Insights into the shape effect of H2 self-selective Ni catalysts for efficient acetone hydrogenation

Abstract

The shape-function relationship for designing catalysts is always a focus to study. This article describes the influence of Ni catalysts surface structure on acetone hydrogenation. We report H2 as a morphology-directing agent to selectively synthesize branched Ni (Ni-BN), which exposes substantial stepped Ni(322) facet (~99%) that has elegant activity for acetone hydrogenation. In contrary, Ni nanoparticle (Ni-NP) prepared without H2 mainly exposes flat Ni(111) and Ni(100) facets and these facets perform less activity for acetone hydrogenation to isopropanol. Subsequently, DFT studies of reaction mechanism on different facets reveal that the step site in Ni(322) facet displays lower activation barriers than that of Ni(111) and Ni(100) facets. With help of kinetic growth model and microkinetics study, quantitative shape-function relationship of Ni-BN for acetone hydrogenation to isopropanol can be further established. This work not only clarifies the catalytic activity of Ni on acetone hydrogenation but also provides a method accessing the intrinsic kinetics of the reaction.