 The study reveals that the exposed 1-1-1 plane of CU in SNS4 octahedral nanocrystals is an effective adsorption and activation center for selectively photocatalytic CO2 reduction to methane with non-metal sulfur atoms serving as active sites. The carbon atom of CO2 adsorbed on the electron-pore sulfur atom of CU in SNS4 promotes the conversion of CO2 to CH4 by stabilizing intermediates. Modifying the nanocrystals with co-catalysts can further enhance the separation of photo-generated charge carriers and improve both activity and selectivity for CH4 products. This article was authored by Yao Chai, Yu Huokong, Minit Lin, and others.