Manipulated photocatalytic air-concentration CO₂ into CH₃OH by dual hetero-metal atom pair sites

Carbon dioxide (CO₂) reduction encompasses intricate protonation steps, frequently leading to unpredictable products. To achieve target product selectivity, it is essential to strategically manipulate the reaction pathway. Herein, we build Cu-Ag dual hetero-metal atom pair sites for photoreduction of 0.03% CO₂ into methanol (CH₃OH). <i>In situ</i> Fourier transform infrared spectroscopy is employed to probe the formation of the CHO* group, a critical intermediate during the synthesis of CH₃OH, in the CO₂ photoreduction on CuAg/In₂O₃ nanosheets. Nevertheless, this critical intermediate is not detected under similar conditions on In₂O₃ nanosheets. Additionally, theoretical calculations reveal that the energy barrier for the formation of CHO* intermediates (0.31 eV) is lower than that required for the desorption of CO* intermediates to produce carbon monoxide (0.57 eV) on the CuAg/In₂O₃ nanosheet slab. That suggests a pronounced selectivity toward the production of CH₃OH. Consequently, the CuAg/In₂O₃ nanosheets realize photoreduction of 0.03% CO₂ into CH₃OH without any sacrificial agent, achieving a formation rate of 3.67 μmol g^-1 h^-1.