Visible light driven photocatalyst for degradation of pharmaceutical wastewaters

2018 Fiscal Year Annual Research Report

• Project/Area Number: 18F18387
• Research Institution: Kyushu University
• Principal Investigator: 笹木 圭子 九州大学, 工学研究院, 教授 (30311525)
• Co-Investigator(Kenkyū-buntansha): SEKAR KARTHIKEYAN 九州大学, 工学(系)研究科(研究院), 外国人特別研究員
• Project Period (FY): 2018-11-09 – 2021-03-31
• Keywords: Core-shell structure / Cu/Cu2O photocatalyst / visible light

Outline of Annual Research Achievements

The first part of JSPS fellowship, we have synthesized family of shape and size-controlled core shell-Cu/Cu2O as a promising visible light photocatalyst, since it possesses a direct band gap (1.9-2.4 eV) and high absorption coefficient across the solar spectrum. The chosen Cu based materials are earth abundant, economically viable for large scale catalytic processes such as organic decomposition. Therefore, we focused a facile one pot approach for systematic well-defined shape and size-controlled core-shell Cu/Cu2O photocatalyst synthesis, characterization and applied as a photocatalyst for model pharmaceutical compound (N-acetyl-para-aminophenol) photo mineralization. Shape control was achieved through the reduction of Cu(II) salts by H4N2.H2O in the presence of polyethylene glycol as a structure-directing agent. The resulting core-shell structure possessed lengths tunable from 200 to 1500 nm, dependents on the time and capping agent concentration. The surface and bulk properties of core-shell Cu/Cu2O photocatalysts was performed by diverse analytical facilities such as DRUVS, powder XRD, HRTEM, SEM and XPS, confirmed the morphology and surface properties. The above synthesized different core-shell catalyst showed excellent photodegradation activity of N-acetyl-para-aminophenol (as a model pharmaceutical pollutant) under visible light. Identification of by-products via HPLC on going experiment.

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

During 4 months we have synthesized a series of shape and size-controlled core shell-Cu/Cu2O and characterized them by DRUVS, powder XRD, HRTEM, SEM and XPS, confirmed the morphology and surface properties. The results provided us enough information to go to the next step.

Strategy for Future Research Activity

First phase of the present project will be demonstrating the facile one-pot systematic synthesis of well-defined hollow, core-shell, hierarchical Cu2O photocatalyst and control the morphology for band engineering and position towards visible active. And then synthesis of wide band gap nanofiber/ nanorods TiO2 photocatalyst using low cost, non -toxic precursor. The above core shell/hollow p-type Cu2O embedded in to n-type TiO2 nanofiber catalyst wrapped with RGO to minimize recombination, efficient charge separation properties to enhance antibiotics removal rate. To be check the charge transport properties by DRS-UV, XPS, TPRL etc., To be check the catalytic efficiency by paracetamol model substrate under visible light.
Second phase of the project will be develop new 2D/2D materials e.g. Hollow Cu2O/g-C3N4/RGO composites for visible light photocatalytic activity towards complex Ciprofloxacin, Trimethoprim, Ibuprofen, Iopamidol etc., The 2D/2D material design will be tuning the electronic properties (controlled size, morphology, core shell etc) for efficient utilize visible light region, and then create interfacial interaction between core -shell and bench mark photocatalyst (e.g. TiO2, ZnO) towards overall range light absorption . Finally, the minimize the change recombination by RGO introduction into the heterogeneous composites for prolong decomposition of antibiotics. The electronic, surface/bulk properties, surface area, band position, CB, VB positions and life time properties by various analytical tools.