Carbon-metal metal-metal synergistic mechanism of ethylene electro-oxidation electrolysis of water on TMN sites in graphene.

Acetaldehyde (AA) and ethylene oxide (EO) are important fine chemicals, and are also substrates with wide applications for high-value chemical products. Direct electrocatalytic oxidation of ethylene to AA and EO can avoid the untoward effects from harmful byproducts and high energy emissions. The most central intermediate state is the co-adsorption and coupling of ethylene and active oxygen intermediates (*O) at the active site(s), which is restricted by two factors: the stability of the *O intermediate generated during the electrolysis of water on the active site at a certain applied potential and pH range; and the lower kinetic energy barriers of the oxidation process based on the thermo-migration barrier from the *O intermediate to produce AA/EO.

Non-metal boron atoms on a CuB monolayer as efficient catalytic sites for urea production.

An electrocatalytic C-N coupling reaction to convert CO and N into urea under mild conditions has been proposed to be a promising alternative experimentally, but the development of highly stable, low-cost and high-performance non-metal catalytic sites remains rare and challenging. Herein, a global-minimum CuB monolayer with superior stability has been identified based on first-principles computations, and the most significant finding is that the CuB monolayer possesses the best catalytic activity among the reported urea catalysts thermodynamically and kinetically. All possible reaction pathways to form urea (NHCONH) starting from the CO molecule and N molecule, including the CO pathway, OCOH pathway, CO pathway, NCON pathway and mixed pathway, as well as the kinetic energy barriers of six possible C-N coupling reactions are systematically investigated.