CH_4检测元件中Pd/Al_2O_3催化剂的制备及反应性能

Preparation and Working Performances of Pd/Al_2O_3 Catalyst in Methane Sensors

为提高矿井CH4浓度检测中催化元件的稳定性和可靠性,针对催化元件中催化剂性能这一核心问题进行研究是解决问题的关键.对催化剂结构的表征以及对催化元件工作性能和催化剂反应性能进行了测试,结果表明:经900℃焙烧处理的催化剂载体A l2O3具有适宜于反应的颗粒分散度与孔径分布,催化元件表现出较好工作性能.采用真空干燥处理制备的负载量为3%的Pd/A l2O3催化剂具有较高的反应活性;但助剂的加入使得反应活性有所降低;采用HC l作竞争吸附剂可使活性组分均匀分布于A l2O3内孔;载体的二次成型工艺在一定程度上降低了电桥的零点漂移,提高了催化元件的稳定性.

To improve the stability and reliability of methane sensors in mines, researching the properties of catalysts in methane sensors is crucial. The structures and reaction activities of catalysts and the working performances of methane sensors were tested. The results show that the Al22O3 calcined at 900℃ has preferable granule dispersiveness and aperture distribution and could make the sensors exhibit superior working performances. The catalysts dried in vacuum desiccator and contained 3 % Pd have high activity, however, adding catalyst accelerators decrease the activity of catalyst. Adopting HCl as sorption agent was benefit to the distribution of active components. Two-molding process could reduce the zero-excursion of electric bridge and improve the stability of methane sensors.