Affiliation:
1. Beijing National Laboratory for Molecular Sciences (BNLMS) College of Chemistry and Molecular Engineering Peking University Beijing 100871 P. R. China
2. Chemistry and Chemical Engineering Guangdong Laboratory Shantou 515031 P. R. China
3. School of Chemistry Sun Yat-sen University Guangzhou 510275 P. R. China
4. Department of Chemistry City University of Hong Kong Kowloon 999077 Hong Kong P. R. China
Abstract
AbstractThe conversion of CO2 into fuels or commodity chemicals by electrochemical or photochemical reduction is a promising strategy to relieve the ongoing energy crisis and increasing environmental pollution. Inspired by naturally occurring bimetalloenzymes, we have designed hetero–bimetallic CO2 reduction catalysts (FeM) that involve linking an iron tetraphenylporphyrin (FeP) with a tripyridylamine (TPA) moiety, which provides a distal chelating site for Cu2+ or Zn2+. We found that the introduction of Cu2+ or Zn2+ to FeP greatly enhances its efficiency as a catalyst for the electrochemical reduction of CO2. To gain insights into the observed synergistic effect, we performed mechanistic studies together with density functional theory (DFT) calculations. Our results show that Cu2+ or Zn2+ activates CO2 towards reduction due to its Lewis acidity; it also functions as an oxo acceptor from CO2. FeM also functions as an efficient catalyst for the visible‐light‐driven reduction of CO2 using either [Ru(bpy)3] Cl2 or fac‐Ir(ppy)3 (where bpy=2,2’‐bipyridine, ppy=2‐phenylpyridine) as photosensitizer and 1,3‐dimethyl‐2‐phenyl‐2,3‐dihydro‐1H‐benzo[d] imidazole (BIH) as sacrificial reductant. Again, the catalytic efficiency is enhanced by the presence of Cu2+ or Zn2+. Our results provide a general strategy for the design of a series of hetero‐bimetallic catalysts for the reduction of CO2.