Optimizing hydrogen evolution activity of nanoporous electrodes by dual-step surface engineering

Abstract

The hydrogen evolution reaction (HER) from electrocatalytic water splitting represents an important approach for efficient hydrogen production, in which the HER feasibility relies on electrocatalysts as well as the art of electrode design. Herein, a considerate surface engineering strategy is developed for promoting HER process taking place on nanoporous HER electrodes. Cobalt nanopore arrays (CoNPA) are fabricated as the representative nanoporous HER electrode. Then an ultrathin titanium dioxide (TiO2) with optimized thickness is conformally coated onto CoNPA for improving the wettability in order to expose more active sites, followed by a well-dispersed platinum (Pt) nanoparticles with an ultralow mass loading (ca. 54 μg cm−2) anchored on TiO2 layer for enhancing the HER activity. The advanced features of nanoporous architecture in combination with the synergistic contribution from ultrathin TiO2 layer and well-dispersed Pt nanoparticles enable CoNPA@TiO2@Pt electrode exhibit outstanding HER performance in alkaline conditions, i.e., an overpotential of 29 mV needed to reach the catalytic current density of 10 mA cm−2 and long-termed performance as well as structure stability. Not limited to the HER electrodes, the similar strategy is also expected to be further applied to the rational design and nanoengineering of electrodes for other electrochemical energy conversion and storage devices.