(A) CO₂ photoreduction into fuels such as CH₄ and CO through the use of dual-metal-site catalytic systems (“H⁺ + e⁻” refers to the proton-coupled electron transfer process and “−H₂O” means the desorption of H₂O molecules after the intermediates react with the proton-electron pair). (B) 3D colormap surface with the projection of in situ Fourier transformed infrared spectroscopy (FTIR) spectra for coadsorption of a mixture of CO₂ and H₂O vapor on the mildly oxidized SnS₂ atomic layers. (C) CO TPD spectra for the SnS₂ atomic layers, the poorly oxidized and the mildly oxidized SnS₂ atomic layers. (A) Adapted with permission from Ref. [71], copyright 2019 Springer Nature; (B and C) adapted with permission from Ref. [73], copyright 2017 American Chemical Society.