Regulated reaction pathway of CO 2 photoreduction into CH 4 by metal atom pair sites

The carbon dioxide (CO 2 ) reduction process involves complex protonation, making the resulting product often unpredictable. To achieve the desired product, it is crucial to manipulate the reaction steps. Herein, we build the metal atom pair sites for selective CO 2 photoreduction into methane. As a prototype, Ni atom pair sites loaded on the MoS 2 nanosheets were synthesized and verified by high‐resolution transmission electron microscopy (HRTEM), X‐ray photoelectron spectroscopy (XPS) and X‐ray absorption near edge structure spectra (XANES). In‐situ Fourier transform infrared spectroscopy (FTIR) monitors the *CHO group, a crucial intermediate in CH 4 production, during CO 2 photoreduction on the Ni‐MoS 2 nanosheets, whereas this monitoring is not observed for the MoS 2 nanosheets. Also, theoretical calculations disclose that over the Ni‐MoS 2 nanosheet slab, the formation energy of *CHO intermediates is determined to be lower (0.585 eV) than the desorption energy of *CO intermediates for CO production (0.64 eV), implying the higher selectivity of CH 4 production. Accordingly, the Ni‐MoS 2 nanosheets demonstrate a methane formation rate of 27.21 μmol·g −1 ·h −1 , coupled with an impressive electron selectivity of 94.2%.