Enhanced hydrophobic microporous Pt/silica with high adsorption and catalytic oxidation for trace toluene removal

The molecular sieve has problems of high-temperature desorption, low-temperature desorption rate, and poor moisture resistance in purifying VOCs, therefore a microporous bifunctional system for adsorption/catalysis was developed by varying the mass percentage of Pt/microporous silica (Pt/MS) from 1.0 wt% to 3.5 wt% to obtain the best adsorption/catalytic performance for trace toluene. The synthesized Pt/MS catalyst was also hydrophobically modified to improve the resistance to water vapor, denoted as Pt/MS-H. 2.0Pt/MS-H possessed the optimum saturation adsorption capacity of 56.09 mg/g for toluene and the desorption temperature was lower to 60ºC. The synthesized catalyst had excellent adsorption/desorption cycling performance, maintaining approximately 95% of the adsorption capacity after five adsorption/desorption cycles, together with an excellent peak-smoothing effect on toluene adsorption. The samples were analyzed for various characterizations. The specific surface area of the synthesized catalyst was 650–750 m2/g, the pore size was 1.1–1.5 nm, and the pore volume was 0.28–0.35 m2/g. The best trace toluene conversion capacity was T90 = 149ºC. It can be regarded as a powerful supplementary material of the VOCs adsorption-catalysis combination.