Regulating the Selective Dispersion of Tungsten Oxide to Promote Propane Combustion on Pt-Nanoparticle Catalysts Supported on WOx/ZrO2 by Tuning the Zirconia Crystal Phase

Low-temperature catalytic oxidation of propane on Pt-based catalysts is of paramount importance but remains a major challenge for the emission control of volatile organic compounds (VOCs). Here, we report the promoting effects of doped WOx on 0.5 wt % Pt/ZrO2 catalysts for propane oxidation, which strongly depended on the crystal structure of ZrO2. Among them, 0.5 wt % Pt/WOx/t-ZrO2 shows the highest catalytic activity, the T-90 is 216 degrees C, which is about 155 and 80 degrees C lower than that of Pt/t-ZrO2 and Pt/WOx/m-ZrO2, respectively, and the turnover frequency (TOF) of Pt/WOx/t-ZrO2 at 190 degrees C is about 3 times that of Pt/WOx/m-ZrO2. Multicharacterization results show that compared with Pt/ WOx/m-ZrO2, doped WOx can be highly dispersed on t-ZrO2 and form the solid solution-like (Zr1-xWxO2+x/2) nanolayer structure at the catalyst surface, which produces additional strong Bronsted acid sites and metallic Pt (Pt-0) sites via an electron transfer from W to Pt on Pt/WOx/t-ZrO2. The synergistic effect of Pt-0 and strong acidity at the Pt-Zr(1-x)WxO(2+x/2) interface facilitates the rapid removal of surface intermediates including carboxylate and CO generated during the reaction and promotes C3H8 oxidation on Pt/WOx/t-ZrO2. This work highlights a direction for the design of high-efficiency metal oxide-modified Pt/ZrO2 nanoscale catalysts by changing the crystal structure of the ZrO2 support for the removal of VOCs.

Automated summary

This study reports the promoting effects of doped WOx on Pt/ZrO2 catalysts for propane oxidation. It is found that doped WOx can be highly dispersed on t-ZrO2 and form a nanolayer structure. This structure produces additional strong acid sites and metallic Pt sites, which facilitate the propane oxidation reaction. The results highlight the design of efficient Pt/ZrO2 catalysts for the removal of VOCs by changing the crystal structure of the ZrO2 support.