二氧化硅负载钌催化剂催化氨硼烷水解产氢研究

采用浸渍-还原法制备了Ru/SiO2催化剂,并考察了钌负载量、还原剂硼氢化钠的用量、还原温度以及反应条件对催化剂Ru/SiO2催化BH3NH3水解产氢的影响。结果表明,在钌的负载量为0.1%(质量分数)、还原剂硼氢化钠与钌的物质的量比为2.2∶1、还原温度为303 K时制备的催化剂,催化BH3NH3水解产氢速率最快转化频率TOF为140.8 L H2/(mol Ru·min)]。搅拌转速为450 r/min时,氨硼烷向催化剂表面传质最快,产氢速率最大。氨硼烷水解反应由催化剂界面反应控制,产氢速率与催化剂用量成正比。随着反应温度的升高,Ru活化的氨硼烷分子能量增加,反应速率逐渐增加。反应动力学计算表明Ru/SiO2催化剂催化BH3NH3水解产氢反应对氨硼烷浓度为零级反应,活化能为45 kJ/mol。

Research on Ru/SiO2 catalysts for hydrogen generation from catalytic hydrolysis of ammonia borane

Ru/SiO₂ catalysts were synthesized via an impregnation-reduction method.The effect of Ru loading amount,amount of NaBH₄ as the reducing agent,reduction temperature as well as the reaction conditions was investigated on the hydrogen generation from hydrolysis of BH₃NH₃ over Ru/SiO₂ catalyst.Results showed that when Ru/SiO₂ was prepared under the condi-tions as follows: Ru loading amount was 0.1%（mass fraction）,n（NaBH₄）∶n（Ru）=2.2∶1 and reduction temperature was 303 K,the highest catalytic activity towards hydrogen generation from hydrolysis of BH₃NH₃ was observed and the turnover frequency （TOF） reached up to 140.8 L/（mol·min）,the volume-to-molar ratio of H₂ to Ru .When stirring speed reached 450 r/min,the highest BH₃NH₃ adsorption rate was observed,leading to the highest reaction rate of hydrogen generation.Further,hydrolysis of BH₃NH₃ was controlled by the surface reaction of catalyst,and the catalytic activity towards hydrogen production increased with enhancing the amount of used catalyst.With increasing the reaction temperature,the activation energy of BH₃NH₃ was enhanced over Ru,resulting in the improvement of reaction rate.According to the kinetic study,H₂ production from the hydro-lysis of BH₃NH₃ over Ru/SiO₂ was a zero order reaction against the concentration of BH₃NH₃,and the Eawas 45 kJ/mol.