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

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2022-04, Vol.433, p.134571, Article 134571
• Main Authors: Zheng, Yuexi, Shang, Pengfei, Pei, Feng, Ma, Guang, Ye, Zhiguo, Peng, Xinyuan, Li, Duosheng
• Format: Article
• Language: English
• Subjects: Bicontinuous nanoporous alloy; Electrocatalytic activity; Hydrogen evolution reaction; Long-term stability; Nanoscale Kirkendall effect
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2022.134571

A bicontinuous nanoporous PtNiMg alloy of ultralow noble-metal content achieves an extremely low overpotential and Tafel slope of the hydrogen evolution reaction (HER) at an ultrawide range of HER current densities in an alkaline medium. Comprehensive studies reveal that the 3D bicontinuous nanoporous structure, perfect synergistic effect of Ni and Pt species, high structural stability and excellent conductivity dramatically improves the electrocatalytic activity and long-term stability of the new type of alloy. [Display omitted] •The nanoscale Kirkendall effect achieves a nanoporous alloy of ultralow noble-metal content.•Achieves an extremely low overpotential and Tafel slope of the hydrogen evolution reaction.•The distinctive architecture accomplishes the outstanding performance. 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.