CoB/C催化硼氢化钠水解制氢的性能

Catalytic Performance of CoB/C for Hydrolysis of NaBH_4 Aqueous Solution

使用浸渍负载-还原法及化学镀法制备了活性炭负载的CoB催化剂,研究了这些催化剂催化硼氢化钠水解制氢反应的性能。在温度为20℃，反应液为1％NaBH4＋5％NaOH的条件下，浸渍负载-还原法制备的CoB／C催化剂的产氢活性为2 022mL·min^-1（Co）,而化学镀法制备的CoB／C催化剂的产氢活性可达2503 mL·min^-1·g^-1（Co），相同条件下非负载的CoB催化剂的产氢活性仅为1 351mL·min^-1·g^-1（Co）。化学镀法制备的CoB／C催化剂重复使用5次后其活性仍能保持初始活性的70％，而浸渍负载的CoB／C催化剂及非负载的CoB催化剂的活性分别降至初始活性的30％和10％,化学镀法制备的CoB／C催化剂显示出更好的催化性能。此外该催化剂在空气中放置30d后催化活性没有明显下降，这为其存储和使用带来了便利。进一步的物理化学表征表明。非负载的CoB极易团聚，形成的二次粒子粒径在400～800nm，而活性炭负载的CoB催化剂团聚现象则大大减弱,CoB的分散性明显好于非负载催化剂。载体的存在可进一步阻止CoB活性组分在催化反应过程中发生团聚而避免活性下降。化学镀法制备的催化剂中，载体与CoB之间有更强的相互作用而使得后者结合紧密，分散良好，不易流失，催化剂整体上具有更好的稳定性。

The activated carbon supported CoB catalysts were prepared by using impregnation-reduction method （denoted as CoB/C-Imp） and electroless deposition method （denoted as CoB/C-ED）, respectively. The catalytic properties were studied on the hydrolysis of NaBH4 aqueous solution. The catalytic activity of CoB/C-ED, CoB/C- Imp and unsupported CoB was 2 022, 2 503 and 1 351 mL·min^-1·g-^1 （Co）, respectively. After 5 cycles, the CoB/ C-ED could retain 70% initial activity, but CoB/C-Imp and unsupported CoB could only retain 30% and 10% initial activity. The CoB/C-ED shows the best catalytic performance. Furthermore, no obvious decrease in the activity is observed for CoB/C-ED even after it is exposed to air for 30 days, this good anti-oxidation property is favorable for storage and use. Further physicochemical characterization of these catalysts reveals that the unsupported CoB is easily agglomerated and the size of the secondary particles is in the range of 400-800 nm. After CoB supported on carbon, the agglomeration is greatly restrained. The dispersion of CoB for the CoB/Ccatalysts is improved compared to the unsupported CoB. The support could also reduce the agglomeration of CoB particles during the catalytic reaction. The CoB particles combine much stronger with the activated carbon support for the CoB/C-ED catalyst, thus resulting in better dispersion and stability, and lesser leaching.