A Low-Cost Metal-Free Graphite Felt Electrode for Coal-Assisted Water Electrolysis for Hydrogen Production

Abstract

Cheap, active and stable electrodes are vital for coal-assisted water electrolysis for hydrogen production (CAWE). Conventional CAWE uses relatively costly metal-based anodes such as Pt, SnO2/Ti, and IrO2-RuO2/Ti. Previous work confirms that metal-free carbon anodes, however, demonstrate excellent performance in biomass-assisted water electrolysis. Inspired by this, this work examines the feasibility and effectiveness of low-cost graphite felt (GF) anodes in CAWE. The results show that GF is a promising candidate for CAWE. Compared to Pt, SnO2/Ti, Pt/Ti, IrO2-RuO2/Ti, and IrO2-Ta2O5/Ti, GF has higher reactivity for the CAWE. The current density is higher than 5 mA cm−2 when the cell voltage is 1 V for coal electrolysis at Pt∥GF. When the current density is 1 mA cm−2, 5 mA cm−2, 10 mA cm−2, and 50 mA cm−2, the cell voltage of water electrolysis at Pt∥IrO2-RuO2/Ti is 1.84 times, 1.64 times, 1.50 times and 1.13 times that of coal electrolysis at Pt∥GF, respectively. Compared with precious metal-based electrodes, GF electrodes used for CAWE can greatly reduce the cost. Therefore, this study provides important guidance for the industrial development of CAWE.