Interface-Engineering-Induced C-C Coupling for C2H4 Photosynthesis from Atmospheric-Concentration CO2 Reduction.

Producing ethylene (C2H4) from carbon dioxide (CO2) photoreduction under mild conditions is primarily restricted by the difficulty of C-C coupling. Herein, we designed highly active metal atom clusters anchored on semiconductor nanosheets, which established heteroatom sites on the interface to steer C-C coupling, realizing air-concentration CO2 photoreduction into C2H4 in pure water. As an example, the Pd nanoclusters loaded on ZnO nanosheets are prepared, demonstrated by the X-ray photoelectron spectroscopy and high-angle annular dark-field image. In situ Fourier transform infrared spectroscopy confirms the C-C coupling step over the Pd-ZnO nanosheets, while quasi in situ X-ray photoelectron spectroscopy illustrates the active sites of Pd and Zn atoms on the Pd-ZnO nanosheets during CO2 photoreduction. Density functional theoretical calculations unveil the transition state energy barrier of C-C coupling of CO* and COH* intermediates are only 0.998 eV, hinting the easy C-C coupling to produce C2 fuels. Therefore, the Pd-ZnO nanosheets realize C2H4 photosynthesis by atmospheric-concentration CO2 reduction with the formation rate of 1.03 μmol g-1 h-1, while the ZnO nanosheets only acquired the carbon monoxide product.