Hydrophobically modified mesoporous silica supported Pt as a dual-function adsorbent buffer-catalyst for toluene removal under low-temperature

Abstract

A bifunctional adsorption-catalysis system for the abatement of trace amounts of toluene was developed and realized by loading different amounts of Pt on mesoporous silica synthesized with ionic liquid with hydrophobic modification. The textural properties were evaluated using BET, contact angle, XRD, IR, XPS, TEM, and H₂-TPR techniques. The capability of the synthesized catalysts for room-temperature adsorption and low-temperature catalysis of toluene was appraised. The hydrophobic sample exhibited better toluene adsorption capacity of 53.1 mg g⁻¹ than SiO₂-350 and 3.0Pt/SiO₂ samples with 28.3 mg g⁻¹ and 18.9 mg g⁻¹, respectively. Furthermore, the hydrophobic sample showed increased maximum desorption temperatures of 52 °C in comparison with those at 44 °C and 37 °C, which acted as a good adsorption buffering system. 3.0Pt/SiO₂-H showed the best toluene conversion capacity at T₉₀ = 129 °C, together with superior water vapor resistance and sequential capture-destruction performances. The increased bifunctional adsorption-catalysis performance with hydrophobic modification may be ascribed to the change in surface functional groups. The prepared system could be a valuable candidate material for adsorption-catalysis integration and assistance for VOCs elimination technology in barren waste gases.