Butadiene hydrogenation on N-doped carbon-hosted non-noble metal nanostructures

Abstract

Diverse N-doped carbon-supported non-noble metal nanostructures (Ni, Co, Fe, Cu) are designed, and explored in selective butadiene hydrogenation. Focusing on particle size and composition, optimal catalytic performance is observed with Ni catalysts, where smaller metallic Ni particles of ca. 6.2 nm exhibit superior activity and larger ones (14–47 nm) display much higher total butene selectivity. An integral approach combining detailed kinetics, chemisorption, and dual-beam Fourier transform infrared spectroscopic study is performed to rationalize the Ni particle size effect. The findings reveal that smaller Ni particles offer improved activation of butadiene and hydrogen due to advantageous adsorption dynamics. Spectroscopic examinations further suggest different adsorption configurations existing on Ni particles, with larger particles displaying strong π-adsorption, which impedes hydrogen replacement. Additionally, the stability of the catalysts is scrutinized under various reaction conditions, revealing that deactivation occurs more rapidly at lower temperatures, primarily due to mild coke deposition.