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[Display omitted] This work firstly demonstrates the ethanolamine (ETA)-assisted hydrothermal synthesis of BiVO 4 , with different ratios of exposed {1 1 0}/{0 1 0} planes and relates this to performance in photocatalytic oxidative coupling of benzylamine under visible light. {1 1 0}-dominant BiVO 4 exhibits outstanding photocatalytic activity at room temperature owing to synergistic effects of largely exposed {1 1 0}-oxidative facet along with excellent charge generation and migration abilities, as evidenced by X-ray diffraction patterns, electrochemical impedance spectra, and photocurrent responses. The catalyst can successfully transform benzylamine derivatives to corresponding imines with selectivities of >85%, indicating a wide scope of amine substrates that can be used with the developed catalyst. Based on radical scavenging, spin-trapping EPR, and Mott-Schottky results, a plausible oxidative coupling mechanism via a O 2 –-assisted route and band energy diagram of the catalyst are proposed. This work highlights the influence of ETA in controlling resultant exposed crystal facets of the final BiVO 4 , which is the main factor governing oxidative amine coupling activity. Importantly, the tunability of exposed {1 1 0}/{0 1 0} facet of BiVO 4 controlled by ETA as well as a correlation between {1 1 0} facet and the coupling activity of benzylamine firstly disclosed in this work could be readily extended for designing functional catalysts with desired performances. [ABSTRACT FROM AUTHOR]

[Display omitted] Herein, new Bi 2 MoO 6 /Cs 3 Sb 2 Br 9 heterostructure (BiMo/CSB) was investigated for the first time as a visible-light-driven photocatalyst for C(sp3)–H bond activation using molecular oxygen as a green oxidant and toluene as a model substrate. The optimized BiMo/CSB photocatalyst exhibited enhanced toluene oxidation activity (2,346 μmol g-1h−1), which was almost two- and five-fold that of pristine CSB (1,165 μmol g-1h−1) and BiMo (482 μmol g-1h−1), respectively. The improved photocatalytic performance was essentially attributed to the formation of staggered band energy lineup in the BiMo/CSB hybrid, which promoted S-scheme charge transfer across the BiMo/CSB heterointerface as supported by ultraviolet photoelectron spectroscopy (UPS), density functional theoretical (DFT), time-resolve photoluminescence (TRPL), and photoelectrochemical studies. Spin–trapping electron paramagnetic resonance (EPR) and radical scavenging studies revealed that photoinduced hole, molecular oxygen, and superoxide radical are key active species in this photocatalytic system. The developed BiMo/CSB catalyst provided good selectivity toward benzaldehyde product (94–98 %), presumably due to the inhibiting effect of benzyl alcohol on benzaldehyde oxidation. No significant change in structure and morphology was observed for the spent catalyst, however small negative shift of Sb 3d and Bi 4f binding energy was found suggesting partial reduction of Sb3+ and Bi3+. This work not only provides a new visible-light-driven photocatalyst for C(sp3)–H bond activation but also opens the doors for exploitation of the conversion and functionalization of this inert bond toward the production of high value-added organic chemicals. [ABSTRACT FROM AUTHOR]

The energy band diagram and band offsets of the novel CoTiO 3 /Ag 3 VO 4 heterojunction photocatalyst are investigated by X-ray photoelectron spectroscopy for the first time. Excluding the strain effect, the valence-band and conduction-band offsets are determined to be 0.2 ± 0.3 eV and −0.6 ± 0.3 eV, respectively. The CoTiO 3 /Ag 3 VO 4 composite forms a type-II heterojunction, for which the photogenerated charge carriers could be effectively separated. The results suggest that determination of the energy band structure is crucial for understanding the photogenerated charge transfer mechanism at the interfaces, hence the corresponding photocatalytic activity and would also be beneficial to the design of new and efficient heterostructure-based photocatalysts. [ABSTRACT FROM AUTHOR]

The role of CoTiO 3 and the possible active species in the methylene blue (MB) degradation over the visible-light-driven CoTiO 3 /Ag 3 VO 4 catalyst have firstly been investigated in this work. CoTiO 3 is found to play important roles in enhancing the visible light-harvesting ability of the composite and increasing electron–hole separation efficiency due to the hybrid effect between Ag 3 VO 4 and CoTiO 3 . The indirect probe experiments reveal that CoTiO 3 /Ag 3 VO 4 heterostructure provides large amount of active species, therefore a high photocatalytic activity could be obtained. The results clearly suggest that the photocatalytic MB degradation over this hybrid catalyst is mainly governed by direct hole oxidation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bi 2 MoO 6 shows superior activity in nitrobenzene reduction over Bi 4 MoO 9. • Bi 2 MoO 6 photocatalyst solely produces aniline, azoxy- and azo-benzene in one pot. • Adding KOH or N 2 H 4 ·H 2 O completely switches product selectivity with excellent yield (>98%). • Plausible reactions at solid–liquid interface and band energy diagram are proposed. Poor product selectivity of metal oxide photocatalysts is one of crucial issues limiting their application in photocatalytic organic synthesis particularly when multiple parallel reactions as well as several intermediates and products are involved, as in the reduction of nitrobenzene (NB) in this present study. Accordingly, catalyst modification is often needed. Herein, we first demonstrate that without catalyst modification it is feasible to control product selectivity over a single bismuth molybdate photocatalyst to selectively prepare three different valuable compounds including aniline (AN), azobenzene (AZO) and azoxybenzene (AZX) with high efficacy. Two widely used bismuth molybdate photocatalysts, namely Bi 2 MoO 6 and Bi 4 MoO 9 , were studied and compared. Bi 2 MoO 6 offers better visible-light-driven photocatalytic performance than Bi 4 MoO 9 partly due to its narrow band gap energy and efficient charge carrier separation and transfer as evidenced from UV–vis DRS, EIS, and transient photocurrent studies. The roles of hydrazine hydrate, alcohol solvent, and KOH additive on the transfer hydrogenation of NB were examined and their concentrations were optimized to solely obtain the three different products with excellent selectivity (>98%). Based on UV–vis DRS and Mott-Schottky analysis, the band energy level of Bi 2 MoO 6 and plausible reactions at solid–liquid interface are proposed. The capability to control product selectivity over a single photocatalyst in one pot demonstrated in this work would make the process more practical especially for continuous flow photochemical systems. [ABSTRACT FROM AUTHOR]

• CB heterojunction with enhanced photoactivity in oxidative coupling of benzylamine was prepared. • Improved activity was due to excellent charge transfer and separation derived from a staggered band lineup. • Results reveal O 2 –-assisted mechanism with carbocation as a possible intermediate. • Under anaerobic condition, the reaction proceeds probably via carbon-centered radical. Herein, the photocatalytic activity of g-C 3 N 4 /BiOBr (CB) heterojunction in the oxidative C–N coupling of benzylamine under atmospheric air using cool white LED light was reported for the first time. The CB heterojunction was prepared by two-step combustion-coprecipitation method. By tuning the weight percentage of g-C 3 N 4 , the optimal catalyst containing 10.2 wt% of g-C 3 N 4 provided the highest benzylamine conversion of ca. 94% and the best N -benzylidenebenzylamine yield of ca. 82% within 4 h irradiation. The influences of catalyst amount, substrate concentration, light intensity and reaction temperature on photocatalytic performance were also discussed. The CB catalyst also successfully oxidized N -heterocyclic amines and secondary amines into their corresponding imines which extends the scope and potential use of this catalyst in the syntheses of other C N containing biologically active compounds. The enhanced performance of CB heterojunction was mainly ascribed to improved charge transfer and separation intrinsically derived from the staggered band energy configuration of the CB heterojunction as evidenced from photoelectrochemical, steady-state photoluminescence and time-resolved fluorescence studies. Electron paramagnetic resonance (EPR), Hammett and active species quenching results revealed the O 2 –-assisted mechanism with a possible carbocationic intermediate being generated. Under anaerobic condition, the reaction can also proceed probably through carbon-centered radical. Based on UV–vis, XPS and Mott-Schottky results, band energy level diagram and a plausible reaction mechanism at solid-liquid interface were also revealed. [ABSTRACT FROM AUTHOR]