Oxygen Vacancies of Cr-Doped CeO2 Nanorods That Efficiently Enhance the Performance of Electrocatalytic N2 Fixation to NH3 under Ambient Conditions.

Producing ammonia (NH3) by electrocatalytic N2 fixation is a promising and environmentally friendly strategy, in comparison to the Haber-Bosch process with high consumption of energy and CO2 emissions. Because of the extremely high bond energy, it is indispensable to explore valid catalysts to activate the triple bond. In this paper, Cr-doped CeO2 nanorods are developed to serve as non-noble-metal electrocatalysts for an electrocatalytic N2 reduction reaction. Introducing Cr into the catalyst leads to an increase of the oxygen vacancies. In a 0.1 M Na2SO4 solution, the Cr0.1CeO2 nanorods achieve a high Faradaic efficiency (3.84%) and a large NH3 yield (16.82 μg h-1 mgcat.-1) at -0.7 V versus reversible hydrogen electrode. The Cr0.1CeO2 nanorods also exhibit high stability during the reaction.