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

The precise regulation of active sites to steer reaction pathway for photocatalytic CO₂ 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 CO₂. 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 CO₂ 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 (*CO₂ 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 CO₂ 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 CO₂ reduction.