Synthesizing nickel single atom catalyst via SiO₂ protection strategy for efficient CO₂ electroreduction to CO in a...

At present, electrochemical CO₂ reduction has been developed towards industrial current density, but the high faradaic efficiency at wide potential range or large current density is still an arduous task. Therefore, in this work, the highly exposed Ni single atoms (NiNCR-0.72) was synthesized through simple metal organic frameworks (MOFs)-derived method with SiO₂ protection strategy. The obtained catalyst keeps CO faradaic efficiency (FE_CO) above 91 % under the wide potential range, and achieves a high FE_CO of 96.0 % and large CO partial current density of -206.8 mA cm^-2 at -0.7 V in flow cell. The experimental results and theoretical calculation disclose that NiNCR-0.72 possesses the robust structure with rich mesopore and more highly exposed Ni-N active sites under SiO₂ protection, which could facilitate CO₂ transportation, lower energy barrier of CO₂ reduction, and raise difficulty of hydrogen evolution reaction. The protection strategy is instructive to the synthesis of other MOFs-derived metal single atoms.