Researchers at Austria's Montanuniversitat Leoben and TU Wien have developed copper-doped perovskite-type oxide catalysts that improve the efficiency and durability of methanol steam reforming (MSR), a process used to generate hydrogen on demand for fuel cells. The catalysts require significantly less active copper than conventional industrial catalysts while operating at comparatively low temperatures with high hydrogen yield.
Methanol is gaining attention as a hydrogen carrier because it can be stored and transported as a liquid, is chemically stable at ambient pressure, and can be produced from renewable sources such as biomass or captured CO2 combined with green hydrogen. Steam reforming releases the hydrogen bound in methanol, offering a route to decentralized, on-demand hydrogen production without extensive infrastructure - useful for portable fuel cells and small-scale refueling stations. Conventional Cu/ZnO/Al2O3 catalysts used for MSR, however, suffer from thermal instability, sintering and side reactions that reduce selectivity and durability over time.
To address these limitations, the team turned to perovskite-type oxides as a catalyst support, exploiting their ability to host copper on the B-site of the perovskite lattice and release it as anchored metallic nanoparticles through exsolution under reducing conditions. The researchers synthesized two families of calcium-doped ferrite perovskites - Nd0.6Ca0.4Fe1-xCuxO3 and Pr0.6Ca0.4Fe1-xCuxO3 - with copper loadings of 0, 3 and 10 mol% on the B-site, to study how A-site element choice (neodymium vs. praseodymium) and copper content affect catalytic activity, selectivity and long-term stability.
The neodymium-based catalyst with 10% copper doping (NCF-Cu10) delivered the highest selectivity toward hydrogen and CO2, while the equivalent praseodymium-based catalyst (PCF-Cu10) showed the lowest onset temperature for the reaction. Both 10%-copper catalysts exhibited a sudden jump in activity at a specific temperature, which the team linked - via in-situ synchrotron X-ray diffraction at DESY's PETRA III facility in Germany and in-house near-ambient-pressure X-ray photoelectron spectroscopy - to the reduction of oxidized Cu2O nanoparticles back to their catalytically active metallic state.
In 65-hour long-term testing, the two catalysts behaved very differently. NCF-Cu10 lost activity quickly in the first hours of operation but then partially recovered, retaining 21% of its initial activity by the end of the test at both 300°C and 350°C, a behavior the researchers attribute to dynamic restructuring and re-nucleation of copper nanoparticles on the catalyst surface. PCF-Cu10, in contrast, degraded continuously, retaining just 9% of its initial activity at 350°C and 30% at 300°C, as its copper nanoparticles grew steadily larger and changed shape over time. The team concluded that lower operating temperatures around 300°C help preserve catalytic performance over time.
"With perovskite-based catalysts, we are creating the foundations for compact, demand-based hydrogen generation - efficient, stable and with lesser use of materials," said Christoph Rameshan, professor at the Chair of Physical Chemistry at Montanuniversitat Leoben. Tobias Berger, a PhD student in Rameshan's group and lead author of the study, added: "Our results show that methanol can develop into a real enabler for decentralized hydrogen applications as a manageable energy source with modern catalysis."
The researchers position the work as a foundation for future development of dynamic, self-regenerating catalytic systems for methanol steam reforming, including benchmark testing and optimization of reaction conditions for practical fuel cell applications.
