Identification of the activity source of CO2 electroreduction by strategic catalytic site distribution in stable supramolecular structure system

Identification of the real catalytic site in CO₂ reduction reaction (CO₂RR) is critical for the rational design of catalysts and the understanding of reactive mechanisms. In this study, the catalytic activity of pyridine-containing materials was for the first time structurally demonstrated in CO₂RR by crystalline supramolecular coordination compounds model system. The system consists of three stable supramolecular coordination compounds (Ni-TPYP, Ni-TPYP-1 and Ni-TPP) with different numbers (4, 2 and 0) of active pyridine groups (i.e. uncoordinated pyridine nitrogen atoms). The electrocatalytic test results show that with the decrease of the number of active pyridine groups, the CO₂RR performance is gradually reduced, mainly showing the reduction of highest FE_CO (99.8%, 83.7% and 25.6%, respectively). The crystallographic, experimental and theoretical evidences prove that the CO₂RR activity is more likely derived from uncoordinated pyridine nitrogen than the electrocatalytic inert metal nickel in porphyrin center. This work serves as an important case study for the identification of electrocatalytic activity of pyridine-containing materials in CO₂RR by simple supramolecular model system.     

二溴羧基偶氮胂催化光度法测定水中痕量锰

研究了在NH_3．H_2O-NH_4Cl 介质中锰催化 H_2O_2氧化二溴羧基偶氮胂褪色的最佳条件。λ_(max)=565nm，表观摩尔吸光系数为2．6×10~4 L·moL~(-1)·cm~(-1)，线性范围为0～2．1 μg/25 mL。用于水样中痕量锰的测定，结果满意。     

木屑制取草酸新法

通过硫酸水解,将木屑中的纤维素转化为葡萄糖,在催化剂作用下,用硝酸将其氧化,制取了草酸.经研究,本法最佳配料比及工艺条件为:干木屑∶硫酸(50%)∶硝酸(65%)∶催化剂=30g∶30mL∶4mL∶0.03g,浸泡水解时间为4h以上,反应时间5h以上,反应温度控制在65～70℃.所得草酸纯度为97.5%,收率达50%.对产品理化数据指标及工艺环保措施进行了分析.     

结晶紫催化动力学光度法测定微量草酸

在稀磷酸介质中,微量草酸对KBrO3氧化结晶紫的褪色反应有显著的活化作用,据此建立了测定微量草酸的新方法。方法的线性范围是O.5-5.0μg/mL,检出限为O.2μg/mL.方法简便,快速,灵敏度高,用于茶叶中草酸含量的测定,结果满意。     

从硫化铜矿制取硫酸铜工艺研究

硫化铜经粉碎，催化焙烧，浸取，铁屑置换制海绵铜，再制取符合GB473－93优等品的硫酸铜产品。     

稀土复合固体超强酸SO_4~(2-)/TiO_2/Ce~(4+)催化合成乙酸环己酯及动力学研究

研究了以稀土复合固体超强酸SO42-/TiO2/Ce4+为催化剂合成乙酸环己酯的反应,在反应温度分别为100℃、110℃、120℃下,测出酯化反应的动力学参数,建立了动力学方程,并与无催化剂作用下合成乙酸环己酯反应的活化能及动力学方程进行了比较.实验结果表明,该催化酯化反应的优化合成条件是:乙酸用量为0.262 1mol时,醇酸摩尔比为1.5:1,催化剂用量为1.0g,带水剂环己烷的加入量为12mL.稀土复合固体超强酸SO42-/TiO2/Ce4+可使反应的活化能明显降低,是合成乙酸环己酯的有效催化剂.     

Effect of support calcination temperature on the Ru-Ce-B/ZrO_2 catalysts for benzene selective hydrogenation to cyclohexene

The effect of support calcination temperature on the benzene selective hydrogenation performance of the Ru-Ce-B/ZrO2 catalysts was investigated.It was found that with increasing calcination temperature,the surface area decreased,on the contrary,the pore size and the amount of monoclinic phase increased.With increasing support calcination temperature,the activity of the catalyst roughly decreased and cyclohexene selectivity increased.The activity decreased due to the decrease of the surface areas.The increase of the cyclohexene selectivity was correlated not only with the decrease of the surface areas but also with the increase of monoclinic phases,rich in surface hydroxyl,and the enlarged pore size of zirconia.This suggests the monoclinic zirconia with a medium surface area,rather than a big one,and a mesoporous structure,even including some macropores,is an ideal support of the catalyst for benzene selective hydrogenation.     

汽车尾气催化处理实验研究

以汽车尾气模拟装置中产生的气体作为模拟废气,对于JFG型三元催化剂处理汽车排气中CO、HC和NO的三效性能进行了考察,结果表明该催化剂具有低起燃愠度,良好的冷启动性能和良好的三效性能。同时和HPA-8型催化剂进行了对比,发现HPA-8型催化剂具有优异的控CO和NO的性能。     

阻抑甲基橙褪色催化动力学光度法测定痕量钴(Ⅱ)

在稀HNO4介质中,Co(Ⅱ)对高碘酸钾氧化甲基橙褪色反应具有阻抑作用,且阻抑反应的强弱与加入Co(Ⅱ)离子浓度成正比,由此建立了阻抑甲基橙褪色催化动力学光度法测定痕量Co(Ⅱ)的新光度分析方法。研究了最佳实验条件,吸光度为502nm处,阻抑反应吸光度(A)与非阻抑反应吸光度(A0)的差值△A与钴(Ⅱ)质量浓度在0.003-1.0μg/25 mL范围内有良好的线性关系,检出限为1.0981×10-10g/mL。测定了动力学参数,反应为准一级反应,表观活化能为63.24 kJ/mol,在80℃下反应的表观速率常数为6.70×10-4/s。该方法可用于药用VB12针剂中痕量Co(Ⅱ)测定,回收率在97~102%之间,符合痕量分析要求。     

Synthesis of polyketone by copolymerization of styrene and CO using carbon nanotube-complex Pd2+ catalyst

The dipping method was devised to deposit Pd onto carbon nanotube as supported catalyst(Pd/CNT) for the copolymerization of carbon monoxide(CO) and styrene(ST) towards the formation of polyketone(PK).The Pd/CNT was characterized by X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD) and high-resolution transmission electron microscopy(HRTEM).The construction and crystallization property of PK were evaluated by Fourier transform infrared spectroscopy(FTIR),13C-nuclear magnetic resonance(NMR) and XRD,respectively.The catalyst showed excellent activity and reusability in promoting the fabrication of PK.It can be recycled 14 times with the highest total catalytic activity of 4 239.64 gPK/(gPd·h) at Pd content of 8.63wt%.The results indicate that the prepared catalyst is effective to catalyze the copolymerization of CO and styrene.