Alleviating Ni electron depletion of Ni phthalocyanine by doping electron-deficient boron in CNTs support for enhanced CO2 electroreduction

Abstract

Dispersed nickel phthalocyanine (NiPc) on carbon nanotubes (CNTs) is the promising electrocatalyst for carbon dioxide reduction (CO2RR), but the strong interfacial electron interaction causes Ni electron depletion, limiting CO2RR performance. Herein, engineering the heteroatom doping in CNTs is proposed to alleviate electron depletion of Ni sites toward effective CO2RR. Boron heteroatoms induce electron-enriched Ni sites in NiPc/B-CNTs compared to phosphorus, nitrogen, and fluorine doped catalysts, resulting in superior CO2RR performance. Impressively, the NiPc/B-CNTs presents high CO Faraday efficiency (FECO) of >98 % from −20 to −80 mA cm−2 and excellent stability up to 37 h with sustained FECO of > 90 % in neutral electrolyte. Theoretical and experimental investigation reveals that implanting B heteroatoms alleviates Ni electron depletion via weakening electron transfer from NiPc to CNTs and thus reduces reaction barrier of *COOH formation, facilitating CO2RR. This study highlights importance of modifying carbon substrate in development of supported molecular catalysts for practical applications.