H2吸附对Hi／海泡石催化剂的表征

对研制的Ｎｉ／海泡石苯加氢催化剂进行了氢气吸附性能的研究，得到了氢吸附量与加氢活性关系。并对催化剂制备过程中不同焙烧温度、不同镍含量的催化剂用氢吸附法进行了表征。通过程序升温脱附求得了氢气、苯、环己烷的脱附活化能及脱附动力学方程。     

H＿2吸附对Ni／海泡石催化剂的表征

对研制的Ｎｉ／海泡石苯加氢催化剂进行了氢气吸附性能的研究，得到了氢吸附量与加氢活性关系．并对催化剂制备过程中不同焙烧温度、不同镍含量的催化剂用氢吸附法进行了表征．通过程序升温脱附（ＴＰＤ图）求得了氢气、苯、环已烷的脱附活化能及脱附动力学方程．     

Pt/Nd2O3-WO3/ZrO2催化甘油氢解制1,3-丙二醇

制备不同Nd2O3质量分数的2％ Pt/Nd2O3-WO3/ZrO2催化剂.通过N2物理吸附,NH3程序升温脱附(NH3-TPD)、H2程序升温脱附(H2-TPD)、CO脉冲吸附等方法表征催化剂的物理化学性质.用固定床连续流动反应器考察催化剂对甘油氢解制1,3-丙二醇反应的催化性能.结果表明,引入Nd2 O3提高了催化剂的H2吸附量,进而提高了催化剂的催化活性;焙烧温度对催化剂性能有重要影响.在4 MPa、130℃、质量分数为60％甘油水溶液进料、液体体积空速(LHSV)0.25 h-1反应条件下,2％ Pt/0.25NdWZ (700,450)催化剂催化甘油氢解反应,甘油转化率为75.2％,1,3-丙二醇产率达28.9％,产物中n(1,3-丙二醇)/n(1,2-丙二醇)达到21.9.     

硅胶的孔径结构对脱附活化能的影响

该文为研究硅胶孔结构对水蒸气吸附速率／脱附活化能的影响，在吸附水蒸气动力学实验中采用了间歇式吸附方法，用程序升温脱附技术测定了水在硅胶上的程序升温脱附（TPD）曲线并估算了水的脱附活化能。结果表明：A型、B型和C型硅胶的平均孔径分别为2nm、5．28nm和10．65nm。在10％～45％低湿范围内，硅胶的平均孔径越大，其吸附初始阶段的吸附速率越快，平衡吸湿量越小；高湿度条件下，硅胶的平均孔径和孔容越大，其吸附初始阶段的吸附速率越慢，平衡吸湿量越大。水分子在A型、B型和C型硅胶上的脱附活化能分别为35．54kJ／mol、31．41kJ／mol和26．16kJ/mol，说明水分子在硅胶上的脱附活化能随着硅胶的孔径增加而明显减小。与微孔硅胶相比．在中高湿度下中孔硅胶有较大的平衡吸附量和较低的脱附活化能。     

改性沸石分子筛的脱水速度对制冷影响

用不同钙离子浓度对NaY沸石分子筛进行改性,得到一系列不同交换度的样品,用高真空重量法测定了样品在25℃和120℃时的吸附等温线,求得样品在5mm Hg(～1.2℃)时从25℃升温到120℃的脱水量;从热重分析得出样品的脱水速率和脱附活化能,脱附活化能都在10千卡以下。利用自行设计的制冷模拟装置测定了样品的制冷容量,发现制冷容量与样品的脱附活化能、脱水速率和脱附量之间存在很好的平行关系,脱附活化能低的样品,其制冷容量较高。     

苯在Silicalite-1分子筛上的吸附和脱附

采用重量法研究了苯在silicalite-1分子筛上303K时的吸附和室温至400.C的热脱附行为.结果表明苯在303 K时的吸附和脱附等温线有两个台阶,并且出现了滞后环.DTG曲线展示了当每单位晶胞吸附量小于4个分子时只有一个热脱附峰;而当每单位晶胞吸附量大于4个分子时有两个热脱附峰,并且在TG曲线上每单位晶胞吸附量为4个分子处有一个拐点.DTG曲线揭示了苯在silicalite-1上存在两种吸附位置,吸附在不同位置上的分子之间存在平衡关系,不同升温速率对热脱附几乎无影响.     

Co掺入对CeMoO_x/Al_2O_3协同催化NO、CO和C_3H_8的影响

采用挤出成型法将Co掺入CeMo_(0.15)O_x/Al_2O_3制备系列催化剂CeMo_(0.15)Co_(0.15)O_x/Al_2O_3,研究Co掺入对协同催化脱除CO、NO和C_3H_8的影响。采用X线衍射仪(XRD)、N2吸附/脱附法、NH3程序升温脱附法(NH_3-TPD)、NO程序升温脱附法(NO-TPD)、H_2程序升温还原法(H_2-TPR)和X线光电子能谱(XPS)等手段对催化剂进行表征。结果表明:Co掺入有利于CeMo_(0.15)O_x/Al_2O_3氧化CO和C_3H_8,CeMo_(0.15)Co_(0.15)O_x/Al_2O_3在空速7 200 h~(-1)条件下,NO的转化率为98.85%,CO的转化率为79.41%,C_3H_8的转化率为81.33%。催化剂中Co的掺入会提高氧化-还原性能、酸量、NO吸附-脱附能力、Ce~(3+)浓度以及化学吸附氧浓度。这些结果均有利于提高协同催化脱除CO、NO和C_3H_8的活性。     

用光电子能谱研究金属锰、镁表面与甲醇、乙醇反应

用XPS和UPS法研究金属Mn、Mg表面与CH_3OH、C_2H_5OH的反应,室温下,ROH(R=CH_3,C_2H_5)以RO~-的形态吸附在Mg表面,Mn表面有较高的活性,ROH除以RO~-的形态被吸附外,部分还分解为O~(2-)和脱附的碳氢化合物,加热至600K时,Mn表面RO~-完全分解为O~(2-)和R,后者与表面氢结合后脱附,部分C_2H_5O~-中的碳成无定形碳并在～675K加氢脱附,ROH在氧化锰表面除以RO~-的形态被吸附外,在高于650K时还产生CH_2O_(a)、C_2H_4O_(a)等,这些物种在700K依然存在,氧化使锰表面断裂R—O和C—C键的活性降低而其脱氢活性仍然存在。     

LiOH改性对铂钨锆催化剂的影响

采用共浸渍-焙烧法制备不同LiOH质量分数改性的铂钨锆催化剂(Pt-WZr),通过N_2等温吸附-脱附、X线衍射(XRD)、NH_3-程序升温脱附(NH_3-TPD)、H_2-程序升温还原(H_2-TPR)、CO脉冲吸附、H_2-程序升温脱附(H_2-TPD)对催化剂的理化性质进行表征。使用连续流动的固定床反应器考察催化剂对甘油氢解制备1,3-丙二醇的催化性能,使用高温水热釜考察钨锆复合氧化物的水热稳定性。结果表明:适量LiOH的引入能够显著调节催化剂的酸强度,减少强酸量、增大弱酸量,有利于提高催化剂表面活性组分Pt的分散度,增强Pt与钨锆载体间的相互作用,促使催化剂中的四方相ZrO_2向单斜相ZrO_2转变。LiOH的引入显著提高了甘油转化率和1,3-丙二醇收率,当LiOH质量分数为1.0%时,甘油转化率和1,3-丙二醇收率达到最优,分别为85.8%和39.7%。与未改性的钨锆复合氧化物相比,LiOH改性后的钨锆复合氧化物水热稳定性得到显著提高。     

NDA99树脂吸附处理含邻氯苯胺废水的研究

目的 研究NDA99树脂对含邻氯苯胺的3,3’-二氯联苯胺生产废水的吸附与脱附效果.方法 Agilent1100高效液相色谱仪测定邻氯苯胺在不同条件吸附下的浓度;采用重铬酸钾法测定COD,寻求最佳工艺条件.结果 在常温条件下,树脂最佳吸附流速为3 BV/h,最佳吸附量为30BV/批,此条件下出水中COD＜500 mg/L,邻氯苯胺含量＜5 mg/L;在1 BV/h的脱附流速下,脱附温度为50℃,脱附剂选用1 BV 8％ HCl＋1 BV 4％ HCl＋3 BV H2O组合而成,脱附率可达98％.在最佳吸附—脱附条件下,连续进行10批次的吸附-脱附实验,吸附出水中COD为267～465mg/L,邻氯苯胺含量为2.13～4.85 mg/L,低于国标（GB8978-1996）中三级排放标准：CODCr＜500 mg/L、邻氯苯胺＜5.0 mg/L.结论 NDA99树脂对该废水吸附性能稳定,吸附效果良好,具有一定的实用价值.     

新型储氢复合材料Mg/MWNTs的氢化性能

采用催化反应球磨方法,研制成复合材料Mg-MWNTs(w=5%,20%).利用储放氢实验装置,测试了Mg/MWNTs吸放氢动力学性能.研究发现,复合材料Mg-MWNTs(w=5%,20%)在298 K和2.0 MPa氢压时最大储氢量都很低;在373 K、473 K和553 K温度时,Mg-5%(w)MWNTs的最大储氢量分别为5.34%、5.89% 和6.08%;而Mg-20%(w) MWNTs只有2.11%、2.68% 和2.75%.与其它储氢复合材料相比,复合材料Mg-5%(w)MWNTs在保持较好的最大储氢量基础上,具有很好的吸放氢动力学性能.     

热处理对多壁碳纳米管储氢性能的影响

文章采用容量法测量在常温下压力升高到10 MPa时,多壁碳纳米管的吸附储氢性能,分析了热处理对碳纳米管的结构和吸附储氢量的影响。采用透射电镜(TEM)、激光拉曼光谱(Raman)和低温N2吸附(BET)对碳纳米管的微观结构进行表征。结果发现,热处理能明显地提高碳纳米管的石墨化程度,热处理后碳纳米管的质量储氢容量从原来的1.90%升高到2.17%。     

Hydrogen storage of multiwalled carbon nanotubes coated with Pd-Ni nanoparticles under moderate conditions

A type of novel material with a high hy-drogen storage capacity was prepared by supporting PdNi18 alloy nanoparticles,which were synthesized by using a new colloid method,on the surface of pretreated multiwalled carbon nanotubes (MWCNTs). The average PdNi18 alloy particle sizes calculated from XRD patterns were ca. 3 nm,and the high dis-persion of these particles on MWCNTs was con-firmed by TEM image. Hydrogen storage perform-ance of the composite was investigated under mod-erate pressure (0.1―1.5 MPa) at room temperature,and a maximum storage capacity of ca. 2.3 wt% was achieved under 1.5 MPa at room temperature,which was much higher than that reported previously under the same conditions.     

氨改性介孔Si02用于C02／N2变压吸附分离

在323．15K下,以月桂酸为结构导向剂（SDA）、r-氨丙基三乙氧基硅烷为助结构导向剂和硅酸乙酯为硅源,采用阴离子表面活性剂法直接合成氨改性介孔Si02（AMS）用于C02／N2变压吸附分离．对样品进行低温N2吸附脱附、X射线衍射（XRD）和透射电镜（TEM）表征,然后用动态法测量其C02、N2穿透曲线并计算吸附量．结果发现,在323．15K、常压下合成吸附剂AMS对C02／N2的吸附量分别为0．60mmol／g和0．03mmol／g．采用抽真空的方法对吸附剂进行再生,发现75％以上的吸附态C02能够解吸,经过多次吸附／解吸循环C02吸附特性不变．同时利用Aspenadsim软件对吸附过程进行模拟,模拟结果与实验数据吻合良好．     

车用天然气储罐脱附放气过程热力特性分析

车用吸附天然气储罐在脱附放气过程中产生的热效应,严重影响了储罐的脱附效率和汽车行驶速度.建立了天然气、活性炭吸附剂和天然气储罐的热质交换模型,模拟计算了脱附过程中储罐内温度、压力和脱附量的变化,分析了温度、压力等热力参数对脱附速度和脱附量的影响.计算结果表明:储罐的自然脱附过程是吸热过程,在脱附过程中,储罐内的平均温度由293.15K降到了250.46K;储罐中心处温降最大,由293.15K降至244K,降幅达到了49.15K;自然对流下的脱附效率比等温脱附降低了24.49%;在自然对流条件下,壁面所提供的热量越少,脱附速度越小,脱附效率也就越低.     

Hydrogen storage properties of MgH_2 co-catalyzed by LaH_3 and NbH

To improve the hydrogen storage properties of Mg-based alloys, a composite material of MgH_2 + 10wt%LaH_3 + 10wt%NbH was prepared by a mechanical milling method. The composite exhibited favorable hydrogen desorption properties, releasing 0.67wt% H2 within 20 min at 548 K, which was ascribed to the co-catalytic effect of LaH_3 and NbH upon dehydriding of MgH_2. By contrast, pure MgH_2, an MgH_2 + 20wt%LaH_3 composite, and an MgH_2 + 20wt%NbH composite only released 0.1wt%, 0.28wt%, and 0.57wt% H2, respectively, under the same conditions. Analyses by X-ray diffraction and scanning electron microscopy showed that the composite particle size was small. Energy-dispersive X-ray spectroscopic mapping demonstrated that La and Nb were distributed homogeneously in the matrix. Differential thermal analysis revealed that the dehydriding peak temperature of the MgH_2 + 10wt%LaH_3 + 10wt%NbH composite was 595.03 K, which was 94.26 K lower than that of pure MgH_2. The introduction of LaH_3 and NbH was beneficial to the hydrogen storage performance of MgH_2.     

碳纳米管阵列储氢的分子动力学模拟

采用分子动力学方法,模拟了常温和不同压强下,氢在不同管径和管间距的单壁碳纳米管阵列(SWCNTA—S ingle-walled Carbon Nanotube Arrays)中的物理吸附过程.重点研究了压强、管径和管间距对SWCNTA(管内和管间隙)物理吸附储氢的影响.发现氢分子主要储存在SWCNTA的管壁附近,适当地增大管径和管间距可有效增加SWCNTA的物理吸附储氢量,使其在常温下具有较高的储氢能力,并给出了相应的理论解释.计算结果表明,在常温和中等压强下,SWCNTA的物理吸附总储氢量(重量百分比)可达4.2%,从而为同等条件下SWCNTA具有较高储氢能力的实验结果提供了直接的理论支持.     

Hydrogen storage properties of MgH2 co-catalyzed by LaH3 and NbH

To improve the hydrogen storage properties of Mg-based alloys, a composite material of MgH2 + 10wt%LaH3 + 10wt%NbH was prepared by a mechanical milling method. The composite exhibited favorable hydrogen desorption properties, releasing 0.67wt% H2 within 20 min at 548 K, which was ascribed to the co-catalytic effect of LaH3 and NbH upon dehydriding of MgH2. By contrast, pure MgH2, an MgH2 + 20wt%LaH3 composite, and an MgH2 + 20wt%NbH composite only released 0.1wt%, 0.28wt%, and 0.57wt% H2, respectively, un-der the same conditions. Analyses by X-ray diffraction and scanning electron microscopy showed that the composite particle size was small. Energy-dispersive X-ray spectroscopic mapping demonstrated that La and Nb were distributed homogeneously in the matrix. Differential thermal analysis revealed that the dehydriding peak temperature of the MgH2 + 10wt%LaH3 + 10wt%NbH composite was 595.03 K, which was 94.26 K lower than that of pure MgH2. The introduction of LaH3 and NbH was beneficial to the hydrogen storage performance of MgH2.     

Improvement in hydrogen storage performance of Mg by mechanical grinding with molten salt etching Ti3C2Clx

Mg-based materials are currently a hot research topic as hydrogen storage materials due to their considerable theoretical hydrogen storage capacity. However, the kinetic performance of hydrogen absorption and desorption of Mg is too slow and requires high temperature, which seriously hinders the application of this material. MXene is a new type of two-dimensional material with significant role in improving thermodynamics and kinetics. In this experiment, a two-dimensional layered MXene containing Cl functional group was prepared by molten salt etching using the Ti-containing MAX phase as the raw material. Then different ratios of Ti₃C₂Cl_x were uniformly dispersed onto the surface of Mg by high energy ball milling. The samples were characterized by hydrogen absorption and desorption kinetics, SEM, XRD, XPS, and DSC to investigate the effect of Ti₃C₂Cl_x on the hydrogen absorption and desorption performance of Mg. The onset hydrogen absorption temperature can be reduced to room temperature and the hydrogen release temperature is reduced by 200 ​°C by doping Ti₃C₂Cl_x. And there is also 5.4 ​wt% hydrogen storage in the isothermal hydrogen absorption test at 400 ​°C. The results of DSC demonstrate that the E_a of Mg+15 ​wt% Ti₃C₂Cl_x was reduced by 12.6% compared to pristine Mg. The ΔH is almost invariable. The results of XPS show that the presence of multivalent Ti promotes electron transfer and thus improves the conversion between Mg²⁺/Mg and H⁻/H. This study provides a guideline for further improving the hydrogen absorption and desorption performance of Mg-based hydrogen storage materials.     

多壁碳纳米管及其对H_2吸附体系的Raman光谱

利用原位和非原位紫外 Raman谱法 ,对以 CH4 为碳源 ,由催化法制备的多壁碳纳米管( MWCNTs) ,K -修饰的该类 MWCNTs,以及它们对 H2 的吸附体系进行了 Raman谱表征 ,观测到可分别归属于类石墨结构的基频模 D和 G以及它们的三阶组合频 ,表面 C-H3基和 C-H2 基等的特征Raman峰 ;H2 在这类碳纳米管上的吸附态包括解离吸附生成表面 C-H3和非解离吸附分子氢 H2 ( a) ;在相同实验条件下 ,K -修饰体系上这两类氢吸附物种的表面浓度都比未经 K -修饰的相应体系高 .