PEG修饰的CoB催化氨硼烷水解产氢性能研究

Performance of PEG Modified CoB Catalyst for Hydrogen Generation from Hydrolysis of Ammonia Borane

摘要: 在氢能的利用中，高效氨硼烷水解产氢催化剂至关重要，本研究选择Co(NO₃)₂∙6H₂O和NaBH₄作为原料，采用化学还原法制备了PEG修饰的CoB催化剂。系统探究了不同分子量PEG、不同PEG用量修饰的CoB催化剂对催化氨硼烷水解产氢性能的影响，同时还探究了搅拌速率、催化剂用量、反应温度对氨硼烷水解产氢性能的影响。利用X射线衍射仪测定了PEG修饰的CoB催化剂的物相结构。实验结果表明，氨硼烷水解的产氢速率与PEG修饰的CoB催化剂的用量呈正比，说明反应处于反应动力学控制阶段，外扩散效应已被消除。当搅拌速率达到750 r∙min⁻¹时，PEG修饰的CoB催化剂催化氨硼烷水解产氢速率最快，但进一步提高转速会导致颗粒团聚。质量分数为2%的PEG6000修饰的CoB表现出最佳的活性，PEG6000修饰的CoB催化氨硼烷水解产氢效果最佳，测得氨硼烷水解反应的活化能为44.04 kJ∙mol⁻¹，TOF值为761.22 mol H₂∙mol⁻¹ CoB∙min⁻¹。

Abstract: In the utilization of hydrogen energy, efficient ammonia borane hydrolysis hydrogen production catalysts are of vital importance. In this study, Co(NO₃)₂∙6H₂O and NaBH₄ were selected as raw materials, and PEG-modified CoB catalysts were prepared by the chemical reduction method. The effects of CoB catalysts modified with PEG of different molecular weights and different PEG dosages on the hydrogen production performance of ammonia borane hydrolysis were systematically investigated. Meanwhile, the effects of stirring rate, catalyst dosage and reaction temperature on the hydrogen production performance of ammonia borane hydrolysis were also investigated. The phase structure of the PEG-modified CoB catalyst was determined by X-ray diffractometer. The experimental results show that the hydrogen production rate of ammonia borane hydrolysis is directly proportional to the dosage of PEG-modified CoB catalyst, indicating that the reaction is in the kinetic control stage, and the internal and external diffusion effects have been eliminated. When the stirring rate reaches 750 r∙min⁻¹. The PEG-modified CoB catalyst has the fastest hydrogen production rate for the hydrolysis of ammonia borane, but further increasing the rotational speed will lead to particle agglomeration. The PEG6000-modified CoB with a mass fraction of 2% exhibited the best activity and had the best catalytic effect on the hydrolysis of ammonia borane to produce hydrogen. The activation energy of the ammonia borane hydrolysis reaction was measured to be 44.04 kJ∙mol⁻¹, and the TOF value was 761.22 mol H₂∙min⁻¹ CoB∙min⁻¹.