Laser-assisted scalable synthesis of metal oxides for efficient hydrogen production through anion exchange membrane water electrolysis

The development of highly active, stable, and low-cost electrocatalysts is crucial for the large-scale production of green hydrogen through water electrolysis. Herein, we developed a scalable pulse laser-assisted synthesis method suitable for industrial use, resulting in high-performance Fe₂O₃-NiO@NF (FeNi@NF) and Pt-NiO@NF (PtNi@NF) materials for electrocatalytic water splitting that even outperform traditional lab-scale materials. Adjusting laser energy and pulse delay to control localized heating enables the ultrafast growth of metal oxide materials on substrates exposed to laser within a precursor-containing liquid with high precision. The optimized PtNi@NF electrocatalyst requires only 20 mV overpotential to initiate HER and needs 105 and 154 mV overpotential to reach current densities of 50 and 100 mA cm^-2, respectively. The optimized FeNi@NF electrocatalyst requires just 170 mV overpotential to initiate OER and achieves potential values of 1.45 V, 1.62 V, and 2.2 V at current densities of 100 mA cm^-2, 500 mA cm^-2, and 2000 mA cm^-2, respectively. The PtNi@NF and FeNi@NF electrocatalysts demonstrate high stability, with no significant changes in potentials over 100 hours for HER and 200 hours for OER. The two-electrode setup, PtNi@NF//FeNi@NF (cathode/anode), which requires overall cell potentials of 1.49 V and 1.60 V to reach current densities of 25 and 100 mA cm^-2, respectively, outperforms the benchmark reported for RuO₂ and Pt@SS electrocatalysts. We also examined the overall water splitting at different temperatures, and the setup shows a decrease in overpotential as the temperature increases. At 70°C, it requires only 1.49 V cell voltage to reach 100 mA cm^-2, which is 110 mV less than the potential needed for water splitting at room temperature, due to improved kinetics and faster diffusion. In a zero-gap anion exchange membrane water electrolyzer (AEMWE) operating at room temperature, our PtNi@NF//FeNi@NF materials deliver 2A at 2.12 V in a 12 cm² full cell, producing 37.21 mmol/h H₂ gas with nearly 100% Faradaic efficiencies, contributing to an economically competitive hydrogen production cost of US$2.35 kgH₂⁻¹. This study highlights that the laser focal spot acts as a precisely targeted chemical reactor, providing unique experimental conditions for producing highly selective and stable nanostructured oxide materials suitable for the production of green hydrogen.

Dr. Farhan Arshad is a Postdoctoral Researcher at Interdisciplinary Research Center for Hydrogen Technologies & Carbon Management (IRC-HTCM), King Fahd University of Petroleum and Minerals (KFUPM), Saudi Arabia. He completed his PhD degree from Lahore University of Management Sciences (LUMS), Lahore, Pakistan. His research focuses on developing self-supported nanostructured electrocatalysts for the production of green hydrogen through water splitting, seawater splitting, and alcohol oxidation-assisted water splitting. He has extensively published his research in leading international journals.