Top-down preparation of Ni-Pd-P@graphitic carbon core-shell nanostructure as a non-Pt catalyst for enhanced electrocatalytic reactions

Abstract

Electrochemical reactions such as the oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and methanol oxidation reaction (MOR) are essential for energy conversion applications such as water electrolysis and fuel cells. Furthermore, Pt or Ir-related materials have been extensively utilized as electrocatalysts for the OER, ORR, and MOR. To reduce the utilization of precious metals, innovative catalyst structures should be proposed. Herein, we report a bi-metallic phosphide (Ni2P and PdP2) structure surrounded by graphitic carbon (Ni-Pd-P/C) with an enhanced electrochemical activity as compared to conventional electrocatalysts. Despite the low Pd content of 3 at%, Ni-Pd-P/C exhibits a low overpotential of 330 mV at 10 mA cm(-2) in the OER, high specific activity (2.82 mA cm(-2) at 0.8 V) for the ORR, and a high current density of 1.101 A mg(-1) for the MOR. The superior electrochemical performance of Ni-Pd-P/C may be attributed to the synergistic effect of the bi-metallic phosphide structure and core-shell structure formed by graphitic carbon. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.