Influence of particle size in Pd-catalysed selective hydrogenation of 1,3-butadiene

Abstract

Supported Pd nanoparticles are widely used as catalysts for the selective hydrogenation of alkynes and diolefins. They have a high activity, but it remains challenging to limit over–hydrogenation to alkanes. We varied the nanoparticle size of a Pd on carbon catalyst from 2 to 17 nm and studied its effect on the catalytic activity and selectivity in the selective hydrogenation of 1,3-butadiene in the presence of an excess of propylene. The butadiene hydrogenation activity per metal surface atom increased slightly with Pd particle size, from 17 s−1 to 34 s−1 at 25 °C for 2 nm to 17 nm particles. Contrarily, the propylene hydrogenation activity decreased with particle size: from 2.6 s−1 to 0.4 s−1 from 2 to 17 nm particles. Overall, a higher product selectivity was obtained with increasing particle size over the full butadiene conversion range. Altogether, this paper provides useful insight for the rational design of monometallic Pd-catalyst for selective hydrogenation.