Non‐Metal Sulfur Doping of Indium Hydroxide Nanocube for Selectively Photocatalytic Reduction of CO₂ to CH₄: A “One Stone Three Birds” Strategy

Photocatalytic CO₂ reduction is considered as a promising strategy for CO₂ utilization and producing renewable energy, however, it remains challenge in the improvement of photocatalytic performance for wide‐band‐gap photocatalyst with controllable product selectivity. Herein, the sulfur‐doped In(OH)₃ (In(OH)_xS_y‐z) nanocubes are developed for selective photocatalytic reduction of CO₂ to CH₄ under simulated light irradiation. The CH₄ yield of the optimal In(OH)_xS_y‐1.0 can be enhanced up to 39 times and the CH₄ selectivity can be regulated as high as 80.75% compared to that of pristine In(OH)₃. The substitution of sulfur atoms for hydroxyl groups in In(OH)₃ enhances the visible light absorption capability, and further improves the hydrophilicity behavior, which promotes the H₂O dissociation into protons (H^*) and accelerates the dynamic proton‐feeding CO₂ hydrogenation. In situ DRIFTs and DFT calculation confirm that the non‐metal sulfur sites significantly weaken the over‐potential of the H₂O oxidation and prevent the formation of ·OH radicals, enabling the stabilization of ^*CHO intermediates and thus facilitating CH₄ production. This work highlights the promotion effect of the non‐metal doping engineering on wide‐band‐gap photocatalysts for tailoring the product selectivity in photocatalytic CO₂ reduction.