Density functional theory study of copper tungstate

Copper tungstate (CuWO4) has attracted growing interest as a visible-light-responsive photocatalyst for solar-driven water splitting and carbon dioxide reduction, owing to its suitable band gap and chemical stability under a range of conditions. However, a detailed understanding of its surface redox properties, water adsorption behaviour, and catalytic mechanisms remains limited. This thesis presents a systematic computational study of the structural, electronic, and catalytic properties of CuWO4 using density functional theory (DFT), including on-site Coulomb and dispersion corrections (DFT+U-D3).
The equilibrium morphologies and stabilities of low-index surfaces were first examined through surface energy calculations and surface phase diagrams, revealing that the (010) and (110) facets are predominant under typical synthesis and operating conditions. Next, the adsorption of water on both pristine and reduced surfaces was investigated to understand its role in the initial stages of the photocatalytic water splitting reaction. Surface phase diagrams were constructed to evaluate water coverage as a function of temperature and pressure.
Finally, the mechanisms of water splitting and hydrogen evolution were explored through detailed analysis of reaction intermediates, charge redistribution, and transition states. The results indicate that oxygen vacancies on the reduced (010) surface enhance catalytic activity by stabilizing key intermediates and promoting charge localization. These findings offer important insights into the catalytic behaviour of CuWO4 and support its potential use in the development of solar-driven hydrogen production technologies.