Au/SnO2催化氧化CO性能的研究

以SnO2为载体,Au为活性组分,采用真空浸渍法、共沉淀法、沉积-沉淀法制备CO氧化的催化剂,同时还制备双金属体系催化剂Au-Pd/SnO2和Au-Pt/SnO2.用气相色谱对所制备的催化剂进行活性评价,运用DSC、SEM、XRD、BET等对催化剂进行表征.在本实验条件下,载体二氧化锡焙烧温度为500℃,催化剂成型温度为350℃,金负载量为3%(wt.)时,用沉积.沉淀法制备的Au/SnO2活性最好,在18℃,空速为24 000 h-1条件下就能将CO(浓度为4%)完全氧化为CO2;添加铂和钯可提高Au/SnO2对CO的催化活性.     

制备方法对Mn-Ce/TiO2催化剂低温选择性催化还原活性的影响

采用溶胶凝胶法、浸渍法以及两者相结合的方法制备了Mn-Ce/TiO2催化剂.运用XRD、BET和SEM等技术对催化剂进行了表征,发现溶胶凝胶法制备的Mn-Ce/TiO2催化剂为锐钛矿结构,具有较大的比表面积,中孔结构丰富,Mn、Ce活性组分在载体表面高度分散或形成了无定形结构.实验研究了催化剂对氨选择性催化还原NO反应的催化性能,结果表明,用溶胶凝胶法制备的Mn-Ce/TiO2催化剂脱硝活性最好,当Mn、Ce负载量为20％,NH3/NO摩尔比为1.1,空速为9 436 h-1,烟气温度为240℃时,NO转化率大于90％.     

不同方法制备LaCu0.8Zn0.2Al11O19-δ催化剂及其催化分解N2O活性研究

采用共沉淀法、溶胶-凝胶法和反相微乳液法制备了六铝酸盐催化剂LaCu0.8Zn0.2Al11O19-δ,进行了X射线衍射(XRD)和BET表征.并考察了它们对N2O催化分解反应的活性,研究了制备方法对催化剂LaCu0.8Zn0.2Al11O19-δ的结构、粒径、比表面积和催化分解N2O活性的影响.结果表明,3种方法制备的催化剂经1200℃焙烧4 h后.都能形成六铝酸盐晶相,其中反相微乳液法制备的催化剂具有较小的粒径和较大的比表面积,其催化分解N2O的活性表现最佳,起始反应温度(T10%)为494℃,完全反应温度(T99%)为678℃.     

Au/SnO2催化氧化CO性能的研究

以SnO₂为载体，Au为活性组分，采用真空浸渍法、共沉淀法、沉积沉淀法制备CO氧化的催化剂，同时还制备双金属体系催化剂Au-Pd/SnO₂和Au-Pt/SnO₂。用气相色谱对所制备的催化剂进行活性评价，运用DSC、SEM、XRD、BET等对催化剂进行表征。在本实验条件下，载体二氧化锡焙烧温度为500 ℃，催化剂成型温度为350 ℃，金负载量为3%(wt.)时，用沉积-沉淀法制备的Au/SnO₂活性最好，在18 ℃，空速为24 000 h-1条件下就能将CO（浓度为4%）完全氧化为CO₂；添加铂和钯可提高Au/SnO₂对CO的催化活性。     

石墨烯/碳化钴钼复合材料作为微生物燃料电池阴极催化剂的研究

用改良Hummers法和碳热还原法分别制备了石墨烯和碳化钴钼。用透射电镜(TEM)、扫描电子显微镜(SEM)和X射线衍射仪(XRD)表征了材料的形貌和结构。用循环伏安(CV)表征了其氧还原(ORR)催化性能,结果表明,复合材料的氧还原峰电流和起峰电位均大大优于单一材料。旋转圆盘电极(RDE)实验表明复合材料的氧还原反应为高效的四电子转移过程。含有6 mg·cm~(-2)石墨烯/碳化钴钼复合材料作为阴极催化剂的微生物燃料电池(MFCs)最大功率密度为418 mW·m~(-2),达到商业铂碳的68.3%。因此,廉价的石墨烯/碳化钴钼复合材料作为MFCs阴极氧还原催化剂具有巨大的应用潜力。     

催化湿法氧化处理垃圾渗滤液中Co/Bi催化剂的回收与再生

利用硝酸盐熔融法制备Co/Bi催化剂,用于催化湿法氧化(CWAO)处理垃圾渗滤液。对一次利用后的 Co/Bi催化剂进行回收和再生,在反应温度260 ℃、催化剂用量 2 g、氧分压 0. 5 MPa条件下,催化剂的回收率可达到(97. 09±0. 74)%。利用XRD、BET分析方法对新鲜制备、一次回收、一次再生、二次回收的催化剂进行表征,根据表征结果可知催化剂的活性为:新鲜制备>一次再生>二次回收>一次回收。利用上述催化剂在不同温度条件下降解垃圾渗滤液,在 280 ℃、300 ℃条件下,催化剂的活性为新鲜制备≈一次再生>一次回收,而在220 ℃、240 ℃、260 ℃条件下,则是新鲜制备>一次再生≈一次回收,表明低温条件下,一次再生的催化剂和一次回收的催化剂出现失活现象,并分析了催化剂失活的原因。     

添加壳聚糖溶胶-凝胶法制备的TiO_2光催化剂及其光催化性能研究

采用添加壳聚糖(CTS)的溶胶-凝胶法制备了具有较高光催化活性的TiO_2光催化剂,并用XRD、TEM、BET和IR等手段对其进行表征。结果表明,CTS的添加使TiO_2衍射强度增强、分散性提高、比表面积增大从而使光催化活性提高;用所制备的催化剂光催化降解甲基橙反应60 min后,其去除率由不添加CTS所制备TiO_2的32%提高到48%,TOC去除率由14%提高到23%。     

La0.9Ce0.1MnO3光催化降解含酚废水

采用氨基乙酸法制备催化剂钙钛矿锰氧化物(La0.9Ce0.1MnO3),用X射线衍射(XRD)技术对所制备的催化剂进行表征.采用模拟含酚废水,以间苯二酚为污染物、紫外灯为光源,考察反应时间、溶液pH以及催化剂加入量对催化剂降解间苯二酚的影响.结果表明,随着反应时间的延长,间苯二酚的降解率逐步增大,最后趋于平稳；溶液最佳...     

γ-Al_2O_3负载Ni、Fe催化剂同时脱硫脱硝

采用浸渍法制备了不同负载量的Ni(x)Fe(y)/γ-AL2O3催化剂,通过XRD、H2-TPR、BET和SEM对催化剂进行表征,使用微型催化反应装置考察催化剂在以CO作为还原气时,同时脱硫脱硝的催化活性。结果表明,Ni O和Fe2O3做为活性组分可以很好地分散在γ-Al2O3载体上,并且不破坏其结构;Ni(8)Fe(2)/γ-Al2O3催化剂有最佳的脱硫脱硝活性,脱硫率达到96.55%,脱硝率达到97.92%。     

光还原法制备Ag/TiO_2催化剂及光催化性能

采用光还原法制备了Ag/TiO_2催化剂,通过X射线衍射(XRD)、扫描电子显微镜(SEM)、场发射透射电子显微镜(TEM)、N_2吸附-脱附(BET)和X射线光电子能谱(XPS)等测试手段对催化剂自身结构、形貌和孔结构等性质进行表征,并研究其对亚甲基蓝的光催化性能。结果表明,Ag的沉积能够大幅提高催化剂的光响应度,大大提高光催化活性。当Ag的摩尔分数为3%时,在可见光照射90 min后,催化剂对亚甲基蓝的脱色率达到78.52%。     

Ni/Fe-supported over hydrotalcites precursors as catalysts for clean and selective oxidation of Basic Yellow 11: Reaction intermediates determination

In this work, Basic Yellow 11 (BY 11) was employed as model compound to study catalytic wet air oxidation as a pre-treatment step to the conventional biological oxidation. Ni and Fe catalysts supported over hydrotalcite (HT) were prepared by incipient wetness and excess impregnation to obtain catalysts with different metal loadings (from 1 to 10 wt.%). HTs were synthesized by co-precipitation and characterized with XRD, X-ray fluorescence (XRF), BET, thermogravimetric analysis and SEM. Results showed that dye conversion increased with Ni and Fe content up to 7 wt.% and that the most effective catalyst were prepared by incipient wetness impregnation. The influence of metal loading in the catalyst, and the preparation method as well as the reaction conditions was investigated. A mechanism and reaction pathways for BY 11 during catalytic liquid phase oxidation have also been proposed.     

Mg/Al/Fe复合氧化物吸附去除水体中氟化物的研究

采用水热法合成了不同铁掺杂量的Mg/Al/Fe型类水滑石(MAF),根据X射线衍射(XRD)的测定结果,铁存在一个最佳投加量,铁的掺杂量过大则会导致水滑石的层状结构被破坏。通过扫描电镜(SEM)和比表面分析仪(BET)研究了MAF焙烧后的复合金属氧化物(CMAF)的结构和性能,并考察了CMAF对水中氟离子的吸附性能。与CMA相比(铁掺杂量为零),CMAF对氟离子的吸附去除效率明显提高(最大吸附容量75.2 mg/g),整个吸附过程可以用Langmuir吸附等温线更好地描述。通过XRD测定和晶格参数计算,CMAF的结构由吸附前的复合氧化物恢复到层状水滑石结构,表明氟离子在水滑石重构过程中作为层间阴离子进入到水滑石内部,从而达到较高的除氟效率。     

CaH_2对Cu-Ce-La-ZSM-5催化分解NO性能的影响

实验采用一步离子交换法制备Cu-Ce-La-ZSM-5催化剂,然后采用共混法制得Cu-Ce-La-ZSM-5/CaH2催化剂。采用扫描电镜(SEM),电感耦合等离子体发射光谱(ICP-AES),X射线衍射(XRD),红外(FTIR)以及NO吸脱附(NO-TPD)对催化剂进行表征。结果显示CaH2的加入使得催化剂中铜离子存在形式发生变化,催化剂表面变光滑洁净,并且吸附NO能力增强。NO催化分解实验的结果表明CaH2提高了催化剂活性和抗氧性。CaH2助催性是由于其受热分解过程中产生的H2能将Cu2+还原为具有催化活性的Cu+,同时使催化剂表面洁净光滑更容易吸附NO。     

Synthesis and characterisation of Pd-modified N-doped TiO2 for photocatalytic degradation of natural organic matter (NOM) fractions

Introduction

The removal of natural organic matter (NOM) from water is becoming increasingly important in order to prevent the formation of carcinogenic disinfection by-products. The inadequate removal of NOM has a bearing on the capacity of the other treatment processes to remove organic micro-pollutants or inorganic species that may be present in the water. New methods are therefore currently being sought to effectively characterise NOM and also to ensure that it is sufficiently removed from drinking water sources.

Methodology

Nitrogen- and palladium-co-doped TiO₂ was synthesised by a modified sol?Cgel method and evaluated for its photocatalytic degradation activity on NOM fractions under simulated solar radiation. The photocatalyst was characterised by FT-IR, Raman, XRD, DRUV?Cvis, SEM, TEM, EDS, XPS and TGA. FT-IR confirmed the presence of OH groups on thermally stable, nearly spherical anatase nanoparticles with an average diameter of 20?nm. PdO species appeared on the surface of the TiO₂ as small uniformly dispersed particles (2 to 3?nm). A red shift in the absorption edge compared to commercial anatase TiO₂ was confirmed by DRUV?Cvis. In order to gain a better insight into the response of NOM to photodegradation, the NOM was divided into three different fractions based on its chemical nature.

Results and discussion

Photodegradation efficiencies of 96, 38 and 15?% were realised for the hydrophobic, hydrophilic and transphilic NOM fractions, respectively. A reasonable mechanism was proposed to explain the photocatalytic degradation of the NOM fractions. The high photocatalytic activity could be attributed to the larger surface area, smaller crystalline size and synergistic effects of the co-dopants N and Pd in the TiO₂ crystal.     

CaH2对Cu-Ce-La-ZSM-5催化分解NO性能的影响

实验采用一步离子交换法制备Cu-Ce-La-ZSM-5催化剂,然后采用共混法制得Cu-Ce-La-ZSM-5/CaH2催化剂。采用扫描电镜（SEM）,电感耦合等离子体发射光谱（ICP-AES）,X射线衍射（XRD）,红外（FTIR）以及NO吸脱附（NO-TPD）对催化剂进行表征。结果显示CaH2的加入使得催化剂中铜离子存在形式发生变化,催化剂表面变光滑洁净,并且吸附NO能力增强。NO催化分解实验的结果表明CaH2提高了催化剂活性和抗氧性。CaH2助催性是由于其受热分解过程中产生的H2能将Cu^2＋还原为具有催化活性的Cu^＋,同时使催化剂表面洁净光滑更容易吸附NO。     

热镀锌厂酸洗废水和锌灰中回收硫化锌

从热镀锌厂的酸洗废水和锌灰中回收硫化锌,采用X射线能谱仪(EDS),X射线衍射仪(XRD),傅里叶红外光谱仪(FTIR)和场发射透射电镜(FETEM)表征样品ZnS性质,电感耦合等离子发射体(ICP-OES)分析上清液性质,并研究该反应动力学过程。EDS和ICP分析表明,样品ZnS纯度达到85.45%,其上清液含有高浓度铁,含量为2 g/L,可用于制备复合亚铁絮凝剂,而其他重金属离子浓度均低于电镀废水排放标准。XRD分析表明,样品ZnS是立方晶型,调节pH和采用滴加方式能有效改善样品ZnS的晶型。采用Scherrer公式计算晶体粒径,结果表明,晶粒大小在3~6 nm之间。FTIR分析表明,样品ZnS呈现良好的红外透明性,且温度、pH和滴加方式对样品的红外透光性基本没有影响。FETEM结合XRD图表明,该纳米晶呈片状,近似为球形,呈多层叠加,分散性不明显,有团聚现象。动力学实验表明,逆一级动力学方程适合描述硫化沉淀的反应动力学过程,活化能为39.04 kJ/mol,沉淀过程受化学反应和扩散联合控制。     

Ti-Ce-Zr-Ox复合脱硝催化剂的制备及其性能研究

采用共混法制备了Ti-Ce-Zr-Ox复合脱硝催化剂TiCe0.1Zr0.1O2.4,运用X射线衍射、氮气物理吸附、扫描电镜等表征手段,分别对该催化剂的晶型、表面积、孔分布及结构形貌进行了分析,同时考察了反应温度、空速、水蒸气和SO2对该催化剂NH3选择性催化还原NO的影响.结果表明,TiCe0.1Zr0.1O2.4催...     

Preparation of the Mn/Co mixed oxide catalysts for low-temperature CO oxidation reaction

The Mn/Co mixed powders with various Mn/Co molar ratios were prepared by the coprecipitation method and used in low-temperature CO oxidation. The physicochemical characteristics of these powders were characterized using the Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), temperature-programmed reduction (TPR), and scanning electron microscopy (SEM) analyses. The results demonstrated that the Mn/Co molar ratio significantly affected both the textural and catalytic properties and the sample with a Mn/Co = 1:1 possessed a BET area of 123.7 m²g⁻¹ with a small mean pore size of 6.44 nm. The catalytic results revealed that the pure cobalt and manganese catalysts possessed the low catalytic activity and the pure Co catalyst is not active at temperatures lower than 140 °C. The highest catalytic activity was observed for the catalyst with a Mn/Co = 1. The obtained results showed that the incorporation of Pd into the Mn/Co catalyst significantly enhanced the catalytic activity for oxidation of carbon monoxide and the highest CO conversion was observed for the catalyst with 1 wt.% Pd and this catalyst exhibited a CO conversion of 100% at 80 ^°C.

     

铈改性Al2O3担载Pd催化剂的CO氧化性能研究

浸渍法制备了Al2O3＋CeO2为载体的Pd催化剂，对制备中各因素对催化剂效果的影响作了初步研究。考察了活性组分含量与催化剂性能的关系以及焙烧温度、水蒸气对催化剂活性的影响。结果表明，稀土Ce元素的存在使催化剂的性能得到明显改善。制备过程中焙烧步骤对催化剂的活性影响很大，催化剂制备必须高于600℃焙烧。     

Fe/Ce/沸石负载型类芬顿催化剂制备及其特性

采用柠檬酸盐溶胶-凝胶法制备了Fe/Ce/沸石负载型芬顿催化剂,通过透射电镜(TEM)和X射线衍射(XRD)对其进行表征,并将其作为非均相类芬顿催化剂处理孔雀石绿染料溶液。研究表明,通过掺杂Ce,可提高催化剂颗粒分散度和催化剂表面的氧气含量,进而提高催化活性。在催化剂投加量3.0 g/L,H2O2投加量67 mg/L,pH=8.0的条件下,反应30 min后,浓度为150 mg/L的孔雀石绿溶液脱色率可达97.3%。