文摘
The dehydrogenation of bioethanol to acetaldehyde and hydrogen is a sustainable process, owing to the atom-economical transformation and easy separation of the products. However, oxide-supported Cu catalysts show a low selectivity to acetaldehyde because of considerable side reactions caused by their oxygen-rich surfaces. A conventional carbon-supported Cu catalyst shows high selectivity, but is quickly deactivated owing to the migration and agglomeration of copper particles. Here, we have produced a highly porous nitrogen-rich carbon support that contains 6.2 wt % N and can nicely disperse and stabilize Cu nanoparticles (∼6.3 nm). If used for ethanol dehydrogenation, approximately 98 % selectivity to acetaldehyde has been achieved, with excellent anti-agglomeration ability for as long as 500 min. X-ray photoelectron spectroscopy (XPS) data prove that electrons transfer to the Cu particles from the N sites. Theoretical calculations further show that nitrogen sites enhance the adsorption of Cu20 clusters and can stabilize them against coalescence and that graphitic-N sites (approximately 40 % of total N content) are the most significant.