Performance of shape-controlled Pd nanoparticles in the selective hydrogenation of acetylene

Monodispersed Pd nanoparticles with controlled shapes, either cubes or spheres, were prepared and used as catalysts for acetylene hydrogenation at atmospheric pressure to investigate the effect of the Pd surface structure on the catalytic performance. Catalyst containing cubic Pd nanoparticles, whose surface consisted of the Pd(1 0 0) structure, exhibited higher acetylene conversion and ethylene selectivity than catalysts containing spherical nanoparticles, which had a significant amount of Pd(1 1 1) facets. These results were consistent with the observation that the temperatures for the decomposition of Pd hydride and the desorption of C2 hydrocarbons from Pd surface were lower for the cubic Pd particles than for the spherical particles. The selectivity of Pd nanocubes was better than that of catalysts containing smaller Pd nanoparticles that were prepared using an incipient wetness method, confirming the importance of the Pd(1 0 0) structure in catalyst design for selective acetylene hydrogenation.