Doping sp-hybridized B atoms in graphyne supported single cobalt atoms for hydrogen evolution electrocatalysis

摘要

Electrochemical water splitting to hydrogen is considered as a promising approach for clean H-2 production. However, developing highly active and inexpensive electrocatalysts is an important part of the hydrogen evolution reaction (HER). Herein, we present a multifaceted atom (sp(2)-and sp-hybridized boron) doping strategy to directly fine-modify the electronic structures of the active site and the HER performance by the density functional theory calculations. It is found that the binding strength between the Co atom and the B doped graphyne nanosheets can be enhanced by doping B atoms. Meanwhile, the Co@B-1-GY and Co@B-2-GY catalysts exhibit good thermodynamic stability and high HER catalytic activity. Interestingly, the Co@B-2-GY catalyst has an ideal HER performance with the Delta G(H center dot) value of -0.004 eV. Moreover, the d-band center of the Co atoms is upshifted by the sp(2)-or sp-hybridized B dopants. The concentrations of the sp-hybridized B atoms have a positive effect on the electrons transformation of the Co atoms. The interaction between the H and Co atoms becomes strong with the increase of the concentrations of the sp-hybridized B atoms and thus the corresponding catalysts show sluggish HER kinetics. This investigation could provide useful guidance for the experimental groups to directly and continuously control the catalytic activity towards HER by precisely doping multifaceted atoms. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.