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

Abstract

Electro-oxidative organic upgrading is recently considered as a promising strategy for energy saved H 2 co-generation but still challenging for high productivity of value-added chemicals at large current density. Herein, the synthesized defects-rich Ni 3 S 2 -CNFs nanoheterostructures exhibit robust electrocatalytic performance for selectively catalyzing methanol to value-added formate with high productivity and without CO 2 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 H 2 co-generation from water with reduced energy consumption. DFT calculations indicate the in situ formed Ni–OOH and SO x species with synergistic effect can effectively modulate the d band center of Ni 3 S 2 in Ni 3 S 2 -CNFs nanoheterostructures, acting as unique collaborative active sites for the thermodynamically favorable conversion from methanol to formate and suppressing the further oxidation to CO 2 , resulting in the high activity and selectivity of CO 2 -emission-free methanol upgrading reaction. The novel defects-rich Ni 3 S 2 -CNFs nanoheterostructures achieve the electrocatalytic CH 3 OH selective upgrading at large current densities (> 700 mA cm −2 ) without CO 2 emission, producing value-added chemical (formate) with high productivity and simultaneously boosting the cathodic H 2 generation with reduced energy consumption. • Novel defects-rich Ni 3 S 2 -CNFs nanoheterostructures are synthesized as highly active and selective electrocatalysts. • The electro-oxidative methanol selective upgrading is achieved at large current density (> 700 mA cm −2 ) without CO 2 emission. • The co-generation of value-added chemical and H 2 is achieved with high productivity and less energy consumption. • Ni–OOH and SO x species with synergistic effect act as novel collaborative active sites for methanol selective upgrading.