Ultrathin B₄C nanosheets prepared by gradual oxygen etching for hydrogen evolution reaction

Ultrathin B 4 C nanosheets are fabricated via a facile gradual oxygen etching method, which show a typical 2D structure with a high surface-to-thickness ratio. Electrochemical measurements demonstrate that ultrathin B 4 C nanosheets exhibit significantly improved electrocatalytic performance for hydrogen evolution reaction compared to bulk B 4 C with a lower Tafel slope of 108 mV dec −1 and enhanced kinetics. Thus, gradual oxygen etching as a promising strategy provides a new way to obtain novel 2D materials.