木质素模板法制备纳米花状炭负载Ag-ZnO及其光催化CO_(2)转化

Preparation of Nano-flower-shaped Carbon Loaded Ag-ZnO Using Lignin Template Method and Its Photocatalytic CO_(2)Conversion

以碱木质素(AL)为模板,制备纳米级碱木质素负载氧化锌(ZnO/AL)复合材料,并在此基础上负载银纳米粒子(AgNPs),后经高温煅烧制备纳米花状炭负载银-氧化锌(Ag-ZnO/C)复合材料,利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)和X射线光电子能谱(XPS)等技术对复合材料进行了表征,并评估其光催化转化CO_(2)的能力。研究结果表明:以木质素为模板时,ZnO/AL在后续煅烧过程中依然可维持纳米花的形貌结构,并且木质素能够原位还原银离子为AgNPs使其均匀负载于ZnO花片层上。能量色散X射线(EDX)分析表明:Ag-ZnO/C复合材料主要由C(14.7%)、O(14.4%)、Zn(34.1%)和Ag(18.0%)元素组成,结合TEM、XRD及XPS分析,证明了Ag-ZnO/C复合材料已经成功制备。比较了Ag^(+)/Zn^(2+)物质的量比分别为1∶2(Ag_(0.1)-ZnO 0.2/C)和1∶10(Ag_(0.1)-ZnO_(1.0)/C)时复合材料光催化转化CO_(2)的能力,光电流响应及阻抗谱测试结果表明:Ag_(0.1)-ZnO_(1.0)/C的光电流强度较高,电阻较小,光催化活性更优。Ag_(0.1)-ZnO_(1.0)/C光催化CO_(2)转化,CH 4一直持续偏低,反应10 h时CO的产率可达114.9μmol/g。

Using lignin(AL)as a template,nanoscale lignin-loaded zinc oxide(ZnO/AL)composite materials were prepared.Silver nanoparticles(AgNPs)were loaded onto this base material,and a nano-flower-shaped carbon loaded silver-zinc oxide(Ag-ZnO/C)composite material was prepared through high-temperature calcination.The composite materials were characterized using scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS),and their ability for photocatalytic conversion of CO_(2)was evaluated.The research results showed that when using lignin as a template,ZnO/AL could maintain the nano-flower morphology and structure during the subsequent calcination processes,and lignin could reduce silver ions in situ to AgNPs,uniformly loading them on the ZnO petal layers.Energy-dispersive X-ray spectroscopy(EDX)results showed that Ag-ZnO/C composite material was mainly composed of C(14.7%),O(14.4%),Zn(34.1%)and Ag(18.0%)elements.Combined with TEM,XRD,and XPS analysis,the successful preparation of the Ag-ZnO/C composite material was confirmed.The ability of photocatalytic CO_(2)conversion of the composite materials with different Ag^(+)/Zn^(2+)ratios of 1∶2(Ag_(0.1)-ZnO 0.2/C)and 1∶10(Ag_(0.1)-ZnO_(1.0)/C)was compared.Photocurrent response and impedance spectroscopy test results indicated that Ag_(0.1)-ZnO_(1.0)/C had higher photocurrent intensity,lower resistance,and superior photocatalytic activity.The photocatalytic CO_(2)conversion by Ag_(0.1)-ZnO_(1.0)/C showed consistently low CH 4 production,and the CO yield could reach 114.9μmol/g after 10 hours of reaction.