Optimal methodology for explicit solvation prediction of band edges of transition metal oxide photocatalysts

Abstract

The conduction and valence band edges (EC and EV) of a material relative to the water redox potential levels are critical factors governing photocatalytic water splitting activity. Here we discuss the large discrepancy in the experimentally measured EC and EV of various transition metal oxides (TMOs) in vacuum and in an aqueous solution. We speculate that the discrepancy stems from the different degree of electron transfer across the surface due to the different environment at the surface of the TMOs in vacuum and water. Accurately modeling the electronic structure at TMO/water interfaces is a significant challenge, however. Using first-principles density functional theory calculations on rutile titanium dioxide and cobalt monoxide model systems, here we identify the optimal approaches to accurately predict the band edge positions in vacuum and water. We then validate the optimized schemes on other TMOs, demonstrating good agreement with experimental measurements in both vacuum and water.

Spontaneously formed gradient chemical compositional structures of niobium doped titanium dioxide nanoparticles enhance ultraviolet- and visible-light photocatalytic performance

“…HO 2 − radical and H 2 O 2 formed and attacked to MO molecules leading decoloration. The reported energy levels of valence band maximum and conduction band minimum of anatase, rutile, and TiNb 2 O 7 (as a typical example of Nb-rich titanium oxides) consistent with our hypothesis 45 , 64 .

Figure 8 Schematic illustration of proposed mechanism of enhanced photocatalytic performance by Nb doped TiO 2 nanoparticles with gradient chemical compositional structure.

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Figure 8 Schematic illustration of proposed mechanism of enhanced photocatalytic performance by Nb doped TiO 2 nanoparticles with gradient chemical compositional structure. The reported energy levels were used 45 , 61 , 64 .

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Atomic Layer Deposition for the Photoelectrochemical Applications

“…Diagram constructed from literature data. [ 83–87 ] Note that for ALD‐deposited ultrathin films the band positions may differ due to quantum confinement effect, doping effect, impurities, or interface strain.…”

The pulsed laser ablation synthesis of colloidal iron oxide nanoparticles for the enhancement of TiO2 nanotubes photo-activity

“…11). Such an energy bands configuration promotes the accumulation of minor charge carriers over FeO NPs, which reduces the electron-hole recombination rate [26,82] and in consequence the photocurrent boost is noticed.…”