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

Graphical abstract Highlights • Novel hybrid nanoporous electrodes were fabricated for efficient hydrogen evolution. • Hydrogen evolution activity was improved though dual-step surface engineering strategy. • Overpotential of 29 mV and Tafel slope of 42 mV per decade were achieved. • DFT theoretical simulations identified the hydrogen evolution mechanism. 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 (TiO 2) 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 TiO 2 layer for enhancing the HER activity. The advanced features of nanoporous architecture in combination with the synergistic contribution from ultrathin TiO 2 layer and well-dispersed Pt nanoparticles enable CoNPA@TiO 2 @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. [ABSTRACT FROM AUTHOR]