Enhanced hydrogen evolution via nano-patterned Pt-based metallic glass and dynamic copper oxide foam formation

• Nano-patterned Pt-based bulk metallic glass (Pt-BMG) outperformed the flat and micro-patterned ones in hydrogen evolution. • Nano-patterned Pt-BMG demonstrates outstanding long-term stability and self-improving behavior in the stability test. • Surface characterizations confirmed a Cu x O foam formation on top of the nano-patterned surface during the stability test. • A three-step process is proposed to explain the Cu x O formation via dynamic hydrogen bubble templating electrodeposition. • The synergy of metallic glasses, thermoplastic patterning, and dynamic bubble templating provides an approach to synthesizing metal or metal-oxide foams. Hydrogen is a promising energy carrier for replacing fossil fuels, and hydrogen production via hydrogen evolution reaction (HER) is an environmentally friendly option if electrocatalysts with low overpotentials and long-term stability are used. In this work, the electrocatalytic performance of Pt 57.5 Cu 14.7 Ni 5.3 P 22.5 bulk metallic glass (BMG) with flat, micro-patterned, and nano-patterned surfaces for HER in 0.5 M H 2 SO 4 is studied. The nano-patterned Pt-BMG demonstrates outstanding long-term stability and self-improving behavior with a final overpotential of 150 mV and a Tafel slope of 42 mV dec −1 after 1000 linear sweep voltammetry (LSV) cycles, which is respectively 42 % and 37 % lower than in the first LSV cycle. X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) indicate the formation of a layer of CuO/Cu 2 O foam deposited on top of the nano-patterned surface during the stability test of 1000 LSV cycles. A three-step process is proposed to explain the formation of Cu x O foam via dynamic hydrogen bubble templating (DHBT) electrodeposition from Cu dissolution of the Pt-BMG without using copper salt. This work provides a method to create Cu x O foams that could be used for various applications. Moreover, nano-patterned BMGs with DHBT deposition offer a feasible strategy to synthesize metal or metal-oxide foams.