Expanding catalytic applications of Pt-functionalized metal organic frameworks (Pt/ZIF-8): effects of calcination temperatures and metal loadings

ZIF-8 with and without Pt loadings (0·4 and 2·1 wt.%) were prepared at different calcination temperatures (300 and 400°C). The characterization from Brunauer–Emmett–Teller surface measurement and powder X-ray diffraction reveals that calcination temperatures and Pt loadings have a significant effect on the porosity and crystallinity of ZIF-8-based materials. ZIF-8 calcined at 300°C (ZIF8-300) has a surface area of more than 800 m²/g with excellent crystallinity, while ZIF-8 calcined at 400°C (ZIF8-400) only has a surface area of less than 100 m²/g with nearly amorphous structure; Pt loading reduces the surface area by blocking the micropores and lowers the overall Bragg peak intensity by the inclusion of guest Pt(NH₃)₄(NO₃)₂ molecules and/or the formation of Pt nanoparticles in the framework. The surface area and crystallinity decrease with the increase in Pt loadings. 2·1 wt.% Pt/ZIF8-300 has a surface area of 355 m²/g and thermal stability up to 500°C; this catalyst shows potential activities for partial oxidation of methanol because Pt nanoparticles (10 nm) are highly and uniformly distributed in ZIF-8 framework.