Synergistic adsorption and activation of nickel phthalocyanine anchored onto ketjenblack for CO2 electrochemical reduction

Highlights: • NiPc/KB was synthesized by a rapid and facile one-step in-situ π-π stacking method. • TOF for converting CO₂ to CO is enhanced by greater than 251 times. • Faradaic efficiency for CO reaches to 98.2%. • DFT calculations reveal the synergistic catalytic processes of NiPc/KB in ECR. Designing a facile and high-yield strategy to prepare highly active and selective electrocatalysts for CO₂ reduction is beneficial to the industrial application. However, there are still many challenges in catalyst preparation. Besides, further mechanism studies on catalytic process for enhancing CO₂ reduction are not clear. Herein, We have found that nickel phthalocyanine facilely incorporated into defect-rich ketjenblack by π-π stacking method can greatly improve its ECR performance. Nickel phthalocyanine/ketjenblack compounds show high selectivity and activity, 251 times turnover frequency for converting CO₂ to CO compared to pristine nickel phthalocyanine, and keep above FE_CO of 90% under large potentials regions from −0.65 to −1.05 V vs RHE. Fundamentally density functional theory (DFT) calculations reveal that nickel phthalocyanine molecules anchored onto ketjenblack enhance the electron acceptability, decrease the formation energy of the *COOH and inhibit the rival hydrogen evolution reaction (HER), thus showing extremely high synergistic catalytic properties in ECR.