摘要
铌酸铵草酸盐水合物是优质催化剂五氧化二铌的前驱体,制备过程中温度的选择和控制对产品的质量和性能有直接影响。本实验利用差热热重同步测定仪(TG-DTA)对铌酸铵草酸盐水合物在氮气和空气下的测试结果进行比较,利用热重/傅里叶变换红外光谱仪(TG/FTIR)对分解逸出气进行红外在线检测和分析,并利用可视化样品观察-热重分析仪(Real View-TG)对试样在热分解过程中的形貌进行实时拍摄,发现铌酸铵草酸盐水合物在400℃前出现3个失重过程,依次脱除H2O,COCO2CO、CO2NH3,但随着NH3的脱除和高活性催化剂Nb2O5的生成,部分CO逸出气发生二次反应(CO歧化反应),生成了碳(固体)和CO2(气体)。600℃附近的失重过程仅出现在空气气氛下,是逸出气二次反应产物碳与空气气氛中氧气发生氧化反应所致。
Ammonium niobate（V） oxalate hydrate （ANO）is an excellent precursor for the preparation of Nb205 catalyst. The selection and control of the temperature in the preparation process remarkably in- fluence the quality and performance of the product. The decompositions of ANO under the nitrogen and air atmosphere monitored by means of simultaneous thermal analyzer（TG-DTA） were compared, while the e- volved gases were characterized and analyzed by online thermogravimetry/Fourier transform infrared spectrometry （TG/FTIR）. The sample morphology was examined by real-view thermogravimetry（Real view- TG）. Three weight loss steps were observed before 400℃ and H2O,COCO2CO, CO2, NH3 evolved sequentially with an increase of temperature. Accompanied by the evolution of NH3 and generation of highly active Nb205, some of evolved CO underwent secondary reaction, i. e. , the disproportionation of CO, to produce C （solid） and CO2 （gas）. The weight loss happened at near 600℃ in air, which was due to the oxidation of C, but no such a reaction was observed in inert atmosphere.
作者
章斐
赵博涵
Zhang Fei;Zhao Bohan(Analytical Instrumentation Center,Peking University;College of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China)
出处
《分析仪器》
CAS
2018年第4期154-158,共5页
Analytical Instrumentation
