Facile synthesis of holey lamellar CuO via ultrasonic chemical etching toward highly efficient hydrogenation of 4-nitrophenol under mild conditions

Abstract Rational engineering the structural and superficial characters of catalysts to tailor their properties is a pursuit for the catalyst design. In this work, via an ultrasonic-assisted H2O2 etching strategy, a kind of copper oxide catalyst (CuO-60) with a holey lamellar structure was prepared and structurally characterized by a series of characterization techniques including SEM, HRTEM, XRD, N2 adsorption, XPS and H2-TPR. Interestingly, this strategy can not only generate defect rich surface but also achieve morphology reconstruction, thereby affording high-density active sites on CuO-60. As a low-cost catalyst, CuO-60 displays exceptional high catalytic activity and stability for the hydrogenation of 4-nitrophenol (4-NP) under mild conditions (25 ​°C and 1 ​atm). The 4-NP conversion over CuO-60 reaches up to 99% within 12 ​min, which is nearly 43-fold faster than that of the pristine CuO control. The correlation between the microstructure of the catalyst and the enhanced catalytic performance was well established. The outstanding catalytic properties can be ascribed to the synergistic effects of structure porousness, which renders in more exposed active sites, and unique redox behavior of electropositive Cu sites during catalytic process. Additionally, a catalytic mechanism is also proposed and rationalized.