CO2-emission-free electrocatalytic CH3OH selective upgrading with high productivity at large current densities for energy saved hydrogen co-generation

Electro-oxidative organic upgrading is recently considered as a promising strategy for energy saved H2 co-generation but still challenging for high productivity of value-added chemicals at large current density. Herein, the synthesized defects-rich Ni3S2-CNFs nanoheterostructures exhibit robust electrocatalytic performance for selectively catalyzing methanol to value-added formate with high productivity and without CO2 emission, in which the large current density (> 700 mA cm−2) is achieved with high faradaic efficiency (> 90%). By replacing the sluggish OER, the methanol upgrading reaction can greatly boost H2 co-generation from water with reduced energy consumption. DFT calculations indicate the in situ formed Ni–OOH and SOx species with synergistic effect can effectively modulate the d band center of Ni3S2 in Ni3S2-CNFs nanoheterostructures, acting as unique collaborative active sites for the thermodynamically favorable conversion from methanol to formate and suppressing the further oxidation to CO2, resulting in the high activity and selectivity of CO2-emission-free methanol upgrading reaction.