CH(4) Synthesis from CO(2) and H(2)O of an Electron Source over Rh–Ru Cocatalysts Loaded on NaTaO(3):Sr Photocatalysts

[Image: see text] CO(2) reduction as an artificial photosynthetic system is a promising technology to produce green energies and chemicals because it uses light energy to convert H(2)O and CO(2) into valuable products such as CO, HCOOH, CH(3)OH, CH(4), and preferably higher hydrocarbons. In photocatalytic reduction, water should be used as hydrogen and electron sources for CO(2) reduction. Moreover, CH(4) formation is an attractive and challenging topic because of the eight-electron-reducing product of CO(2). Herein, we report the development of a new Rh–Ru cocatalyst decorated on an alkaline earth-doped NaTaO(3) surface for the photocatalytic CO(2) reduction to form CH(4) using water as an electron donor. CH(4) was obtained by a photocatalytic “uphill” reaction of CO(2) reduction using Rh–Ru cocatalyst-loaded NaTaO(3):Sr, water, and CO(2) in an aqueous suspension system. About 10% of a selectivity (electronic efficiency) was obtained for CH(4) formation under ambient conditions accompanied with O(2) evolution of the oxidation product of H(2)O.