A one-pot hydrothermal synthesis of 3D nitrogen-doped graphene aerogels-supported NiS_2 nanoparticles as efficient electrocatalysts for the oxygen-reduction reaction

摘要

Nitrogen-doped graphene aerogels-supported NiS_2 nanoparticles (NiS_2/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 NiS_2. The nitrogendoped graphene (NG) hybrids show an interconnected reticulation of NG sheets with uniform deposition of NiS_2 NPs, and the NiS_2 NPs are deposited on the NG layers. In studying the effects of the NG and NiS_2/NG for the ORR, we found that NiS_2/NG shows a more positive onset potential, higher current density, and higher electron transfer number (~4) for the oxygenreduction reaction (ORR) in alkaline media than NG. Furthermore, NiS_2/NG shows better durability and methanol tolerance than the commercial Pt/C catalyst.