水热法制备Ni/Nd2O3催化剂及其催化水合联氨制氢

采用水热合成法制备了Ni/Nd₂O₃催化剂,对其催化水合联氨制氢性能进行了考察,探讨了催化剂合成条件及催化体系中NaOH浓度对催化性能的影响,并采用XRD、XPS、TEM、TG对催化剂进行了分析表征。结果表明,当Ni/Nd=94∶6、水热条件为8h、120℃时,合成的Ni/Nd₂O₃催化剂在催化水合联氨制氢时表现出了最优的催化性能,其H₂选择性为95.9%。该催化剂中Ni的结晶度较高,Nd以Nd₂O₃的形式存在,具有促进颗粒分散、暴露活性位点、协助Ni、Nd电子转移等优点。与不加NaOH溶液的催化制氢体系相比,当NaOH的加入浓度为1.3mol/L时,催化剂催化水合联氨的制氢速率提高了约3.7倍。催化剂可维持良好的稳定性,循环使用5次后H₂选择性仍高达94.4%。

Preparation of Ni/Nd2O3 catalysts by hydrothermal method and its catalytic decomposition of hydrated hydrazine for hydrogen production

Ni/Nd₂O₃ catalyst was prepared by hydrothermal method, and its performance in hydrogen production was investigated. The effects of the catalyst synthesis condition and NaOH concentration on the catalytic performance were discussed, and the catalyst was characterized by XRD, XPS, TEM and TG. The results show that when the catalyst with a Ni/Nd molar ratio of 94∶6 and reaction time 8h at 120℃,the highest H₂ selectivity of 95.9% could be achieved. The crystallinity of Ni of the catalyst is fairly high and the Nd species exist in the form of Nd₂O₃, which is beneficial for promoting particle dispersion, exposing active sites and assisting the electron transfer between Ni and Nd. NaOH with varied concentration can change the alkaline state of the system, compared with the reaction system without NaOH solution. When the NaOH concentration is 1.3mol/L, the hydrogen production rate is increased about 3.7 times. After 5 times of catalyst cycling, the selectivity of H₂ is still up to 94.4%, which indicates that the catalyst by hydrothermal synthesis has good stability.