WO_(3-x)/CFs三相催化剂的制备及其可见光催化转化甲烷制甲醇  

Preparation of WO_(3-x)/CFs triphase catalyst and visible-light photocatalytic conversion of methane to methanol

作　　者：荣丽青 杨娟[1,2,3] 戴俊 王大钊[1] RONG Liqing;YANG Juan;DAI Jun;WANG Dazhao(School of Safety Science and Engineering,Henan Polytechnic University,Jiaozuo 454003,China;State Collaborative Innovation Center of Coal Work Safety and Clean-efficiency Utilization,Jiaozuo 454003,China;School of Chemistry and Chemical Engineering,Henan Polytechnic University,Jiaozuo 454003,China)

机构地区：[1]河南理工大学安全科学与工程学院,焦作454003 [2]煤炭安全生产与清洁高效利用省部共建协同创新中心,焦作454003 [3]河南理工大学化学化工学院,焦作454003

出　　处：《复合材料学报》2023年第5期2709-2721,共13页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(52074103,U2004194);河南省自然科学基金(202300410181);河南省科技攻关重点项目(222102320095);河南省教育厅重点科研项目(21 A440008)。

摘　　要：将甲烷选择性转化为平台分子甲醇是有效利用天然气资源的理想途径之一,低碳排放的光催化技术可在室温常压下活化与转化甲烷,但水相光催化体系的甲烷转化性能仍较低。采用水热法首先合成富含氧缺陷的氧化钨(WO_(3-x)),借助聚四氟乙烯浓缩液(PTFE)将WO_(3-x)负载至碳纤维(CFs)表面制备WO_(3-x)/CFs三相光催化剂,改变PTFE添加量可调控WO_(3-x)/CFs的表面浸润性,通过XRD、SEM、水接触角、电子顺磁共振波谱仪(EPR)和低温氮吸脱附等测试技术对催化剂的形貌、结构与表面特性进行系统表征。可见光催化实验结果表明:WO_(3-x)/CFs三相体系可显著提升甲烷至甲醇的转化性能,最优催化剂WO_(3-x)/CFs-0.3的甲烷转化量为2522.20μmol·g^(-1),分别为WO_(3-x)/氧化铟锡导电玻璃(Glas)与粉末WO_(3-x)两相体系的1.76倍和2.48倍;相应的甲醇产生量为1918.83μmol·g^(-1),分别为WO_(3-x)/Glas与粉末WO_(3-x)体系的2.81倍和4.69倍,同时三相体系的甲醇选择性高达76.76%。WO_(3-x)/CFs光催化性能增强主要源于疏水性催化剂形成的气-液-固三相界面,消耗的甲烷可经CFs气体传输通道直接传质至催化界面,促进甲烷分子活化与转化。此外,三相光催化体系循环稳定性优异,WO_(3-x)/CFs-0.3经6次循环后甲醇产生量仍可达1506.98μmol·g^(-1)。Selective conversion of methane into platform molecule methanol is one of the ideal ways to effectively utilize natural gas resources.Photocatalytic technology with low carbon emission can activate and transform methane at room temperature and atmospheric pressure,whereas the methane conversion performance of aqueous photocatalytic system is still low.Oxygen defects-rich WO_(3-x)was firstly synthesized through hydrothermal method and then triphase photocatalyst WO_(3-x)/CFs was constructed by loading WO_(3-x)on carbon fiber(CFs)with polytetrafluoroethylene concentrate(PTFE).Changing the addition amount of PTFE,the surface wettability of WO_(3-x)/CFs can be regulated.The morphology,structure and surface properties of triphase catalysts were systematic ally characterized by XRD,SEM,water contact angle,electron paramagnetic resonance(EPR)and low temperature nitrogen adsorption-desorption.The results of visible-light photocatalytic experiments show that WO_(3-x)/CFs triphase system can significantly improve the conversion performance of methane into methanol.Methane conversion amount of the optimal WO_(3-x)/CFs-0.3 catalyst is 2522.20µmol·g^(−1),which is 1.76 times and 2.48 times of WO_(3-x)/Indium tin oxide conducting glass(Glas)and powder WO_(3-x)diphase systems,respectively.Methanol yield of WO_(3-x)/CFs-0.3 triphase system is 1918.83µmol·g^(−1),which is 2.81 times and 4.69 times of WO_(3-x)/Glas and powder WO_(3-x)systems respectively,and meanwhile methanol selectivity of triphase WO_(3-x)/CFs system is up to 76.76%.The enhanced photocatalytic performance of WO_(3-x)/CFs is primarily due to the gas-liquid-solid triphase interface formed by the hydrophobic catalyst.The consumed methane can be directly transferred to the catalytic interface through gas transport channel in CFs,promoting the activation and conversion of methane molecules.Additionally,the triphase photocatalytic system shows excellent cyclic stability and the methanol yield of WO_(3-x)/CFs-0.3 can still reach 1506.98µmol·g^(−1)after 6 cyc

关 键 词：甲烷 甲醇 可见光催化 WO_(3-x) 三相界面 碳纤维 

分 类 号：TB333[一般工业技术—材料科学与工程]