High-performance Pd-N (N = Ga or Ag) bimetallic monolithic catalyst for the hydrogenation of 2-ethylanthraquinone: Experimental and DFT studies

Abstract

• A series of Pd-Ga(Ag)/silicon Dioxide/cordierite bimetallic monolithic catalysts were prepared. • 0.6%Pd-0.3%Ga/SD/C catalyst is superior to 0.9%Pd/SD/C due to synergistic effect. • The mechanism of eAQ-PdN ( N = Ga and Ag) surface interactions was explored by DFT calculations. The catalytic performance of Pd-N/Silicon Dioxide/Cordierite (Pd-N/SD/C) ( N = Ga and Ag) bimetallic monolithic catalysts for 2-ethylanthraquinone (eAQ) hydrogenation was investigated. Catalyst characterization by HRTEM, XPS, and TPR reveal that Pd-Ga/SD/C can form an alloy structure to produce significant synergetic effects. Moreover, the use of different Pd/Ga mass ratio in catalysts reveals that when the mass ratio of Pd and Ga/Ag = 2:1, Pd-Ga/SD/C obtains the highest yield of H 2 O 2 and selectivity toward active quinones, which can reach 7.4 g L −1 and 90%. Moreover, to have a deep understanding of the eAQ-PdN(1 1 1) or eAQ-Pd(1 1 1) interaction mechanism, the calculation of eAQ adsorption on Pd-N/SD/C catalysts surface was performed by density functional theory (DFT). It is shown that the higher catalytic activity over Pd-Ga/SD/C is due to the stronger carbonyl group of eAQ adsorption on Pd 3 Ga 1 (1 1 1).