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Bismuth vanadate (BiVO 4 ) has been widely investigated as a photocatalyst or photoanode for solar water splitting, but its activity is hindered by inefficient cocatalysts and limited understanding of the underlying mechanism. Here we demonstrate significantly enhanced water oxidation on the particulate BiVO 4 photocatalyst via in situ facet-selective photodeposition of dual-cocatalysts that exist separately as metallic Ir nanoparticles and nanocomposite of FeOOH and CoOOH (denoted as FeCoO x ), as revealed by advanced techniques. The mechanism of water oxidation promoted by the dual-cocatalysts is experimentally and theoretically unraveled, and mainly ascribed to the synergistic effect of the spatially separated dual-cocatalysts (Ir, FeCoO x ) on both interface charge separation and surface catalysis. Combined with the H 2 -evolving photocatalysts, we finally construct a Z-scheme overall water splitting system using [Fe(CN) 6 ] 3−/4− as the redox mediator, whose apparent quantum efficiency at 420 nm and solar-to-hydrogen conversion efficiency are optimized to be 12.3% and 0.6%, respectively. Artificial photosynthesis offers an integrated means to convert light to fuel, but efficiencies are often low. Here, authors report a Z-scheme system utilizing Ir and FeCoO x co-catalysts to enhance charge separation on BiVO 4 facets that achieves high quantum efficiencies for overall water splitting.

Solar-driven hydrogen peroxide (H 2 O 2 ) production presents unique merits of sustainability and environmental friendliness. Herein, efficient solar-driven H 2 O 2 production through dioxygen reduction is achieved by employing polymeric carbon nitride framework with sodium cyanaminate moiety, affording a H 2 O 2 production rate of 18.7 μmol h −1 mg −1 and an apparent quantum yield of 27.6% at 380 nm. The overall photocatalytic transformation process is systematically analyzed, and some previously unknown structural features and interactions are substantiated via experimental and theoretical methods. The structural features of cyanamino group and pyridinic nitrogen-coordinated soidum in the framework promote photon absorption, alter the energy landscape of the framework and improve charge separation efficiency, enhance surface adsorption of dioxygen, and create selective 2e − oxygen reduction reaction surface-active sites. Particularly, an electronic coupling interaction between O 2 and surface, which boosts the population and prolongs the lifetime of the active shallow-trapped electrons, is experimentally substantiated. Solar-driven H 2 O 2 production presents a renewable approach to chemical synthesis. Here, authors perform a mechanistic analysis on the contribution of the sodium cyanaminate moiety to the 2-electron oxygen reduction reaction performance of polymeric carbon nitride frameworks.

Bi 3 TiNbO 9 , a layered ferroelectric photocatalyst, exhibits great potential for overall water splitting through efficient intralayer separation of photogenerated carriers motivated by a depolarization field along the in-plane a -axis. However, the poor interlayer transport of carriers along the out-of-plane c -axis, caused by the significant potential barrier between layers, leads to a high probability of carrier recombination and consequently results in low photocatalytic activity. Here, we have developed an efficient photocatalyst consisting of Bi 3 TiNbO 9 nanosheets with a gradient tungsten (W) doping along the c -axis. This results in the generation of an additional electric field along the c -axis and simultaneously enhances the magnitude of depolarization field within the layers along the a -axis due to strengthened structural distortion. The combination of the built-in field along the c -axis and polarization along the a -axis can effectively facilitate the anisotropic migration of photogenerated electrons and holes to the basal {001} surface and lateral {110} surface of the nanosheets, respectively, enabling desirable spatial separation of carriers. Hence, the W-doped Bi 3 TiNbO 9 ferroelectric photocatalyst with Rh/Cr 2 O 3 cocatalyst achieves an efficient and durable overall water splitting feature, thereby providing an effective pathway for designing excellent layered ferroelectric photocatalysts. Solving the interlayer charge transfer issue of Bi 3 TiNbO 9 is crucial for overcoming its limitation in photocatalytic overall water splitting. Here, the authors introduced gradient doping to promote the separation and transfer of photogenerated charges and enhance the photocatalytic activity.

Highly photocatalytically active cobalt-doped ZnO （ZnO：Co） nanorods have been prepared by a facile hydrothermal process. X-ray diffraction, X-ray photoelectron spectroscopy, Raman scattering and UV-vis diffuse reflectance spectroscopy confirmed that the dopant ions substitute for some of the lattice zinc ions, and furthermore, that Co〉 and Co〉 ions coexist. The as-prepared ZnO：Co samples have an extended light absorption range compared with pure ZnO and showed highly efficient photocatalytic activity, only requiring 60 rain to decompose -93% of alizarin red dye under visible light irradiation （λ 〉 420 nm）, The photophysical mechanism of the visible photocatalytic activity was investigated with the help of surface photovoltage spectroscopy. The results indicated that a strong electronic interaction between the Co and ZnO was present, and that the incorporation of Co promoted the charge separation and enhanced the charge transfer ability and, at the same time, effectively inhibited the recombination of photogenerated charge carriers in ZnO, resulting in high visible light photocatalytic activity.

Aurivillius‐type compounds ((Bi2O2)2+(An–1BnO3n+1)2−) with alternately stacked layers of bismuth oxide (Bi2O2)2+ and perovskite (An−1BnO3n+1)2− are promising photocatalysts for overall water splitting due to their suitable band structures and adjustable layered characteristics. However, the self‐reduction of Bi3+ at the top (Bi2O2)2+ layers induced by photogenerated electrons during photocatalytic processes causes inactivation of the compounds as photocatalysts. Here, using Bi3TiNbO9 as a model photocatalyst, its surface termination is modulated by acid etching, which well suppresses the self‐corrosion phenomenon. A combination of comprehensive experimental investigations together with theoretical calculations reveals the transition of the material surface from the self‐reduction‐sensitive (Bi2O2)2+ layer to the robust (BiTiNbO7)2− perovskite layer, enabling effective electron transfer through surface trapping and effective hole transfer through surface electric field, and also efficient transfer of the electrons to the cocatalyst for greatly enhanced photocatalytic overall water splitting. Moreover, this facile modification strategy can be readily extended to other Aurivillius compounds (e.g., SrBi2Nb2O9, Bi4Ti3O12, and SrBi4Ti4O15) and therefore justify its usefulness in rationally tailoring surface structures of layered photocatalysts for high photocatalytic overall water‐splitting activity and stability. By rationally tailoring the surface structure of Aurivillius compounds to expose robust perovskite layer, stable photocatalytic overall water splitting with greatly enhanced activity is achieved by both inhibiting the Bi3+ self‐reduction and promoting the effective migration of photogenerated electrons to the cocatalyst.

A novel Pt/CeO 2 /ZnO ternary composite is synthesized via two simple procedures of hydrothermal and photoreduction. The crystal structure, morphology, and composition of as-prepared samples are characterized by XRD, SEM, HRTEM, XPS and UV–Vis DRS. Because both ZnO and CeO 2 are good photocatalytic semiconductors, photocatalytic activities of the samples are evaluated by the degradation of phenol aqueous solution (25 mg/L). Under the strong interaction among the Pt, CeO 2 and ZnO, the maximum photocatalytic activity is observed in the Pt/CeO 2 /ZnO ternary composites and 91% phenol can be degraded in 60 min under UV light irradiation. The probable photocatalytic mechanism is discussed by active species trapping experiments along with SPV, TPV, PL and PA measurements. The enhanced photocatalytic activity is attributed to the redox cycle of Ce 4+ ↔ Ce 3+ , the effective interface between ZnO and CeO 2 as well as the electron transfer action of Pt nanoparticles. The photocatalytic activity almost unchanged after four cycles and proves excellent reusable photocatalysts. This work shows the synergistic effect of rare earth elements and noble metals in the photocatalytic process, which facilitates their practical application in toxic pollution abatement.

The periodical distribution of N and C atoms in carbon nitride (CN) not only results in localized electrons in each tri-s-triazine unit, but oxidation and reduction sites are in close contact spatially, resulting in severe carrier recombination. Herein, the hydrothermal method was first employed to synthesize carbon nitride (HCN), and then picolinamide (Pic) molecules were introduced at the edge of the carbon nitride so that the photo-generated electrons of the whole structure of the carbon nitride system were transferred from the center to the edge, which effectively promoted the separation of photo-generated carriers and inhibited the recombination of carriers in the structure. The introduced picolinamide not only changed the π-conjugated structure of the entire system but also acted as an electron-withdrawing group to promote charge transfer. The photocatalytic hydrogen evolution rate (HER) of the optimized HCN-Pic-1:1 sample could reach 918.03 μmolg−1 h−1, which was 11.8 times higher than that of the HCN, and the performance also improved.

Perovskite solar cells (PSCs) are currently attracting a great deal of attention for their excellent photovoltaic properties, with a maximum photoelectric conversion efficiency (PCE) of 25.5%, comparable to that of silicon-based solar cells. However, PSCs suffer from energy level mismatch, a large number of defects in perovskite films, and easy decomposition under ultraviolet (UV) light, which greatly limit the industrial application of PSCs. Currently, quantum dot (QD) materials are widely used in PSCs due to their properties, such as quantum size effect and multi-exciton effect. In this review, we detail the application of QDs as an interfacial layer to PSCs to optimize the energy level alignment between two adjacent layers, facilitate charge and hole transport, and also effectively assist in the crystallization of perovskite films and passivate defects on the film surface.

ABSTRACT The simultaneous accumulation of photo‐holes and the specific activation of substrates present a significant challenge in photo‐oxidation. Herein, we propose a dual‐channel collaborative catalytic platform based on hollow TiO2 microspheres, using Cu single‐atom (SA) catalysts and a composite polymer chain, to create separating pathways for unidirectional photogenerated electron/hole extraction. Ferrocene‐functionalized graphene quantum dots are incorporated within the polymer chain for driving benzylamine (BA) oxidation. Quasi in situ transient photovoltage and femtosecond transient absorption tests reveal that leveraging the ultrafast charge separation capability of Cu SAs (0.44 ps) not only accelerates hole transport kinetics but also induces requisite Lewis acidity for the adsorption and activation of BA. In an air atmosphere, the rate of imine production reaches 4.81 mmol g−1 h−1 (selectivity of 98%). This study demonstrates the rational design of an SA/polymer chain dual‐driven catalytic platform for optimizing kinetics and precisely controlling photocatalytic transformations in organic chemistry. Effective separation of the photogenerated charge pair was achieved through the incorporation of spatially separated dual‐channels (Cu atom and PDDA‐GQD‐FcA chain). By serving as a medium, GQD‐FcA offers appropriate acidity and organic adsorption sites on the catalyst surface, achieving the accelerated migration kinetics of photogenerated holes between the catalyst and the organic substrate.

Constructing π‐conjugated polymer structures through covalent bonds dominates the design of organic framework photocatalysts, which significantly depends on the selection of multiple donor‐acceptor building blocks to narrow the optical gap and increase the lifetimes of charge carriers. In this work, self‐bipolarized organic frameworks of single aromatic units are demonstrated as novel broad‐spectrum‐responsive photocatalysts for H2O2 production. The preparation of such photocatalysts is only to fix the aromatic units (such as 1,3,5‐triphenylbenzene) with alkane linkers in 3D space. Self‐bipolarized aromatic units can drive the H2O2 production from H2O and O2 under natural sunlight, wide pH ranges (3.0‐10.0) and natural water sources. Moreover, it can be extended to catalyze the oxidative coupling of amines. Experimental and theoretical investigation demonstrate that such a strategy obeys the mechanism of through‐space π‐conjugation, where the closely face‐to‐face overlapped aromatic rings permit the electron and energy transfer through the large‐area delocalization of the electron cloud under visible light irradiation. This work introduces a novel design concept for the development of organic photocatalysts, which will break the restriction of conventional through‐band π‐conjugation structure and will open a new way in the synthesis of organic photocatalysts. An entirely new strategy is developed to construct self‐bipolarized organic photocatalysts with single aromatic units. The resultant alkane‐linked organic frameworks can successfully drive the H2O2 production from H2O and O2 under natural sunlight irradiation.