Discovery and characterization of transition metal phosphides as electrocatalysts and photocatalysts for the hydrogen evolution reaction

Abstract

Platinum is a highly active and acid stable electrocatalyst for the hydrogen evolution reaction (HER). Nonetheless, its high cost and scarcity limits its utility in clean energy systems on a large scale. Nanostructured transition metal phosphides have recently emerged as Earth-abundant alternatives for the catalytic prodn. of mol. hydrogen from acidic aq. solns. Phosphides of nickel, cobalt, iron, molybdenum, and tungsten have been evaluated for the HER and found to require low overpotentials to produce H2 at operationally relevant current densities for photoelectrochem. cells, while at the same time exhibiting high stability under strongly acidic conditions. Furthermore, the microwire geometry allows the fabrication of photocathodes entirely comprised of Earth-abundant materials that exhibit performance comparable to that of devices that contain Pt.