沉淀pH对CuO/ZnO/Al_(2)O_(3)催化剂结构及CO/CO_(2)/H_(2)合成甲醇性能的影响  

Effect of Precipitation pH on Structure of CuO/ZnO/Al_(2)O_(3)Catalyst and Its Performance for CO/CO_(2)/H_(2)Conversion to Methanol

作　　者：莫文龙[1] 王海龙[1] 马凤云[1] 从蕊 黄河[1] 张书培 杨晓勤 MO Wenlong;WANG Hailong;MA Fengyun;CONG Rui;HUANG He;ZHANG Shupei;YANG Xiaoqin(State Key Laboratory of Chemistry and Utilization of Carbon-based Energy Resources,Northwest Energy Carbon Neutrality Engineering Research Center of the Ministry of Education,Key Laboratory of Coal Clean Conversion&Chemical Engineering Process(Xinjiang Uyghur Autonomous Region),School of Chemical Engineering and Technology,Xinjiang University,Urumqi Xinjiang 830017,China;Xinjiang Yihua Chemical Industry Co.,Ltd.,Changji Xinjiang 831700,China)

机构地区：[1]新疆大学化工学院,省部共建碳基能源资源化学与利用国家重点实验室,西北能源碳中和教育部工程研究中心,煤炭清洁转化与化工过程新疆维吾尔自治区重点实验室,新疆乌鲁木齐830017 [2]新疆宜化化工有限公司,新疆昌吉831700

出　　处：《当代化工》2024年第11期2668-2672,2677,共6页Contemporary Chemical Industry

基　　金：中央引导地方科技发展专项项目(项目编号:ZYYD2022C16);昌吉州科技支撑产业高质量发展专项项目(项目编号:2022Z04)。

摘　　要：采用共沉淀法制备系列铜基催化剂(CuO/ZnO/Al_(2)O_(3)),探讨制备过程中沉淀pH对催化剂及其前驱体组成和结构的影响,并在浆态床中考察铜基催化剂的CO/CO_(2)/H_(2)合成甲醇性能,包括CO转化率XCO、甲醇选择性SM及甲醇时空收率STY等。结果表明:所制备的催化剂前驱体中锌孔雀石(Cu,Zn)_(2)CO_(3)(OH)_(2)和绿铜锌矿(Cu,Zn)5(CO_(3))_(2)(OH)_(6)的总相对含量均在40%(摩尔分数)左右,可获得较高的Cu^(2+)和Zn^(2+)被取代率。其中,pH为7.5~8.0时的Cu^(2+)和Zn^(2+)被取代率合计高达51.55%。XRD分析发现,前驱体中除了上述物相,还包括孔雀石Cu_(2)CO_(3)(OH)_(2)和水锌矿Zn_(5)(CO_(3))_(2)(OH)_(6),且4种物相均具有较强的衍射峰,说明存在一定的结晶度,即铜锌间相互作用力较强。焙烧后的XRD分析显示,所制备的CuO/ZnO/Al_(2)O_(3)催化剂中CuO和ZnO物相特征衍射峰发生了重叠现象,当pH为7.5~8.0时的重叠峰强度较大,说明二者的结合力更强,形成了较稳定的固熔体。催化剂的CO/CO_(2)/H_(2)合成甲醇性能显示,pH为7.5~8.0时所得催化剂活性最高,其CO转化率XCO=40.6%,甲醇选择性SM=99.7%,甲醇时空收率STY=283.5 g·kg^(-1)·h^(-1),表现出较好的催化性能。Co-precipitation method was used to prepare a series of copper based catalysts(CuO/ZnO/Al_(2)O_(3)),and the influence of precipitation pH on the composition and structure of the catalyst and its precursor during the preparation process was explored.The methanol synthesis performance(including CO conversion XCO,methanol selectivity SM,and methanol space-time yield STY)from CO/CO_(2)/H_(2)by copper-based catalyst was investigated in a slurry bed reactor.The results showed that the total relative contents of rosasite(Cu,Zn)2CO3(OH)_(2)and aurichalcite(Cu,Zn)5(CO_(3))_(2)(OH)_(6)in the catalyst precursors prepared by this method were about 40%(mole fraction),resulting in high replacement rates of Cu^(2+)and Zn^(2+).Among them,the total substitution rate of Cu^(2+)and Zn^(2+)at the pH of 7.5~8.0 was as high as 51.55%.XRD analysis for the precursors found that in addition to the above phases,the precursor also included malachite Cu_(2)CO_(3)(OH)_(2)and hydrozincite Zn5(CO_(3))_(2)(OH)_(6),and all the four precursor phases presented strong diffraction peaks,indicating that there was a certain degree of crystallinity,that was,the interaction between copper and zinc was strong.XRD analysis for the catalysts(after calcination)showed that the characteristics diffraction peaks of CuO and ZnO phases in the prepared CuO/ZnO/Al_(2)O_(3)catalyst were overlapped.And the intensity of the overlapping peaks was higher as the precipitation pH was selected as 7.5~8.0,indicating a stronger binding force between the two phases,and the formation of stable solid melt CuO-ZnO was observed.Performance of the catalyst for methanol synthesis from CO/CO_(2)/H_(2)showed that the catalyst with higher activity was obtained at the precipitation pH of 7.5~8.0,with CO conversion of 40.6%,methanol selectivity of 99.7%,and methanol space-time yield of 283.5 g·kg^(-1)·h^(-1).

关 键 词：共沉淀法 甲醇合成 Cu基催化剂 

分 类 号：O643.36[理学—物理化学]