CO2 hydrogenation to CH3OH over PdZn catalysts, with reduced CH4 production - data

Abstract: Metallic Pd, under CO₂ hydrogenation conditions (> 175 °C, 20 bar in this work), promotes CO formation via the reverse water gas shift (RWGS) reaction. Pd-based catalysts can show high selectivity to methanol when alloyed with Zn, and PdZn alloy catalysts are commonly reported as a stable alternative to Cu-based catalysts for the CO₂ hydrogenation to methanol. The production of CH₄ is sometimes reported as a minor by-product, but nevertheless this can be a major detriment for an industrial process, because methane builds up in the recycle loop, and hence would have to be purged periodically. Thus, it is extremely important to reduce methane production for future green methanol synthesis processes. In this work we have investigated TiO₂ as a support for such catalysts, with Pd, or PdZn deposited by chemical vapour impregnation (CVI). Although titania-supported PdZn materials show excellent performance, with high selectivity to CH₃OH + CO, they suffer from methane formation (> 0.01 %). However, when ZnTiO₃ is used instead as a support medium for the PdZn alloy, methane production is greatly suppressed. The site for methane production appears to be the TiO₂, which reduces methanol to methane at anion vacancy sites.

This data set contains an excel file with the catalyst characterisation (XRD for supports, annealed and reduced samples, in situ XRD reduction for Pd/ZnO; XPS for Pd(3d), Zn(2p) and Zn(LM2); BET surface area; TEM images and particle count; CO2 hydrogenation data including CO2 conversion, product selectivity and productivity).

Research results based upon these data are published at https://doi.org/10.1002/cctc.202000974