Nanocage-Shaped Co3- x Zrx O4 Solid-Solution Supports Loaded with Pt Nanoparticles as Effective Catalysts for the Enhancement of Toluene Oxidation.

Nanocage-shaped Co3- x Zrx O4 solid-solution supports and the corresponding platinum loaded nanocomposites, yPt/Co3- x Zrx O4 (x =0.27, 0.50, 0.69; y = 0.5, 1.0, 2.0 wt.%), are successfully fabricated via a Cu2 O nanocube hard template method and a glycol reduction method, respectively. The hollow nanocage structures obviously improve surface areas; moreover, the Zr doping forms the Co3- x Zrx O4 solid-solution supports, and the corresponding yPt/Co3- x Zrx O4 catalysts promote the enhancement of catalytic performance. Catalytic activity toward toluene combustion is enhanced for the 2.0 wt% Pt/Co2.73 Zr0.27 O4 catalyst. The catalysts are characterized using multiple techniques. Pt nanoparticles are uniformly dispersed across the Co2.73 Zr0.27 O4 nanocage surface. The 2.0 wt% Pt/Co2.73 Zr0.27 O4 catalyst exhibits the highest catalytic activity among all the samples and demonstrates good stability, with 90% toluene conversion obtained at a temperature of 165 °C. The same catalyst accomplishes full toluene oxidation at 180 °C, at a weight hourly space velocity of 36 000 mL h-1 g-1 . The apparent activation energy (Ea ) over the yPt/Co2.73 Zr0.27 O4 samples are significantly lower than those over the Co3- x Zrx O4 supports, with the 2.0 wt% Pt/Co2.73 Zr0.27 O4 catalyst exhibiting the lowest Ea value. These findings demonstrate the potential of the 2.0 wt% Pt/Co2.73 Zr0.27 O4 catalyst as a promising catalyst toward atmospheric toluene removal.