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Small. 2018 Oct;14(41):e1802824. doi: 10.1002/smll.201802824. Epub 2018 Sep 14.

Sub-1.5 nm Ultrathin CoP Nanosheet Aerogel: Efficient Electrocatalyst for Hydrogen Evolution Reaction at All pH Values.

Author information

1
Collaborative Innovation Center for Marine Biomass Fibers, Materials and Textiles of Shandong Province, School of Environmental Science and Engineering, Qingdao University, Qingdao, 266071, P. R. China.
2
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Science, Taiyuan, 030001, China.
3
Analytical and Testing Centre, South China University of Technology, Guangzhou, 510640, China.
4
College of Chemical and Environmental Engineering, Shandong University of Science and Technology, Qingdao, 266590, P. R. China.
5
Queensland Micro- and Nanotechnology Centre (QMNC), Griffith University, Nathan, Brisbane, QLD, 4111, Australia.

Abstract

Transition metal phosphides (TMPs) are certified high performance electrocatalysts for the hydrogen evolution reaction (HER). The ultrathin 2D structure of TMPs can offer abundant adsorption sites to boost HER performance. Herein, an ice-templating strategy is developed to prepare CoP aerogels composed of 2D ultrathin CoP nanosheets (<1.5 nm) using sustainable alginate biomass (seaweed extract) as the precursor. The highly porous aerogel structure can not only deliver facile mass transfer, but also prevent aggregation of the nanosheets into layered structures. As expected, the obtained CoP nanosheet aerogels exhibit remarkable stability and excellent electrocatalytic HER performance at all pH values. For instance, the sample CoP-400 presents a low overpotential of 113, 154, and 161 mV versus RHE at a current density of 10 mA cm-2 in 0.5 m H2SO4, 1 m KOH, and 1 m phosphate buffer solution, respectively. In addition, CoP-400 displays low Tafel slopes at all pH values due to the interconnected highly porous structure of the aerogel, indicating that the sample can provide low-resistance channels for mass transport. Density functional theory calculations reveal that P-top and Co bridge on (011) facet of CoP are more favorable sites during the process of HER in acid and alkaline solutions, respectively.

KEYWORDS:

DFT calculations; all pH values; hydrogen evolution reaction; ice‐templating; ultrathin CoP nanosheet aerogel

PMID:
30350551
DOI:
10.1002/smll.201802824

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