棒状纳米氧化锌制备工艺优化及脱硫机理研究

ZnO脱硫剂有着优良的脱硫性能，在H2S脱除的过程中得到广泛应用。本文采用均匀沉淀法，研究了不同反应温度、反应时间对纳米ZnO制备的影响，得到棒状纳米ZnO制备的最佳工艺：在温度为60℃下反应6h，可以制得成分纯净、形貌为棒状且分布均匀的纳米ZnO。以制得的ZnO为脱硫剂，探讨脱硫时间对脱硫剂和脱硫产物的影响，得到ZnO的脱硫机理。     

氧化铈高温煤气脱硫剂的还原与硫化

采用硝酸铈为原料制取 Ce O2 ,用干混法制备 Ce O2 高温煤气脱硫剂 .在固定床反应器中考察煅烧温度、硫化温度、反应空速及还原时间对脱硫剂脱硫效率的影响 .结果表明 :在 60 0℃～80 0℃的范围内 ,脱硫效率随着煅烧、硫化温度的升高而升高 ;温度为 80 0℃的情况下 ,脱硫效率随着反应空速的降低而增加 ;脱硫剂预还原时间越长 ,脱硫剂的脱硫效率越高 .     

活性炭负载纳米ZnO的结构及常温脱除H2S的性能

采用均匀沉淀法分别以煤质炭和椰壳炭为载体,纳米ZnO为活性组分制备了活性炭负载纳米ZnO脱硫剂。利用X射线衍射和扫描电子显微镜对脱硫剂的结构进行表征,并在固定床反应器上考察了H2S的吸附性能。结果表明:所制备的脱硫剂表面负载了纳米ZnO晶体,活性炭表面孔的数量影响纳米ZnO的晶粒尺寸,椰壳炭负载的纳米ZnO晶粒尺寸为11.4nm,而煤质炭上纳米ZnO晶粒为68.9nm;活性炭载体提高了脱硫活性组分的利用率,椰壳炭负载后样品的脱硫活性明显好于煤质炭。当空速为4600/h时,300℃焙烧1h的椰壳炭负载纳米ZnO样品的穿透时间可高达48min。炭表面纳米ZnO晶粒尺寸是影响H2S脱除性能的主要因素。     

CuO脱硫剂脱除SO2的工艺条件研究

用干混法制备了一系列以CuO为主要活性组分的SO₂脱硫剂，考察了脱硫剂反应条件对脱硫活性的影响。结果表明，烟气中的O₂对于CuO脱硫剂的活性有显著的促进作用，能增加脱硫剂硫容；脱硫剂显示较高活性的温度范围350～500 ℃；空速在1 800～4 200 h^－1操作范围内，脱硫剂可维持较高且比较稳定的硫容。     

纳米ZnO室温脱硫剂再生条件研究

对纳米ZnO室温脱硫剂再生温度、再生反应混合气的组分等再生条件进行了研究,进行了多次再生循环试验,并对再生尾气检测方法进行了分析.结果表明,纳米ZnO室温脱硫后脱硫剂表面产生多种硫物种,再生温度高有利去除表面覆盖的脱硫产物,但高温再生增大纳米ZnO粒径,降低纳米ZnO的脱硫性能.在450℃中温,含氧5％的再生反应混合气...     

改性活性炭脱硫剂脱硫性能的研究

对煤质活性炭改性,包括加压水热活化、浸渍铜氨络合液,通过正交实验对改性活性炭脱硫剂的脱硫性能进行研究。结果表明,改性活性炭脱硫剂的最佳制备工艺条件为:加压水热活化压力为4.052 MPa,CuO/C为2.5%,煅烧温度为500℃,脱硫温度为25℃。各因素对改性活性炭脱硫活性的影响顺序为加压水热活化>煅烧温度>CuO/C>脱硫温度。     

复合型钴锌纳米线的制备及其脱硫性能

采用水热法合成了Co–ZnO复合纳米线,通过改变Na OH浓度考察其对Co–ZnO复合纳米线结构和形貌的影响,并用等体积浸渍法负载金属Ni,制备反应吸附脱硫剂。以正庚烷/噻吩为模拟油,在反应温度为320℃、压力0.6 MPa、进料的体积空速为6 h–1及氢油体积比为100:1的条件下,考察了复合型钴锌纳米线负载镍脱硫剂、负载型镍钴锌脱硫剂和无钴添加负载型镍锌脱硫剂的脱硫性能。结果表明:Na OH浓度为1 mol/L时制备的Co–ZnO复合纳米线有良好的纳米形貌,负载活性组分Ni后脱硫效果最好;复合型钴锌纳米线负载镍脱硫剂中Co掺杂比负载型脱硫剂更均匀,Co掺杂使氧化态的Ni变得容易还原,相同条件下可以得到更多的活性位,进而有利于脱硫剂脱硫,其脱硫性能明显高于负载型镍钴锌脱硫剂和无钴添加负载型镍锌脱硫剂,达到93%(质量分数)以上。     

磷酸活化褐煤半焦用于柴油吸附脱硫的研究

采用磷酸活化褐煤半焦为载体,负载多种金属氧化物制备了催化裂化(FCC)柴油吸附脱硫剂。煅烧温度、载样种类、浸渍比、煅烧时间和浸渍时间等因素都会对脱硫剂的性能产生显著的影响,按正交实验设计方法,采用FCC柴油为原料,考察了这5种因素对脱硫活性的影响。结果表明,半焦载体的煅烧温度对于脱硫活性的影响最为显著,最佳的煅烧温度为700℃,其他影响因素依次为:载样种类CuO、浸渍比1.5∶1、煅烧时间1.5 h和浸渍时间20 h。实验还考察了采用最佳制备条件得到的吸附脱硫剂在空速为2 h-1和120℃条件下的脱硫性能,并对其失活样品在350℃进行水蒸气再生。结果表明,无论是新鲜脱硫剂还是再生样品,其脱硫率都随脱硫时间的延长而下降,且再生后脱硫剂脱硫效果明显下降。     

CuO/ATP常温脱硫剂的制备及其性能评价

用直接沉淀法制备了负载型CuO/ATP常温脱硫剂,用TEM、XRD对CuO/ATP进行了表征,并从扩散及热力学角度分析了焙烧温度、负载量、流速、硫化温度对H₂S吸附性能的影响。结果表明,CuO分散在ATP表面,而其分散状态取决于焙烧温度和负载量。焙烧温度过高或负载量过高都将导致CuO的分散性变差,降低气体在脱硫剂中的扩散速率,使得脱硫剂的活性降低。降低流速可使脱硫剂的利用率达到97%,而降低硫化温度至0℃时,脱硫剂性能仍然表现良好,硫容达到了33.17%。     

活性半焦在FCC柴油吸附脱硫中的应用研究

利用活性半焦对FCC柴油进行固定床吸附脱硫实验。按正交设计方法考察床层高径比、固定床温度、空速、催化剂种类和金属氧化物焙烧温度对脱硫率的影响。结果表明,各因素对脱硫率影响的大小顺序及最佳工艺条件为：空速（2 h^-1）＞床层高径比（7.5）＞固定床温度（120 ℃）＞催化剂种类（负载CuO）＞焙烧温度（350　℃）。考察了最佳工艺条件下活性半焦的脱硫性能,并对其600 ℃进行热再生三次。结果表明,最佳工艺条件下,脱硫剂脱硫率达55.95％,随脱硫时间的延长,脱硫剂新鲜样和再生样脱硫率均下降,随再生次数的增加,脱硫率降低,但降低缓慢。经新鲜样和再生样脱硫后,柴油产品收率均在81％以上,而油品总收率在93％以上。     

系列催化剂同时脱硫脱硝性能

FCC烟气中的SO₂和NO是主要的大气污染物,选择性催化还原是一种很好的脱除方法。采用浸渍法制备了CuO不同负载量的CuO/γ-Al₂O₃系列催化剂,通过XRD和H₂-TPR对催化剂进行表征,使用常压固定床流动法微型催化反应装置考察催化剂在以CO为还原气时,同时脱硫脱硝的催化活性。结果表明,CuO作为活性组分很好地分散在γ-Al₂O₃载体上,不破坏其结构;不同CuO负载量的CuO/γ-Al₂O₃催化剂具有良好的脱硫脱硝活性,脱硝率超过95.00%,脱硫率最低也能达到80.00%,CuO负载质量分数为10%的CuO/γ-Al₂O₃催化剂有最佳的脱硫脱硝活性;以CO作还原剂,CuO/γ-Al₂O₃系列催化剂的活性温度较高,脱硝率在700 ℃达到最大,为97.90%,脱硫率在760 ℃达到最大,为93.34%。CuO负载质量分数为10%的CuO/γ-Al₂O₃催化剂可作为一种较好的高温脱硫脱硝催化剂。     

Low-temperature and highly sensitivity H2S gas sensor based on ZnO/CuO composite derived from bimetal metal-organic frameworks

The bimetallic metal-organic frameworks (MOF) Zn/Cu-BTC were prepared by a facile solvothermal method in one step and used as a self-sacrificed template to obtain the ZnO/CuO composites. The composites with different Cu/Zn molar ratios were characterized by XRD, FESEM, and XPS. The ZnO/CuO composite exhibited an octahedral structure, and a p-n heterojunction may be formed between p-type CuO and n-type ZnO. To prove its functional characteristics, the ZnO/CuO composite was used as a sensing material to test its gas sensitivity. The effect of Cu/Zn molar ratios was examined, and the results showed that the optimized ZnO/CuO (1: 0.33) composite based gas sensor exhibited reasonable selectivity to 10 ppm H₂S, operated at 40 °C. The sensitivities were improved by 17.1 times and 327.8 times compared with the pristine CuO and ZnO based gas sensors, respectively. Moreover, the detection limit to H₂S of such sensors could be reduced as low as 300 ppb. The sensing mechanism has been thoroughly studied and such ZnO/CuO composite is an ideal candidate for highly sensitive detection for H₂S with low power consumption in the real application.     

Fabrication and photoresponse of ZnO nanowires/CuO coaxial heterojunction

The fabrication and properties of n-ZnO nanowires/p-CuO coaxial heterojunction (CH) with a photoresist (PR) blocking layer are reported. In our study, c-plane wurtzite ZnO nanowires were grown by aqueous chemical method, and monoclinic CuO (111) was then coated on the ZnO nanowires by electrochemical deposition to form CH. To improve the device performance, a PR layer was inserted between the ZnO buffer layer and the CuO film to serve as a blocking layer to block the leakage current. Structural investigations of the CH indicate that the sample has good crystalline quality. It was found that our refined structure possesses a better rectifying ratio and smaller reverse leakage current. As there is a large on/off ratio between light on and off and the major light response is centered at around 424 nm, the experimental results suggest that the PR-inserted ZnO/CuO CH can be used as a good narrow-band blue light detector.     

在超细催化剂CuO/ZnO/SiO_2上CO_2加氢合成甲醇的优化研究

本文考察了焙烧温度、还原温度、反应温度、反应压力和体积空速对用于ＣＯ２加氢反应的超细ＣｕＯ／ＺｎＯ／ＳｉＯ２催化剂性能和产物分布的影响，确定了催化剂的合适焙烧温度、还原温度，并对ＣＯ２加氢反应条件进行了优化     

Ce掺杂的蛋壳型CuO/ZnO/SiO2颗粒催化剂的制备和表征

用添加表面活性剂的两步沉淀法制备了以蛋壳型纳米空心SiO2为载体的CuO/ZnO催化剂和掺杂Ce的CuO/ZnO催化剂,初步考察了两组催化剂用于一氧化碳加氢合成甲醇的催化性能,并采用TEM, BET, XRD, XPS等方法对催化剂的结构进行了表征. 结果表明,以纳米空心SiO2为载体的CuO/ZnO催化剂具有较大的比表面积,活性成分在载体表面分散均匀,粒径在13 nm左右. 加入掺杂剂Ce能有效提高催化剂的活性和选择性：一方面,Ce可以降低Cu 2p3/2和Zn 2p3/2的表面结合能, 使氧化铜更容易被氢气还原成铜;另一方面,Ce也能增强铜锌之间的相互作用,抑制铜粒子的烧结,改善活性成分的分散.     

新型CuO/ZnO催化剂的制备及其在水煤气变换反应中的应用

首次采用沉积沉淀法,以Cu（OH）₂为前驱体制备不同CuO负载质量分数的CuO/ZnO水煤气变换（WGS）催化剂,并运用XRD、N₂物理吸附和TPR等方法对催化剂进行结构表征。结果表明,活性组分CuO在载体ZnO表面的分散程度、颗粒大小及CuO和ZnO之间相互作用对催化剂的活性均有影响。CuO的适宜负载质量分数为20％,所得CuO/ZnO催化剂样品WGS反应活性较好,在350 ℃,CO转化率可达95.5％。     

CuO nanosheets/ZnO nanorods synthesized by a template-free hydrothermal approach and their optical and magnetic characteristics

Nanostructured CuO/ZnO heterojunctions were fabricated via a template-free hydrothermal reaction. The prepared CuO/ZnO nanocomposites are composed of one dimensional (1D) hexagonal ZnO nanorods and two-dimensional (2D) monoclinic CuO nanosheets. The single crystal nature of both ZnO and CuO was confirmed. Optical spectra show the widened absorption range from UV to visible light, which suggests the potential of the obtained CuO/ZnO composites for visible-light-driven photocatalyst. The point defects at the interface play the leading role in triggering ferromagnetism of CuO/ZnO composites. Fundamentally, the ferromagnetism can be understood by the charge-transfer mechanism according to Stoner theory. The findings can give a further insight into the ferromagnetic origin of nonmagnetic composites and the integration of ferromagnetic and photocatalytic properties into an identical sample.     

CuO纳米微球的低温液相合成及其性能表征

以CuSO4·5H2O为铜源、Na2CO3为沉淀剂,在80℃水浴中通过简单的液相沉淀法一步合成了CuO纳米微球。利用X-射线衍射（XRD）、扫描电子显微镜（SEM）、紫外-可见分光光度计及WS-30A气敏测试系统对样品的结构形貌和性能进行了表征。结果表明,所得产物为单斜结构的纳米微球,且该产物具有较好的光催化和气敏性能。     

Fabrication of bimetallic Cu–Zn adsorbents with high dispersion by using confined space for gas adsorptive separation

The number of active components and their dispersion degree are two key factors affecting the performance of adsorbents. Here, we report a simple but efficient strategy for dispersing active components by using a confined space, which is formed by mesoporous silica walls and templates in the as-prepared SBA-15 (AS). Such a confined space does not exist in the conventional support, calcined SBA-15, which does not contain a template. The Cu and Zn precursors were introduced to the confined space in the AS and were converted to CuO and ZnO during calcination, during which the template was also removed. The results show that up to 5 mmol·g^–1 of CuO and ZnO can be well dispersed; however, severe aggregation of both oxides takes place in the sample derived from the calcined SBA-15 with the same loading. Confined space in the AS and the strong interactions caused by the abundant hydroxyl groups are responsible for the dispersion of CuO and ZnO. The bimetallic materials were employed for the adsorptive separation of propene and propane. The samples prepared from the as-prepared SBA-15 showed superior performance to their counterparts from the calcined SBA-15 in terms of both adsorption capacity of propene and selectivity for propene/propane.