Najran University

About: Najran University is a education organization based out in Najrān, Saudi Arabia. It is known for research contribution in the topics: Photocatalysis & Population. The organization has 751 authors who have published 1809 publications receiving 28233 citations.

Zinc Oxide Nanostructures for NO2 Gas–Sensor Applications: A Review

Abstract: Because of the interesting and multifunctional properties, recently, ZnO nanostructures are considered as excellent material for fabrication of highly sensitive and selective gas sensors. Thus, ZnO nanomaterials are widely used to fabricate efficient gas sensors for the detection of various hazardous and toxic gases. The presented review article is focusing on the recent developments of NO2 gas sensors based on ZnO nanomaterials. The review presents the general introduction of some metal oxide nanomaterials for gas sensing application and finally focusing on the structure of ZnO and its gas sensing mechanisms. Basic gas sensing characteristics such as gas response, response time, recovery time, selectivity, detection limit, stability and recyclability, etc are also discussed in this article. Further, the utilization of various ZnO nanomaterials such as nanorods, nanowires, nano-micro flowers, quantum dots, thin films and nanosheets, etc for the fabrication of NO2 gas sensors are also presented. Moreover, various factors such as NO2 concentrations, annealing temperature, ZnO morphologies and particle sizes, relative humidity, operating temperatures which are affecting the NO2 gas sensing properties are discussed in this review. Finally, the review article is concluded and future directions are presented.

Hierarchical porous carbon aerogel derived from bagasse for high performance supercapacitor electrode

Abstract: Renewable, cost-effective and eco-friendly electrode materials have attracted much attention in the energy conversion and storage fields. Bagasse, the waste product from sugarcane that mainly contains cellulose derivatives, can be a promising candidate to manufacture supercapacitor electrode materials. This study demonstrates the fabrication and characterization of highly porous carbon aerogels by using bagasse as a raw material. Macro and mesoporous carbon was first prepared by carbonizing the freeze-dried bagasse aerogel; consequently, microporous structure was created on the walls of the mesoporous carbon by chemical activation. Interestingly, it was observed that the specific surface area, the pore size and distribution of the hierarchical porous carbon were affected by the activation temperature. In order to evaluate the ability of the hierarchical porous carbon towards the supercapacitor electrode performance, solid state symmetric supercapacitors were assembled, and a comparable high specific capacitance of 142.1 F g−1 at a discharge current density of 0.5 A g−1 was demonstrated. The fabricated solid state supercapacitor displayed excellent capacitance retention of 93.9% over 5000 cycles. The high energy storage ability of the hierarchical porous carbon was attributed to the specially designed pore structures, i.e., co-existence of the micropores and mesopores. This research has demonstrated that utilization of sustainable biopolymers as the raw materials for high performance supercapacitor electrode materials is an effective way to fabricate low-cost energy storage devices.

Ag Nanowire Reinforced Highly Stretchable Conductive Fibers for Wearable Electronics

Abstract: Stretchable conductive fi bers have received signifi cant attention due to their possibility of being utilized in wearable and foldable electronics. Here, highly stretchable conductive fi ber composed of silver nanowires (AgNWs) and silver nanoparticles (AgNPs) embedded in a styrene‐butadiene‐styrene (SBS) elastomeric matrix is fabricated. An AgNW-embedded SBS fi ber is fabricated by a simple wet spinning method. Then, the AgNPs are formed on both the surface and inner region of the AgNW-embedded fi ber via repeated cycles of silver precursor absorption and reduction processes. The AgNW-embedded conductive fi ber exhibits superior initial electrical conductivity ( σ 0 = 2450 S cm −1 ) and elongation at break (900% strain) due to the high weight percentage of the conductive fi llers and the use of a highly stretchable SBS elastomer matrix. During the stretching, the embedded AgNWs act as conducting bridges between AgNPs, resulting in the preservation of electrical conductivity under high strain (the rate of conductivity degradation, σ / σ 0 = 4.4% at 100% strain). The AgNW-embedded conductive fi bers show the strain-sensing behavior with a broad range of applied tensile strain. The AgNW reinforced highly stretchable conductive fi bers can be embedded into a smart glove for detecting sign language by integrating fi ve composite fi bers in the glove, which can successfully perceive human motions.