Designing efficient catalysts and understanding the underlying mechanisms for anodic nucleophile electrooxidation are central to the advancement of electrochemically-driven technologies. Here, a heterostructure of nickel boride/nickel catalyst is developed to enable methanol electrooxidation into formate with a Faradaic efficiency of nearly 100%. Operando electrochemical impedance spectroscopy and in situ Raman spectroscopy are applied to understand the influence of methanol concentration in the methanol oxidation reaction. High concentrations of methanol inhibit the phase transition of the electrocatalyst to high-valent electro-oxidation products, and electrophilic oxygen species (O* or OH*) formed on the electrocatalyst are considered to be the catalytically active species. Additional mechanistic investigation with density functional theory calculations reveals that the potential-determining step, the formation of *CH2O, occurs most favorably on the nickel boride/nickel heterostructure rather than on nickel boride and nickel. These results are highly instructive for the study of other nucleophile-based approaches to electrooxidation reactions and organic electrosynthesis.

No abstract

No abstract

Urea electrooxidation reaction (UOR) plays an important role in environmental protection and energy regeneration. The extensively studied nickel-based catalysts exhibit good activity for UOR, but urea is more prone to be overelectrooxidized to another pollutant NO x – (x = 2, 3). Herein, the Cu/Ni-B interface catalyst is presented. The introduction of Cu significantly enhances the Faradaic efficiency of N2 (nearly 70% at 1.70 V versus RHE). Electrochemical tests and in situ Raman spectroscopy results show that the introduction of Cu significantly affects the density of OH* species on the catalyst in the UOR process. It is proposed that with a moderate decrease in OH* density, the catalyst can provide enough sites for urea molecules to allow simultaneous adsorption of the two N atoms, facilitating the process of N-N coupling to form N2. This work is also instructive for the design of electrocatalysts for other nucleophile electrooxidation reactions.

No abstract