Insights to the N2O decomposition in environmental catalysis: evaluation and advanced outlook

Abstract

Nitrous oxide (N2O) is a potent greenhouse gas and a significant contributor to stratospheric ozone depletion. Its emission arises from a combination of natural and anthropogenic sources, including microbial processes like nitrification, denitrification, nitrifier denitrification and abiotic chemical pathways such as chemodenitrification and hydroxylamine oxidation. Effective decomposition of N2O into harmless nitrogen and oxygen is therefore critical for climate mitigation. This review provides a comprehensive overview of the current state of N2O decomposition, with a focus on mechanisms, catalyst composition and material design strategies. Catalysts are categorized based on their decomposition mechanisms–direct catalytic decomposition (DCD), selective catalytic reduction (SCR) and surface-catalysed redox pathways – as well as their compositions including precious and non-precious metal-based catalysts. Further, a progress-based classification is presented, encompassing classical metal oxides, spinel oxides, layered double hydroxides, MXenes, and metal organic frameworks (MOFs). Emerging systems such as antenna-reactor catalysts and quantum dots are also discussed for their unique properties and potential. Mechanistic insights into N2O activation, including thermal, surface-catalysed, Mars-van Krevelen-type redox, radical and photocatalytic pathways are explored in depth. This review highlights the significance of catalysts design, oxygen vacancy engineering and atomically dispersed active sites in enhancing activity and selectivity. Future perspectives emphasized the development of low-cost, thermally stable and environmentally benign catalysts, along with mechanistic understanding through in-situ studies and computational modelling. This review aims to guide the rational design of next-generation catalysts for efficient N2O abatement across industrial and environmental systems.