Porous Amorphous-Crystalline Heterostructured CoNiP Nanowire Arrays for Enhanced Hydrogen Evolution Performance under Acid-Base Conditions

A novel porous amorphous-crystalline heterostructured CoNiP nanowire arrays ((a-c)CoNiP/CC) is presented. TEM observations and compositional calculations revealed ≈14.5% of the amorphous regions (a-CoNiP) are interleaved in the crystalline regions (c-(Co 3.6 Ni 0.4 )P 4 ), forming massive amorphous-crystalline heterogenous interfaces composed of the same elements. Only 38 and 64 mV overpotentials for the (a-c)CoNiP/CC catalyst are required to reach the current density of −10 mA cm 2 in acid and alkaline electrolyte, respectively, which is very close to the overpotentials (35 and 55 mV) of the commercial Pt/C HER catalyst. The theoretical calculation revealed that the (a-c)CoNiP/CC has a completely different enhancement mechanism of HER reaction in acid-base electrolytes. In particular, due to the natural corrosion resistance of the amorphous interface, the HER performance of this catalyst under the high current density condition is much better than that of the Pt/C catalyst either in acidic or in alkaline, suggesting its prospect for commercial applications.