Semiconductors photocatalyst, applied in the degradation of organic pollutants in water, were summarized due to its durability, low cost, low toxicity, super-hydrophilicity, and remarkable chemical and photochemical stability. Firstly, this paper intensively summarized the photocatalytic activity of single semiconductors photocatalyst. However, single semiconductors photocatalyst showed some drawbacks that is fast recombination of electron/hole, low adsorption about visible light and low surface coverage of photocatalysts. Thus, coupling semiconductors with desirable matching electronic bandgap and doping semiconductor photocatalysts have been discussed detailly. Notably, the Ag-based semiconductor photocatalysts has been highlight. The indicators for evaluating photocatalysis properties including pollution adsorption, kinetic and recyclability were discussed in detail. In addition, the mechanisms of photocatalytic reaction were discussed, which showed the mechanism is redox reaction and the process could degrade a wide range of organic pollutants into easily degradable intermediates or less toxic small molecular substances.

Action and mechanism of semiconductor photocatalysis on degradation of organic pollutants in water treatment: A review

Enhanced photocatalytic and antibacterial activities of Ag-doped TiO2 nanoparticles under visible light

Lightweight Ni Foam-Based Ultra-Broadband Electromagnetic Wave Absorber

The CO2 methanation mechanism was studied for Ni/CeO2 and Ni/Al2O3 catalysts. The higher methanation activity and selectivity of Ni/CeO2 is attributed to: i) Ni/CeO2 combines two types of active sites efficient for CO2 dissociation at the NiO-Ceria interface and for H2 dissociation on Ni0 particles; ii) water desorption is the slowest mechanism step, and, due to the high oxygen mobility throughout the ceria lattice, water is not necessarily formed on the same active sites that chemisorb CO2, i.e., the CO2 chemisorption sites are not blocked by water molecules; iii) the Ni/CeO2 surface does not accumulate carbon-containing species under reaction conditions, which allows faster chemisorption and dissociation of CO2. The Ni/Al2O3 catalyst handicaps are that all the steps of the mechanism take place on the same active sites, and the slow release of water and the accumulation of surface formates on these sites delay the chemisorption of further CO2 molecules.

Isotopic and in situ DRIFTS study of the CO2 methanation mechanism using Ni/CeO2 and Ni/Al2O3 catalysts

Colossal Permittivity Materials as Superior Dielectrics for Diverse Applications

The present work focuses on the synthesis, characterization and photocatalytic activity of a nanosized Fe-doped TiO2 photocatalyst. The samples were synthesized by the sol–gel method and characterized by using techniques such as x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDS), UV–visible spectroscopy, photoluminescence (PL) spectroscopy, Raman spectroscopy and Fourier-transform infrared (FTIR). The powder XRD spectra revealed that the synthesized samples are pure and crystalline in nature and show a tetragonal anatase phase of TiO2. The Raman spectroscopy also confirmed the formation of an anatase phase structure in both pure and Fe-doped TiO2 nanoparticles (NPs). The UV–visible and PL spectra illustrated the red shift in Fe-doped TiO2 NPs. The FTIR spectra indicated the vibrational band of the Ti–O lattice. The photocatalytic experimental results demonstrate that Fe-doped TiO2 NPs effectively degrade MB under visible-light illumination. Interestingly, the prepared TiO2 NPs with a dopant concentration of 3.0 mole% showed the maximum photocatalytic activity under investigation.

https://iopscience.iop.org/article/10.1088/2053-1591/aa576d/pdf

Photocatalytic performance of Fe-doped TiO2 nanoparticles under visible-light irradiation

Improved photocatalytic activity of Sr doped SnO2 nanoparticles: A role of oxygen vacancy

Electric transport and enhanced dielectric permittivity in pure and Al doped NiO nanostructures

We emphasized on a detailed investigation of the structural, optical, and magnetic properties of pure and Ni-doped SnO2 nanoparticles (NPs) synthesized by a sol-gel process. An extensive structural study has been carried out using various characterization techniques. The X-ray Diffraction (XRD) spectra show the formation of the single phase tetragonal structure of pure and Ni-doped SnO2 NPs without any noticeable impurity phase such as NiO. XRD results indicate that the crystallite size of SnO2 is found to be decreased with Ni doping, which has also been confirmed by the Field Emission Scanning Electron Microscopy study. X-ray Photoelectron Spectroscopy (XPS) measurements displayed a clear sign for Ni2+ ions occupying the lattice sites of Sn4+ in the SnO2 host which also gives clear evidence for the formation of single phase Sn1-xNixO2 NPs. The optical analysis shows a significant decrease in the energy gap of SnO2, i.e., (from 3.71 eV to 3.28 eV) as Ni concentration increases which may be correlated with...

Ateeq Ahmed

Papers

Enhanced photocatalytic and antibacterial activities of Ag-doped TiO2 nanoparticles under visible light

Photocatalytic performance of Fe-doped TiO2 nanoparticles under visible-light irradiation

Improved photocatalytic activity of Sr doped SnO2 nanoparticles: A role of oxygen vacancy

Electric transport and enhanced dielectric permittivity in pure and Al doped NiO nanostructures

Enhanced room temperature ferromagnetism in Ni doped SnO2 nanoparticles: A comprehensive study