Computational Analysis of the Catalytic and Ferroelectric Properties of Polyoxometalates

Identifier:  TDX:4221

Handle: https://hdl.handle.net/20.500.11797/TDX4221

Authors:  Wang, Fei

Abstract:
Polyoxometalates, or POMs in short, are a type of molecular oxides that have great versatility in terms of their composition, electronic structure, charge distribution and applications. Among the applications, its catalytic, photocatalytic and electrocatalytic properties stand out. This thesis is divided into two distinct parts. The first focuses on the use of polyoxometalates in electrocatalysis and photocatalysis, while the second part reports the characterization of ferroelectricity, a property that has recently been detected in some polyoxometalate salts. Using various theoretical methods, including classical molecular dynamics MD methods, DFT methods and ab initio CASSCF/CASPT2 methods, the redox behaviors of a series of POMs in the electro- and photocatalytic transformation reactions of carbon dioxide and carbon monoxide. The reaction mechanisms and the role played by POMs as catalysts have been analyzed in detail. It has been a challenge to calculate the ferroelectric polarization for a system as large and complex as a polyoxometalate salt. Firstly, this property was analyzed in a much simpler system such as a hybrid organic-inorganic perovskite (HOIP). Then, with the experience gained, the ferroelectric polarization in Preyssler [XP5W30O110]q- anions was analyzed, in which the origin of the polarization was determined by decomposing the ferroelectric effect into three contributions.