Water Adsorption by [Titanium/Chromium]-Decorated Zinc Oxide Microstructure: Physical and Electronic-Structural Analysis by Quantum Density of States

This research article wants to explore the electronic-structure traits of transition metals of titanium (Ti) and chromium (Cr) doped-zinc oxide (ZnO) heterocluster through H2O molecule adsorption using first-principles studies. A detailed study was performed using “DFT” calculations at the “CAM-B3LYP-D3/6-311+G(d,p)” level to investigate how H2O is captured by a ZnO, Zn(Ti)O or Zn(Cr)O heterocluster. The weak signal strength observed near the parallel edge of the nanocluster sample could be because of the non-spherical arrangement of the ZnO, Zn(Ti)O or Zn(Cr)O heterocluster caused by H/OH binding. This hypothesis about energy absorption was supported by analyzing the density distributions of “TDOS, PDOS, OPDOS, LOL” for both the bare and water-coated ZnO, Zn(Ti)O and Zn(Cr)O heteroclusters. An isosurface map showed a larger area involved in H2O adsorption on the ZnO, Zn(Ti)O or Zn(Cr)O surface, leading to the formation of a hydrated ZnO–H2O, Zn(Ti)O-H2O and Zn(Cr)O- H2O complexes, with specific atoms labeled as “O1, Zn15/Ti15/Cr15, O27, H29, and H30.” Based on this, it could be said that the Zn/Ti/Cr in the cubic ZnO, Zn(Ti)O or Zn(Cr)O, respectively has a greater ability to accept electrons during H2O adsorption. It’s also important to note that when all the surface elements of ZnO, Zn(Ti)O or Zn(Cr)O are covered by “OH–/ H+” ions, the semiconducting treatment is restored. These findings suggest that the electronic properties can be adjusted by controlling the adsorption position on the ZnO, Zn(Ti)O or Zn(Cr)O surface. This study aims to explore methods for treating water and enhancing the effectiveness of titanium zinc oxide and chromium zinc oxide alloy photocatalysts in removing pollutants. The findings can potentially lead to the development of more efficient water purification processes through further research on photocatalysts.