Electrode Structure and Composition Control in Liquid-Phase Plasma-Assisted Methanol Decomposition for Efficient Hydrogen Generation

Methanol is an attractive liquid hydrogen carrier owing to its high hydrogen density, convenient storage and transport, and its potential for sustainable production from renewable carbon resources. Plasma-assisted methanol decomposition offers a flexible and on-demand pathway for hydrogen generation under near-ambient conditions, avoiding the limitations of conventional thermocatalytic processes. In this work, a liquid-phase plasma discharge system was developed for methanol decomposition, in which plasma-catalyst synergistic effects promote molecular activation, accelerate reactions, and suppress carbon deposition. Systematic evaluation of electrode geometry demonstrates that the needle–needle configuration enhances hydrogen production by 10.3%, achieving a hydrogen flow rate of 685.75 ± 11.96 mL/min compared with a conventional needle–ring design, owing to its more concentrated and spatially distributed discharge. Further performance improvements are obtained using tungsten–nickel (W–Ni) alloy electrodes, which increase the hydrogen flow rate to 754.98 ± 15.04 mL/min, effectively mitigate carbon deposition, and maintain a high energy conversion efficiency of 56.72 ± 0.25%. As a result, the optimized system achieves a specific energy consumption of 1.14 ± 0.03 kWh/Nm3 H2, representing a 10.5% reduction relative to pure tungsten electrodes. These findings underscore the critical roles of plasma-catalyst synergy and electrode material engineering in the development of efficient, durable, and energy-efficient hydrogen production systems from methanol or other liquid fuels.