Effect of Shell Pore Microstructure of the Pd Hollow Catalysts Pd@HMAN for H2O2 Generation

Pd-based hollow catalysts, Pd@HMAN, in which Pd was used as core and hollow aluminosilicate (HMAN) as shell, have been successfully synthesized by self-assembling method. Pd@HMAN-M (M = 1, 1.5, 2, 2.5) with uniform Pd nanoparticle size (~ 9.3 nm) and different shell volume (0.06–0.18 cm 3 g −1 ) were prepared by varying the addition amount of tetraethyl orthosilicate (TEOS). It is found that the shell pore size of 1–3.5 nm of the catalysts Pd@HMAN-M was conducive to the mass transfer of H 2 , O 2 and H 2 O 2 , and the larger the shell pore volume of Pd@HMAN-M was, the larger the adsorption amount of reactant H 2 was, and thus the higher selective and productive of H 2 O 2 could be obtained. The catalyst Pd@HMAN-1.5 had the highest H 2 O 2 selectivity (81%) and productivity (795 mmol g Pd −1 h −1 ) at atmospheric pressure due to its most substantial shell pore volume of (0.18 cm 3 g −1 ) and H 2 adsorption amount. Graphic Abstract