Construction of Atomically Dispersed Ni on Tensile‐Strained TiO ₂ for Enhanced Photocatalytic Reduction of CO ₂ to HCOOH

Abstract Solar‐driven photocatalytic CO ₂ reduction offers a promising pathway for sustainable fuel production; however, its efficiency is hindered by rapid carrier recombination and slow surface reaction kinetics. In this study, tensile‐strained Ni/TiO ₂ catalysts are synthesized via the in situ topological transformation of bimetallic metal–organic frameworks (MOFs). By modulating the ethylene glycol/water solvent ratios (a 3:1 volume ratio achieving 3% lattice expansion), precise control over strain levels is achieved. Advanced characterization confirms the incorporation of atomically dispersed penta‐coordinate Ni species into TiO ₂ lattices. The induced strain not only facilitates the efficient separation and migration of photogenerated carriers but also enhances CO ₂ adsorption capacity, resulting in a significant HCOOH yield of 140.0 µmol g ⁻¹ h ⁻¹ for Ni/TiO ₂ ‐EG45, which is ≈5 times higher than that of low‐strain counterparts. Furthermore, introducing H ₂ O ₂ promotes proton‐coupled electron transfer, thereby further enhancing both the yield (242.7 µmol g ⁻¹ h ⁻¹ ) and selectivity (≈100%) of HCOOH production. This strain engineering approach provides novel insights into microenvironment regulation for designing highly efficient photocatalytic systems.