Dual-function hydrogen selective catalytic reduction (H2-SCR): enabling NOx reduction to ammonia synthesis

Abstract

This review explores the growing promise of hydrogen-selective catalytic reduction (H₂-SCR) as a dual-function technology for efficient NO_x mitigation and sustainable ammonia (NH₃) synthesis. Beyond its exceptional NO_x conversion efficiency and minimal byproduct formation, H₂-SCR offers a novel route for green NH₃ generation via catalytic pathways that utilize renewable hydrogen. This emerging strategy challenges the conventional energy-intensive Haber-Bosch process by enabling decentralized and low-carbon NH₃ production under in situ reaction conditions. The review presents an in-depth analysis of the fundamental principles of H₂-SCR, recent advancements in catalyst design, key operational factors, and integration with existing emission control systems. Particular focus is given to the mechanistic insights underpinning NH₃ formation during NO_x reduction, emphasizing its role in circular nitrogen management. By aligning environmental remediation with sustainable fertilizer production, H₂-SCR positions itself as a transformative solution in the context of global decarbonization goals and future green ammonia technologies.