Photocatalysis

About: Photocatalysis is a research topic. Over the lifetime, 67088 publications have been published within this topic receiving 2145233 citations. The topic is also known as: photocatalyst.

Advances in Heterogeneous Photocatalytic Degradation of Phenols and Dyes in Wastewater: A Review

Abstract: The heterogeneous photocatalytic water purification process has gained wide attention due to its effectiveness in degrading and mineralizing the recalcitrant organic compounds as well as the possibility of utilizing the solar UV and visible light spectrum. This paper aims to review and summarize the recently published works in the field of photocatalytic oxidation of toxic organic compounds such as phenols and dyes, predominant in wastewater effluent. In this review, the effects of various operating parameters on the photocatalytic degradation of phenols and dyes are presented. Recent findings suggested that different parameters, such as type of photocatalyst and composition, light intensity, initial substrate concentration, amount of catalyst, pH of the reaction medium, ionic components in water, solvent types, oxidizing agents/electron acceptors, mode of catalyst application, and calcinations temperature can play an important role on the photocatalytic degradation of organic compounds in water environment. Extensive research has focused on the enhancement of photocatalysis by modification of TiO2 employing metal, non-metal, and ion doping. Recent advances in TiO2 photocatalysis for the degradation of various phenols and dyes are also highlighted in this review.

Photocatalytic Activity for Water Decomposition of RuO2-Dispersed Zn2GeO4 with d10 Configuration

Abstract: RuO2-dispersed Zn2GeO4 was found to become a stable photocatalyst for the overall splitting of water to produce H2 and O2. The photocatalytic properties were examined under various experimental conditions, and the band structure of Zn2GeO4 was revealed based on the DFT calculation. The photocatalytic activity depended on calcination temperatures of Zn2GeO4 and the amount of RuO2 loaded, and the combination of highly crystallized Zn2GeO4 with dispersed small RuO2 particles provided large photocatalytic activity. The GeO4 tertrahedron of Zn2GeO4 is so heavily distorted to generate a dipole moment inside, and the good photocatalytic performance of RuO2-dispersed Zn2GeO4 is in line with the view that the electron−hole separation upon photoexcitation is promoted by a local electric field due to dipole moment. The DFT calculation showed that the top of the valence band (HOMO) was composed of the O 2p orbital, whereas the bottom of conduction band (LUMO) was formed by the Ge 4p orbital with a small contribution ...

Nanocrystalline TiO2 Photocatalytic Membranes with a Hierarchical Mesoporous Multilayer Structure: Synthesis, Characterization, and Multifunction†

Abstract: A novel sol–gel dip-coating process to fabricate nanocrystalline TiO2 photocatalytic membranes with a robust hierarchical mesoporous multilayer and improved performance has been studied. Various titania sols containing poly(oxyethylenesorbitan monooleate) (Tween 80) surfactant as a pore-directing agent to tailor-design the porous structure of TiO2 materials at different molar ratios of Tween 80/isopropyl alcohol/acetic acid/titanium tetraisopropoxide = R:45:6:1 have been synthesized. The sols are dip-coated on top of a homemade porous alumina substrate to fabricate TiO2/Al2O3 composite membranes, dried, and calcined, and this procedure is repeated with varying sols in succession. The resulting asymmetric mesoporous TiO2 membrane with a thickness of 0.9 μm exhibits a hierarchical change in pore diameter from 2–6, through 3–8, to 5–11 nm from the top to the bottom layer. Moreover, the corresponding porosity is incremented from 46.2, through 56.7, to 69.3 %. Compared to a repeated-coating process using a single sol, the hierarchical multilayer process improves water permeability significantly without sacrificing the organic retention and photocatalytic activity of the TiO2 membranes. The prepared TiO2 photocatalytic membrane has great potential in developing highly efficient water treatment and reuse systems, for example, decomposition of organic pollutants, inactivation of pathogenic microorganisms, physical separation of contaminants, and self-antifouling action because of its multifunctional capability.

Bismuth Oxybromide with Reasonable Photocatalytic Reduction Activity under Visible Light

Abstract: The original bismuth-based oxyhalide, known as the Sillen family, is an important photocatalyst due to its high photocatalytic oxidation activity. Here, we report a bismuth-based photocatalyst, Bi24O31Br10, with reasonable reduction activity. The photoreduction capability of Bi24O31Br10 in H-2 evolution from water reduction is 133.9 mu mol after 40 h under visible light irradiation. Bi24O31Br10 presents the highest activity among Bi2O3, BiOBr, and Bi24O31Br10 in photocatalytic reduction of the Cr (VI) test, and Cr (VI) ions are totally removed in 40 mm. The Mott-Schottky test shows the bottom of the conduction band fits the electric potential requirements for splitting water to H-2. First-principles calculations indicate the conduction band of Bi24O31Br10 mainly consists of hybridized Bi 6p and Br 4s orbitals, which may contribute to the uplifting of the conduction band.