Significant Absorption In Visible Region Research Articles

Computational exploration of janus ZrMCO2 (M=Ti, hf) MXenes for optoelectronic and photocatalytic applications

MXenes exhibit unique structural flexibility, excellent carrier mobility and abundant active sites, making them valuable catalysts in photocatalysis. The electronic properties and photocatalytic activity of Janus ZrMCO2 (M = Ti, Hf) MXenes are investigated by hybrid HSE06 functional. Photocatalytic activities of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are further explored. Structural stability is proved by negative cohesive energy and elastic stiffness coefficients. ZrTiCO2 and ZrHfCO2 are all direct semiconductors. Ti/Hf doping makes conduction band minimum (CBM) have a redshift and induces the reduction of band gaps of Janus systems. The three systems are potential photocatalysts due to their appropriate bandgaps and significant absorption in visible region. The irradiation-generated holes and electrons can easily drive the HER or OER on ZrHfCO2 MXene due to the small overpotential. ZrHfCO2 and Zr2CO2 are highly efficient for photocatalytic hydrogen production with STH efficient of 30.3%. Hf doping improves the photocatalytic reduction of CO2, while The Ti/Hf doping doesn't improve the N2 reduction.

First principles study on copper and iridium co-doped SrTiO3 for shifting the optical absorption into visible region

Density functional theory (DFT) investigation is performed to observe the opto-electronic properties of iridium and copper co-doped structure of Pristine SrTiO3 (Cubic Perovskite). Results suggest that copper and iridium co-doped structure of SrTiO3 has significant absorption in visible region of the spectrum, which is a result of red shift phenomenon in the wavelength range 400–750 nm observed in this structure. However, in individual copper and iridium structures the optical absorption is mainly in ultraviolet (UV) region which limits its use in light-based devices and applications. The shift in absorption from UV to visible region in the co-doped structure extracts the maximum utilization of solar light and finds wide range of optical applications like solar cells. Refractive index and dielectric constants were also calculated and their peak values were found to be in correlation with the peaks in absorption spectrum.

Synthesis, characterization and performance of visible light active C-TiO2 for pharmaceutical photodegradation

The present paper deals with photocatalytic degradation of carbamazepine and diclofenac by using a modified catalyst with band gap excitations in visible light. The C-doped TiO2 was synthesized using a microwave digestion method from titanium oxyacetylacetate with glucose as the carbon source. The synthesized catalyst was then characterized using Scanning Electron microscopy (SEM), X-ray Diffractometry (XRD), X-ray photoelectron spectroscopy (XPS) and UV-VIS-NIR spectrophotometer. The TiO2 present was in anatase phase and showed significant absorption in visible region. The catalyst was tested for the degradation of carbamazepine and diclofenac under visible light, where complete removal was achieved and the reaction followed first order kinetics. System parameters like catalyst and pollutant concentration, light intensity and time of reaction, were optimized using response surface methodology. In optimum conditions (catalyst concentration of 244mg/L and light intensity of 7715lx) 99% removal was achieved.