Modification of Black Phosphorus Nanosheets with a Ni-Containing Carbon Layer as Efficient and Stable Hydrogen Production Electrocatalysts.

Few-layered black phosphorus (FP) has recently attracted extensive research in the energy and materials fields. However, because of its chemically unstable nature under ambient conditions, very positive hydrogen adsorption energy and less active sites, FP has not been an efficient catalyst for the hydrogen evolution reaction (HER). In this research, we have developed a new strategy to overcome FP's drawbacks and to make it an active and stable HER catalyst. Our approach is to deposit a Ni2+-anchored thin carbon layer onto the surface of FP via controlled decarboxylation of Ni ethylenediaminetetraacetate (Ni-EDTA). The carbon layer on the surface of FP prevents it from making direct contact with its external environment, thereby greatly improving its stability. At the same time, transition-metal Ni that is dispersed in its carbon layer changes its hydrogen adsorption energy so as to improve its electrocatalytic activity. The prepared FP@Ni-C shows an outstanding HER performance with an overpotential of only 284 mV to obtain 10 mA cm-2 current density with excellent electrocatalytic stability. The FP@Ni-C catalyst showed almost no activity loss during a 12 h catalyst life test. This study provides a new approach to the synthesis of highly efficient and stable electrocatalysts based on two-dimensional materials, using a facile catalyst preparation method.