M.M. Arafat

Bio: M.M. Arafat is an academic researcher from University of Malaya. The author has contributed to research in topics: Intermetallic & Thermal oxidation. The author has an hindex of 12, co-authored 20 publications receiving 751 citations.

Gas sensors based on one dimensional nanostructured metal-oxides: a review.

Abstract: Recently one dimensional (1-D) nanostructured metal-oxides have attracted much attention because of their potential applications in gas sensors. 1-D nanostructured metal-oxides provide high surface to volume ratio, while maintaining good chemical and thermal stabilities with minimal power consumption and low weight. In recent years, various processing routes have been developed for the synthesis of 1-D nanostructured metal-oxides such as hydrothermal, ultrasonic irradiation, electrospinning, anodization, sol-gel, molten-salt, carbothermal reduction, solid-state chemical reaction, thermal evaporation, vapor-phase transport, aerosol, RF sputtering, molecular beam epitaxy, chemical vapor deposition, gas-phase assisted nanocarving, UV lithography and dry plasma etching. A variety of sensor fabrication processing routes have also been developed. Depending on the materials, morphology and fabrication process the performance of the sensor towards a specific gas shows a varying degree of success. This article reviews and evaluates the performance of 1-D nanostructured metal-oxide gas sensors based on ZnO, SnO2, TiO2, In2O3, WOx, AgVO3, CdO, MoO3, CuO, TeO2 and Fe2O3. Advantages and disadvantages of each sensor are summarized, along with the associated sensing mechanism. Finally, the article concludes with some future directions of research.

In-situ fabricated gas sensors based on one dimensional core-shell TiO2-Al2O3 nanostructures

Abstract: A novel in-situ sensor fabrication method consisting of one dimensional (1-D) core-shell TiO2-Al2O3 nanostructures is reported. The 1-D nanostructures were synthesized on Ti-6Al-4V (Ti64) particles by a robust, simple, inexpensive and highly scalable route based on thermal oxidation. The in-situ fabricated sensors were tested in various reducing and oxidizing gases including hydrogen (H2), hydrogen sulfide (H2S), carbon monoxide (CO), methane (CH4), methanol (CH3OH), ethanol (C2H5OH), ethylene (C2H4), nitrogen dioxide (NO2) and oxygen (O2). The selectivity, sensitivity, optimum operating temperature, response time and recovery time of the sensors were examined. Results reveal that the as-grown 1-D nanostructures are 1–5 μm long with diameter of 30–100 nm. The core and shell of the 1-D nanostructures consist of rutile-TiO2 and corundum-Al2O3, respectively. The growth direction of TiO2 and Al2O3 are 〈002〉 and 〈110〉, respectively. The sensors consisting of 1-D core-shell TiO2-Al2O3 nanostructures show n-type sensing behavior. Selective sensitivity is seen towards H2S, CH3OH and C2H5OH in N2 background with response values of 38.7, 349.6 and 1108.9, respectively. The response time of the sensors decreases and recovery time increases with increasing the concentration of target gases. An electron tunneling assisted surface depletion model is proposed to explain the sensing mechanism of these sensors.

Gas Sensors Based on One Dimensional Nanostructured Metal‐Oxides: A Review

Abstract: Recently one dimensional (1-D) nanostructured metal-oxides have attracted much attention because of their potential applications in gas sensors. 1-D nanostructured metal-oxides provide high surface to volume ratio, while maintaining good chemical and thermal stabilities with minimal power consumption and low weight. In recent years, various processing routes have been developed for the synthesis of 1-D nanostructured metal-oxides such as hydrothermal, ultrasonic irradiation, electrospinning, anodization, sol-gel, molten-salt, carbothermal reduction, solid-state chemical reaction, thermal evaporation, vapor-phase transport, aerosol, RF sputtering, molecular beam epitaxy, chemical vapor deposition, gas-phase assisted nanocarving, UV lithography and dry plasma etching. A variety of sensor fabrication processing routes have also been developed. Depending on the materials, morphology and fabrication process the performance of the sensor towards a specific gas shows a varying degree of success. This article reviews and evaluates the performance of 1-D nanostructured metal-oxide gas sensors based on ZnO, SnO2, TiO2, In2O3, WOx, AgVO3, CdO, MoO3, CuO, TeO2 and Fe2O3. Advantages and disadvantages of each sensor are summarized, along with the associated sensing mechanism. Finally, the article concludes with some future directions of research.

Nanoscale metal oxide-based heterojunctions for gas sensing: A review

Abstract: Metal oxide-based resistive-type gas sensors are solid-state devices which are widely used in a number of applications from health and safety to energy efficiency and emission control. Nanomaterials such as nanowires, nanorods, and nanoparticles have dominated the research focus in this field due to their large number of surface sites facilitating surface reactions. Previous studies have shown that incorporating two or more metal oxides to form a heterojunction interface can have drastic effects on gas sensor performance, especially the selectivity. Recently, these effects have been amplified by designing heterojunctions on the nano-scale. These designs have evolved from mixed commercial powders and bi-layer films to finely-tuned core–shell and hierarchical brush-like nanocomposites. This review details the various morphological classes currently available for nanostructured metal-oxide based heterojunctions and then presents the dominant electronic and chemical mechanisms that influence the performance of these materials as resistive-type gas sensors. Mechanisms explored include p–n and n–n potential barrier manipulation, n–p–n response type inversions, spill-over effects, synergistic catalytic behavior, and microstructure enhancement. Tables are presented summarizing these works specifically for SnO2, ZnO, TiO2, In2O3, Fe2O3, MoO3, Co3O4, and CdO-based nanocomposites. Recent developments are highlighted and likely future trends are explored.

One-dimensional titanium dioxide nanomaterials: nanotubes.

Abstract: In the present review we try to give a comprehensive and most up to date view to the field, with an emphasis on the currently most investigated anodic TiO2 nanotube arrays. We will first give an overview of different synthesis approaches to produce TiO2 nanotubes and TiO2 nanotube arrays, and then deal with physical and chemical properties of TiO2 nanotubes and techniques to modify them. Finally, we will provide an overview of the most explored and prospective applications of nanotubular TiO2.

Recent Progress on the Development of Chemosensors for Gases.

Abstract: Xin Zhou,†,‡ Songyi Lee,† Zhaochao Xu,* and Juyoung Yoon*,† †Department of Chemistry and Nanoscience, Ewha Womans University, Seoul 120-750, Republic of Korea ‡Research Center for Chemical Biology, Department of Chemistry, Yanbian University, Yanjii 133002, People’s Republic of China Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Shahekou, Dalian, Liaoning, People’s Republic of China