Synthesis and Co2 Photocatalytic Reduction of Heterometallic-Doped Ti-Mofs

Abstract

Four new transition metal doped titanium metal-organic frameworks, [Ti2L2M(phen)] (M = Co2+, Ni2+, Cu2+, Zn2+, L = Embonic acid, phen = 1,10-phenanthroline), have been synthesized under solvothermal conditions utilizing the Ti4L6 precursors. In the structure of [Ti2L2M(phen)], a dinuclear titanium cluster is formed by coordinating two Ti atoms with two L ligands. The oxygen atoms from the carboxylate groups of the L ligands, which possess vacant coordination sites, further interact with the M(phen) unit, resulting in a Z-shaped one-dimensional chain-like structure. All compounds are determined by single crystal X-ray diffraction analysis, thermogravimetric analysis, PXRD, XPS, UV–vis and IR spectra, etc. Notably, all frameworks exhibit excellent stability and can be used as heterogeneous catalysts to reduce CO2 to syngas (CO+H2) under light conditions. Specifically, the total yield of syngas for Ti2L2-Co is up to 20.3 mmol g–1 h–1.

Keywords: Titanium−oxo clusters, Metal-organic framework, Molecular building blocks, Photocatalysis