A. M. El-Sayed

Some Semiconductor Properties of Carboxymethyl Cellulose-Copper Complexes

Abstract Metal chelates of three grades of carboxymethyl cellulose (CMC) (LI-L3) with Cu(II) ions, either originating from CuCl2 or CuSO4, were prepared and characterized by elemental analysis, infrared spectra, and electrical conductivity studies. The results showed that the degree of substitution of CMCs and the origin of the Cu(II) ion have a profound effect on the amount of metal included in the polymer complexes and the structure and the electrical conductivity of the prepared complexes. CMC acts as a uninegatively charged bidentate ligand when it is chelated with Cu(II) of CuCl2 via the carboxymethyl group and exhibits the formula Cu(L)2, whereas it acts as a binegatively charged bitentate ligand when it is chelated with CuSO4 via the carboxymethyl and secondary hydroxyl groups and exhibits the formula CuL.2H2O. The investigation revealed that the electrical conductivity depends on the temperature and has two maximum peaks. The values of the activation energy for the conductivity of CMC and their co...

Highly Sensing Properties Sensors Based on Ce-doped ZnO and SnO2 Nanoparticles to Ethanol Gas

The detection of different types of gases and quantification of their precisely concentration have wide applications in different fields like domestic gas alarms, medical diagnostic equipment, industrial safety, environmental pollution, military field and food industry [Papadopoulos et al (1996), Wang C et al (2009), Wetchakun et al (2011), Brudzewski et al (2012), Mielle et al (2001) and Fleming (2001)]. With numerous industries that utilize or produce ethanol, it is apparent that reliable methods are needed Abstract

Influence of single and binary transition metal dopants (Mn, Fe, or Co) on the structure, optical, and magnetic properties of SnO2 nanoparticles

Nanoparticles samples of pure SnO2, Sn0.99Mn0.01O2, Sn0.98Mn0.02O2, Sn0.98Mn0.01Fe0.01O2, Sn0.96Mn0.02Fe0.02O2, Sn0.98Mn0.01Co0.01O2 and Sn0.96Mn0.02Co0.02O2 were synthesized by sol-gel method. X-ray diffraction analysis and Fourier transform infrared spectra of all prepared samples confirmed the formation of single phase SnO2 with tetragonal rutile structure. The average crystallite sizes of the prepared samples were estimated to be in the range of 7–12 nm. Energy-dispersive X-ray spectroscopy analysis of Sn0.98Mn0.02O2, Sn0.96Mn0.02Fe0.02O2, and Sn0.96Mn0.02Co0.02O2 samples evidently proved the existence of Mn, Fe, Co, Sn, and O elements only without any impurity, indicating the high purity of the prepared samples. Transmission electron microscopy images showed the formation of ultra-fine spherical nanoparticles in all samples with average particles sizes of 8.5–15 nm. From the UV–Vis absorption spectra results, the band gap energy value of the pure SnO2 nanoparticles was estimated to be 3.90 eV and it varied with dopant type and its concentration. Room temperature magnetic hysteresis loops of all samples exhibited ferromagnetic behavior. Clear enhancement in the room temperature ferromagnetism was achieved in pure SnO2 nanoparticles after doping with Mn and codoping with (Mn, Fe) or (Mn, Co) dopants. The maximum value of the saturation magnetization was found in Sn0.96Mn0.02Fe0.02O sample, while Sn0.96Mn0.02Co0.02O sample displayed the higher values of coercivity and retentivity.Graphical Abstract