Copper-based catalysts are widely applied for industrial hydrogenation reactions. Addition of promoters is often crucial to enhance catalytic activity, selectivity and stability.1 Manganese oxide (MnOx) was proposed as a more environmentally-friendly replacement for the commonly used chromium promoter.2 However, the promoter effects are not yet fully understood. We used inert graphitic carbon supports, which have a tunable surface chemistry and a weak interaction with the active metals, to facilitate characterization and fundamental studies.3 Highly dispersed and well-defined CuMnOx nanoparticles were obtained using facile and scalable co-impregnation of the graphitic carbon supports with the mixed metal precursors solution, followed by drying and thermal treatment to decompose the metal precursors (Fig. 1 A). With a constant Cu loading, we achieved similar CuMnOx nanoparticle sizes over a wide range of Mn concentrations (Fig. 1 B). Analyses by TPR and STEM-EDX indicate close contact between Cu and MnOx, essential to efficiently induce the promoter effects (Fig. 1C). The influence of MnOx promoter concentrations is currently being investigated for the catalytic gas-phase hydrogenation of ethyl acetate to ethanol. Preliminary results showed a strong effect of increasing Mn concentrations upon catalytic performance. The nature of the MnOx promotor effects for activity and stability over time for this important hydrogenation reaction will be presented at the conference. These findings may contribute to implementing MnOx as an efficient promoter for a range of different hydrogenation reactions.

Manganese promoter effects in carbon-supported copper-based ester hydrogenation catalysis

256th National Meeting (2018)

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