Synthesis of TS-1 encapsulated Pt (Pt@TS-1) catalyst with hierarchical pores and its enhanced performance in the oxidation of toluene

Abstract

Generally, the distribution, dispersion and size of Pt nanoparticles are critical issues for high catalytic activity. A series of TS-1 encapsulated Pt (xPt@TS-1 x = 1.70, 0.81, 0.22, 0.08) catalysts with hierarchical pores were prepared by one-pot hydrothermal method and alkali etching treatment, and their catalytic performance were also investigated in the oxidation of toluene. The physicochemical properties of these catalysts were analyzed by XRD, TEM, N2 adsorption-desorption, ICP-OES and XPS etc. Among these catalysts, the 0.22Pt@TS-1 sample with very low Pt loading (0.22 wt%) showed good catalytic activity (T50 = 144 °C and T90 = 147 °C under WHSV of 20,000 mL∙h−1 g−1) and high TOF value (3.6 × 10−4 S-1), moreover, it also exhibited good continuous cycle use, long-term activity stability and water resistance. The preparation method can limit the aggregation and growth of Pt nanoparticles to obtain high dispersion of Pt in TS-1, which can enhance the catalytic oxidation of toluene. In addition, the hierarchical pores formed by alkali etching treatment can shorten the mass transfer path and promote the mass transfer diffusion, which is also conducive to the catalytic activity.