High-performance Ti0.95Co0.05N@NC–based ORR catalysts: organic-nitrogen nitrogenize and their application in rechargeable Zn-air batteries

Abstract

The exploration of cheap, stable, and highly efficient non-precious metal catalyst is conducive to extending the practical applications of zinc-air batteries (ZABs). Herein, a simple, environmental friendly and low-cost method was proposed to fabricate nitrogen-doped carbon–coated TiN nanoparticle composites (TiN@NC). Dicyandiamide was applied as the nitrogen source instead of ammonia reduction, based on which Ti0.95Co0.05N@NC was synthesized. Oxygen reduction reaction (ORR) measurement shows that the onset potential of Ti0.95Co0.05N@NC was 30 mV higher compared to TiN@NC, which is attributed: (i) Cobalt was doped into TiN lattice. (ii) After cobalt doping, the graphitization degree of carbon was increased to facilitate electron transport. (iii) Controlling the reservation of nitrogen to form more N-C active sites in Ti0.95Co0.05N@NC may further promote the performance of ORR. The performance of the ZABs was effectively improved after cobalt doping. It is believed to make it more convenient to prepare binary transition metal nitride nanostructures.