M.-F. Hsieh, A. Swain, Y. Zheng
The University of Texas at Austin,
United States
Keywords: bubble-printing synthesis technique, high-entropy alloys, hydrogen evolution reaction
Summary:
High-entropy alloys (HEAs), composed of five or more elements, offer tremendous potential for the hydrogen evolution reaction (HER) due to their unique compositional flexibility, atomic disorder, and exceptional stability in harsh electrochemical environments. These properties enable tunable catalytic activity, superior corrosion resistance, and extended durability. However, conventional HEA synthesis methods suffer from high energy consumption, lengthy processing times, and challenges in achieving uniform nanoscale element distribution, impeding the rapid discovery and optimization of HEA catalysts. In this study, we present a novel bubble-printing synthesis that overcomes these challenges by enabling the rapid, precise, and scalable fabrication of HEAs with tailored compositions and micropatterns. This technique employs opto-thermally generated microbubbles induced by a continuous-wave laser at the interface of a precursor solution and a gold nanoparticle-deposited electrode. The microbubbles effectively concentrate metal ions through Marangoni convection, surface tension, and gas pressure, while localized reduction at the substrate facilitates the in-situ formation of multi-element HEAs. The as-synthesized CuFeRhPdPt HEA demonstrates exceptional HER performance in acidic media, achieving remarkably low overpotentials of 12 mV at 10 mA/cm2 and 78 mV at 500 mA/cm2, with stable operation over 24 hours at 10 mA/cm2 in 0.5 M H2SO4. Furthermore, this method successfully synthesizes HEAs containing up to seven elements, offering unparalleled control over both composition and micropatterns. The bubble-printing technique represents a cost-effective platform for the rapid screening and scalable fabrication of advanced HER electrocatalysts, paving the way for sustainable energy innovations.