PtPd/molecular sieve as dual-functional monolithic adsorbent/catalyst for effective removal of trace toluene at low-temperature and their electric-heating performance

Abstract

A dual-functional adsorption–catalytic system for elimination of trace toluene is developed and realized over molecular sieve-hosted varied ratio of platinum and palladium catalysts. PtPd/molecular sieve exhibites PdO and PtO2 around 2–3 nm particles with uniform loading verified by XRD, TEM, Raman and XPS. The adsorption–desorption–catalysis for trace toluene purification is evaluated on the quartz micro-reactor and the self-made electrically heated equipment. 3Pt1Pd/molecular sieve shows toluene adsorption capacity of 18.22 mg/g and desorption efficiency about 77%, together with the maximum desorption temperature at 100 °C. 3Pt1Pd/molecular sieve owns toluene conversion with 38.3% and 100% at 100 and 200 °C, accompanied with the higher CO2 selectivity of 0.0% and 150.0%, separately, due to the higher Pd2+ content. The catalyst displays water vapor endurance, reproducibility, and 83.0% carbon balance during the whole adsorption–desorption–catalysis within 150 min, which highlights the sustainable applicability in lean VOCs abatement. Furthermore, the possible catalytic reaction pathway of toluene oxidation is proposed based on the in-situ DRIFTS experiments.