Recent advances in noble metal free doped graphitic carbon nitride based nanohybrids for photocatalysis of organic contaminants in water: A review

Advanced oxidation processes (AOPs) introduce a hopeful technology for the removal of water polluted with hard degradable organic compounds. Today, one of the main effective AOP technologies to degrade these hazardous organics is via the photocatalytic process. The present review focuses on the recent progress in the fixed-bed and immobilized nanophotocatalysts and also their applications for resolving the environmental concerns. Various organics elimination using a variety of photocatalysts and innovative reactors are discussed. This critical review summarizes the recent progress in the synthesis and modification (physical and chemical) of semiconductors. Furthermore, different ways of photocatalysts immobilization are explained in details. By considering different dangerous chemicals present in wastewater and different industries, catalytic methods used by researchers to degrade these organic compounds are reviewed. In addition, the degradation pathway of some organics through the catalytic operation is described.

Application of Heterogeneous Nano-Semiconductors for Photocatalytic Advanced Oxidation of Organic Compounds: A Review

N self-doped ZnO derived from microwave hydrothermal synthesized zeolitic imidazolate framework-8 toward enhanced photocatalytic degradation of methylene blue.

Enhanced photocatalytic activity of surface disorder-engineered CaTiO3

In the present study, mpg-C3N4/Ag/ZnO NWs/Zn photocatalyst plates were fabricated through facile dip-coating process of silver (Ag) and mesoporous graphitic carbon nitride (mpg-C3N4) onto zinc oxide nanowires (ZnO NWs) previously formed by electrochemical anodizing of Zn plates. The structure, optical and electrochemical characterizations of the fabricated samples were investigated by XRD, FESEM, EDX, TEM, FTIR, BET, PL, UV–vis DRS, and EIS analyses. To evaluate the photocatalytic activity of the plates, the main key factors such as number of photocatalyst plates, dye concentration, initial pH, and reaction time for the degradation of Direct Orange 26 (DO26) dye under ultraviolet (UV) light illumination were studied. The best photocatalytic efficiency of 94 % was achieved using four photocatalyst plates, 10 mg/L DO26, and pH = 6 in 120 min of reaction time. The integration of the mpg-C3N4/Ag/ZnO NWs/Zn plates, adsorption, and photolysis inferred the existence of a synergy index of 5 for the degradation of target pollutant. In the presence of edetate disodium (EDTA-2Na) and ethanol (EtOH), degradation efficiency of DO26 was remarkably dropped to 43.6 % and 19.3 % by the photocatalytic process respectively, indicating the major role of h+ and OH in the destruction of target molecules. The overwhelming photocatalytic mechanism of the photocatalyst was further clarified for the elimination of DO26. The fabricated photocatalyst demonstrated remarkable stability and recyclability for four consecutive catalytic cycles. Fabrication of the mpg-C3N4/Ag/ZnO NWs/Zn plates is anticipated to be a rational design for photocatalytic degradation of various pollutants.

Facile fabrication of mpg-C3N4/Ag/ZnO nanowires/Zn photocatalyst plates for photodegradation of dye pollutant

Fabrication of cost effective g-C3N4+Ag activated ZnO photocatalyst in thin film form for enhanced visible light responsive dye degradation

Cost-effective fabrication of ZnO/g-C 3 N 4 composite film coated stainless steel meshes for visible light responsive photocatalysis

Cost-effective fabrication of (g-C3N4 + Mo) added photostable ZnO thin films for enhanced visible light responsive photocatalytic dye degradation

The aim of this work is to investigate the effects of film thickness, light intensity and Ag incorporation on the photoctalytic efficacy of zinc oxide films. ZnO films with different thicknesses were prepared using an automated home-made jet nebuliser spray technique. The results show that the thickness of the film has no appreciable influence on the photocatalytic efficiency of ZnO films whereas the light intensity strongly influences the photocatalytic activity of ZnO films. It is also found that doping of Ag with ZnO causes considerable enhancement in the photocatalytic activity. The dye degradation rate constant in the case of undoped ZnO film with thickness 400 nm is 0.0263min-1, whereas for Ag doped ZnO film having the same thickness, it is 0.0530 min−1. The reason for this enhancement in the photocatalytic efficacy of ZnO:Ag film is addressed with the help of optical band gap and the reported characteristics of Ag.

Photocatalytic efficacy of ZnO films – light intensity and thickness effects

This study focuses the effect of Mg doping level (0–12 at.% in steps of 3 at.%) on the photocatalytic efficacy of ZnO:F:Mg nanopowder synthesised using a simple cost-effective chemical method. The structural, surface morphological, photoluminescence studies were carried out for all the samples. The photocatalytic dye degradation study under visible light against the two different dyes viz methylene blue (MB) and malachite green (MG) revealed that ZnO:F:Mg nanopowder doped with 12 at.% of Mg shows superior photocatalytic activity compared to other doped and undoped samples for both the dyes examined. The degradation efficiency of undoped ZnO is found to be 65 and 74% for MB and MG, respectively, whereas the F + Mg co-doped ZnO nanopowder (10 + 12 at.%) exhibits enhanced photocatalytic activity against both the dyes and the degradation efficiency values for MB and MG are 88 and 97%, respectively. The reasons for this enhancement are addressed appropriately with the evidences obtain from photoluminescence and X-ray diffraction studies.

E. Sindhuja

Papers

Fabrication of cost effective g-C3N4+Ag activated ZnO photocatalyst in thin film form for enhanced visible light responsive dye degradation

Cost-effective fabrication of ZnO/g-C 3 N 4 composite film coated stainless steel meshes for visible light responsive photocatalysis

Cost-effective fabrication of (g-C3N4 + Mo) added photostable ZnO thin films for enhanced visible light responsive photocatalytic dye degradation

Photocatalytic efficacy of ZnO films – light intensity and thickness effects

Synergistic effects of Mg and F doping on the photocatalytic efficiency of ZnO nanoparticles towards MB and MG dye degradation