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Photocatalytic hydroxy group transformation to carbonyl is an important application in organic chemistry. It seems challenging to acquire great selectivity toward carbonyl products in green water solution, especially for the wide-bandgap semiconductors which always need to seek assistance from organic media like acetonitrile. Herein, we cast off the dependence on such organic solvents and develop an efficient NixSy modification on ZnS nanorods, for selective oxidation of benzyl alcohols coupled with H2 evolution in anaerobic water. The ternary augmentation in H2 production, alcohol conversion, and, more strikingly, benzaldehyde selectivity (from 8.1% to 90.5%) was simultaneously achieved by loading NixSy cocatalysts. Mechanism investigations indicated a striking transformation from hole-predominant oxidation on ZnS surface to an electron-initiating dehydrogenation of alcohols on NixSy nanoparticles. Besides, NixSy nanoparticles tend to swiftly desorb the produced benzaldehyde, thereby resulting in promote...

Photocatalysis arises as a green, sustainable approach to conventional industrial catalysis for the synthesis of valuable organic chemicals from biomass. However, photoinduced holes and/or reactive oxygen species are usually fatal to the selective redox process, and are responsible for inducing undesirable side reactions especially in the presence of water. Herein, we demonstrate a cascade strategy of photocatalytic oxidation/hydrogenation that could manage the efficient conversion (99%) of 5-hydroxymethylfurfural (HMF) to 2,5-bis(hydroxymethyl)furan (BHMF) with high selectivity (∼99%). The first reaction is conducted under UV irradiation, with the amorphous TiO2 surface storing the photoinduced electrons, and the protons extracted from alcohol via photooxidation. On subsequently switching to the dark, the stored H+/e− pairs undergo proton-coupled electron transfer (PCET) and contribute to the selective hydrogenation of HMF. This route effectively mitigates the negative impact of H2O and active species on the product selectivity. The oriented adsorption for the aldehyde group of HMF as well as the promoted product desorption bring about the high selectivity of BHMF over amorphous TiO2. The cascade catalytic pathway based on the stored H+/e− provides a reliable approach for biomass functionalization.

The cascading of methane valorization and methanol upgrade, both of which are important in C1 chemistry, becomes a promising strategy to fabricate value-added chemicals from methane directly. Reconciling the contradiction between the C‒H bond activation of methane and the over-oxidation susceptibility of methanol is critical but challenging. Herein, we report the piezocatalytic methane conversion over hydroxyapatite (HAp) under ultrasonic vibration at ambient conditions, obtaining alcohols as liquid products without any sign of CO or CO2. Mechanistic studies reveal that the piezocatalytic effect of HAp drives H2O and methane activation and supplies hydroxyl radical (·OH) to attack the methane C‒H bond, while the ultrasonic-induced negative surface charge (SC) promotes methanol dehydration into methyl carbene as a fascinating C1 building block to facilitate product upgrade into C2 and C3 alcohols. Attributing to the enriched SC which tunes the surface acid-base property, piezocatalysis presents a new approach for C‒C coupling.

Back reaction is an important factor hindering the efficiency of photocatalytic reaction in suspension system. Pt is an excellent cocatalyst that is widely used in photocatalytic CO2 reduction, however, its effects on the forward and back reactions have not been clearly clarified. Here, Pt modified hexagonal tungsten oxide (h-WO3) is prepared and the role of Pt is investigated based on the performance of CO2 reduction and its back reactions behavior. Appropriate amount of Pt modification proves not only to improve charge separation and transfer efficiency, but also to enhance CO2 adsorption and activation ability. Therefore, Pt modified h-WO3 promotes forward reactions of photocatalytic CO2 reduction to CO and CH4. Furthermore, the back reactions of CO* and CH4 oxidation to CO2 are confirmed and accelerated with excess Pt modified on h-WO3, which limit the further improvement of CO2 reduction performance. The enhanced CO adsorption strength and electronic localization with excess Pt modification may contribute to the accelerated back reactions.