A new active species of Pd-Nx synthesized by hard-template method for efficiently catalytic hydrogenation of nitroarenes

A new active species of Pd-N-x has been synthesized by hard-template method using metal oxide and dicyandiamide as precursor for the hydrogenation of nitroarenes to anilines. The hydrogenation of 4-nitrophenol (4-NP) was employed as a probe reaction to investigate the catalytic performance. The conversion of 4-NP can reach 99% within 1 h under mild conditions on the Pd/g-C3N4(MoO3)-200 catalyst, which showed much higher activity than the contrasting Pd/g-C3N4 catalyst (11% conversion) prepared by conventional method. A series of fresh and used Pd/g-C3N4, Pd/g-C3N4(MOx), Pd/g-C3N4(MoO3)-X catalysts were characterized. The results indicated that the high catalytic activity and stability of as prepared Pd/g-C3N4(MoO3)-200 catalyst were due to the formation of active Pd-N-x species, and the catalytic performance has a positive correlation with the proportion of Pd-N-x. Moreover, the Pd/g-C3N4(MoO3)-200 catalyst also exhibited excellent catalytic performance towards the hydrogenation of other nitroarenes. (C) 2021 Elsevier Inc. All rights reserved.