Phytic acid-assisted fabrication of porous leaf-like hollow structured Co2P @ C for efficient hydrogen evolution

Abstract

Transition metal phosphides (TMPs) are considered promising electrocatalysts for the hydrogen evolution reaction (HER). Although wet-chemistry and gas-solid reaction methods are widely used for TMPs synthesis, it remains challenging to synthesize porous hollow structured TMPs via a facile, green and sustainable pathway. We report here an eco-friendly phytic acid (PA)-assisted phosphidation strategy to synthesize a novel porous leaf-like hollow structured Co2P @ C catalyst (Co2P @ C ML). Its synthesis involves precipitation of leaf-like microstructured Co-based zeolitic-imidazolate frameworks (Co-ZIF ML), chemical etching of Co-ZIF ML to form PA cross-linked Co complexes and a final pyrolysis step to get Co2P @ C ML with abundant Co2P nanoparticles loaded on P-doped carbon matrix. The Co2P @ C ML catalyst demonstrates excellent HER catalytic performances with low overpotentials at 10 mA cm−2, small Tafel slopes and high catalytic durability in 0.5 M H2SO4 and 1 M KOH. The presented PA-assisted phosphidation synthetic strategy can be readily extended to the design and synthesis of other well-defined hollow structured TMPs@C materials for various applications.