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CoCr2O4 nanospheres for low temperature methane oxidation
CrystEngComm ( IF 2.6 ) Pub Date : 2020-06-17 , DOI: 10.1039/d0ce00698j
Yiling Dai 1, 2, 3, 4 , Haiyan Wang 2, 3, 4, 5 , Shida Liu 2, 3, 4, 5 , Kevin J. Smith 2, 3, 4, 5 , Michael O. Wolf 1, 2, 3, 4 , Mark J. MacLachlan 1, 2, 3, 4
Affiliation  

Spinel CoCr2O4 nanostructured catalysts were prepared by a facile solvothermal method using benzyl alcohol as both a structure-directing agent and a reagent. The growth mechanism of the CoCr2O4 nanospheres was studied by Fourier-transform infrared (FTIR) spectroscopy and powder X-ray diffraction (PXRD). The influence of solvothermal reaction time on the morphology, structure, and oxidation states of the products was investigated through scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). It was found that early in the reaction, the CoCr2O4 spheres are coated with parasitic Co3O4 nanoparticles that disappear after long reaction times to yield smooth CoCr2O4 particles. The catalytic performance of the noble metal-free nanospheres was optimized for oxidation of methane to CO2 as evaluated at a high space velocity of 180 000 mL g−1 h−1, reaching 100% conversion below 500 °C. Importantly, samples prepared with 8 h solvothermal treatment exhibit excellent stability, maintaining 80% conversion in the presence of 10% H2O and 5 ppm SO2 after 10 cycles (∼170 h). The high stability gives these nanomaterials valuable potential for application in natural gas vehicles.

中文翻译:

CoCr2O4纳米球用于低温甲烷氧化

尖晶石CoCr 2 O 4纳米结构催化剂是通过使用苯甲醇作为结构导向剂和试剂的溶剂热法制备的。通过傅立叶变换红外光谱(FTIR)和粉末X射线衍射(PXRD)研究了CoCr 2 O 4纳米球的生长机理。通过扫描电子显微镜(SEM),高分辨率透射电子显微镜(HRTEM)和X射线光电子能谱(XPS)研究了溶剂热反应时间对产物形态,结构和氧化态的影响。发现在反应的早期,CoCr 2 O 4球被寄生的Co 3包覆。O 4纳米颗粒在长时间反应后消失,生成光滑的CoCr 2 O 4颗粒。如在180000 mL g -1 h -1的高空速下评估的,在500°C以下达到100%的转化率时,不含贵金属的纳米球的催化性能针对甲烷氧化成CO 2进行了优化。重要的是,用8小时溶剂热处理制备的样品表现出出色的稳定性,在10个循环(约170小时)后,在10 %H 2 O和5 ppm SO 2的存在下保持80%的转化率。高稳定性使这些纳米材料在天然气汽车中具有宝贵的应用潜力。
更新日期:2020-07-06
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