Mo掺杂Co-B非晶态合金的制备及催化硼氢化钠水解制氢性能

Preparation of Mo-doped Co-B Amorphous Alloy and Its Catalytic Performance on Sodium Borohydride Hydrolysis for Hydrogen Production

硼氢化钠作为金属氢化物,因具有储氢密度大、产氢纯度高、反应温度低、储存运输安全、能源循环利用率高等特点,成为目前产氢技术研究领域的热点之一。硼氢化钠水解产氢技术的关键在于催化剂。本研究采用化学还原法制备了掺杂助催剂Mo的三元非晶态Mo-Co-B纳米合金粉末,并将其用于催化硼氢化钠水解制氢。采用X射线衍射(XRD)仪、场发射透射电镜(FETEM)、扫描电镜(SEM)、能谱分析(EDS)对样品的结构、表面形貌、元素成分进行了表征。通过排水法进行NaBH 4溶液水解产氢反应,研究了催化剂的催化性能。结果表明,Mo的适量掺入能显著减小催化剂的粒径,增大其比表面积,提高Co-B催化剂的催化性能,但过量的Mo会导致粉末中的金属氧化物增多,不利于催化。当Mo/Co物质的量比为0.05时,催化剂表现出最佳的催化活性。此外,研究了催化剂用量、反应温度、NaBH 4浓度等因素对NaBH 4溶液水解产氢反应的影响。

As a metal hydride,sodium borohydride has become one of the hot spots in the field of hydrogen production due to its large hydrogen storage density,high hydrogen production purity,low reaction temperature,safe storage and transportation,and excellent energy cycle utilization.The key technology of hydrolysis of sodium borohydride to produce hydrogen lies in catalyst.In this study,a series of Mo-doped ternary Mo-Co-B amorphous alloy powders,catalysts for sodium borohydride hydrolysis for hydrogen production,were prepared by chemical reduction.The structure and properties of the Mo-Co-B alloy samples were characterized by X-ray diffractometer(XRD),field emission transmission electron microscope(FETEM),scanning electron microscope(SEM)and energy dispersive spectrometer(EDS).Furthermore,the catalytic activity of the samples was investigated by NaBH 4 hydrolysis reaction.As could be seen from the results,appropriate doping of Mo in Co-B contributed to reducing the particle size,enlarging the specific surface area and improving the catalytic activity of Co-B amorphous alloy.Whereas,excess Mo did harm to the catalytic reaction due to the increase of metal oxide in catalyst powder.The Mo-Co-B amorphous alloy exhibited optimum catalytic performance when n(Mo)/n(Co)was 0.05.Besides,the effects of reaction temperature,catalyst amount and NaBH 4 concentration on hydrogen generation rate were discussed as well.