Rational design of CuO/SiO2 nanocatalyst with anchor structure and hydrophilic surface for efficient hydrogenation of nitrophenol

Abstract

Morphology and surface property are critical property-defining factors for metal oxide catalysts, therefore, the rational engineering on these aspects is considered as the effective means to enhance their overall catalytic activities. In this work, a silicon oxide (SiO2) with hierarchical structure was successfully prepared and applied as carrier for the design of SiO2-supported copper oxide catalysts (CuO/SiO2-x, x represents treating temperature of SiO2 during preparation). The morphology and composition of thus-obtained catalysts were characterized by XRD, SEM, HRTEM, XPS, FTIR, contact angle and N2 adsorption. Interestingly, even with relatively large CuO particles, excellent activity was also achieved in hydrogenation of nitrophenol under relatively mild conditions (25 ​°C and 1 ​atm). Over the optimal CuO/SiO2-800 catalyst, the 4-nitrophenol (4-NP) conversion reached 99% in 60 ​s and its hydrogenation rate was about 9.2 times that of bare CuO catalyst. Additionally, it could also be reused for at least eight times without obvious fading in efficiency. The excellent catalytic performance can be attributed to the synergy between surface-anchored structure in which more active sites can be exposed, and hydrophilic surface to promote the adsorption and diffusion of substrate molecules during hydrogenation process.