on commercial copper foam (COFTh‐Cu). The COFTh‐Cu demonstrates a high H2‐evolution photocurrent density of 56 μA cm−2 at 0.3 V vs. RHE, sustaining stability for 12 h. The as‐prepared COFTh‐Cu represents a 4.5‐fold increase in current density compared to traditional spin‐coating methods and outperforms most COF photocathodes without cocatalysts. This innovative copper surface‐mediated approach for preparing photocathodes opens up a crucial pathway towards the realization of highly active COF photocathodes. [ABSTRACT FROM AUTHOR]

Green hydrogen (H2) production from solar water splitting necessitates photoelectrodes with superior photoelectrochemical (PEC) activity and durability. However, surface defects and photocorrosion instability—especially at high potentials—limit PEC performance and stability. Herein, the prototypical bismuth vanadate (BiVO4) photoanode is used to demonstrate a holistic approach to improve photocurrent density and long‐term stability. In this approach, high surface‐area nanostructuring of BiVO4 is combined with barium (Ba) doping with semi‐crystalline hafnium oxide (HfO2) surface passivation and single‐atom nickel platinum (NiPt) catalysts. The introduction of Ba2+ ions into BiVO4 increases the concentration of conductive V4+ ions or the ratio of V4+ ions to oxygen vacancies, avoiding V5+ dissolution during water oxidation. The semi‐crystalline HfO2, which serves as a passivation layer, prevents BiVO4 photocorrosion by suppressing harmful chemical reactions when holes are transferred to the electrolyte. The synergistic use of isolated single‐atom and Ni‐Pt coordination improves charge transfer at the photoanode/electrolyte interface, leading to enhanced PEC kinetics and stability. As a result, a photoelectrode is demonstrated with ≈6.5 mA cm−2 at 1.23 V versus a reversible hydrogen electrode (RHE) and continuous operation for 800 h with a negligible degradation rate. This work provides a promising approach to improve photoanodes for PEC H2 production. [ABSTRACT FROM AUTHOR]

One of the most promising approaches to addressing the current global energy and environmental crisis is the development and utilization of hydrogen energy. Photoelectrochemical (PEC) water splitting represents a clean and sustainable method for converting solar energy into hydrogen. In this article, we employed a hydrothermal-photodeposition method to fabricate Au@Pt decorated polyaniline (PANI)/TiO 2 (TNAP), which realized the synergy of p-n heterojunction and surface plasmon resonance (SPR). Experimental results revealed that p-n heterojunction can be formed between PANI and TiO 2 , whereas PANI can utilize visible light and the strong interaction between Au and PANI can realize the rapid transfer of hot electrons. Meanwhile, the outer layer Pt nanoparticles can accelerate water oxidation reaction kinetics. Therefore, the as-prepared TNAP exhibited the synergy promotion of p-n heterojunction and SPR effect, which is benefit for promoted light utilization and efficient charge transfer and separation. The optimized TNAP structure achieved hydrogen evolution rate of 19.26 μmol/cm2·h and photocurrent density of 1.20 mA/cm2 at a bias of 1.23 V vs. RHE, which is significantly higher than that of single semiconductor. This article suggests that the synergy promotion of SPR effect and p-n heterojunction is an efficient strategy to promote the efficiency of PEC water splitting. [Display omitted] • PANI/TiO 2 p-n heterojunction realizes the spatial separation of charge carriers. • Au NPs induced strong SPR effect and improve light utilization efficiency. • Strong interaction between PANI and Au promotes the transfer of hot electrons. • Surface Pt act as active sites and accelerate water oxidation reaction. • TNAP exhibited the synergy promotion of p-n heterojunction and SPR effect. [ABSTRACT FROM AUTHOR]