Tuning Particle Sizes and Active Sites of Ni/CeO Catalysts and Their Influence on Maleic Anhydride Hydrogenation.

Supported metal catalysts are widely used in industrial processes, and the particle size of the active metal plays a key role in determining the catalytic activity. Herein, CeO-supported Ni catalysts with different Ni loading and particle size were prepared by the impregnation method, and the hydrogenation performance of maleic anhydride (MA) over the Ni/CeO catalysts was investigated deeply. It was found that changes in Ni loading causes changes in metal particle size and active sites, which significantly affected the conversion and selectivity of MAH reaction. The conversion of MA reached the maximum at about 17.5 Ni loading compared with other contents of Ni loading because of its proper particle size and active sites. In addition, the effects of Ni grain size, surface oxygen vacancy, and Ni-CeO interaction on MAH were investigated in detail, and the possible mechanism for MAH over Ni/CeO catalysts was deduced. This work greatly deepens the fundamental understanding of Ni loading and size regimes over Ni/CeO catalysts for the hydrogenation of MA and provides a theoretical and experimental basis for the preparation of high-activity catalysts for MAH.