Effective Magnetic Field Regulation of the Radical Pair Spin States in Electrocatalytic CO2 Reduction.

Regulation of the radical pair spin states allows effective optimization of the electrocatalytic CO2 reduction reaction. This study for the first time reports an experimental observation of significantly boosting the catalytic activity of tin nanoparticle catalysts by an external magnetic field for electrocatalytic CO2 reduction to formate/formic acid. We reveal that enhancing the amount of singlet radical pairs via magnetic field-facilitated triplet → singlet spin evolution can significantly increase the catalytic activity toward an efficient overall electrochemical CO2 reduction reaction. When a common Sn nanoparticle electrode was used as an example, in a constant applied magnetic field (about 0.9 T), the yield of formic acid can be nearly doubled compared to that of zero magnetic field. This finding suggests the merits of radical pair spin states in the electron-transfer process and paves the way toward high formate production in electrocatalytic reduction of CO2.