Joule heating of CuO-ZnO/Ni foam catalyst for high H2 production and energy-saving of methanol decomposition: From the performance to mechanism

• Joule heating rates of metal skeleton catalysts above 10°C/s. • Joule heating method improves methanol conversion by over 80 % at 300 °C. • Energy consumption of Joule heating at 300 °C is 29 % of that by external heating. • Joule heating promotes the migration of oxygen and redox of Cu/Zn species. Methanol, as a H 2 storage carrier, is a good option to tackle with the challenges of H 2 storage and transportation. To improve hydrogen production and reduce energy consumption, a new approach of electrified methanol decomposition (MD) by Joule heating was investigated in this work. The conductive metal skeleton catalysts were prepared using nickel foam (NF) as a catalyst support and employing a hydrothermal-impregnation method to load the Cu/Zn active components. The catalyst heats up rapidly upon energizing, and the heating rates reaches over 10 °C/s. The Joule heating method significantly promotes the methanol conversions of CuO-ZnO/NF, CuO/NF, and ZnO/NF. Methanol conversion over CuO-ZnO/NF at 300 °C under Joule heating is over 80 % higher than that of conventional external heating, while its energy consumption is only 29 % of that under external heating. As a result, methanol conversion per unit power in Joule heating condition increases by 5.6 times compared with that in external heating. The in/ex-situ characterizations reveal that the Joule heating of metal skeleton catalyst promotes the lattice oxygen release of NF skeleton and redox of Cu/Zn species, which generates an extra electrochemical effect on the reaction. This study of Joule heating provides a new strategy of converting methanol to H 2 in a more efficient, energy-saving, and flexible way, and has important application potential in hydrogen energy and chemical energy storage (“Power-to-X”).