Efficient Non-PGM Electrocatalysts for Hydrazine Electrooxidation in Alkaline Media

Abstract

Hydrazine electrooxidation (HzOR) is considered one of the hydrogen production methodologies. For enhancing HzOR activity and reducing the use of PGM metals, we synthesized core-shell structured catalysts, varying by different transition metal species and pyrolysis temperature. As a result, Ni@NC-600, Fe@NC-600 and Co@NC-500, 600, 700, 800 and 900 are synthesized and tested for HzOR. Co@NC shows quite low onset potential, each trend of initial activity and durability is related to the graphitization of carbon shell and the ratio between hexgonal close packed (HCP) Co and face centered cubic (FCC) Co. The initial activity depends on the number of active sites, that is more blocked with the presence of highly graphitized carbon shell. However, Co@NC-900 didn’t show the best durability because too much graphitized carbon which block lots of active sites. In conclusion, Co@NC-800 is the most optimized catalyst for HzOR. Co@NC-800 shows Ponset at the potential of -0.134 V, which is much lower than Ponset of 40% Pt/C. However, the activity of 40% Pt/C is more higher than Co@NC-800 over the potential of 0.1 V, which could be attributed to the difference of the surface area of two catalysts.