Nanocrystalline Co0.85Se Anchored on Graphene Nanosheets as a Highly Efficient and Stable Electrocatalyst for Hydrogen Evolution Reaction

Bo Yu; Fei Qi; Yuanfu Chen; Xinqiang Wang; Binjie Zheng; Wanli Zhang; Yanrong Li; Lai-Chang Zhang

doi:10.1021/acsami.7b09108

Nanocrystalline Co_0.85Se Anchored on Graphene Nanosheets as a Highly Efficient and Stable Electrocatalyst for Hydrogen Evolution Reaction

ACS Appl Mater Interfaces. 2017 Sep 13;9(36):30703-30710. doi: 10.1021/acsami.7b09108. Epub 2017 Aug 31.

Authors

Bo Yu¹, Fei Qi¹, Yuanfu Chen¹, Xinqiang Wang¹, Binjie Zheng¹, Wanli Zhang¹, Yanrong Li¹, Lai-Chang Zhang²

Affiliations

¹ State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China , Chengdu 610054, People's Republic of China.
² School of Engineering, Edith Cowan University , 270 Joondalup Drive, Joondalup, Perth, Western Australia 6027, Australia.

PMID: 28829113
DOI: 10.1021/acsami.7b09108

Abstract

For the first time, a porous and conductive Co_0.85Se/graphene network (CSGN), constructed by Co_0.85Se nanocrystals being tightly connected with each other and homogeneously anchored on few-layered graphene nanosheets, has been synthesized by a facile one-pot solvothermal method. Compared to unhybridized Co_0.85Se, CSGN exhibits much faster kinetics and better electrocatalytic behavior for hydrogen evolution reaction (HER). The HER mechanism of CSGN is improved to Volmer-Tafel combination, instead of Volmer-Heyrovsky combination, for Co_0.85Se. CSGN has a very low Tafel slope of 34.4 mV/dec, which is much lower than that of unhybridized Co_0.85Se (41.8 mV/dec) and is the lowest ever reported for Co_0.85Se-based electrocatalysts. CSGN delivers a current density of 55 mA/cm² at 250 mV overpotential, much larger than that of Co_0.85Se (33 mA/cm²). Furthermore, CSGN shows superior electrocatalytic stability even after 1500 cycles. The excellent HER performance of CSGN is attributed to the unique porous and conductive network, which can not only guarantee interconnected conductive paths in the whole electrode but also provide abundant catalytic active sites, thereby facilitating charge transportation between the electrocatalyst and electrolyte. This work provides insight into rational design and low-cost synthesis of nonprecious transition-metal chalcogenide-based electrocatalysts with high efficiency and excellent stability for HER.

Keywords: Co0.85Se nanocrystals; electrocatalytic activity; graphene; hydrogen evolution reaction; solvothermal reaction; transition-metal chalcogenide.