应用化学拔尖人才培养目标下的综合化学实验教学改革

根据综合化学实验课程设立的目标和教学现状,以培养应用化学学科拔尖人才、提高学生学术素养为目的,本文阐述了如何将线上和线下相结合的混合模式教学方法应用到本科生日常实验课程教学中。本文会以“致霾柴油车尾气催化剂的制备及台架测试” 实验教学为例详细阐述线上线下混合模式教学在综合化学实验课程中的应用。在教学过程中,将线上视频教学、虚拟仿真实验模拟演示实验过程和线下实验室实操相结合,并以手写报告、讨论汇报等多种教学手段为辅助,以更好地培养化学类本科生科研创新能力和提高学生的自主学习积极性[1],在丰富课程教学元素的同时充分调动学生的课程实验兴趣。

《综合化学实验》课程新体系的研究与构建

本文以《综合化学实验》课程新体系的研究与构建为研究目的,探讨了随着化学教育的深入发展,传统的《综合化学实验》课程体系的不足逐渐显现。为了更好地培养学生的实验技能、创新能力和团队协作精神,本研究致力于构建一个新的课程体系。新体系强调实验技能与理论知识的整合、创新能力培养、团队协作能力与实践精神的培养,并强调与科研的结合,以期提升教学质量。

Co_(0.2)/Ce_(1-x)Zr_xO_2催化剂的制备、表征及其催化碳烟燃烧反应性能

采用微孔扩散-共沉淀法制备了不同Ce/Zr摩尔比的Ce1-xZrxO2(x=0,0.2,0.4,0.5)固溶体,并以此为载体用超声波助分散等体积浸渍法制备了Co0.2/Ce1-xZrxO2催化剂,考察了催化剂中Ce/Zr比对其催化柴油车尾气碳烟颗粒物燃烧反应性能的影响.结果表明,在催化剂与碳烟颗粒松散接触条件下,Co0.2/Ce1-xZrxO2催化剂催化碳烟颗粒物燃烧的活性非常高.其中Co0.2/Ce0.8Zr0.2O2催化剂活性最高,T10,T50,T90和SmCO2分别为316oC,385oC,413oC和99.9%.这与目前文献报道的松散接触条件下活性最高的担载Pt催化剂相近.应用X射线衍射、透射电镜、扫描电镜、紫外-可见漫反射和傅里叶变换红外光谱技术对Ce1-xZrxO2固溶体及Co0.2/Ce1-xZrxO2催化剂进行了表征.结果表明,Ce1-xZrxO2固溶体由纳米级小颗粒组成(平均粒径在10nm左右).适量的Ce/Zr比有利于改善立方尖晶石型Co3O4在Ce1-xZrxO2固溶体表面的分散,从而提高催化剂活性.程序升温还原结果表明,Co0.2/Ce0.8Zr0.2O2催化剂具有最优的低温还原特性,与它具有最高的催化活性相一致.

金属有机骨架材料MIL-53(Al)负载纳米Pd颗粒:一种CO氧化的活性催化剂(英文)

通过等体积浸渍法制备了金属有机骨架材料MIL-53(Al)(MIL:Materials of Institut Lavoisier)负载纳米Pd催化剂.采用X射线衍射(XRD)、透射电子显微镜(TEM)和X射线光电子能谱(XPS)等手段对催化剂的结构进行了表征.催化剂在反应前后XRD衍射峰保持不变,说明载体MIL-53(Al)具有良好的稳定性.采用TEM对催化剂进行表征,结果表明,MIL-53(Al)的多孔晶体结构有助于形成高度分散的纳米Pd颗粒,样品2.7%(w)Pd/MIL-53中Pd颗粒的平均粒径为2.21 nm.该催化剂在CO氧化反应中表现出较高的催化活性,115°C达到完全转化.同时催化剂可循环使用,多次反应后催化活性和催化剂结构都保持稳定.

L/W复合分子筛的合成及在催化裂化汽油加氢改质催化剂中的应用

报道了一种新型复合分子筛L/W的制备、表征及应用.采用X射线衍射(XRD)、扫描电子显微镜(SEM)、红外光谱(IR)、氮气吸附-脱附、吡啶红外光谱(Py-IR)、氢气程序升温还原(H2-TPR)及拉曼光谱(Raman)等手段系统地比较了复合分子筛与机械混合分子筛的差异.结果表明,机械混合分子筛中的L和W分子筛均以独立相存在,而复合分子筛中L分子筛是部分生长在W分子筛之上的;并且复合分子筛表现出了更大的比表面积和孔径以及更适宜的酸性分布,这有利于反应物的扩散,增强了B酸与L酸的协同效应.在催化裂化反应中,复合分子筛催化剂比机械混合分子筛催化剂具有更高的脱硫活性(脱硫率93.3%)以及更低的辛烷值损失(ΔRON=-1.15).

Synthesis of K-doped three-dimensionally ordered macroporous Mn_(0.5)Ce_(0.5)O_δ catalysts and their catalytic performance for soot oxidation

A series of K-doped Mn0.5Ce0.5Oδ （K-MCO） catalysts with three-dimensionally ordered macroporous （3DOM） structure and different K loadings were successfully synthesized using simple methods. These catalysts exhibited well-defined 3DOM nanostructure, which consisted of extensive interconnecting networks of spherical voids. The effects of the calcination temperature and calcination time on the morphological characteristics and crystalline forms of the catalysts were systematically studied. The catalysts showed high catalytic activity for the combustion of soot. 3DOM 20% K-MCO-4h catalyst, in particular, showed the highest catalytic activity of all of the catalysts studied （e.g., Ts0 = 331 ~C and Smco2 = 95.3%）. The occurrence of structural and synergistic effects among the K, Mn, and Ce atoms in the catalysts was favorable for enhancing their catalytic activity towards the combustion of diesel soot. Furthermore, the temperatures required for the complete combustion of the soot （〈400 ℃） were well within the exhaust temperature range （175-400 ℃）, which means that the accumulated soot can be removed under the conditions of the diesel exhaust gas. These catalysts could therefore be used in numerous practical applications because they are easy to synthesize, exhibit high catalytic activity, and can be made from low cost materials.

TiO_(2)催化剂催化CO_(2)还原的研究进展

碳排放量的不断增加导致环境问题日益严重,寻找解决途径已成为全球共同关注的焦点。通过光催化、电催化还原CO_(2)可以将其转化为有用的燃料或化学品。TiO_(2)因具有化学性质稳定、催化活性高、价格低廉、无毒无污染等优点而备受青睐。综述了光催化CO_(2)还原和电催化CO_(2)还原的反应机理;阐述了TiO_(2)在光催化和电催化还原CO_(2)中的应用和优势、不同表面改性技术对TiO_(2)的催化性能的影响以及TiO_(2)的形貌对CO_(2)还原催化活性和选择性的影响;对TiO_(2)基催化剂催化性能的提升方法进行了讨论。综述为可持续碳转化提供科学基础,并有助于进一步实验和理论探索TiO_(2)的作用机理。

Synthesis of a chabazite-supported copper catalyst with full mesopores for selective catalytic reduction of nitrogen oxides at low temperature

A series of meso‐microporous copper‐supporting chabazite molecular sieve（CuSAPO‐34） catalysts with excellent performance in low‐temperature ammonia selective catalytic reduction（NH3‐SCR）have been synthesized via a one‐pot hydrothermal crystallization method. The physicochemical properties of the catalysts were characterized by scanning electron microscopy, transmission electron microscopy, N2 adsorption‐desorption measurements, X‐ray diffraction, 27 Al magic angle spinning nuclear magnetic resonance, diffuse reflectance ultraviolet‐visible spectroscopy, inductively coupled plasma‐atomic emission spectroscopy, X‐ray photoelectron spectroscopy, temperature‐programmed reduction measurements, and electron paramagnetic resonance analysis. The formation of micro‐mesopores in the Cu‐SAPO‐34 catalysts decreases diffusion resistance and greatly improves the accessibility of reactants to catalytic active sites. The main active sites for NH3‐SCR reaction are the isolated Cu^2＋ species displaced into the ellipsoidal cavity of the Cu‐SAPO‐34 catalysts.

Effects of Au-Ce strong interactions on catalytic activity of Au/CeO_2/3DOM Al_2O_3 catalyst for soot combustion under loose contact conditions

Au/3DOM（three-dimensionally ordered macroporous） Al2O3 and Au/CeO2/3DOM Al2O3 were prepared using a reduction-deposition method and characterized using scanning electron microscopy,N2 adsorption-desorption,X-ray diffraction,transmission electron microscopy,ultraviolet-visible spectroscopy,temperature-programmed hydrogen reduction,and X-ray photoelectron spectroscopy.Au nanoparticles of similar sizes were well dispersed and supported on the inner walls of uniform macropores.The norminal Au loading is 2%.Al-Ce-O solid solution in CeO2/3DOM Al2O3 catalysts can be formed due to the incorporation of Al^3＋ ions into the ceria lattice,which causes the creation of extrinsic oxygen vacancies.The extrinsic oxygen vacancies improved the oxygen-transport properties.The strong metal-support interactions between Au and CeO2 increased the amount of active oxygen on the Au nanoparticle surfaces,and this promoted soot oxidation.The activities of the Au-based catalysts were higher than those of the supports（Al2O3 or CeO2/3DOM Al2O3） at low temperature.Au/CeO2/3DOM Al2O3 had the highest catalytic activity for soot combustion,with T（10）,T（50）,and T（90） values of 273,364,and 412℃,respectively.

Ni-Mo氮化物催化剂:合成及其丙烷氨氧化催化性能(英文)

分别采用溶胶-凝胶法、旋转蒸发微波干燥法、共沉淀法、浸渍法和机械混合法制备Ni-Mo氧化物前驱体.以H2和N2的混合气为氮化气体,采用程序升温氮化法合成了镍钼氮化物催化剂.利用X射线衍射、总氮含量分析、X射线光电子能谱及H2程序升温还原对Ni-Mo氧化物前体及氮化物催化剂进行了表征.将上述Ni-Mo氮化物催化剂用于丙烷氨氧化反应中.结果表明,Ni-Mo氧化物前驱体的制备方法影响其氮化物催化剂上丙烷氨氧化反应性能.Ni-Mo氮化物催化剂中氮物种的移动性及反应性对产物丙烯腈选择性的影响较大,共沉淀法制备的催化剂存在大量的活性氮物种,因而具有良好的催化丙烷氨氧化反应活性.

薄层氮化碳光催化还原CO_2性能研究

以氮化碳(g-CN)为原料,采用水蒸汽焙烧剥离法在Ar/H2O氛围下制备薄层氮化碳(Hg-CN),并对其进行XRD、TEM、FT-IR、BET和UV-Vis DRS等表征。结果表明,进行剥离后,H-g-CN比表面积相比剥离前明显增大。H-g-CN的光催化还原CO_2活性大大高于未剥离gCN的活性,光照反应9 h,H-g-CN光催化还原CO_2活性由剥离前的11. 4μmol·g^(-1)提高至24. 6μmol·g^(-1),H-g-CN的CO选择性为91. 2%,未剥离的g-CN的CO选择性为89. 1%,并提出相应的反应机理。

基于有机硅表面活性剂的环保泡沫灭火剂的制备及灭火性能研究

为了解决传统含氟泡沫灭火剂难以降解和存在生态危害性的难题,本工作研发了基于低毒环保有机硅表面活性剂的环保泡沫灭火剂。实验结果表明,该泡沫灭火剂为均一、稳定的溶液,凝固点为-10.5℃,pH值为8.2,发泡倍数为7.2,25%析液时间为4.0 min,表面张力为22.4 mN/m,铺展系数为正值。泡沫混合液的BOD_(5)/COD数值为0.37,具有良好的生物降解性和环境友好性以及优异的灭火能力,能成功快速扑灭55B和144B非水溶性易燃液体油盘火,灭火性能满足国家标准(IIA级别)。本研究可为高效环保泡沫灭火剂的研发奠定理论基础并提供实验依据。

光催化CO_(2)还原成C_(2+)产物催化剂及其反应机理研究进展

传统工业过程,尤其是依赖于煤炭、石油和天然气等化石燃料的生产活动,导致了CO_(2)的高浓度排放。工业烟气中的CO_(2)治理是降低重点行业污染排放、打好污染防治攻坚战的重中之重。近年来,我国在降污减碳方面取得了显著成果。光催化CO_(2)还原技术以直接利用清洁的太阳能和在室温下进行反应等诸多优势,目前广泛应用于CO_(2)资源化利用。在过去的几十年里,研究者致力于提高光催化CO_(2)转化的活性研究。然而,关于提高该过程选择性的研究相对缺乏,特别是关于高价值C_(2+)产品的生成。鉴于当前的研究趋势和新兴技术,首先阐述了目前应用广泛的CO_(2)资源化利用技术并进行了对比分析,接着阐明该反应中C—C偶联的热力学限制、动力学特征、光催化剂表面活化基本原理和机制,进而概述目前可用提高C_(2+)产物选择性的技术,并综述了各技术目前存在的缺点。最后,总结了目前研究现状并指明了现存的问题,并对该领域的未来前景和工业化应用做出了指引。

有机氯硅烷高沸物催化裂解材料研究进展

有机硅材料具有防潮、耐腐蚀、耐高低温、无毒无味以及生理惰性等优异的性能,已被广泛应用于各个领域。有机硅单体的生产过程会产生约7%的副产物,以成分复杂及工业价值低的有机氯硅烷高沸物为主,因其易燃、有刺激性气味和具有强的腐蚀性,对环境及人体健康有重大危害。随着有机硅单体产能日益增加,有机氯硅烷高沸物的有效利用成为一个亟待解决的难题。高沸物的再利用主要是通过制备有机硅下游产品和裂解制备有机硅单体来实现,而后者需要在催化剂存在的条件下将高沸物中含有的Si-Si键和Si-C-Si断裂,并选用合适的封端剂将其转化成甲基氯硅烷单体。目前,路易斯酸、有机胺、过渡金属元素、活性炭和分子筛等是催化裂解的主要催化剂,各自工艺的操作条件及催化性能迥异。高沸物的裂解率最高可以达到99%以上,但由于生产工艺复杂、操作成本高等问题的限制,严重阻碍了其工业推广与应用。本文归纳了有机氯硅烷高沸物催化裂解材料的研究进展,分别对铝基化合物、有机胺或季铵盐、过渡金属及其化合物、分子筛或活性炭和金属磷酸盐等催化剂展开介绍,概括了以上各类催化剂的研究现状及面临的问题,并对其发展前景进行了合理的分析与讨论,以期为制备出高效、可工业化的有机氯硅烷高沸物裂解催化剂提供参考。

创新创业人才培养模式下《物理化学》教学改革的探讨

《物理化学》教学对于学生创新创业能力的培养和科研应用意识的培养具有十分重要作用,然而它的发展现状并不乐观。其原因包含教学方法、教学内容以及学生主观态度等诸多因素,而且《物理化学》课程在教学过程中,因过于迎合学生需要,造成教学内容以及方式有些畸形,失去了与实际情况自然现象联系的理念。文章根据教学过程实践,通过对高校现代物理化学教育改革的现状进行反思,提出为了促进《物理化学》教学的发展,应依照《物理化学》学科的本身特点,进行教学,鼓励学生与自然现象相联系,使学生把自然现象与抽象的物理化学概念和公式相联系,以产生共鸣的目的,达到高校《物理化学》教育改革的目标。

Three-dimensional ordered macroporous perovskite-type La_(1-x)K_xNiO_3 catalysts with enhanced catalytic activity for soot combustion: the Effect of K-substitution

Three-dimensional ordered macroporous (3DOM) La1?xKxNiO3 perovskite-type catalysts were successfully prepared by a colloidal crystal template method and characterized by scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray scattering elemental mapping, X-ray diffraction, Raman and X-ray photoelectron spectroscopy, and temperature-programmed reduction of H2. Further, their catalytic activity in soot combustion was determined by temperature-programmed oxidation reaction. K substitution into the LaNiO3 lattice led to remarkably improved catalytic activity of this catalyst in soot combustion. Amongst various catalysts, La0.95K0.05NiO3 exhibited the highest activity in soot combustion (with its T50 and CO2 S values being 338 °C and 98.2%, respectively), which is comparable to the catalytic activities of Pt-based catalysts under the condition of poor contact between the soot and the catalyst. K-substitution improves the valence state of Ni and increases the number of oxygen vacancies, thereby leading to increased density of surface-active oxygen species. The active oxygen species play a vital role in catalyzing the elimination of soot. The perovskite-type La1?xKxNiO3 nanocatalysts with 3DOM structure without noble metals have potential for practical applications in the catalytic combustion of diesel soot particles.

Fabrication of ultrafine Pd nanoparticles on 3D ordered macroporous TiO_2 for enhanced catalytic activity during diesel soot combustion

Nanocatalysts consisting of three‐dimensionally ordered macroporous(3DOM)TiO2‐supported ultrafine Pd nanoparticles(Pd/3DOM‐TiO2‐GBMR)were readily fabricated by gas bubbling‐assisted membrane reduction(GBMR)method.These catalysts had a well‐defined and highly ordered macroporous nanostructure with an average pore size of 280 nm.In addition,ultrafine hemispherical Pd nanoparticles(NPs)with a mean particle size of 1.1 nm were found to be well dispersed over the surface of the 3DOM‐TiO2 support and deposited on the inner walls of the material.The nanostructure of the 3DOM‐TiO2 support ensured efficient contact between soot particles and the catalyst.The large interface area between the ultrafine Pd NPs and the TiO2 also increased the density of sites for O2 activation as a result of the strong metal(Pd)‐support(TiO2)interaction(SMSI).A Pd/3DOM‐TiO2‐GBMR catalyst with ultrafine Pd NPs(1.1 nm)exhibited higher catalytic activity during diesel soot combustion compared with that obtained from a specimen having relatively large Pd NPs(5.0 nm).The T10,T50 and T90 values obtained from the former were 295,370 and 415°C.Both the activity and nanostructure of the Pd/3DOM‐TiO2‐GBMR catalyst were stable over five replicate soot oxidation trials.These results suggest that nanocatalysts having a 3DOM structure together with ultrafine Pd NPs can decrease the amount of Pd required,and that this approach has potential practical applications in the catalytic combustion of diesel soot particles.

钾调变Mo/SBA-15催化剂用于乙烷选择氧化制乙醛(英文)

采用两步浸渍法制备钾改性的Mo/SBA-15催化剂.采用N2吸附,X射线衍射(XRD),透射电镜(TEM),紫外-可见(UV-Vis)吸收光谱,拉曼(Raman)光谱,NH3程序升温脱附(NH3-TPD),CO2程序升温脱附(CO2-TPD),H2程序升温还原(H2-TPR)等手段表征催化剂的物理化学性质.研究结果表明,在Mo0.75/SBA-15中添加K之后,有新物种钾钼酸盐生成,并且当K/Mo的摩尔比不同时,钼物种的存在状态也不同.添加钾之后,催化剂的活性和总醛(甲醛、乙醛、丙烯醛)的选择性均有所提高,并且受钾的添加量影响.在575°C时,在K0.25-Mo0.75/SBA-15催化剂上醛的收率可高达8.5%(摩尔分数).

Three-dimensionally ordered macroporous CeO_2/Al_2O_3-supported Au nanoparticle catalysts: Effects of CeO_2 nanolayers on catalytic activity in soot oxidation

A series of catalysts consisting of three‐dimensionally ordered macroporous(3DOM)x‐CeO2/Al2O3‐supported Au nanoparticles(x=2,10,20,and40wt%)were successfully synthesized using a reduction‐deposition method.These catalysts were characterized using scanning electron microscopy,the Brunauer‐Emmett‐Teller method,X‐ray diffraction,transmission electron microscopy,ultraviolet‐visible spectroscopy,and temperature‐programmed reduction by H2.Au nanoparticles of mean particle size5nm were well dispersed and supported on the inner walls of uniform macropores.The3DOM structure improved the contact efficiency between soot and the catalyst.An Al‐Ce‐O solid solution was formed in the multilayer support,i.e.,x‐CeO2/Al2O3,by the incorporation of Al3+ions into the CeO2lattice,which resulted in the creation of extrinsic oxygen vacancies.Strong interactions between the metal(Au)and the support(Ce)increased the amount of active oxygen species,and this promoted soot oxidation.The catalytic performance in soot combustion was evaluated using a temperature‐programmed oxidation technique.The presence of CeO2nanolayers in the3DOM Au/x‐CeO2/Al2O3catalysts clearly improved the catalytic activities in soot oxidation.Among the prepared catalysts,3DOM Au/20%CeO2/Al2O3showed high catalytic activity and stability in diesel soot oxidation.

用于液体火灾的环保泡沫灭火剂研究现状

传统水成膜泡沫灭火剂(AFFF)具有良好的灭火性能,是目前扑灭液体火灾最好的灭火剂,但是其组成成分涉及全氟辛烷磺酰基化合物(PFOS)等难分解的物质,严重危害环境。随着各国环保政策法规的日益完善,未来PFOS被全面取代是大势所趋。近年来国内外很多研究者也在积极研发环保泡沫灭火剂,目前研发趋势主要包含两个方向:一个是研发含氟的环保泡沫灭火剂,用短链氟碳表面活性剂来替代长链氟碳表面活性剂,在满足灭火需求的同时减小对环境的危害,虽然环境问题暂时得到解决,但其使用周期较短,且从长远来看是否对环境友好还缺乏直接的证据;另外一个是研发无氟的环保泡沫灭火剂,主要是利用碳氢表面活性剂和其他表面活性剂进行复配,其中使用最多的是有机硅表面活性剂。本文归纳了近年来用于液体火灾的环保泡沫灭火剂的研究进展,分别对含氟和无氟泡沫灭火剂展开介绍,概括了各种环保泡沫灭火剂的研究现状及面临的问题,并对其发展前景进行了合理的分析讨论,以期为制备出效果更好、性能更优、对环境无危害的环保泡沫灭火剂提供参考。