Ni/sepiolite hydrogenation catalysts: Part 1: Precursor–support interaction and nature of exposed metal surfaces

A 10% loaded nickel on sepiolite catalyst has been prepared by a precipitation method and the characteristics of the resultant material compared with a similarly prepared Ni/silica catalyst and a sample in which only ion exchanged nickel was present in the sepiolite. Samples have been characterised by infrared (IR) and X-ray photoelectron spectroscopies, ²⁹Si MAS–NMR and X-ray diffraction in an attempt to determine the nature of the nickel species present in the precursor stage. Nickel silicate species have been identified for both supports but this precursor is more resistant to reduction for the sepiolite which leads to the formation of catalysts with lower metal areas than the silica support. The nature of the reduced nickel particles has been determined by hydrogen chemisorption, IR of adsorbed CO and temperature programmed desorption of hydrogen.