Carbon-wrapped copper catalyst boosts biofuel precursor production

Researchers from Southeast University in Nanjing, China, in collaboration with Zhejiang University and the Henan Academy of Sciences, have developed a carbon-layer-modified copper catalyst that significantly enhances the hydrogenation of furfural to furfuryl alcohol. This study, published in Catalysis Letters, highlights the use of a carbon layer to improve the selectivity of copper catalysts, achieving over 99% selectivity for furfuryl alcohol.

Furfural, derived from hemicellulose-rich agricultural residues, is a key platform molecule in the bioeconomy. Its conversion to furfuryl alcohol is economically significant but challenging due to competing reactions. The carbon layer on the catalyst moderates the acidity of the support and protects copper particles from deactivation, addressing issues like resinification and copper sintering.

The research team systematically optimized the carbon loading, achieving complete furfural conversion at 160 degrees Celsius with high selectivity. Characterization techniques revealed that the carbon layer converts strong acid sites to medium-strength ones, reducing side reactions that degrade furfuryl alcohol.

The carbon treatment also increased the ratio of Lewis to Brønsted acid sites, enhancing the catalyst's performance by favoring aldehyde activation over deactivation pathways. This bifunctional catalyst design, combining well-dispersed copper with re-engineered acid sites, demonstrates durability across multiple reaction cycles.

Density functional theory calculations supported the experimental findings, showing that the carbon layer promotes the preferred adsorption geometry for furfural, enhancing selectivity. This approach to catalyst design, using carbon as an electronic and acidic regulator, offers potential economic and environmental benefits for biomass upgrading operations.

The study was supported by various Chinese research programs, and the authors report no competing interests. This work provides a blueprint for next-generation hydrogenation catalysts, utilizing abundant copper and carbon to improve biofuel precursor production.