复合催化剂Co@Co_3O_4催化硼氢化钠水解制氢性能研究

Hydrogen generation from hydrolysis of sodium borohydride solution via the Co@Co_3O_4 composite catalysts

采用不同的方法还原钴盐制备钴微粉,并用不同的氧化方法得到Co@Co_3O_4复合催化剂,探究了复合结构中钴微粉的制备方法、氧化方法、退火温度对Co@Co_3O_4催化剂催化硼氢化钠制氢性能的影响。利用能量散射X射线谱仪(EDS)、场发射扫描电子显微镜(SEM)、X射线衍射(XRD)等手段对样品的元素组成,微观形貌和结构进行了表征。利用碱性硼氢化钠水解制氢反应考察了所制备的Co@Co_3O_4复合催化剂的产氢性能。结果表明,化学还原法制备的钴微粉粒径较小、形貌均一,而退火后的Co@Co_3O_4复合催化剂具有磁性,这有利于催化剂的分离与收集。20mL含w(硼氢化钠)=4%的溶液在40℃时的产氢速率约为11.0L/(g·min)。

In this paper,Co powder was obtained by reduced cobalt salt via different methods,and Co@Co_3O_4 composite catalyst was prepared by different oxidation methods.The influences of Co@Co_3O_4 composite catalyst preparation conditions such as the different preparation methods of Co powder,oxidation ways and annealing temperature were investigated for hydrolysis of sodium borohydride solution.Energy dispersive X-ray spectrometer(EDS),field emission scanning electron microscope(SEM)and X-ray diffraction(XRD)were used to characterize the surface element composition,morphology and the structure of Co@Co_3O_4 composite catalyst.Hydrolysis of sodium borohydride solution to produce hydrogen was used as a probe reaction to evaluate the catalytic activity of the obtained catalyst.The results showed that the Co powder synthesized by chemical reduction method has the smallest particle size and uniform morphology.It is convenient to separate and collect the catalyst owing to the magnetism of the annealed Co@Co_3O_4 composite catalyst.The average hydrogen generation rate at 40℃ was 11.0L/(g·min)with 20 mL 4% NaBH_4 solution.