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

[Display omitted] Cubic Pd nanoparticle catalysts supported in Al2O3 showed enhanced selectivity for acetylene hydrogenation due to the weaker adsorption of reactants. •Cubic Pd nanoparticles were synthesized and supported on Al2O3.•Organic contaminants were removed from Pd surface without structure deterioration.•Cubic Pd catalysts showed higher activity and selectivity in acetylene hydrogenation.•Easier decomposition of subsurface H in Pd(100) contributed to its higher activity.•The strong adsorption of reactants on Pd(111) surface decreased ethylene selectivity. 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(100) structure, exhibited higher acetylene conversion and ethylene selectivity than catalysts containing spherical nanoparticles, which had a significant amount of Pd(111) 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(100) structure in catalyst design for selective acetylene hydrogenation.