A self-supporting bifunctional catalyst electrode made of amorphous and porous CoP3 nanoneedle array: exhaling during overall water splitting. (10th October 2021)

• Record Type: Journal Article
• Authors: Zhang, Junyu; Liu, Yan; Zhang, Jiupeng; Zhang, Yu; Yuan, Shisheng; Wang, Deguo; Lian, Jianshe; Jiang, Qing; Wang, Guoyong
• Is Part Of: Electrochimica acta. Volume 393(2021)
• Publication Date: 2021-10-10
• Subjects: Gibbs free energy -- Water-splitting catalyst -- Metal phosphides -- Nano-porous structure -- Laplace pressure gradient; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2021.138986
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: A synthetic strategy to prepare amorphous cobalt phosphide with uniform texture. A regulation mechanism based on molecular structure to fabricate nanoscale holes on amorphous structures. The effects of amorphization and nano-hole defects for electronic environment and active sites of the catalyst are compared and analyzed. A structural mechanism for spontaneously gas exhausting during water-splitting process. Large current density (1 A cm −2 ) and long-term working stability. Abstract: The current bottleneck that clean energy cannot be fully utilized is that grid-level energy storage technology is still expensive. To become the energy storage link for clean energy usage, it is necessary to find electrodes with low cost and high energy conversion efficiency for hydrogen production by water splitting. In this article, we provide a strategy to make an electrode with the excellent catalyst of amorphous and porous CoP3, which is shaped into hollow needles. The porous structure fully exposes the active sites, amorphization modulates the electronic environment and accelerates the gas desorption process. The geometric gradient of the electrode's needle shape leads to Laplace force acting on the catalytic process: gas attached on the surface can be driven to coalesce and detach due to the conversion of excess surface energy into kinetic energy. The general consideration about dehydrogenation overpotential and degassing overpotential makes our final electrodes as both anode and cathode of overall water-splitting device exhibit an excellent catalytic performance with a partial current density over 1 A cm −2, even better than the asymmetrical precious metals benchmark Pt/C || RuO2 pair. Graphical abstract: Image, graphical abstract We provided a strategy to prepare the efficient CoP3 catalysts with amorphization and porous structure, the water-splitting of which is better than that of Pt/C || RuO2 . When H2 bubbles are generated on the surface, they move directionally to the tip and spontaneously detach because of the Laplace force.