Decrypting the photocatalytic bacterial inactivation of hierarchical flower-like Bi(2)WO6 microspheres induced by surface properties: Experimental studies and ab initio calculations

Bi2WO6 is considered an effective photocatalyst, even under the visible part of the solar spectrum, and recent advances in the modification of its structure leave promise for harnessing its enhanced effectiveness. Our experimental E. coli disinfection results have shown that the flower-like morphology brought considerable enhancement to the overall performance over the nanoparticle form. To clarify the photocatalytic mechanism of Bi2WO6, a combination of experimental and computational methods has been employed to investigate the surface properties of Bi2WO6 nanosheets self-assembly flower-like architecture. Although experimental evidence has determined the band edge positions of the as-synthesized samples, so as to address the photocatalytic properties, the mechanistic basis of this concept remains unclear. The calculation results demonstrated here deepen our understanding and indicate the potential of surface configuration to considerably alter the electronic structure and related photocatalytic properties of Bi2WO6 nanosheets. Firstly, we consider a range of surface slab models of Bi2WO6 (010) facet and calculate their surface Gibbs free energies. Having determined that the bi-termination is energetically more favorable by ab initio atomistic thermodynamics, hydrogen passivated termination was proved to be most stable. Through the analysis of the electronic band structure within the DFT-1/2 scheme and work function of the most stable termination, excellent agreement of experimental and theoretical predictions provided a meaningful understanding on the kinetic dependence of photocatalytic bacterial inactivation.