Self-standing nanoporous NiPd bimetallic electrocatalysts with ultra-low Pd loading for efficient hydrogen evolution reaction

• The NiPd bimetallic electrocatalyst owns the least weight loading of Pd. • The Ni-Pd bond enhances the HER performance and stability. • Overpotential of the NiPd bimetallic electrocatalyst is superior to commercial Pt/C electrode at large current densities. • The results provide a direct molecular design principle to construct costless electrocatalysts for commercial applications. The decrease of noble metal content is an efficient way to achieve commercial electrocatalysts with a low fabrication cost. However, it is difficult to balance between a stable bimetallic structure and an ultra-low loading of noble metals in alloys. In the present work, a highly efficient nanoporous NiPd/metallic glass (np-NiPd/MG) electrocatalyst was synthesized by combining dealloying and galvanic replacement reaction to minimize the Pd utilization rate in alloys. Sandwich-like structures with nanoporous layers on the surface of both sides and inner metal glass matrix were observed, which exhibited a remarkable catalytic activity for hydrogen evolution reaction with a low overpotential. The np-NiPd/MG showed a rather low Pd loading (14 Pd μg cm −2 ). The excellent catalytic properties are endowed by abundant active sites, improved intrinsic activity, and fast species and electrons transport. This work provides a promising strategy to fabricate highly efficient self-standing electrocatalysts for industrial hydrogen production. A nanoporous NiPd bimetallic electrocatalyst with sandwich-like self-standing structures provides a strong bonding between the active Pd sites and the nanoporous Ni substrate by replacing Pd on the surface of Ni-based ligaments. The least weight loading of Pd in alloys was achieved with excellent HER performances. This work paves the way for fabricating economical noble-metallic HER electrocatalysts for industrial application.