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羰基硫(COS)广泛存在于以煤、焦炭、渣油和天然气等为原料生产的化工原料气中,不仅腐蚀管道设备,使下游催化剂发生硫中毒,而且还会造成环境污染.因此,COS脱除具有重要意义.在各种方法中,催化水解COS(COS+H_2O→CO_2+H_2S)由于具有反应条件温和、转化率高和副反应少等优点越来越受重视.其关键在于发展高效的催化剂.近年来,金属-有机骨架材料(metal-organic frameworks,MOFs)由于其独特的物理化学性质引起人们广泛关注.与传统材料相比,MOFs不仅拥有超高的比表面积和规则的孔道结构,而且其结构具有可设计性强和易调变等特点,是一类非常有潜力的多相催化剂.然而,目前MOFs在催化水解COS方面的研究应用未见报道.此外,MOFs的合成方法主要有水/溶剂热法、扩散法和微波辅助加热法等.近年来新发展的电化学法具有合成效率高、操作方便和环境友好等优点,在材料合成中显示出巨大的优越性,但利用电化学法合成MOFs相关研究还较少.本文采用快速温和的电化学方法制备了典型的Cu-MOFs(HKUST-1).该方法可以有效缩短反应时间,通过调节反应电压(15–30 V),在室温下电解3 h,可得到一系列HKUST-1样品.根据合成中设置的电压值,样品分别命名为HKUST-1-E15,HKUST-1-E20,HKUST-1-E25和HKUST-1-E30.XRD表征结果显示,不同电压下合成样品的XRD谱图与通过晶体数据拟合的HKUST-1图出峰位置基本一致.SEM结果表明,合成电压对样品形貌的影响很大.HKUST-1-E15主要呈长棒状结构,长约为15μm.随着电压的增大,HKUST-1-E20的形貌逐渐转变为较短的四棱柱体.当电压为25 V时,所得HKUST-1-E25呈八面体状.进一步提高合成电压,HKUST-1-E30颗粒变小,没有特殊形貌,并出现明显的团聚.COS水解测试结果显示,不同电压下合成样品的活性差异大,这主要是由于样品的形貌及比表面积差异引起的.其中,HKUST-1-E25样品的活性较好.在150°C下,该样品对COS的转化率接近100%,比水热法合成的HKUST-1-Hy的活性更高.在此基础上,进一步对活性测试过程的条件进行优化,发现当原料气流速为30 mL/min,水温为40°C时,催化剂的COS水解性能最优.此外,样品的活性稳定性测试结果显示,相比传统的氧化铜材料,HKUST-1是一类较稳定的COS水解催化剂.
Carbonyl sulfide (COS) is widely present in chemical feedstocks produced from coal, coke, residual oil and natural gas, which not only corrodes pipeline equipment but also causes sulfur poisoning on the downstream catalyst and also causes environmental pollution.So COS In addition, COS (COS + H 2 O → CO 2 + H 2 S) has attracted more and more attention due to its advantages of mild reaction conditions, high conversion rate and few side reactions, etc. The key lies in the development of highly efficient Catalysts.In recent years, metal-organic frameworks (MOFs) have drawn much attention due to their unique physicochemical properties.Compared with traditional materials, MOFs not only have super high specific surface area and regular pore structure, However, the structure of MOFs is a promising heterogeneous catalyst because of its strong adaptability and tunability. However, the current research on the catalytic hydrolysis of COS has not been reported. In addition, the synthesis methods of MOFs mainly include: Water / solvothermal method, diffusion method and microwave-assisted heating method, etc. In recent years, the newly developed electrochemical method has the advantages of high synthesis efficiency, convenient operation and environmental friendliness. In the synthesis of materials However, there are few researches on the synthesis of MOFs by electrochemical method.In this paper, a typical mild Cu-MOFs (HKUST-1) was prepared by a rapid and mild electrochemical method, which can effectively shorten the reaction time by A series of HKUST-1 samples were obtained by adjusting the reaction voltage (15-30 V) and electrolysis at room temperature for 3 h. The samples were named HKUST-1-E15, HKUST-1-E20, The characterization results of HKUST-1-E25 and HKUST-1-E30.XRD show that the XRD patterns of synthesized samples at different voltages are basically the same as the peak position of HKUST-1 which is fitted by crystal data.The SEM results show that the voltage The shape of HKUST-1-E20 is gradually changed into a shorter quadrangular prism with the increase of voltage .HKUST-1-E15 mainly has a long rod-like structure with a length of about 15μm. The resulting HKUST-1-E25 showed octahedron shape at a voltage of 25 V. With a further increase in the resultant voltage, the particles of HKUST-1-E30 became smaller with no special morphology and showed significant agglomeration. The results of the COS hydrolysis test showed that different voltages Under the synthetic samples, the activity difference is large, which is mainly caused by the differences of the morphology and the specific surface area of the samples, The activity of HKUST-1-E25 was better than that of HKUST-1-Hy at 150 ° C. The conversion of COS was nearly 100% at 150 ° C, which was higher than that of HKUST-1-Hy synthesized by hydrothermal method.Furthermore, The conditions of the activity testing process were optimized and it was found that when the feed gas flow rate is 30 mL / min and the water temperature is 40 ° C, the COS hydrolysis performance of the catalyst is the best.In addition, the activity stability test results of the samples show that compared with the traditional Copper oxide material, HKUST-1 is a more stable COS hydrolysis catalyst.