Synthesis and characterization of Fe-N-C aerogel catalysts for oxygen reduction reaction

International audienceFe-N-C catalysts have been regarded as the most promising alternative of non-platinium-group-metal (non-PGM) catalysts towards oxygen reduction reaction(ORR) in PEM fuel cells, due to the low price and significant breakthrough in ORR activity and durability in recent decades [1][2]. Numerous studies have been conducted to make further advances in their performance and gain the insight into their catalytic mechanism to ORR, by using different synthesis methods with various carbon, nitrogen and Iron precursors along with a series of optimization of synthesis conditions (e.g. temperature and nature of gases of heat treatment). Nevertheless, some mass transport issues remain. Herein, we developed a highly effective, 3D Fe-N-C aerogel catalysts with resorcinol (R)-formaldehyde (F)-melamine(M) and Iron precursor using “one pot “sol-gel process followed by supercritical drying and heat-treatment in N2and then ammonia (NH3) atmosphere(Figure 1 left). The optimization of Fe-N-C aerogel catalysts was undertaken by varying the initial sol pH,solid (reactants R+M+F) content in the initial solution and heat-treatment parameters. The physico-chemical properties of catalysts were characterized by XRD, SEM, XPS and N2-adsorption/desorption, and the electro-catalytic performance was studied by using cyclic voltammetry and linear sweep voltammetry (rotating disk electrode method) in 0.05 M H2SO4aqueous solution.The correlation between physicochemical characterizationsand the electrochemical performancesof the Fe-N-C aerogel catalysts were discussed, established and compared to Pajarito catalyst.The optimized catalysts with high specific surface area of 1652 m2/gand high content of pyridineN, exhibits an outstandingORR performancesand a better mass transport property compared to the Pajarito catalyst