Highly Efficient Monolithic Catalyst with Excellent Adhesion of SiO2 Coating for Catalytic Hydrogenation in the Rotating Packed Bed Reactor

Monolithic catalysts have great potential to be used in rotating packed bed (RPB) reactors due to the advantages of easy installation and structural stability. However, the complex operation environment of liquid scouring and centrifugal force in the RPB reactor leads to the loss of active material from the substrate. In this work, SiO2 coating was deposited on a nickel foam by the electrodeposition (ED) method to improve the adhesion strength of SiO2 coating. The adhesion properties were tested from three aspects of mechanical stress, thermal stress, and chemical stress. Compared with the traditional impregnation method and slurry circulation method, the ED method can reduce the mass loss rate from higher than 45% to less than 4%. Moreover, the formation of chemical interactions (Si–O–Ni bond), as characterized by Raman and XPS spectroscopy, illustrated the enhanced adhesion strength by the ED method. The ED method also improved the catalytic performance and reusability of the monolithic catalyst installed in the RPB reactor. This work demonstrates that chemical interactions can be used to enhance the coating adhesion strength and provides a new way to develop stable monolithic catalysts.