Ni Nanoparticles Grown on SiO2 Supports Using a Carbon Interlayer Sacrificial Strategy for Chemoselective Hydrogenation of Nitrobenzene and m-Cresol

Abstract

To efficiently increase the dispersity of metal nanoparticles (NPs) of the supported-type catalyst is crucial for promoting their catalytic performance owing to the enlarged amount of exposed active sites and the strengthened metal–support interaction. Therefore, to develop a facile and practical method for preparing a supported-type catalyst with high dispersity is of great significance, but remains a challenge. In this work, inspired by the previously reported non-noble metal sacrificial approach, we report a facile and practical carbon interlayer sacrificial (CIS) strategy for preparing supported Ni NP catalysts on silica rod (10%Ni/r-SiO2-CIS) with high dispersity. This strategy involves two steps: one is depositing carbon on silica rod (r-SiO2) to form the corresponding carbon-coated silica (r-SiO2@C) carrier through a hydrothermal process in the presence of glucose; the other is loading metal precursor on r-SiO2@C through an incipient wetness impregnation (IWI) process followed by hydrogenation for carbon elimination. The method has been extended to the preparation of supported Ni NPs on the silica sphere (10%Ni/s-SiO2-CIS) with high Ni dispersity by using the silica sphere (s-SiO2) as the carrier. For comparison, the conventional-supported Ni NP catalysts (10%Ni/r-SiO2 and 10%Ni/s-SiO2) were also prepared by using a similar method to that for 10%Ni/r-SiO2-CIS and 10%Ni/s-SiO2-CIS except for absence of the carbon-coating process. Owing to the more exposed active sites and the strengthened metal–support resulting from the higher Ni dispersity, both 10%Ni/r-SiO2-CIS and 10%Ni/s-SiO2-CIS catalysts show much superior catalytic properties for the chemoselective hydrogenation of nitrobenzene and m-cresol to their corresponding 10%Ni/r-SiO2 and 10%Ni/s-SiO2. This work opens up an avenue for designing and preparing other outstanding supported metal NP catalysts with high metal dispersity for diverse catalytic transformations.