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”).
Multifunctional composite catalysts show significant potential for enhancing the thermal decomposition and combustion of energetic materials. However, their synergistic mechanisms remain unclear. In this work, we prepared a 3D macroporous (3DM) CuO/ZnO catalyst via PMMA template calcination and combined it with Ti 3 C 2 T x MXene through electrostatic assembly, to form a 3DM CuO/ZnO-Ti 3 C 2 T x heterogeneous catalyst with uniform morphology and high conductivity. Results show that 3DM CuO/ZnO-Ti 3 C 2 T x has a good catalytic effect on TKX-50, which can advance the decomposition peak from 246 to 208 ℃, increase the heat release from 730 to 1106 J/g and boost combustion time from 560 to 790 ms, improve the flame temperature from 773 to 1109 ℃. By combining LAMMPS, materials studio software and TG-MS-IR analysis, the catalytic mechanism of 3DM material on the thermal decomposition of TKX-50 was deeply explored. 3DM materials can adsorb hydroxylamine molecule, accelerate the H + transfer process, achieve rapid exchange of H and OH, and realize the rapid and concentrated release of gas, thereby promoting the decomposition process of TKX-50. Consequently, the construction of composite catalysts with synergy can start from the perspective of forming more heterostructures, which provides better theoretical support for future research on composite catalysts.
Three metal-organic frameworks including Ce-BDC, In-BDC and In/Ce-BDC and corresponding derived CuO/ZnO/In 2 O 3 /CeO 2 catalysts were prepared. The catalyst-loaded cordierite honeycomb ceramic supports were applied in a microreactor for hydrogen production via methanol steam reforming. The In/Ce-BDC-derived catalyst exhibited a methanol conversion rate of 100%, a hydrogen yield of 0.336 mol/h and an energy efficiency of 54% at 300 °C and an inlet methanol flow rate of 0.112 mol/h. Moreover, CO with content lower than 1.5% and catalytic stability of 30 h was recorded. The high specific surface area and superior redox property of the In/Ce-BDC-derived catalyst were characterized. The increased contents of oxygen vacancies and surface oxygen, in collaboration with the improved solid solubility of CuO and ZnO, were associated with the charge exchange induced by the strong interaction between In 2 O 3 and CeO 2 , leading to the excellent catalytic performance of the In/Ce-BDC-derived catalyst.