The Impact of Iron Adsorption on the Electronic and Photocatalytic Properties of the Zinc Oxide (0001) Surface: A First-Principles Study

Abstract

The structural stability, electronic structure, and optical properties of an iron-adsorbed ZnO (0001) surface with three high-symmetry adsorption sites are investigated with first-principle calculations on the basis of density functional theory and the Hubbard-U method. It is found that the iron adatom in the H3 adsorption site of ZnO (0001) surface has the lowest adsorption energy of −5.665 eV compared with T4 and Top sites. For the Top site, compared with the pristine ZnO (0001) surface, the absorption peak located at 1.17 eV has a red shift, and the elevation of the absorption coefficient is more pronounced in the visible-light region, because the Fe-related levels are introduced in the forbidden band and near the Fermi level. The electrostatic potential computation reveals that the work function of the ZnO (0001) surface is significantly decreased from 2.340 to 1.768 eV when iron is adsorbed on the Top site. Furthermore, the degradation mechanism based on the band structure is analyzed. It can be concluded that the adsorption of iron will promote the separation of photoinduced carriers, thus improving the photocatalytic activity of ZnO (0001) surface. Our study benefits research on the photocatalytic activity of ZnO and the utilization rate of solar energy.

First-Principles Calculations of the Electronic Structure and Optical Properties of Yttrium-Doped ZnO Monolayer with Vacancy

“…The spin-up and spin-down components of the Y-V O -ZnO DOS were asymmetrical, suggesting that the spin-polarization mainly came from the 4d and 5s electrons of the Y atom. In summary, the forbidden band width of ZnO ML with Y and vacancy is reduced, and the introduced impurity level will act as a "springboard" for electrons to jump into the CB, which may result in a stronger optical absorption coefficient in the visible light region [60]. The value of DOS near the Fermi level increases because of Y doping, which is also advantageous to the transition of electrons.…”

First-Principles Density Functional Theory Study of Modified Germanene-Based Electrode Materials

“…However, the C Q of germanene-based electrodes materials for supercapacitors has not been fully studied. In the application process and/or growth conditions, the introduction of vacancy defects [ 32 , 33 , 34 ], doping/co-doping [ 35 , 36 , 37 , 38 , 39 , 40 , 41 ], and adsorbents [ 42 , 43 ] could alter the electronic structure, thereby affecting the quantum capacitance. Furthermore, the randomness of defects/doping had an influence on the electronic and transport properties, for example, edge defects have an effect on the transport gap [ 44 , 45 ].…”

Surface Functionalization of Grown-on-Tip ZnO Nanopyramids: From Fabrication to Light-Triggered Applications

“…Similar effects have already been reported in the literature for surfacedoped semiconductors. 74,75 Interestingly, calculation of the optical penetration depth 55,70 yielded values of ≈200 and 140 nm for bare and Ti-modified ZnO samples, respectively. Taking into account that the average deposit thickness was 250 ± 20 nm (see above), these results indicate that the largest part of the incident radiation is effectively absorbed by the developed ZnO-based nanostructures, beneficially affecting in particular Ti-containing systems.…”