Engineering d-orbital of copper single-atom sites toward industrial-level electrocatalytic methanation

Copper (Cu)-based single-atom catalysts (SACs) enable electrocatalytic CO₂ reduction into methane (CH₄) fuel for thermal power plant decarbonization, yet conventional Cu SACs face industrial deployment barriers like instability and sluggish kinetics caused by d - p orbital coupling. Herein, we develop a Cu-Ti₁O₃ catalyst with localized Cu single-atom sites by oxygen vacancy (O_v)-involved orbital engineering, achieving industrial-level CH₄ production. Theoretical and in-situ studies reveal the intensification of the d - d coupling at Cu sites triggered by [Cu-O_v - Ti] motifs, which enhances d-π* polar interactions upon *CO₂ and accelerates C - O bond cleavage in *OCH₃ intermediate. As a result, Cu-Ti₁O₃ achieves a competitive performance, i.e., the highest Faradaic efficiency of 76% and a peak partial current density of 670 mA cm^-2 toward CH₄ (corresponding turnover frequency = 24,930 h^-1), ~3.5-fold promotion over conventional Cu SACs. Furthermore, it demonstrates high durability (>1,230 hours) at an industrial-level current density, exceeding the longevity of conventional Cu SACs by over 20 times. Our findings highlight the prospect of d-orbital engineering in enabling industrial-level electrocatalytic methanation, offering promising implications for decarbonizing traditional power plants.