High-efficient N2O decomposition over dual-phase hydrogen/oxygen-transporting membrane reactors

Abstract

Nitrous oxide (N2O) emissions sourced from agricultural and industrial activities have gained much attention because of their contribution to the global greenhouse effect and ozone layer depletion. Significant efforts have been devoted to developing the cost-effective and highly efficient technologies for N2O removal. The direct N2O decomposition is limited by the thermodynamic equilibrium at high temperatures. Recently, catalytic reduction of N2O with carbon-free hydrogen derived from in situ ammonia decomposition is considered as an ideal approach. Herein, thermal decomposition of N2O is investigated by employing a BaCe0.85Fe0.15O3-δ-BaCe0.15Fe0.85O3-δ (BCF8515-BCF1585) hydrogen-transporting membrane or a Ce0.85Sm0.15O1.925-Sm0.6Sr0.4FeO3-δ (SDC-SSF) oxygen-transporting membrane respectively. It is noted that the membrane catalysis of N2O decomposition by reacting with permeated hydrogen or via in-situ oxygen removal displayed significant advantages over the direct thermal decomposition of N2O under a fixed bed condition. Moreover, the N2O conversion as well as hydrogen/oxygen permeability of such membranes were greatly improved by the introduction of porous Ni–CeO2 or SDC-NCO layers due to the increased catalytic activities and hydrogen/oxygen surface exchange kinetics.