(84p) Engineering Bio-MOF-1 Derived Single-Atom Catalyst with a Hierarchical Porous Nanostructure for Highly Selective CO2 Electroreduction

The increasing concentration of CO₂ in the atmosphere from consumption of large amounts of fossil fuels has caused severe environmental issues and driven the growth of sustainable and clean energy technologies. Electrochemical conversion of CO₂ into valuable fuels and chemicals under ambient conditions has been considered as a promising approach to alleviate excessive CO₂ emissions and to achieve carbon neutrality. In this regard, a promising CO₂ reduction reaction (CO₂RR) electrocatalyst is expected to exhibit high efficiency and selectivity to convert CO₂ into a desired product. Single-atom catalysts (SACs) have been recently explored as outstanding electrocatalysts for CO₂RR because of their preferred benefits, including maximum atom efficiency, unique electronic structure, and unfavorable hydrogen binding. Especially, metal-organic frameworks (MOFs) have been generally used as ideal precursors for preparing SACs, due to their simple preparation, high porosity, structural diversity, and high conductivity. Up to now, several types of MOFs, such as MOF-5, MOF-74, ZIF-8 have been utilized in the field of electrochemical CO₂RR application.

Herein, we employed bio-MOF-1 as attractive precursor for synthesizing SACs. Bio-MOF-1 is composed of Zn and adenine interconnected with biphenyldicarboxylate (BPDC) linkers. With this precursor, we finally designed and synthesized a series of nanosized bio-MOF-1 derived metal-nitrogen carbon catalysts (n-M-BMF-N-C, M = Ni, Fe, Co, Mn, Cu). These five M-N-C catalysts were then experimentally characterized and compared. Notably, electrochemical tests showed that n-Ni-BMF-N-C displayed remarkable CO Faradaic efficiency (FE) of 99 % at -1.0 V, and particularly CO FE was maintained over 90 % in a wide applied potential window, making it one of the most selective M-N-C catalysts reported. The CO₂RR selectivity trend of the n-M-BMF-N-C catalysts can be listed as following order of Cu < Mn < Co < Fe < Ni. The experimental observations have been correlated with density functional theory (DFT) simulations.