One-pot synthesis and characterization of a dual-function hierarchical multiporous composite H₃PW₁₂O₄₀@HKUST-1/γ-Al₂O₃ with enhanced performance in adsorptive desulfurization and acid catalysis

Abstract

A hierarchical multiporous ternary composite HPW@HKUST-1/γ-Al₂O₃ (HPW = phosphotungstic acid) is prepared, in which the nanosized HPW@HKUST-1 is formed on both the external and internal surface of mesoporous γ-Al₂O₃ beads due to the confinement effect of internal pores/channels of the γ-Al₂O₃ beads. The composite not only possesses excellent adsorptive desulfurization capacity (e.g. 65.3 mg S/g MOF for dibenzothiophene; the adsorption capacities decreased in the order of dibenzothiophene > benzothiophene > 3-methylthiophene > 4,6-dimethyldibenzothiophene) superior to HKUST-1/γ-Al₂O₃ beads due to the significant role of the favorable acid-base interaction between acidic HPW and slightly basic sulfur-containing compounds, but also exhibits super acid catalytic activity for hydrolysis of ethyl acetate (325.6 mmol mol_acid⁻¹min⁻¹) and for synthesis of ethyl acetate (75.4 mol mol_acid⁻¹min⁻¹) and n-butyl acetate (13.2 mol mol_acid⁻¹min⁻¹) with selectivity of 100%, due to high dispersion and free access of the HPW in the composite which features high surface area and more easily accessible active sites of HPW and HKUST-1. Besides, the composite features remarkable mechanical strength, chemical/thermal stability, being friendly to the environment, and low cost, can easily be regenerated and reused many times for both acid catalysis reactions and adsorptive desulfurization without observable HPW leaching or material dissolution/decomposition.

Keywords:

• Heteropoly acid
• hierarchical multiporous composite
• desulfurization
• catalysis

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors acknowledge the Natural Science Foundation of China, the Fundamental Research Funds for the Central Universities under Grant no. XK1802-6. Dr Libo Qin acknowledges Educational Commission of ShanXi Province of China under Grant no. 2019L0910. Prof. Xue Duan of Beijing University of Chemical Technology is also acknowledged for his kind support.