Preparation of polythiophene/WO_3 organic-inorganic hybrids and their gas sensing properties for NO_2 detection at low temperature

Polythiophene/WO3（PTP/WO3）organic-inorganic hybrids were synthesized by an in situ chemical oxidative polymerization method,and char- acterized by X-ray diffraction（XRD）,transmission electron microscopy（TEM）and thermo-gravimetric analysis（TGA）.The Polythiophene/ WO3 hybrids have higher thermal stability than pure polythiophene,which is beneficial to potential application as chemical sensors.Gas sensing measurements demonstrate that the gas sensor based on the Polythiophene/WO3 hybrids has high response and good selectivity for de- tecting NO2 of ppm level at low temperature.Both the operating temperature and PTP contents have an influence on the response of PTP/WO3 hybrids to NO2.The 10 wt%PTP/WO3 hybrid showed the highest response at low operating temperature of 70-C.It is expected that the PTP/WO3 hybrids can be potentially used as gas sensor material for detecting the low concentration of NO2 at low temperature.

Key Problems and Countermeasures in CO_(2)Flooding and Storage

Based on literature research in combination with the practice of CO_(2)flooding and storage in Jilin Oilfield,this study assesses the key problems in CO_(2)flooding and storage,proposing the corresponding countermeasures from five aspects of CO_(2)gas source condition,namely geological condition evaluation,scheme design incoordination with other production methods,economic and effectiveness evaluation,together with dynamic monitoring and safety evaluation.The results show that CO_(2)flooding is the most economic and effective CO_(2)storage method.In eastern China,inorganic origin CO_(2)gas reservoirs are widely developed and are especially the most enriched in the Paleozoic carbonate rock strata and the Cenozoic Paleogene–Neogene system,which provide a rich resource base for CO_(2)flooding and storage.In the future,CO_(2)generated in the industrial field will become the main gas source of CO_(2)flooding and storage.The evaluation of geological conditions of oil and gas reservoirs is the basis for the potential evaluation,planning scheme design and implementation of CO_(2)flooding and storage.CO_(2)storage should be below the depth of 800 m,the CO_(2)flooding and storage effects in lowpermeability oil reservoirs being the best.CO_(2)geological storage mechanisms primarily consist of tectonic geological storage,bound gas storage,dissolution storage,mineralization storage,hydrodynamic storage and coalbed adsorption storage.The practice of CO_(2)flooding and storage in Jilin Oilfield demonstratesthat the oil increment by CO_(2)flooding is at least 24%higher than by conventional water flooding.The most critical factor determining the success or failure of CO_(2)flooding and storage is economic effectiveness,which needs to be explored from two aspects:the method and technology innovation along with the carbon peaking and carbon neutrality policy support.After CO_(2)is injected into the reservoir,it will react with the reservoir and fluid,the problem of CO_(2)recovery or overflow will occur,so the dynamic monitoring and safety evaluation of CO_(2)flooding and storage are very important.This study is of great significance to the expansion of the application scope of CO_(2)flooding and storage and future scientific planning and deployment.

Improved formaldehyde gas sensing properties of well-controlled Au nanoparticle-decorated In2O3 nanofibers integrated on low power MEMS platform

Approaches for the fabrication of a low power-operable formaldehyde(HCHO)gas sensor with high sensitivity and selectivity were performed by the utilization of an effective micro-structured platform with a micro-heater to reach high temperature with low heating power as well as by the integration of indium oxide(In2O3)nanofibers decorated with well-dispersed Au nanoparticles as a sensing material.Homogeneous In2O3 nanofibers with the large specific surface area were prepared by the electrospinning following by calcination process.Au nanoparticles with the well-controlled size as a catalyst were synthesized on the surface of In2O3 nanofibers.The Au-decorated In2O3 nanofibers were reliably integrated as sensing materials on the bridge-type micro-platform including micro-heaters and micro-electrodes.The micro-platform designed to maintain high temperature with low power consumption was fabricated by a microelectromechanical system(MEMS)technique.The micro-platform gas sensor consisting with Au-In2O3 nanofibers were fabricated effectively to detect HCHO gases with high sensitivity and selectivity.The HCHO gas sensing behaviors were schematically studied as a function of the gas concentration,the size of the adsorbed Au nanoparticles,the applied power to raise the temperature of a sensing part and the kind of target gases.

High temperature H_(2)S selective oxidation on a copper-substituted hexaaluminate catalyst: A facile process for treating low concentration acid gas

H_(2)S selective catalytic oxidation technology is a prospective way for the treatment of low concentration acid gas with simple process operation and low investment. However, undesirable results such as large formation of SO_(2) and catalyst deactivation inevitably occur, due to the temperature rise of fixed reaction bed caused by the exothermic reaction. Catalyst with high activity in wide operating temperature window, especially in high temperature range, is urgently needed. In this paper, a series of copper-substituted hexaaluminate catalysts (LaCu_(x), x = 0, 0.5, 1, 1.5, 2, 2.5) were prepared and investigated for the H_(2)S selective oxidation reaction at high temperature conditions (300-550℃). The LaCu_(1) catalyst exhibited excellent catalytic performance and great stability, which was attributed to the best reductive properties and proper pore structure. Besides, two facile deep processing paths were proposed to eliminate the remaining H_(2)S and SO_(2) in the tail gas.

Indium-organic framework CPP-3(In)derived Ag/In_(2)O_(3) porous hexagonal tubes for H_(2)S detection at low temperature

There is a great demand for high-performance hydrogen sulfide(H_(2)S)sensors with low operating temperatures.Ag/In_(2)O_(3)hexagonal tubes with different proportions were prepared by the calcination of Ag+-impregnated indium-organic frameworks(CPP-3(In)),and the developed sensors exhibit enhanced gas-sensing performance toward H_(2)S.Gas sensing measurements indicate that the response of Ag/In_(2)O_(3)(2.5 wt%)sensor to 5 ppm H_(2)S has the highest response(119),operated at 70℃.The Ag/In_(2)O_(3)(2.5 wt%)based sensor exhibits short response time(20 s),low detection limit(300 ppb),and good selectivity toward H_(2)S gas,which imply that the CPP-3(In)-derived Ag/In_(2)O_(3)hexagonal tube is a promising candidate to be constructed a low power-consumption H_(2)S sensor.