摘要
有机液态储氢(LOHC)技术通过含氮杂环有机物的催化加氢反应将氢气固定于液态介质中,形成稳定的储氢载体,是一种具有前景的新兴储氢策略.然而,该技术目前主要依赖贵金属催化剂,基于廉价金属的高效催化体系研究尚显不足.本研究采用Ni-Al层状双金属氢氧化物(Ni Al-LDH)衍生镍基催化剂,实现了氮甲基吲哚(NMID)的高效储氢(加氢).系统考察了Ni/Al物质的量比及还原温度对催化性能的影响.结果表明, NiAl-LDH在450℃还原制得的催化剂(Ni_(2)Al_(1-re450))活性最优.通过N2物理吸附(BET)、X射线衍射(XRD)、X射线光电子能谱(XPS)及电感耦合等离子体发射光谱(ICP-OES)表征分析,揭示其优异加氢活性源于较大的比表面积与较小的镍颗粒尺寸.在优化反应条件下(150℃,6 MPa H_(2), 2 h,间歇釜), Ni_(2)Al_(1-re450)可实现NMID的完全转化(100%), 8H-NMID产物收率达96.06%,其性能显著优于商用0.5%Ru/Al_(2)O_(3)催化剂.动力学研究表明, NMID加氢速率与温度呈正相关,表观活化能为61.25 k J/mol,转化频率(TOF)达52.62 h^(-1).在微填充床反应器连续运行测试中(180℃, 6 MPa H_(2)), Ni_(2)Al_(1-re450)展现出优异的稳定性,持续100 h反应期间, NMID转化率稳定在97%~100%, 8H-NMID选择性维持在97%~100%,对应储氢容量达5.55%(w)~5.76%(w).
The advancement of non-noble metal catalysts holds immense importance for the broad industrial use of organic liquid hydrogen storage.In this study,NiaAlb-layered double hydroxides(LDHs)were synthesized via co-precipitation method.Typically,a mixed solution of 100 mL Ni(NO_(3))2·6H_(2)O and Al(NO_(3))3·9H_(2)O was dropped into 100 mL Na_(2)CO_(3) solution under vigorous stirring.The precipitation was carried out at room temperature,to achieve the desired pH value,a 3 mol/L NaOH solution was added to maintain the solution pH between 10±0.5.The resultant green precipitate underwent centrifugation and washing until nearly neutral,followed by drying for an extended period at 110℃.Thereafter,the sample was subjected to reduction at different temperatures for a duration of 2 h,with a meticulously controlled heating rate of 2.5℃/min.Finally,the influence of the Ni/Al ratio and reduction temperature on the catalytic activity was examined.The catalyst obtained by reducing NiAl-LDH at 450℃(Ni_(2)Al_(1-re450))exhibited the highest activity among the catalyst samples examined.Structural and compositional analyses of the catalyst were carried out using X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),inductively coupled plasma optical emission spectrometry(ICP-OES),and N_(2) physisorption analysis(BET).The results indicated that the high hydrogenation activity of Ni_(2)Al_(1-re450) was attributed to its larger specific surface area and smaller nickel particle size.Under the optimized reaction conditions(150℃,6 MPa H_(2),2 h),the catalyst achieved a 100%conversion rate of NMID and a yield of 8H-NMID of 96.06%in a batch reactor,surpassing the commercial 0.5%Ru/Al_(2)O_(3) hydrogenation catalyst.The hydrogenation reaction rate of NMID was positively correlated with temperature,with an apparent activation energy of 61.25 kJ/mol and a turnover frequency(TOF)of 52.62 h^(-1).Moreover,Ni_(2)Al_(1-re450) was continuously operated for 100 h in a micro packed-bed reactor under reaction conditions of 180℃and 6 MPa.The results showed that the NMID conversion rate remained stable between 97%~100%,the selectivity for 8H-NMID was 97%~100%,and the hydrogen storage capacity was 5.55%(w)~5.76%(w).
作者
全洪林
唐鋆磊
张承志
张恒溢
李佳奇
周太刚
Quan Honglin;Tang Junlei;Zhang Chengzhi;Zhang Hengyi;Li Jiaqi;Zhou Taigang(College of Chemistry and Chemical Engineering,Southwest Petroleum University,Chengdu 610500;College of Science,China Agricultural University,Beijing 100193;Tianfu Yongxing Laboratory,Chengdu,610217)
出处
《化学学报》
北大核心
2025年第11期1340-1348,共9页
Acta Chimica Sinica
基金
天府永兴实验室有组织科研(No.2023KJGG10)
西南石油大学自然科学(No.2021JBGS07)资助项目。
关键词
有机液体储氢
镍催化剂
氮甲基吲哚
镍铝水滑石
organic liquid hydrogen storage
nickel catalyst
N-methylindole
nickel aluminum layered double hydroxide
