The effect of the concentration of platinum nanocolloid stabilizer on the rate of catalytic reactions in aqueous solution

The reduction of methyl viologen with hydrogen in the presence of NaOH and neptunium (VI) ions with formic acid in aqueous solutions catalyzed by platinum nanocolloids is studied. It is established that the rate of reaction with the participation of methyl viologen exponentially decreases with an increase in the concentration of a colloid stabilizer (sodium polyacrylate). The rate of neptunium reduction catalyzed by platinum nanoparticles of various sizes also decreases with an increase in the polyacrylate concentration to 4 × 10−3 M. A further increase in the content of stabilizer leads to some acceleration of the reaction. The mechanism of the effect of the stabilizer concentration on the catalytic activity of platinum nanocolloids is discussed.