Converting surface-oxidized cobalt phosphides into Co(PO)-CoP heterostructures for efficient electrocatalytic hydrogen evolution.

Author(s) Mo, Q.; He, L.; Zeng, J.; Gao, Q.
Journal Nanotechnology
Date Published 2019 Sep 27
Abstract

Exploring noble-metal-free electrocatalysts for the hydrogen evolution reaction (HER) is a key issue in a hydrogen economy blueprint. As one of the promising candidates, transition metal phosphides unfortunately suffer from inevitable surface oxidation which obstructs active-site exposure. Herein, a facile reduction followed by a surface phosphorization is introduced to convert surface-oxidized cobalt phosphides to a Co(PO)-CoP heterostructure embedded in N-doped carbon (Co(PO)-CoP/NC), accomplishing an efficient HER in both acidic and alkaline electrolytes. It affords low overpotentials (η ) of 88 and 97 mV to reach a current density of -10 mA cm, and small Tafel slopes of 51 and 61 mV dec in 0.5 M HSO and 1.0 M KOH, respectively, outperforming the parent surface-oxidized CoP and most previously-reported Pt-free electrocatalysts. The remarkably improved electrocatalysis should be ascribed to the strong surface acidity of the Co(PO) component and thereby the promoted HER kinetics on Co(PO)-CoP interfaces. This work will encourage the development of cost-efficient electrocatalysts via surface engineering.

DOI 10.1088/1361-6528/ab2993
ISSN 1361-6528
Citation Mo Q, He L, Zeng J, Gao Q. Converting surface-oxidized cobalt phosphides into Co(PO)-CoP heterostructures for efficient electrocatalytic hydrogen evolution. Nanotechnology. 2019;30(39):394001.

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