高稳定性Ni/SBA-15催化剂的结构特征及其对二氧化碳重整甲烷反应的催化性能

 采用浸渍法制备了Ni含量为2.5%～20%的系列Ni/SBA-15催化剂,在常压连续流动固定床反应器上考察了催化剂对二氧化碳重整甲烷制合成气的催化性能,并用X射线衍射和N2吸附法研究了Ni/SBA-15催化剂的结构特征. 结果表明, Ni/SBA-15催化剂具有很高的CH4和CO2转化率, 12.5%Ni/SBA-15催化剂在800 ℃反应600 h后活性没有明显下降,但反应710 h后CH4的转化率下降了约50%, CO2的转化率下降了约25%. 其活性下降的主要原因是催化剂积炭. 在高温条件下反应时, SBA-15的介孔结构也没有遭到破坏,分子筛的孔壁能有效阻止活性组分Ni的团聚. SBA-15孔中组装一定量的Ni活性组分后,除了SBA-15的介孔外,还会形成另外一种较小的孔,但这不影响SBA-15的有序介孔结构,只是其孔径、孔容和BET比表面积降低.     

助剂对甲烷部分氧化制合成气镍基催化剂性能的影响

考察了添加助剂铈、镧和钙对镍基催化剂反应性能的影响，发现助剂对以α-Al2O3为载体的镍基催化剂的调变作用比以γ-Al2O3为载体的镍基催化剂好，且助剂铈对催化剂的性能改善最好。在此基础上，研究了不同载量的铈对催化剂性能的影响。结果表明，铈的质量分数为1%时对催化剂的性能改善最好。同时采用XRD、XPS、TG等技术，研究了助剂铈对10％Ni/γ-Al2O3催化剂的改性作用。XRD分析表明，铈负载量较低时，催化剂中的CeO2高度分散在催化剂表面，铈负载量较高时，CeO2形成微晶颗粒，降低了催化活性。     

添加碱金属对甲烷与空气制合成气的催化剂性能的影响

考察了添加在镍基催化剂中的碱金属助剂 ,对甲烷与空气制合成气的催化反应性能的影响 ;并用 TPO、TPR、CO2 程序升温脱附 (TPD)、XPS及 CO脉冲色谱技术 ,对催化剂进行了表征 .实验表明 ,碱金属助剂对降低催化剂结炭有一定的作用 ,催化剂的抗积炭性能为 Ni- K2 O/Ca O- Al2 O3>Ni- L i2 O/Ca O- Al2 O3>Ni- Na2 O/Ca O-Al2 O3>Ni/Ca O- Al2 O3.在实验中发现 ,碱金属的添加 ,可使催化剂的 Ni比表面积变小、吸附 CO2 的能力增强 ,且结合能可发生不同程度的改变 .从而解释了碱土金属助剂对催化剂活性和抗积炭性的影响 .实验显示 ,Ni-L i2 O/Ca O- Al2 O3具有较好的活性和抗积炭性能     

甲烷重整制合成气镍催化剂积炭研究

本文综述了甲烷转化制合成气镍催化剂积炭的研究进展,论述了积炭热力学和动力学、积炭类型、积炭机理和影响积炭的因素,详细分析了催化剂的镍粒子尺寸、镍-载体相互作用、载体碱性强度、载体氧化-还原性质和添加助剂对镍催化剂的积炭速率和积炭量的影响,并总结了重整反应工艺参数和反应器形式对镍催化剂积炭的影响。最后指出,采用现代表征手段阐明镍催化剂的积炭机理、种类和数量,明确积炭的规律,可为设计开发抗积炭性能强的镍催化剂提供理论依据;可通过增强金属与载体的相互作用、减小镍粒子的尺寸(镍粒子尺寸小于20 nm)和选择适宜的载体来制备抗积炭性能强的催化剂;可通过采用流化床反应器且优化工艺参数来减少重整过程积炭量;可通过寻求行之有效的积炭催化剂再生方法来解决镍催化剂积炭问题。     

Ni/TiO_2-Al_2O_3催化剂的制备及其在甘油水蒸汽重整制合成气中的应用

采用分步浸渍法制备了TiO2修饰和金属离子(M=Ce2+,La2+,Mn2+,Zr2+,Cd2+)掺杂的Ni基催化剂Catw Ni和Catw Ni/M,其结构和性能经XRD和H2-TPR表征。以甘油水蒸汽重整制合成气为探针反应,考察了TiO2修饰量(w),M,原料液配比r[V(甘油)∶V(水)]及时空速率(LHSV)对Catw Ni/M催化甘油重整反应性能的影响。结果表明:TiO2修饰可适当提高催化剂在甘油重整反应中的催化活性和合成气收率;Cat12Ni具有较佳的催化活性(甘油转化率80%)。M的掺杂是通过降低Ni与载体之间的相互作用以实现催化剂活性的提高(Cat12Ni/M可使甘油的转化率提高至94%以上);掺杂Ce和La可促进Catw Ni在重整反应过程的水气变换反应,而Mn和Cd的掺杂有利于合成气的生成。增加r和LHSV,可使甘油水蒸汽重整制合成气的收率得以提高,但不利于催化剂的稳定性能。     

镧助剂对Ni2P/SBA-15催化剂结构及加氢脱硫性能的影响

以SBA-15为载体,Ni(NO3)2·6H2O为镍源,(NH4)2HPO4为磷源,制备了初始P/Ni比为0.8的Ni,P/SBA-15前驱体,然后添加La助剂,再经过干燥、焙烧和程序升温氧气还原,制备了一系列不同La含量的La-Ni,P/SBA-15催化剂.采用XRD,N2-吸脱附和XPS对催化剂的结构进行了表征,以...     

助剂对CH4,CO2和O2制合成气反应催化剂性能的影响

考察了NiCaO-Al2O3催化剂中添加碱金属、碱土金属、稀土金属氧化物、CuO助剂及CaO含量对催化剂性能的影响。结果表明,10Ni-2K-2Cu15CaO-Al2O3催化剂对CH4、CO2和O2制合成气反应具有较高的催化活性、选择性和较好的抗积炭性能。通过TPR、CO-TPD、XPS和XRD对催化剂进行表征,发现K2O、CuO和CaO的添加削弱了活性组分Ni与载体Al2O3间的相互作用,增加Ni的电子密度,加速了CO与H2的脱附,从而抑制了CH4深度裂解积炭和CO歧化积炭。此外,这些助剂的添加也提高了Ni的分散度,增强了催化剂的抗积炭能力。     

碱性助剂的添加对Ni/CaO-Al2O3催化剂性能的影响

在CH4、 CO2和O2制合成气的反应中, 通过在Ni/CaO-Al2O3催化剂中添加碱性助剂K2O、 MgO和La2O3, 使催化剂的性能得到了改善. 实验结果表明, MgO和La2O3助剂的添加, 有利于提高催化剂的活性;添加K2O, 却相反. 测得催化剂上积炭量的顺序为: Ni-La2O3/CaO-Al2O3相似文献   

La2O3对沼气重整制氢催化剂Ni/γ-Al2O3的影响

用浸渍法制备了不同La2O3含量的Ni/La2O3/γ-Al2O3催化剂,用CH4/CO2体积比为1的混合气体模拟沼气,考察了La2O3对沼气重整制氢催化剂Ni/γ-Al2O3的结构及催化性能的影响.运用XRD、H2-TPR、BET及TEM等手段对催化剂进行了表征.结果表明,La2O3对催化剂Ni/γ-Al2O3的影响主要取决于其含量.载体中La2O3的添加增强了Ni与Al2O3之间的相互作用.添加适量的La2O3能使催化剂具有更好的可还原性,并能增加金属Ni的分散性,抑制反应过程中Ni的烧结,提高载体对CO2的吸附能力,从而改善了催化剂的抗积炭性,使催化剂具有较好的活性及稳定性.反之,过量La2O3的掺杂会使催化剂的抗积炭性及活性下降.当La2O3含量为6%(ω)时,催化剂中Ni晶粒具有较好的分散性、还原性及抗积炭性,从而使催化剂具有更好的活性及稳定性.     

助剂对负载型镍催化剂重整活性和抗积炭性能的影响

应用ＸＲＤ和催化活性评价手段，考察了助剂对Ｃ２重整制合成气的负勒型Ｎｉ催化剂的重整活性和其抗积炭性能的影响。实验结果表明，ＮｉＯ在γ－Ａｌ２Ｏ３表面上最大分散量随ＭｇＯ、Ｌａ２Ｏ３助剂的添加没程度地增大，助剂能影响负载型Ｎｉ催化剂 论性能，ＭｇＯ、Ｌａ２Ｏ３的添加对改善Ｎｉ催化剂的重整活性和抗积炭性能有明显效果，并与助剂的种类添加次序有关。     

Catalytic steam reforming of biomass over Ni-based catalysts: Conversion from poplar leaves to hydrogen-rich syngas

A series of Ni/SBA-15 catalysts with Ni contents from 5 wt%–20 wt%and CaO-12.5%Ni/SBA-15 catalysts with CaO contents from 1.4 wt%–9.8 wt%have been prepared.The structure of the catalysts was characterized using X-ray diffraction(XRD),N2 adsorption-desorption,transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS).The performance of catalytic steam reforming of the poplar leaves to the hydrogen-rich syngas was tested in a fixed-bed reactor.The results indicate that the 7.0wt%CaO-12.5wt%Ni/SBA-15 catalyst exhibits the best performance for the catalytic steam reforming of poplar leaves to hydrogen-rich syngas.The ratio of H2:CO can reach ca 5:1 in the hydrogen-rich syngas.The yield of H2 can reach 273.30 mL/g(poplar leaves).In the CaO-Ni/SBA-15 catalyst,Ni active component mainly fills the role of catalytic steam reforming of the poplar leaves,and CaO active component mainly plays the role as water-gas shift and CO2 sorbent.     

Effect of O2 and H2O on the tri-reforming of the simulated biogas to syngas over Ni-based SBA-15 catalysts

A series of Ni/SBA-15 catalysts with Ni contents from 7.5 wt% to 15 wt% were prepared by impregnation method. The effect of O2 and H2O on the combined reforming of the simulated biogas to syngas was investigated in a continuous flow fixed-bed micro-reactor. The stability of the catalyst was tested at 800 ℃. The results indicated that 10 wt%Ni/SBA-15 catalyst exhibited the highest catalytic activities for the combined reforming of the simulated biogas to syngas. Under the reaction conditions of the feed gas molar ratios CH4/CO2/O2/H2O = 2/1/0.6/0.6, GHSV = 24000 ml•g{cat}-1\cdoth-1 and the reaction temperatureT = 800 ℃, the conversions of CH4 and CO2 were 92.8% and 76.3%, respectively, and the yields of CO and H2 were 99.0% and 82.0%, respectively. The catalytic activities of the catalyst did not decrease obviously after 100 h reaction time on stream.     

Effect of Cu promoter on Ni-based SBA-15 catalysts for partial oxidation of methane to syngas

A series of Ni/SBA-15 catalysts with 5wt% to 15wt% Ni content as well as a series of 12.5%Ni/Cu/SBA-15 catalysts with 1% to 10% copper content were prepared by the impregnation method. The catalytic performance for partial oxidation of methane was investigated in a continuous flow microreactor under atmospheric pressure. The textural and chemical properties of the catalysts were characterized by XRD, TEM, BET and H2-TPR techniques. The results indicated that the catalysts modified with Cu promoter showed better performance than those without modification. For the 12.5%Ni/2.5%/Cu/SBA-15 catalyst, at 850 ◦C the conversion of CH4 reached 97.9% and the selectivity of CO and H2 reached 98.0% and 96.0%, respectively. In XRD patterns of the Ni/Cu/SBA-15 catalyst with 7.5 to 10% Cu contents there were CuO characteristic peaks beside NiO characteristic peaks. The mesoporous structure of SBA-15 was retained in all of the catalysts. TPR analysis of the catalysts revealed that a strong interaction between Ni, Cu promoter and SBA-15 support may be existed. This interaction enhanced significantly the redox properties of the catalysts resulting in the higher catalytic activity.     

Effect of O_2 and H_2O on the tri-reforming of the simulated biogas to syngas over Ni-based SBA-15 catalysts

A series of Ni/SBA-15 catalysts with Ni contents from 7.5 wt% to 15 wt% were prepared by impregnation method.The effect of O2 and H2O on the combined reforming of the simulated biogas to syngas was investigated in a continuous flow fixed-bed micro-reactor.The stability of the catalyst was tested at 800 ?C.The results indicated that 10wt%Ni/SBA-15 catalyst exhibited the highest catalytic activities for the combined reforming of the simulated biogas to syngas.Under the reaction conditions of the feed gas molar ratios CH4/CO2/O2/H2O = 2/1/0.6/0.6,GHSV = 24000 ml gc?a1t h?1 and the reaction temperature T = 800 ?C,the conversions of CH4 and CO2 were 92.8% and 76.3%,respectively,and the yields of CO and H2 were 99.0% and 82.0%,respectively.The catalytic activities of the catalyst did not decrease obviously after 100 h reaction time on stream.     

Effect of MgO promoter on Ni-based SBA-15 catalysts for combined steam and carbon dioxide reforming of methane

A series of Ni/SBA-15 catalysts with Ni contents ranging from 5 wt% to 15 wt%, as well as another series of 10%Ni/MgO/SBA-15 catalysts, in which the range of the MgO content was from 1 wt% to 7 wt%, were prepared, and their catalytic performances for the reaction of combined steam and carbon dioxide reforming of methane were investigated in a continuous flow microreactor. The structures of the catalysts were characterized using the XRD, H2-TPR and CO2-TPD techniques. The results indicated that the CO selectivity for this reaction was very close to 100%, and the H2/CO ratio of the product gas could be controlled by changing the H2O/CO2 molar ratio of the feed gas. The simultaneous and plentiful existing of steam and CO2 had a significant influence on the catalytic performance of the 10%Ni/SBA-15 catalyst without modification. After reacting at 850 °C for 120 h over this catalyst, the CH4 conversion dropped from 98% to 85%, and the CO2 conversion decreased from 86% to 53%. However, the 10%Ni/3%MgO/SBA-15 catalyst exhibited a much better catalytic performance, and after reacting for 620 h, the CO2 conversion over this catalyst dropped from 92% to around 77%, while the CH4 conversion was not decreased. Oxidation of the Ni0 species as well as carbon deposition during the reaction were the main reasons for the deactivation of the catalyst without modification. On the other hand, modification by the MgO promoter improved the dispersion of the Ni0 species, and enhanced the CO2 adsorption affinity which in turn depressed the occurring of carbon deposition, and thus retarded the deactivation process.     

氮化SBA-16负载镍基催化剂的制备及其对甲烷二氧化碳重整反应的催化性能

通过软模板法合成了SBA-16分子筛,采用高温氨气氮化的方法使有序介孔硅材料中的氧原子部分被氮原子取代,得到氮化的SBA-16载体(SBA-16-N)。采用满孔浸渍法制备了镍基催化剂,并将制得的Ni/SBA-16和Ni/SBA-16-N催化剂用于甲烷二氧化碳重整反应。通过透射电镜、氮气物理吸附、X射线衍射、X射线光电子能谱和二氧化碳程序升温脱附等手段研究了载体和催化剂的结构,并利用热重分析对反应之后回收催化剂进行了表征。结果表明,高温氮化后的分子筛中掺入了氮元素,增加了载体的碱性,改善了载体对反应气体的吸附活化能力,增强了载体与金属之间的相互作用,从而提高了催化剂的活性和抗积炭性能。     

Nd,Ce和La改性对Ni/SBA-15催化剂在CH4/CO2重整反应中性能的影响

以稀土金属Nd,Ce或La的氧化物为助剂,采用β-环糊精浸渍法对Ni/SBA-15催化剂进行了改性,并运用X射线衍射、N₂吸附-脱附、程序升温还原和热重等手段考察了改性的催化剂在CO₂重整CH₄制合成气反应中的催化性能. 结果表明,Nd等稀土金属氧化物的添加对催化剂孔结构和晶相结构等性质影响不大,但可影响NiO的还原; Nd的添加使NiO与载体之间以Ni-Nd-O形式相互作用,促进了活性组分NiO的还原. 其中,Nd的添加量为5-10 wt%时所制备的催化剂在重整反应中的催化活性最高,且具有很强的抗积碳性能. La和Ce氧化物促进的Ni催化剂也表现出类似的性质和催化性能.     

微波场中甲烷部分氧化制合成气 Ⅰ.Ni/La_2O_3催化剂在微波场中的升温行为及催化活性

微波场中甲烷部分氧化制合成气Ⅰ．Ｎｉ／Ｌａ２Ｏ３催化剂在微波场中的升温行为及催化活性毕先钧段爱红（云南师范大学化学系，昆明６５００９２）王真洪品杰戴树珊（云南大学化学系，昆明６５００９１）关键词微波，甲烷，合成气，氧化镍，氧化镧分类号Ｏ６４３近年来，...     

CO_2 reforming of glycerol over La-Ni/Al_2O_3 catalyst:A longevity evaluative study

This paper reports on the longevity of glycerol-dry(CO2) reforming over the lanthanum(La) promoted Ni/Al2O3 catalysts.The XRD results showed that the Ni particle was well-dispersed in the presence of La promoter.In addition,via the NH3-TPD analysis,it was found that the La promoter has reduced the acidity of Ni catalyst which may have explained the mitigation of carbon laydown.It was determined that the 3.0 wt% La-promoted Ni/Al2O3 catalyst possessed the largest BET specific surface area of 97 m2 g-1.Consequently,it yielded the best catalytic longevity performance with conversion attained more than 90%,even after 72 h of reaction duration.Significantly,it can be confirmed that the presence of CO2 during the glycerol dry reforming was essential in reducing carbon deposition,most likely via gasification pathway.This has ensured a stability of catalytic activity for a long reaction period(72 h).     

K-La-Ni/Si-2催化低碳烷烃与二氧化碳重整制合成气(英文)

Ｎｉ／Ｓｉ２催化剂具有较好的低碳烷烃与二氧化碳重整制合成气的反应性能，添加Ｌａ２Ｏ３助剂和Ｋ２Ｏ助剂可提高催化剂活性和合成气收率，从而进一步改善催化剂的低碳烷烃与ＣＯ２重整制合成气的反应性能，研制的ＫＬａＮｉ／Ｓｉ２催化剂，用于天然气与ＣＯ２重整反应制合成气可达９７％的低碳烷烃转化率和９５％以上的合成气收率。