Precision-Grown Bi₂O₂Se Flakes for Exceptional Electrocatalytic Performance in Acidic Medium

Efficient hydrogen production via electrochemical water splitting is vital for sustainable energy applications, with the HER in acidic media requiring highly effective catalysts. In this study, we report the synthesis of Bi 2 O 2 Se nanosheets through a scalable hydrothermal method, achieving exceptional catalytic performance in acidic conditions. The Bi 2 O 2 Se nanosheets exhibit a low overpotential of 104 mV at 10 mA cm –2, significantly outperforming other bismuth-based HER catalysts. The superior activity is attributed to the unique structural and electronic properties of Bi 2 O 2 Se, which provide abundant active sites and enhance charge transfer efficiency. Electrochemical studies, including Tafel slope analysis and impedance spectroscopy, confirm rapid HER kinetics and reduced charge-transfer resistance. Additionally, the catalysts demonstrate excellent long-term stability under acidic conditions, maintaining their performance during extended electrolysis. This work highlights the potential of Bi 2 O 2 Se as a highly efficient and cost-effective catalyst tailored for acidic HER applications. The dual-electrode system comprising Bi 2 O 2 Se@CP as the cathode and RuO 2 @CP as the anode demonstrated outstanding performance in overall water splitting. This system required a battery voltage of only 1.49 V to achieve a current density of 10 mA cm –2, highlighting the superior electrocatalytic efficiency of Bi 2 O 2 Se in conjunction with RuO 2 . By offering valuable insights into the design and optimization of bismuth-based materials, these findings pave the way for advancing sustainable hydrogen production technologies through scalable and efficient catalytic solutions.