Synthesis and Enhanced Light Photocatalytic Activity of Modulating Band BiOBrXI1−X Nanosheets

Abstract

The photocatalysis technique has been proven to be a promising method to solve environmental pollution in situations of energy shortage, and has been intensively investigated in the field of pollutant degradation. In this work, a band structure-controlled solid solution of BiOBrXI1−X (x = 0.00, 0.05, 0.10, 0.15, 0.20, 1.00) with highly efficient light-driven photocatalytic activities was successfully synthesized via simple solvothermal methods. The phase composition, crystal structure, morphology, internal molecular vibration, optical properties, and energy band structure were characterized and analyzed by XRD, SEM, HRTEM, XPS, Raman, and UV Vis DRS. To evaluate the photocatalytic activity of BiOBrXI1−X, rhodamine B was selected as an organic pollutant. In particular, BiOBr0.15I0.85 displayed significantly enhanced photocatalytic activity by virtue of modulating the energy band position, optimizing redox potentials, and accelerating carrier separation. Moreover, the enhancement mechanism was elucidated on the basis of band structure engineering, which provides ideas for the design of highly active photocatalysts for practical application in the fields of environmental issues and energy conservation.

Tunable Absorption and Emission in Mixed Halide Bismuth Oxyhalides for Photoelectrochemical Water Splitting

“…The PL peaks for the pristine BiOI and pristine BiOBr samples are centered at 592 and 540 nm, respectively. The PL peaks of the Br-mixed BiOI samples are continuously blue-shifted as the Br content increases, which agrees with the optical absorption data of the as-synthesized samples as well as PL data from the literature. , The PL peak intensity of the 40Br-BiOI is highest among all the samples, which might be due to the strain caused by Br atom incorporation in the BiOI lattice. The strain can tune the electronic band structure as well as enhance the density of states for the carriers in a semiconductor .…”

Hydrothermal Synthesis and Photocatalytic Activity of NiTiO3 for the Degradation of Malachite Green under Visible Light Irradiation

“…Where E e symbolizes the free electrons (e À ) energy on the hydrogen scale (4:5 eV), E g is the gap's energy (2:24 eV), and X is the semiconductor absolute electronegativity ( in, eV), which is attained from the geometric mean of Pearson absolute electronegativity. [77][78][79] Based on Pearson, the electronegativity of NiTiO 3 is founded to 5:79 eV: [80] The measured E CB was + 0:21 eV, whereas the E VB value was þ2:36 eV. The standard potential of Red/Ox (E � O 2 =O* À So, the generated electrons (e À ) in the conductance band (CB) directly reacts with the MG molecules, forming MG@radical ions and resulting in the oxidation process.…”

“…This phenomenon is directly linked to the semiconductor band edge level used. According to Mulliken electronegativity theory, the relationships that determine the position of the valence band VB ð Þ and conduction band CB ð Þ for the NiTiO 3 are as follows: [77][78][79] E VB ¼ X À À E e þ 0:5 E g (6)…”

Visible light active dye-sensitizing titanium dioxide/graphene composites with excellent photocatalytic activity

“…17,20,22 The lamellar spacing of G increased from 0.172 nm to 0.415 nm, as a result of oxidation, calculated using the Scherrer formula (2). 23 This can be attributed to the introduction of numerous oxygen-containing groups, such as -COOH, -OH, and epoxy groups. 24 This indicates that all four materials contain anatase TiO 2 components, and their crystalline shape remains intact during the preparation process.…”