Methanol-water co-electrolysis for sustainable hydrogen production with PtRu/C-SnO2 electro-catalyst

Hydrogen at present is mainly produced from fossil fuels for use in ammonia synthesis, the petrochemical industry, and chemical production. In the future, hydrogen will be increasingly used as an energy vector. Although water electrolysis to produce hydrogen with renewable electricity offers a clean process, the approach is energy intensive, requiring a large renewable resource footprint. Methanol-water co-electrolysis can reduce the energy input by > 50%; its electrochemical oxidation poses complex issues such as poisoning of the catalyst, sluggish oxidation kinetics, and degradation over time. The addition of nano-sized SnO2 to PtRu/C catalyst, to reduce noble metal loading, has been shown here to reduce catalyst leaching and increase the chemical, micro-structural, and performance stability of the methanol-water co-electrolysis process during extended periods of testing. The electrochemical characterization, analysis of the methanol solution, and exit gases, post-cell testing, revealed complete oxidation of methanol with little performance degradation. This is further supported by the stability of the catalyst composition and structure as revealed by the post-mortem XRD and XPS analysis of the cell. The energy balance calculations show that methanol-water co-electrolysis can significantly reduce the renewable energy footprint, and the process can become carbon neutral if bio-methanol is used with renewable electricity.