Aslam Jamal

Exploration of CeO2 nanoparticles as a chemi-sensor and photo-catalyst for environmental applications

CeO₂ nanoparticles were synthesized hydrothermally and utilized as redox mediator for the fabrication of efficient ethanol chemi-sensor. The developed chemi-sensor showed an excellent performance for electrocatalytic oxidization of ethanol by exhibiting higher sensitivity (0.92 μA∙cm⁻²∙mM⁻¹) and lower limit of detection (0.124±0.010 mM) with the linear dynamic range of 0.17 mM-0.17 M. CeO₂ nanoparticles have been characterized by field emission scanning electron microscopy (FESEM), Energy dispersive spectroscopy (EDS), X-ray powder diffraction (XRD), Raman spectrum, Fourier transform infrared spectroscopy (FTIR), and UV-visible absorption spectrum which revealed that the synthesized CeO₂ is an aggregated form of optically active spherical nanoparticles with the range of 15-36 nm (average size of ~25±10 nm) and possessing well crystalline cubic phase. Additionally, CeO₂ performed well as a photo-catalyst by degrading amido black and acridine orange.

Low-temperature growth of ZnO nanoparticles: photocatalyst and acetone sensor.

Well-crystalline ZnO nanoparticles (NPs) were synthesized in large-quantity via simple hydrothermal process using the aqueous mixtures of zinc chloride and ammonium hydroxide. The detailed structural properties were examined using X-ray diffraction pattern (XRD) and field emission scanning electron microscope (FESEM) which revealed that the synthesized NPs are well-crystalline and possessing wurtzite hexagonal phase. The NPs are almost spherical shape with the average diameters of ∼ 50 ± 10 nm. The quality and composition of the synthesized NPs were obtained using Fourier transform infrared (FTIR) and electron dispersed spectroscopy (EDS) which confirmed that the obtained NPs are pure ZnO and made with almost 1:1 stoichiometry of zinc and oxygen, respectively. The optical properties of ZnO NPs were investigated by UV-vis absorption spectroscopy. Synthesized ZnO NPs were extensively applied as a photocatalyst for the degradation of acridine orange (AO) and as a chemi-sensor for the electrochemical sensing of acetone in liquid phase. Almost complete degradation of AO has taken place after 80 min of irradiation time. The fabricated acetone sensor based on ZnO NPs exhibits good sensitivity (∼ 0.14065 μA cm(-2) mM(-1)) with lower detection limit (0.068 ± 0.01 mM) in short response time (10s).

CuO Codoped ZnO Based Nanostructured Materials for Sensitive Chemical Sensor Applications

Due to numerous potential applications of semiconductor transition metal-doped nanomaterials and the great advantages of hydrothermal synthesis in both cost and environmental impact, a significant effort has been employed for growth of copper oxide codoped zinc oxide (CuO codoped ZnO) nanostructures via a hydrothermal route at room conditions. The structural and optical properties of the CuO codoped ZnO nanorods were characterized using various techniques such as UV-visible, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), etc. The sensing performance has been executed by a simple and reliable I-V technique, where aqueous ammonia is considered as a target analyte. CuO codoped ZnO nanorods of thin film with conducting coating agents on silver electrodes (AgE, surface area of 0.0216 cm(2)) displayed good sensitivity, stability, and reproducibility. The calibration plot is linear over the large dynamic range, where the sensitivity is approximately 1.549 ± 0.10 μA cm(-2 )mM(-1) with a detection limit of 8.9 ± 0.2 μM, based on signal/noise ratio in short response time. Hence, on the bottom of the perceptive communication between structures, morphologies, and properties, it is displayed that the morphologies and the optical characteristics can be extended to a large scale in transition-metal-doped ZnO nanomaterials and efficient chemical sensors applications.

Role of ZnO-CeO2 Nanostructures as a Photo-catalyst and Chemi-sensor

ZnO-CeO 2 nanostructures were synthesized by simple and efficient low temperature method. The structure and morphology of the ZnO-CeO 2 nanostructures were characterized by X-ray powder diffraction (XRD) and field emission scanning electron microscopy (FESEM), which revealed elongated shaped CeO 2 nanoparticles with diameters of 40–90 nm distributed on the surface of elongated ZnO nanostructures with diameters of 50–200 nm (edge-centre). Further the structure of the synthesized ZnO-CeO 2 nanostructure was supported by Raman spectra and Fourier transform infrared spectroscopy (FTIR). UV-vis absorption spectrum was used to confirm the optical properties of the CeO 2 doped ZnO nanostructures. Photo-catalytic activity of CeO 2 doped ZnO nanostructure was evaluated by degradation of acridine orange and methylene blue which degraded 84.55% and 48.65% in 170 min, respectively. ZnO-CeO 2 nanostructures also showed good sensitivity (0.8331 μA·cm −2 ·(mol/l) −1 ) in short response time (10 s) by applying to chemical sensing using ethanol as a target compound by I – V technique. These degradation and chemical sensing properties of ZnO-CeO 2 nanostructures are of great importance for the application of ZnO-CeO 2 system as a photo-catalyst and chemical sensor.

Iron Oxide Nanoparticles

Mohammed M. Rahman1, Sher Bahadar Khan1,2, Aslam Jamal3, Mohd Faisal3 and Abdullah M. Aisiri1,2 1The Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah 2Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 3Centre for Advanced Materials and Nano-Engineering (CAMNE), Department of Chemistry, Faculty of Sciences and Arts, Najran University, Najran Kingdom of Saudi Arabia