A facile one-step method for the fabrication of Pd-AlOOH/Al monolithic catalysts via redox reactions of two galvanic cells

In this work, we report a facile and economic one-step method under atmospheric pressure and 50 °C water bath for the fabrication of a three-dimensional (3D) upright-standing boehmite (AlOOH) nanosheet array film on a structured Al honeycomb substrate, in which zero-valence palladium (Pd 0 ) nanoparticles were well distributed at the same time. Redox reactions of two galvanic cells where the Al honeycomb substrate acted as the common anode, but the palladium precursor (Pd(NH 3 ) 4 2+ ) and weak base water (H 2 O + OH − ) served as the electrolyte of cathode I and II, respectively, led to simultaneous formation of Pd 0 nanoparticles at cathode I and AlOOH nanosheets at cathode II on the surface of Al substrate. The resultant AlOOH nanosheet array was uniform and about 300–400 nm thick, and the highly dispersed Pd 0 nanoparticles were also rather small with an average size of 8.4 nm. Hence, the as-obtained Pd-AlOOH/Al monolithic catalysts exhibited high specific surface area and large micro/mesopore structure as compared to pristine Al honeycomb substrate, leading to excellent catalytic activity in total oxidation reaction of toluene.