A self-supporting bifunctional catalyst electrode made of amorphous and porous CoP3 nanoneedle array: exhaling during overall water splitting

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.