Palladium-Modified Tungsten Oxide Process

Palladium is a silver-white transition metal, softer, with good ductility and plasticity, forging, rolling and drawing. Bulk metal palladium can absorb a large amount of hydrogen, the volume significantly expanded, brittle and even broken into pieces. The use of palladium-modified tungsten oxide in the structure will have more oxygen defects, help to improve its surface chemical activity.

Palladium modified tungsten oxide process is as follows:

First, the solid sodium chloropalladate powder is configured as a 10mol / L solution, and then the prepared dark blue defect tungsten oxide powder is dispersed in 20 mL of distilled water. The defect tungsten oxide dispersion and sodium chloropalladate solution was stirred at room temperature for 12h, and the palladium / tungsten oxide composite was obtained by in situ reduction. The amount of sodium chloropalladate added was calculated by calculating the mass ratio of palladium in the composite. When the color of the solution changed from dark blue to light gray, the reaction solution was removed by washing with distilled water and centrifuged to obtain a gray solid product. Dried in a vacuum oven at 60 ° C. for 12 h to finally obtain a composite material in which palladium nanoparticles adhere to the surface of the tungsten oxide. After adding sodium chloropalladate solution, the reaction solution gradually changed from dark blue to gray. This is due to the disappearance of partial oxygen defects and the reduction of palladium to palladium nanoparticles.

The conditions for the synthesis of the palladium / tungsten oxide composite are very mild, and the desired composite material is obtained by directly reducing the two reactants by in situ reduction at room temperature. The obtained composites were characterized by transmission electron microscopy. There are two morphologies of the composite structure, one is tungsten oxide nanowires, a diameter of about 15-20 nm, the other is a palladium nanoparticle size of about 2-5 nm. This mild preparation method can make the palladium / tungsten oxide support basically the same before and after the reaction.

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