MOF-derived cobalt-nickel phosphide nanoboxes as electrocatalysts for the hydrogen evolution reaction.

The development of high-efficiency nonprecious electrocatalysts based on inexpensive and Earth abundant elements is of great significance for renewable energy technologies. Group VIII transition metal phosphides (TMPs) gradually stand out due to their intriguing properties including low resistance and superior catalytic activity and stability. Herein, we adopt a unique MOF-derived strategy to synthesize transition metal phosphide nanoboxes which can be employed as electrocatalysts for the hydrogen evolution reaction. During this process, we converted a Co-MOF to a CoNi-MOF by ion exchange and low-temperature phosphating to achieve CoNiP nanoboxes. The CoNiP nanoboxes can reach a current density of 10 mA cm-2 at a low overpotential of 138 mV with a small Tafel slope of 65 mV dec-1.