Spatially-separated redox sites enabling selective atmospheric CO_(2)photoreduction to CH_(4)

CO_(2)photoreduction to high-valued CH_(4)is highly attractive,whereas the CH_(4)selectivity and activity,especially under atmospheric CO_(2),is still unsatisfying.Here,we design spatially-separated redox sites on two-dimensional heterostructured nanosheets with loaded metal oxides,thus achieving high reactivity and selectivity of photocatalytic atmospheric CO_(2)reduction to CH_(4).Taking the synthetic In_(2)O_(3)/In_(2)S_(3)nanosheets with loaded PdO quantum dots as a prototype,quasi in-situ X-ray photoelectron spectra reveal the Pd sites accumulate photogenerated holes for dissociating H_(2)O and the In sites accept photoexcited electrons to activate CO_(2).Moreover,the Pd-OD bond is confirmed by in-situ Fourier-transform infrared spectra during the D2O labeling experiment,indicating the PdO quantum dots participate in H_(2)O oxidation to supply hydrogen species for CO_(2)methanation.As a result,in a simulated air atmosphere,the PdO-In_(2)O_(3)/In_(2)S_(3)nanosheets enable favorable atmospheric CO_(2)-to CH_(4)photoreduction with nearly 100%selectivity and ultralong stability of 240 h as well as CO_(2)conversion of 48.2%.This study opens an approach towards designing photocatalysts with spatially-separated redox sites to achieve efficient oxidation and reduction of CO_(2)photocatalysis to CH_(4).