HKUST-1-Supported Cerium Catalysts for CO Oxidation

Michalina Stawowy,Bogdan Samojeden,Janusz Trawczyński,Krzysztof Matus,Paulina Jagódka,Agata Łamacz,Joaquin Silvestre-Albero

doi:10.3390/catal10010108

Abstract

The synthesis method of metal–organic frameworks (MOFs) has an important impact on their properties, including their performance in catalytic reactions. In this work we report on how the performance of [Cu3(TMA)2(H2O)3]n (HKUST-1) and Ce@HKUST-1 in the reaction of CO oxidation depends on the synthesis method of HKUST-1 and the way the cerium active phase is introduced to it. The HKUST-1 is synthesised in two ways: via the conventional solvothermal method and in the presence of a cationic surfactant (hexadecyltrimethylammonium bromide (CTAB)). Obtained MOFs are used as supports for cerium oxide, which is deposited on their surfaces by applying wet and incipient wetness impregnation methods. To determine textural properties, structure, morphology, and thermal stability, the HKUST-1 supports and Ce@HKUST-1 catalysts are characterised using X-ray diffraction (XRD), N2 sorption, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). It is proven that the synthesis method of HKUST-1 has a significant impact on its morphology, surface area, and thermal stability. The synthesis method also influences the dispersion and the morphology of the deposited cerium oxide. Last but not least, the synthesis method affects the catalytic activity of the obtained material.

Highlights

HKUST-1, i.e., [Cu3 (TMA)2 (H2 O)3 ]n, is a metal coordination polymer which was reported for the first time in 1999 by Chui et al [1]
Our study revealed that the synthesis method of HKUST-1 has a significant impact on its morphology, surface area, and thermal stability
That cerium deposition over HKUST-1 obtained in the presence of CTAB

Summary

Introduction

HKUST-1, i.e., [Cu3 (TMA) (H2 O)3 ]n , is a metal coordination polymer which was reported for the first time in 1999 by Chui et al [1]. A common approach is to use monodentate ligands that have the same bond functionality as the linker. In such a case, the template (sometimes called the “modulator”) competes with the organic linker to a metal ion and regulates at the same time the nucleation and crystal growth [3]. The template (sometimes called the “modulator”) competes with the organic linker to a metal ion and regulates at the same time the nucleation and crystal growth [3] It has been found [4] that the addition of acetic acid leads to anisotropic growth of crystals, which physically prevents their aggregation

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Conclusion