N, P-doped NiCo2S4 nanospheres with excellent hydrophilicity for efficient oxygen evolution reaction

The rational design of a robust hydrophilic electrocatalyst is essential for enhancing its oxygen evolution reaction(OER). In this work, a nanosphere catalyst (NiCo2S4) composed of 2D-nanosheets was prepared. Interestingly, The hierarchically porous hydrangea-like N,P-NiCo2S4 structure was formed through the doping of nonmetal elements N and P. With the introduction of N and P, the electronic structure of Ni and Co can be optimized and the charge transfer resistance of NiCo2S4 can be reduced, thus improving the kinetics of OER. More importantly, N and P doping increased the hydrophilicity of NiCo2S4, which may have accelerated the surface reconstruction of NiCo2S4, resulting in the generation of truly active sites. Overall, this work not only optimised the electronic structure of NiCo2S4, but also improved its hydrophilicity through the synergistic interaction between the nonmetal elements N and P, which provided ideas for the development of advanced non-noble metal electrocatalysts.