Surface oxygen functionalization of recycled carbon fiber felt for enhanced hydrogen evolution reaction

The development of efficient and sustainable hydrogen evolution reaction (HER) electrodes remains a critical challenge in renewable energy technology. This study presents a novel approach utilizing recycled carbon fiber felt (RCF) with controlled surface functionalization to achieve high-performance electrodes for hydrogen production. Through high-concentration HCl treatment, the oxygen functional group was systematically controlled without compromising the structural integrity. This surface modification strategy enabled a uniform distribution of platinum nanoparticles with significantly reduced Pt crystallite size, resulting in enhanced HER catalytic activity. The optimized Pt/RCF-H-20 electrode demonstrated exceptional electrochemical performance, exhibiting an overpotential of only 13 mV at 10 mA cm -2 , which is superior to the 22 mV for non-functionalized Pt/RCF-L-20. Furthermore, the enhanced wettability and uniform bubble formation observed in the functionalized electrodes further confirm the critical role in the hydrogen evolution process. This work establishes a sustainable pathway for developing high-performance HER electrodes while promoting the utilization of recycled carbon materials. • Controlled oxygen functionalization of recycled carbon felt achieved without compromising structural integrity through scalable HCl treatment. • Surface optimization reduced Pt crystallite size from 21.03 to 10.94 nm, enabling uniform nanoparticle dispersion and enhanced active site utilization. • Systematic surface engineering improved HER performance by 41%, reducing overpotential from 22 mV to 13 mV at 10 mA cm -2 . • Functionalized electrodes demonstrated superior operational stability with uniform current density and consistent hydrogen bubble dynamics.