非晶态Ag表面修饰NiFe_2O_4的制备及对丙酮气体的气敏性能_英文_.pdfVIP

Trans. Nonferrous Met. Soc. China 22 2012 1127?1132 Preparation and gas sensing properties for acetone of amorphous Ag modified NiFe O sensor 2 4 JIAO Wan-li, ZHANG Lei School of Materials Science and Engineering, Shandong University of Technology, Zibo 255049, China Received 23 May 2011; accepted 11 January 2012 Abstract: Nickel ferrite nano-powders were prepared by microwave radiating low-temperature solid-state reaction method, and then modified with Ag by dipping method. The crystal structure and morphology of the samples were characterized by means of X-ray diffraction XRD , scanning electron microscopy SEM and X-ray photoelectron spectroscopy XPS . The gas sensing properties of the samples were also investigated. The results reveal that the Ag, as amorphous structure, can efficiently prevent the reuniting and growing-up of nanosized NiFe O grains, and 1.5% Ag modified NiFe O sensor has a better sensitivity, up to 43, for acetone gas 2 4 2 4 than 1.5%Ag mixed NiFe O sensor prepared by low-temperature solid-state reaction, at an optimal working voltage of 4.5 V. The 2 4 quick response time 1 s and fast recovery time ~10 s are the main characteristics of this sensor. Key words: nickel ferrite; low temperature solid state reaction; dipping method; silver; acetone cases are general complicated, expensive and far from 1 Introduction being environmentally friendly. A novel preparation technique of nanomaterials, convenient and environment Semiconducting metal oxides such as zinc oxide, tin friendly solid state reaction synthesis at ambient oxide and tungsten oxide have been widely studied for conditions, has been developed to prepare nanosized their gas sensing applications; however, presently many compounds. But the heat control problem existing in the other oxides have also been explored for the gas sensing low temperature solid state reaction is not solved devices. Recentl