Controllable synthesis of MOFs-derived porous and tubular bimetallic Fe–Ni phosphides for efficient electrocatalytic water splitting

Abstract

To boost electrocatalytic performance, efficient electrocatalysts generally require an appropriate adsorption/desorption intensity for intermediates, and a favorable transportation capability of mass and electrons. For preparing electrocatalysts with excellent performance, the crystallinity, morphology and composition of the materials should be considered. Aiming to split water, here we proposed a MOF-derived route to prepare a series of composition-tunable Fe–Ni bimetallic phosphides as efficient electrocatalysts. By controlling the phosphating temperature, electrocatalysts with tubular or porous nanostructures can be selectively obtained, and crystallinity, morphology and composition of the electrocatalysts can be well tuned. The effects of synergistic modulation of the above parameters for electrocatalytic hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were deeply explored, and overall water splitting was achieved with an overpotential of about 1.63 V@10 mA cm⁻². This work not only provides a facile method to obtain composition- and morphology-tunable phosphide electrocatalysts for water splitting, but also sheds new light on designing efficient electrocatalysts from a systematic viewpoint.