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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. [ABSTRACT FROM AUTHOR]

Bi3TiNbO9, 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 Bi3TiNbO9 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 Bi3TiNbO9 ferroelectric photocatalyst with Rh/Cr2O3 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 Bi3TiNbO9 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. [ABSTRACT FROM AUTHOR]

Developing the technology for high yielding photocatalytic hydrogen evolution reactions is an important challenge. Development and optimization of photocatalytic junctions is a likely route for achieving this if heterojunctions with suitable band alignments can be achieved in sufficiently high‐density form. Here, a novel anatase‐TiO2/H‐rutile‐TiO2 heterophase homojunction system with near optimum energy band alignment is reported. The resulting as‐prepared catalyst exhibits an excellent photocatalytic hydrogen evolution rate of 29.63 mmol g–1 h–1 under UV–vis light irradiation and an outstanding apparent quantum efficiency of 45.6% at 365 nm. The significant improvement is ascribed to near perfect lattice matching in combination with the rapid separation and transfer of photogenerated carriers in anatase‐TiO2/H‐rutile‐TiO2 heterophase homojunctions. In situ X‐ray photoelectron spectroscopy, electron spin resonance spin‐trapping tests, femtosecond transient absorption spectroscopy, steady‐state surface photovoltage spectroscopy, and transient‐state surface photovoltage with additional ex situ characterizations and theoretical calculations show that the mechanism is enhanced transfer of photogenerated carriers in the anatase‐TiO2/H‐rutile‐TiO2 catalyst. This work provides a pathway for enhancing photocatalytic performance through optimization of heterojunctions. [ABSTRACT FROM AUTHOR]

Charge separation and transfer are central issues dominating the underlying energy conversion mechanisms of photosynthetic systems. Here, inspired by nature, a multi‐interfacial engineering strategy for constructing a strongly coupled interactive transmission network for stable and efficient photocatalytic hydrogen production is proposed. A multivariate all‐solid‐state Z‐scheme with intimate electron interactions is formed through strong bridging bonds due to Ti orbit modulation and stacking hybridization between hybrids. The electron couple structure realizes an efficient carrier directional separation and transfer, enabling the charge separation efficiency to be enhanced dramatically by 7.2 times. Furthermore, the resulting material provides a highly stable photocatalytic hydrogen activity, up to 15.29 mmol h−1 g−1, 18.8 times higher than pure carbon nitride, surpassing many reported photocatalysts. This work represents a significant development and helps develop a sound foundation for future design principles in accelerating charge transfer. [ABSTRACT FROM AUTHOR]

Doping graphitic carbon nitride (g-C3N4) with metal ions has been developed as a facile approach to improve its visible light photocatalytic performance towards hydrogen evolution via water splitting. In this work, a series of In3+ doped g-C3N4 (In-g-C3N4) photocatalysts were prepared via in situ thermal copolymerization by using a mixture of dicyanamide and InCl3 as precursors. It was proposed, for the first time, that the In3+ ions were doped into g-C3N4 in a unique quasi-interlayer fashion, which contributed to tunable separation efficiency and migration ability of the photogenerated carriers by simply adjusting the amount of In3+ doping without changing the band edge of g-C3N4. The In-g-C3N4 photocatalyst doped with an optimal amount of indium ions, i.e., 2.18 wt%, exhibited a hydrogen evolution rate of 1.35 mmol h−1 g−1, 17 times that of pristine g-C3N4 (0.08 mmol h−1 g−1), attributed to the synergistically promoted separation and migration of the photogenerated charge carriers. [ABSTRACT FROM AUTHOR]

A facile synthetic route is presented that produces a porous Ga-In bimetallic oxide nanophotocatalyst with atomically thin pore walls. The material has an unprecedented electronic structure arising from its ultrathin walls. The bottom of the conduction band and the top of the valence band of the material are distributed on two opposite surfaces separated with a small electrostatic potential difference. This not only shortens the distance by which the photogenerated charges travel from the sites where they are generated to the sites where they catalyze the reactions, but also facilitates charge separations in the material. The porous structure within the walls results in a large density of exposed surface reactive/catalytic sites. Because of these optimized electronic and surface structures, the material exhibits superior photocatalytic activity toward the hydrogen evolution reaction (HER). [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

By the aid of transient photovoltage, photo-generated carrier transfer mechanism of SnS 2 /g-C 3 N 4 composite has been suggested by interfacial electric field direction. Constructing heterojunction is an effective way to improve the photo-generated carrier separation efficiency and photocatalytic activity. Here, we construct SnS 2 /g-C 3 N 4 heterojunctions by in-situ growth of SnS 2 on the g-C 3 N 4. By adjusting annealing temperatures, the SnS 2 /g-C 3 N 4 -180 and SnS 2 /g-C 3 N 4 -120 samples could meet Z-scheme carrier transfer mechanism and conventional type-II charge transfer mechanism, respectively. By the aid of surface photovoltage spectra, the photo-generated carrier transfer direction and the driving force of the charge transfer are suggested. This difference in these two charge transfer mechanisms is supposed to be mainly related to the discrepancy in work functions of the SnS 2 treated at different temperatures. This work provides an effective method to understand the Z-scheme carrier transfer mechanism, which could help us to design Z-scheme photocatalysts for higher hydrogen evolution activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surfactant-assisted synthesis of ZnS(C)/BiOBr/GO composite photocatalyst has been prepared successfully for the first time. • The highly dispersed photocatalyst further applied for Rh B, TCH and BB degradation under visible light irradiation. • The highest degradation rate constants for Rh B (0.76750 min−1), TCH (0.05754 min−1) and BB (0.12515 min−1) were achieved. • The energy band structure of ZnS and BiOBr leads to the excellent charge separation efficiency of composites. • The application of surfactant can effectively improve the dispersion and degradation performance of photocatalysts. In this paper, the highly dispersed ZnS(C)/BiOBr/ GO ternary composite was prepared by a two-step hydrothermal method with the help of the surfactant cetyltrimethyl ammonium bromide (CTAB). Its structure and morphology were studied by XRD, SEM, TEM, EDX spectra, UV–VIS absorption spectra, Mott-Schottky curve and Brunau-Emmett-Teller (BET) characterization. The results show that the ZnS(C)/BiOBr/GO ternary photocatalyst with excellent degradation effect and stable specific surface area has been successfully prepared. Orthogonal and photocatalytic experiments showed that the prepared photocatalyst had high photocatalytic performance for the degradation of brilliant blue (BB), Rhodamine B (RhB) and tetracycline hydrochloride (TCH). The degradation rate constants for BB, TCH and RhB were 0.12515, 0.06194 and 0.76750 min−1, respectively. Moreover, the photocatalytic performance of ZnS(C)/BiOBr/GO composite is significantly better than that of the original ZnS(C) and BiOBr. It is worth noting that ZnS(C)/BiOBr/GO ternary composite assisted by CTAB has the best photocatalytic activity, mainly for two reasons. First, the presence of surfactant CTAB significantly reduces the agglomeration of ZnS and enhances the dispersion of ZnS. Second, GO can be used as an electron trapping agent between ZnS and BiOBr to promote carrier separation. Therefore, the synthesis of ternary compounds with appropriate additional surfactants can effectively improve the photocatalytic efficiency of the degradation of organic pollutants. This study is expected to expand the application of surfactants in the preparation of semiconductor photocatalysts. [ABSTRACT FROM AUTHOR]

Designing nanoscale photocatalysts to improve photocatalytic efficiency is a popular research topic. However, for wide application and friendly environment, achieving good dispersion and multiple recycling of photocatalysts at the nanoscale remains challenging. Herein, a general bottom-up assembly method is proposed for designing a class of two-dimensional lamellar membranes (2DLMs) for photocatalytic applications. A bismuth oxychloride (BiOCl) nanosheet (BN) was used as a demo photocatalyst to construct a 2DLM via self-stacking. The designed BiOCl membrane (BM) exhibited excellent physical properties including flexibility, mechanical strength (tensile strength = 15.75 MPa, fracture strain = 0.056%), and translucence, as well as superior photocatalytic performance with excellent recycling stability and reusability. The photocatalytic hydrogen evolution performance of BM was 2.5-fold that of BN particles dispersed in an aqueous solution. Further theoretical calculations revealed that a BM with appropriately sized nanochannels can accelerate water transport, and the main horizontal channel size of the BM (3.13 nm) is very close to the size of the ideal water transport nanochannel. Furthermore, the confined internal space reduces the number of hydrogen bonds for water molecules within the nanochannels, thereby enhancing the interfacial reaction rate and photocatalytic efficiency. This study presents a simple bottom-up assembly method to design photocatalysts with further improved performance. [Display omitted] • A general strategy to design lamellar membrane (LM) for photocatalytic is proposed. • The nanochannels speed up water transport and facilitate photocatalytic reaction. • The hydrogen bonds among water molecules inside nanochannels are weakened. • Photocatalytic H 2 evolution activity of BiOCl LM is 2.5-fold that of its particles. [ABSTRACT FROM AUTHOR]

● LaFeO 3 /In 2 S 3 Z-scheme composite has been prepared successfully for the first time. ● The heterostructured photocatalyst is applied for Rh B, TCH and BB degradation. ● The highest degradation rate was achieved by the prepared photocatalyst. ● The band structure of heterostructure leads to the forming of the Z-scheme route. ● The photoexcited charge in LaFeO 3 /In 2 S 3 transfer in an unobstructed Z-scheme route. [Display omitted] Materials of perovskite-type structure have been widely investigated for their prospect in photocatalysis. In this work, a novel composite material of p-type LaFeO 3 microsphere coated with n-type In 2 S 3 nanoparticles was fabricated to settle the water pollution problems through a mild hydrothermal method. The structure and morphology were studied by XRD, SEM, TEM, EDX mapping and UV–visible absorption spectra. The results indicated that the LaFeO 3 /In 2 S 3 heterostructured photocatalyst was prepared successfully, and show an enhanced BET surface area and visible light absorption. The obtained heterostructured photocatalyst was applied to the photocatalytic degradation of rhodamine B (Rh B), tetracycline (TCH) and brilliant blue (BB). Under optimized conditions, the degradation rate of LaFeO 3 /In 2 S 3 photocatalyst was dozens of times that of the pristine LaFeO 3 and pristine In 2 S 3. Notably, the degradation rate constant for Rh B, TCH and BB was 0.16709, 0.02684 and 0.0175 min−1 over as-prepared LaFeO 3 /In 2 S 3 photocatalyst, respectively. The surface photovoltage (SPV), reactive oxidation species scavenger (ROSs) and work function (WF) tests were applied to investigate the photoexcited charge behavior of LaFeO 3 /In 2 S 3 and the possible mechanism of photocatalytic degradation. The results demonstrate that the band bending is formed at the LaFeO 3 /In 2 S 3 heterostructured interface because the WF of LaFeO 3 is higher that of In 2 S 3 , which leads to the transfer of photoexcited electron from conduction band (CB) of LaFeO 3 to valence band (VB) of In 2 S 3 and the excellent photocatalytic degradation activity of water pollutants. And the Z-scheme charge transfer process was suggested at the LaFeO 3 /In 2 S 3 interface based on the energy band structure of LaFeO 3 and In 2 S 3 and ROSs results. Therefore, we believe that our rationally conceived LaFeO 3 /In 2 S 3 heterostructured photocatalyst advances the development of photocatalytic degradation and environmental remediation. [ABSTRACT FROM AUTHOR]

Exploration of unique and useful photocatalysts is of great importance to address the energy and environmental concerns by utilizing solar energy. Graphite carbon nitride (g-C 3 N 4) is regarded as an effective photocatalyst for the photocatalytic hydrogen evolution. However, the hydrogen production rate of bare g-C 3 N 4 is almost negligible due to a quick recombination of photogenerated electrons and holes. Herein, we modified g-C 3 N 4 with PtCo x cocatalyst to accelerate the transfer of photogenerated charges and to further restrain the recombination of photogenerated electrons and holes in bulk. As a result, the superior electrical conductivity of PtCo x promotes the migration of photogenerated charges and further improves the separation efficiency of photogenerated charges for PtCo x /g-C 3 N 4 photocatalyst, meanwhile, the low overpotential of PtCo x accelerates the reaction kinetics. The enhanced photocatalytic activity of 2.5PtCo x results in hydrogen evolution rate of 11.9 mmol h−1 g−1. PtCo x /g-C 3 N 4 photocatalyst was characterized by systematically examining the photogenerated charges behavior through studying surface photovoltage, transient surface photovoltage, surface photocurrent, and photoacoustic technology. Based on the obtained results, a photocatayltic mechanism is proposed and discussed in detail. This work improves the photocatalytic performance of g-C 3 N 4 and contributes to a theoretical knowledge for the fabrication of future cocatalyst/photocatalyst systems. • PtCo x cocatalyst with low overpotential is prepared on g-C 3 N 4 by solvothermal method, providing a fast reaction kinetics. • The highest photocatalytic H 2 evolution rate when using 2.5PtCo x reaches 11.9 mmol h-1 g-1. • The prominent photocatalytic performance is attributed to improved separation efficiency of photogenerated charges. • The photogenerated charges behavior is characterized by SPV, TPV, SPC, and PA. [ABSTRACT FROM AUTHOR]

In this respect, surface photovoltage spectrum (SPV) has been employed to analyze the carrier transfer mechanism of Ti/α-Fe 2 O 3 /g-C 3 N 4 composite photocatalyst system for the first time. That is, photo-generated carrier interfacial transfer direction is suggested to be the charge driving force between Ti/α-Fe 2 O 3 and g-C 3 N 4 , which could determine the Z -scheme carrier transfer mechanism of Ti/α-Fe 2 O 3 /g-C 3 N 4 photocatalysts. This work provides an effective method to understand the Z -scheme carrier transfer mechanism and could help us to design more effective Z -scheme photocatalysts systems. Unlabelled Image • A new method in understanding the Z -scheme carrier transfer mechanism. • Surface photovoltage spectrum is employed to analyze carrier transfer mechanism. • Ti/α-Fe 2 O 3 /g-C 3 N 4 Z-Scheme photocatalyst system is adopted. • Z-scheme transfer system is analyzed from driving force between the interface. [ABSTRACT FROM AUTHOR]