Ensemble Effect of the Nickel–Silica Interface Promotes the Water–Gas Shift Reaction

Silica is commonly considered an inert support, and limited research has been concentrated on its role in constructing active metal–(hydr)­oxide interfaces. Herein, we found that modifying the surface of nickel with silica will significantly promote its catalytic performance toward the water–gas shift reaction (WGSR), and the well-fabricated Ninp@PS­(H450) exhibits a WGSR rate of up to 725 ± 7 μmolCO gcat –1 s–1 at 350 °C, which is at the highest level compared with previously reported Ni-based catalysts. Combining the experiment and theory, we demonstrated that Niδ+–O–SiO x interfaces divide the Ni surface into small domains consisting of contiguous Ni atoms. With the aid of an ensemble effect, the adsorption energies of CO, OH, and H can be tuned into appropriate ranges. Moreover, the Niδ+–O–SiO x interfaces also inhibit the formation of a dense NiO (or Ni­(OH)2) layer, thus endowing the catalyst with high stability. This study offers valuable insights into the catalytic mechanism linking Ni and silica, which can aid in the development of high-performance Ni-based catalysts.