Emerging electrocatalytic conversion of NOx species into value-added nitrogenous chemicals

Abstract

Excessive nitrogen oxide (NO_x) species such as NO, NO₂, NO₃⁻ and NO₂⁻ are anthropogenically emitted from various human activities such as fossil fuel combustion, vehicle exhaust, agricultural over-fertilization and industrial wastewater, which drastically disrupt the balance of the nitrogen cycle as well as pose great threat to the natural environment and human health. Renewable energy-driven electrocatalytic co-reduction of NO_x and abundant carbon sources has emerged as a very promising and sustainable strategy for the production of value-added chemicals via a decarbonized and energy-efficient route, simultaneously mitigating NO_x pollution. In this review, we systematically summarize the recent advances in the conversion of NO_x species into value-added nitrogenous chemicals, covering various aspects including critical adsorbed intermediates, underlying reaction pathways and multidimensional structure–activity relationships in the NO_x reduction reaction and C–N coupling reaction. Furthermore, the viable upstream-electrolysis-downstream cascade systematic integration with economic assessment is highly emphasized. Finally, a series of remaining challenges are highlighted, and insightful perspectives are proposed for the future development of this exciting direction. It is expected that this critical review will offer valuable guidance and tremendous impetus for the sustainable, economical, large-scale electrified production of diverse value-added nitrogenous chemicals from NO_x species.