Enhancing Pd Catalytic Activity by Amine Group Modification for Efficient Direct Synthesis of H 2 O 2 .

A great deal of research has been carried out on the design of Pd-based catalysts in the direct synthesis of H 2 O 2 , mainly for the purpose of improving the H 2 O 2 selectivity by weakening the activation energy on the Pd active site and thus inhibiting the dissociation of the O-O bonds in O 2 *, OOH*, and HOOH*. However, this often results in insufficient activation energy for the reaction between H 2 and O 2 on Pd, leading to difficulties in improving both the selectivity and productivity of H 2 O 2 simultaneously. Based on this, this study reports an efficient catalyst composed of amine-functionalized SBA-15-supported Pd. The strong metal-support interaction not only makes the PdNPs highly dispersed with more Pd active sites but also improves the stability of the catalyst. The amine group modification increases the proportion of Pd 0 , further enhancing Pd activity and promoting the adsorption and conversion of H 2 and O 2 on Pd, thereby significantly increasing H 2 O 2 productivity. Additionally, the density-functional theory simulation results showed that due to the hydrogen-bonding force between the amine group and H 2 O 2 , this particular anchoring effect would make the hydrogenation and decomposition of H 2 O 2 effectively suppressed. Ultimately, both the selectivity and productivity of H 2 O 2 are improved simultaneously.