Superb three-dimensional porous-structured metal foam-supported Ni/Ce/Al-CF ensemble as an active structured catalyst for hydrogen production via methanol decomposition

Abstract

A series of metal foam-supported Ni-based catalysts-monometallic Ni-CF, bimetallic Ni/Ce-CF, Ni/Al-CF and trimetallic Ni/Ce/Al-CF-were prepared by modified wet chemical etching (MWCE) and employed for hydrogen production via methanol decomposition (MD) in the temperature range of 200–325 ℃. Among those catalysts, the 2Ni/3Ce/3Al-Cu foam (CF) catalyst shows the superior catalytic performance for hydrogen production, achieving a remarkable activity of almost complete methanol conversion (99.3 %) and high H₂ selectivity of 91.8 % at 300 ℃. Moreover, the performance of 2Ni/3Ce/3Al-CF catalyst remained stable during the stability test for up to 40 h at 275 ℃. SEM and BET characterization show that etched copper foam can remarkably enlarge the specific surface area of the structured catalyst, provide more active sites, and enhance its catalytic activity. The strong interaction among Ni, Ce and Al induce the synergistic effect by creating abundant oxygen vacancies in the trimetallic system as evidenced by XPS. H₂-TPR and XPS further revealed a crucial balance between reducibility and metal-support interactions: Al-containing catalysts like 2Ni/3Ce/3Al-CF exhibit higher reduction thresholds and confirming the role of Al in stabilizing oxidized Ni species via strong metal-support interactions. And CH₃OH-TPD analysis indicated the catalyst had much higher low-temperature hydrogen production than other catalysts because of the synergistic effect of three metals, consistent with the catalyst activity test results. The developed strategy may provide insights into the development of the design principles for high-performance structured catalysts for hydrogen production via methanol decomposition.