Achieving an efficient hydrogen evolution reaction with a bicontinuous nanoporous PtNiMg alloy of ultralow Noble-metal content at an ultrawide range of current densities

Abstract

Electrochemical water splitting powered by green electricity generated from intermittent geothermal, wind and solar power is a promising approach to realize large-scale hydrogen production owing to its sustainable and clean characteristics. Developing electrocatalysts with high electrocatalytic activity and long-term stability for the hydrogen evolution reaction (HER) at an ultrahigh current density (>1000 mA cm−2) still needs a breakthrough. Here, a bicontinuous nanoporous PtNiMg alloy with an ultralow noble metal content for the HER is fabricated by a facile high-temperature sintering method based on the nanoscale Kirkendall effect. A bicontinuous nanoporous alloy electrode with an ultralow content of approximately 1 at % Pt for the HER in an alkaline medium achieves an extremely low overpotential of 22 mV at a current density of 10 mA cm−2 and a Tafel slope (30.9 mV dec-1) of the Volmer-Tafel mechanism. The alloy electrode for the HER at a wide current density of 1–2000 mA cm−2 displays superior stability in alkaline media. The 3D bicontinuous nanoporous structure, perfect synergistic effect of Ni and Pt species, high structural stability and excellent conductivity of the 1-PtNiMg-900 alloy achieve outstanding electrocatalytic activity and long-term stability at an ultrawide range of HER current densities. This study greatly improves the electrochemical performance of Pt-based electrocatalysts for the HER via a novel fabrication approach and provides the possibility of large-scale industrial application for H2 production.