A one-pot hydrothermal synthesis of 3D nitrogen-doped graphene aerogels-supported NiS2 nanoparticles as efficient electrocatalysts for the oxygen-reduction reaction

Nitrogen-doped graphene aerogels-supported NiS2 nanoparticles (NiS2/NG) were synthesized by a one-pot hydrothermal method. In the process, L-cysteine was used not only as the nitrogen source to form the nitrogen-doped graphene aerogels, but also the sulfur source to form NiS2. The nitrogen-doped graphene (NG) hybrids show an interconnected reticulation of NG sheets with uniform deposition of NiS2 NPs, and the NiS2 NPs are deposited on the NG layers. In studying the effects of the NG and NiS2/NG for the ORR, we found that NiS2/NG shows a more positive onset potential, higher current density, and higher electron transfer number (similar to 4) for the oxygen-reduction reaction (ORR) in alkaline media than NG. Furthermore, NiS2/NG shows better durability and methanol tolerance than the commercial Pt/C catalyst.