Investigation of the Water Dissociation Energy Barrier on the Crystalline Surface of \mathrm{N}b2O3 Using Density Functional Theory (DFT)

Abstract

This study aims to investigate the mechanism of water molecule dissociation on the crystalline surface of niobium oxide  using density functional theory (DFT), within the broader context of developing efficient catalysts for hydrogen production and renewable energy storage. Computational simulations were carried out using the CP2K package combined with the CI-NEB method to identify the transition state and calculate the energy barrier required to break the  O–H bond in the adsorbed water molecule.

The results show that the most stable adsorption occurs at the on-top site of a niobium atom, with an adsorption energy of approximately . The energy barrier for water dissociation was found to be around . Analysis of the electronic charge density distribution and charge difference further revealed a significant electron transfer from the niobium surface atoms to the adsorbed water molecule, which weakens the O–H bond and facilitates the initial dissociation step.

Moreover, the calculations indicate that the electronic band gap is approximately , enabling the material to absorb part of the visible light spectrum and participate effectively in photo-induced reactions.