Issue 15, 2019

Hierarchical Ni2P/Cr2CTx (MXene) composites with oxidized surface groups as efficient bifunctional electrocatalysts for overall water splitting

Abstract

Electrocatalysis has the potential to become a more sustainable approach to generate hydrogen as a clean energy source. Developing effective electrocatalysts for water splitting is central to the area of renewable energy. Herein, we performed density functional calculations to predict the electrocatalytic performance of a Ni2P surface and Ni2P/Cr2CO2 (MXene) interface as bifunctional electrocatalysts and clarified the mechanisms of the improvement of the electrocatalytic activity of the Ni2P/Cr2CO2 interface. The optimal overpotential of the Ni2P surface for the oxygen evolution reaction is 0.95 V, and the ideal overpotential of the Ni2P/Cr2CO2 interface for the oxygen evolution reaction is 0.80 V. The Gibbs free energy for the adsorption of atomic hydrogen (ΔGH*) on the Ni2P/Cr2CO2 interface can reach −0.09 eV at a suitable hydrogen coverage. The HER processes of both Cr2CO2 and the Ni2P/Cr2CO2 interface follow the Volmer–Heyrovsky mechanism with the activation energy barriers (Ea) of 0.76 eV and 0.68 eV, respectively. The Ni2P/Cr2CO2 interface promotes charge transfer from the Ni atom to O atom, which weakens the interaction between Ni and intermediates and therefore improves the catalytic effect of Ni2P for either the HER or OER. The present results indicate that the hierarchical Ni2P/Cr2CTx composite could be an effective medium for achieving a promising bifunctional electrocatalysis for water splitting.

Graphical abstract: Hierarchical Ni2P/Cr2CTx (MXene) composites with oxidized surface groups as efficient bifunctional electrocatalysts for overall water splitting

Supplementary files

Article information

Article type
Paper
Submitted
01 Jan 2019
Accepted
15 Mar 2019
First published
20 Mar 2019

J. Mater. Chem. A, 2019,7, 9324-9334

Hierarchical Ni2P/Cr2CTx (MXene) composites with oxidized surface groups as efficient bifunctional electrocatalysts for overall water splitting

Y. Cheng, Y. Zhang, Y. Li, J. Dai and Y. Song, J. Mater. Chem. A, 2019, 7, 9324 DOI: 10.1039/C9TA00008A

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