Inert Heteroatom Substitution to Modulate Dual‐Metal‐Sites for Boosting Photoreduction of Diluted CO2

Abstract The precise regulation of active sites to steer reaction pathway for photocatalytic CO 2 reduction is critical, but remains challenges. Herein, an inert heteroatom substitution strategy is developed to activate adjacent dual‐active‐sites for boosting photocatalytic reduction of diluted CO 2 . As a proof of concept, Co 2+ δ /Ni 2+ ζ dual‐active‐sites in layered double hydroxides (LDHs) photocatalyst with high activity is interspaced and regulated by inert Al substitution. The corresponding elementary reaction step is optimized, where the Ni 2+ ζ site shows high activation of CO 2 reduction and weak absorption of *CO, whilst the Co 2+ δ site facilitates water oxidation. Most importantly, the produced *H on the Co 2+ δ site is synchronized with the formation of *COOH on the Ni 2+ ζ site, which synergistically lowers the energy barrier (*CO 2 to *COOH) of the rate‐determining step. Resulting CoNiAl‐LDHs photocatalyst attains nearly 100% selectivity with a production rate of 784 µmol g −1 h −1 toward diluted CO 2 reduction to CO, representing the best performance reported to date. This work delivers a feasible strategy via inert site substitution to activate proximate dual sites, which provides fundamental guidance to design photocatalysts for CO 2 reduction.