Direct synthesis of hydrogen peroxide over Pd nanoparticles embedded between HZSM-5 nanosheets layers

Direct synthesis of hydrogen peroxide (DSHP) was studied over Pd loaded on HZSM-5 nanosheets (Pd/ZN). Pd nanoparticles with average size of ca. 4.3 nm were introduced into the adjacent nanosheet layers (thickness of ca. 2.9 nm) by impregnation method. Pd/ZN with theoretical Si/Al molar ratio of 25 showed the highest selectivity for H2O2 among the prepared catalysts, together with highest formation rate of H2O2 (38.0 mmol·(g cat)−1·h−1), 1.9 times than that of Pd supported on conventional HZSM-5 zeolite (Pd/CZ-50). Better catalytic performance of nanosheet catalysts was attributed to the promoted Pd dispersion which promoted H2 dissociation, more Brønsted acid sites and stronger metal-support interaction which inhibited the dissociation of OO bond in H2O2. The embedded structure sufficiently protected the Pd nanoparticles by space confinement which restrained the Pd leaching, leading to a better catalytic stability with 90% activity retained after 3 cycles, which was almost 3 times than that of Pd/CZ-50 (30.4% activity retained). [Display omitted] •Pd particles were successfully embedded into mesopores formatted by nanosheet layers.•Pd/NS-25 with higher content of B acid sites exhibited a highest formate rate of H2O2.•Metal-support interaction between Pd nanoparticles and acid sites enhanced selectivity for H2O2.•Pd/NS-50 gave high activity 3.2 times than that of Pd/CZ-50.