Electrocatalytic performance of cubic NiS₂ and hexagonal NiS for oxygen reduction reaction

Developing high performance and low cost non-precious metal based catalysts for oxygen reduction reaction (ORR) is essential for a wide range of industrial applications of fuel cells. Here, we report the catalytic performance of a novel cubic NiS₂ and hexagonal NiS catalysts for ORR. Both the NiS₂ and NiS are synthesized by facile one-pot hydrothermal method and exhibit a high level of purity. Compared to conventional Pt/C catalysts, the NiS₂ catalyst yields a higher peak current intensity and enhanced long time running stability despite the half wave potential is 40 mV lower than that of Pt/C catalyst. Rotating disc electrode tests show that the NiS₂ catalyzes ORR mainly happening through 4-electron pathway. Thus, the NiS catalyzes ORR happening through 2-electron pathway. We envision that the NiS₂ catalyst has great potential to be alternate for the Pt/C catalyst for ORR in alkaline fuel cells.