Due to the high dissociation energy cost of water, it is still challenging to generate H* through the hydrogen evolution reaction (HER) in alkaline media. Traditionally, Pt-based nanomaterials are superior HER catalysts, but their high cost and low abundance severely impedes their large-scale application. Thus, designing cost-effective and highly efficient HER electrocatalysts becomes the pivotal task for future research. Although transition metal sulfides (TMS) with high electrical transport and ideal atomic arrangement have been considered as promising noble-metal-free electrocatalysts for HER, their usually show better catalytic performance in acid media. Recently, we report a novel modulation strategy by introducing transition metals in NiS2 nanosheets (NSs) to flexibly optimize the electronic configurations and atomic arrangement. The Co-NiS2 NSs exhibit excellent HER performance with an overpotential of 80 mV at j = 10 mA cm-2 and long-term stability of 90 h in alkaline media. The TOFs of 0.55 and 4.1 s-1 at an overpotential of 100 and 200 mV also confirm their remarkable performance. DFT calculations reveal that the surface dopants abnormally sensitize surface Ni-3d bands in the long-range order towards higher electron-transfer activity, acting as the electron-depletion center. Meanwhile, the high lying surface S-sites possess substantially high selectivity for splitting the adsorbing H2O that guarantee the high HER performance within alkaline conditions. This work opens opportunities for enhancing water splitting by atomic arrangement assisted electronic modulation via a facile doping strategy.

Synthesis of transition metal sulfide nanocrystals and their electrocatalytic properties

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.