Oxidative coupling of methane (OCM) using CO 2 as the oxidant is a potential advancement for methane conversion and greenhouse gases reduction. However, the reaction is usually limited by both high energy consumption and strict reaction condition. Here, we report, for the first time, photoinduced efficient ethylene (C 2 H 4 ) and CO production by OCM over TiO 2 -supported Ag nanoparticles at mild conditions. The success relies on a synergy coupling visible-light-induced strong surface plasma resonance (SPR) effect localized on Ag(0), ultraviolet-light-induced photoelectric effect on TiO 2 , and the separated adsorption of CO 2 and CH 4 on TiO 2 and Ag. The yields of CO and C 2 H 4 reach 1149 and 686 μmol•g −1 •h −1 , respectively, under simulated solar irradiation. The origination of carbon-based gas products from CO 2 and CH 4 is also certified by a 13 C isotope-labeled experiment. This work presents a new and ideal route of photocatalytic OCM reaction for C 2 H 4 and CO production by coupling both SPR and photoelectric effects.

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A novel heterojunction of a MoS2/SrZrO3 photocatalyst was successfully synthesized via a simple hydrothermal process and applied to photocatalytic H2 evolution under UV light irradiation.

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A series of Ce-doped TiO 2 nanoparticles were prepared by a sol−gel process and characterized by XRD, SEM, TEM, EDX mapping, UV−vis DRS, Raman spectroscopy, N 2 adsorption−desorption, PL spectra, CO 2 -TPD, and XPS. It is found that Ce ions can enter the lattice matrix of TiO 2 and occupy of Ti sites. This atom replacement leads to the formation of impurity energy levels in the band gap of TiO 2 , extending light absorption into the visible light region. Because Ce has a more flexible valence state, both Ce 3+ and Ce 4+ could be formed in the composites. The preference facilitates the photoinduced charge separation inside of the crystals. Moreover, Pd nanoparticles were then loaded as a co-catalyst on the surface of doped composites. As the trapping center of electrons, it can efficiently adsorb and activate CO 2 molecules, promoting their transformation into CH 4 . These composites were then evaluated as photocatalysts for CO 2 hydrogenation. While all of them could efficiently catalyze the reaction, 1.0% Pd/ 0.5% Ce-TiO 2 catalysts show the best photocatalytic performance, with CH 4 and CO yields up to 220.61 and 27.36 μmol/g, respectively, under visible light irradiation of 3 h. The improved photocatalytic behavior could be possibly induced by the synergistic effect between Ce and Pd. A probable mechanism was thus proposed based on above characterizations and experimental results.