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This work demonstrated that 75 fold-enhanced photocatalytic hydrogen production over SrTiO 3 /TiO 2 heterostructures by Au plasmon-enhanced electron-phonon decoupling to generate more amounts of energetic electrons for solar water splitting. Such Au modified SrTiO 3 /TiO 2 heterostructures were synthesized by a facile hydrothermal post-photoreduction method, consequently the hydrogen evolution rate is 467.3 μmol g À 1 h À 1 , which is 187 and 75 folds enhancement compared with TiO 2 and SrTiO 3 /TiO 2 samples, respectively. Based on systematic investigations, it is proposed that the internal electric field (IEF) between the interfaces of SrTiO 3 /TiO 2 and the enhanced nearfield amplitudes of localized surface plasmon (LSP) inhibit the recombination of photogenerated electrons and holes in the bulk and accelerate the interfacial transfer of charge carriers. Simultaneously, electron spin resonance (ESR) showed the change of Ti 3 + species in SrTiO 3 /TiO 2 microspheres, mirroring the energetic electron transfer process from Au NPs to SrTiO 3 / TiO 2 microspheres.

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Photocatalytic nonoxidative coupling of CH4 to C2H4 with a high rate and selectivity is considered challenging and impractical due to complex chemical pathways and unfavorable thermodynamics. This work introduces a strategy of tandem photocatalysis based on Au and Pd nanoparticles codeposited on a Bi2NbO5F photocatalyst, which divides the CH4 to C2H4 reaction into two distinct steps carried out in tandem by multiple activity components, i.e., CH4 coupling to C2H6 on Au and C2H6 dehydrogenation on Pd. As a result, the optimized Au–Pd/Bi2NbO5F shows CH4 coupling to C2H4 with a high yield of 22.6 μmol g–1 h–1 and selectivity of 63% under simulated solar light irradiation. The reaction pathway is investigated by a series of activity experiments and in situ characterizations, demonstrating separate steps on Au and Pd. This work proposes a general strategy for the future design of photocatalysts to drive complex reactions efficiently and selectively based on the concept of a tandem system.

The photocatalytic conversion of methane (CH4) into methanol (CH3OH) has evoked great interest recently. In this minireview, we summarize the recent advances and current status on how to construct efficient semiconductor-based photocatalysts for enhancing the CH4 conversion efficiency and selectivity to CH3OH. This minireview firstly introduces the different radicals induced photocatalytic CH4 conversion mechanisms. Then, different strategies proposed for improving the CH4-to-CH3OH performance are highlighted with some selected typical examples, including engineering surface defects, tuning size and morphology, doping with different ions, designing heterojunctions, decorating with cocatalysts, and assisting with oxidants. Finally, we give a concise perspective on the existing challenges and specifically propose further research opportunities on maximizing the photocatalytic performance for CH4 conversion. It is anticipated that this minireview could bring more fundamental insights into the design of advanced photocatalysts toward CH4 to CH3OH conversion under solar light irradiation.