In the pursuit of sustainable hydrogen production, the fabrication of efficient and durable electrocatalysts for water electrolysis is essential [1]. This study aims to advance the development of bifunctional electrocatalysts for efficient water electrolysis, targeting sustainable hydrogen production. Bifunctional electrocatalysts that can drive both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are crucial for efficient and stable operation, especially when the system is powered by intermittent renewable energy sources like wind or solar. A bifunctional catalyst helps maintain the integrity of the electrodes, reducing the impact of reverse currents that occur when the electrolyser is turned on and off. This is significant because reverse currents can lead to electrode degradation, as evidenced by the reduction of the anode surface or oxidation of the cathode surface in alkaline water electrolysers, ultimately lowering the device's durability and efficiency[2].
Water electrolysis is fundamental to producing green hydrogen, a clean fuel that aligns with global sustainability goals [3]. However, the efficiency of this process is constrained by the sluggish kinetics of HER and OER, necessitating the use of high-performance electrocatalysts. Precious metals like platinum (Pt) are known for their superior HER activity but are limited by high cost, scarcity, and reduced performance in alkaline media [4]. To address these issues, we investigated an alternative approach involving Pt nanoparticles embedded iron (III) oxide nanosheets on a nickel foam (NF) with the help of plasma treatment. The plasma etching process played a crucial role in modifying the catalyst's surface, leading to improved nanoparticle adhesion and a higher density of active sites [4]. The defects created during plasma treatment acted as favourable sites for the immobilization of Pt nanoparticles, effectively reducing agglomeration and increasing catalyst dispersion. The fabricated electrode showed a 155% increase in OER current density, reaching 380 mA cm⁻² compared to 180 mA cm⁻² for the pristine NF electrode. It also achieved a HER current density of 200 mA cm⁻², whereas the pristine NF showed less activity at the same potential. This bifunctional activity of the electrode remained stable for up to 140h. The increased current density observed after plasma treatment indicates an enhancement in catalytic efficiency due to the tailored defect sites and optimized binding energy between the catalyst and reactants. This approach offers a pathway to more efficient and sustainable hydrogen production, addressing critical challenges in the field of renewable energy.
References
[1] S. O. Jeje, T. Marazani, J. O. Obiko, and M. B. Shongwe, “Advancing the hydrogen production economy: A comprehensive review of technologies, sustainability, and future prospects,” Int. J. Hydrogen Energy, vol. 78, pp. 642–661, Aug. 2024.
[2] Y. Uchino et al., “Dependence of the reverse current on the surface of electrode placed on a bipolar plate in an alkaline water electrolyzer,” Electrochemistry (Tokyo), vol. 86, no. 3, pp. 138–144, May 2018.
[3] K. Henderson and M. Loreau, “A model of Sustainable Development Goals: Challenges and opportunities in promoting human well-being and environmental sustainability,” Ecol. Modell., vol. 475, no. 110164, p. 110164, Jan. 2023.
[4] M. Perera, M. Barclay, K. (Ken) Ostrikov, J. MacLeod, and A. P. O’Mullane, “Plasma‐electrified synthesis of atom‐efficient electrocatalysts for sustainable water catalysis and beyond,” ChemCatChem, Oct. 2024.