采用尿素水热法制备了类水滑石(Ti1Li3Al2-LDHs),将其负载于氧化椰壳活性炭(OBAC)表面制得Ti1Li3Al2-LDHs@OBAC光催化剂,通过XRD、FT-IR、SEM、TEM、N2吸附-脱附等温线、XPS、CO2静态吸附等温线、CO2-TPD、UV-Vis和EIS等手段对其进行表征,基于Ti1Li3Al2-LDHs构建Ti1Li3Al2-LDHs@OBAC的结构模型,利用CO2-水反应体系研究其光催化CO2还原特性.结果表明:Ti1Li3Al2-LDHs中Ti4+、Li+取代MgAl-LDHs中Mg2+形成以Ti4+、Li+为中心的八面体结构,斜方堆积(3R)形成2D层片结构,层间阴离子为CO32-.Ti1Li3Al2-LDHs@OBAC呈球状包覆结构,六边形层片Ti1Li3Al2-LDHs垂直生长于OBAC表面;在反应温度80 ℃、反应时间8 h条件下,Ti1Li3Al2-LDHs@OBAC的光催化CO2还原CO产率、CH4产率和CO/CH4产率比分别为42.62、1.18 μmol/g和36.OBAC的碳缺陷增强了催化剂对CO2的吸附活化能力,显著提高Ti1Li3Al2-LDHs@OBAC 光催化 CO2 还原活性.
Structure and Photocatalytic CO2 Reduction Characteristics of Ti1Li3Al2-LDHs@OBAC
Ti1Li3Al2-LDHs was synthesized using the urea hydrothermal method,and was loaded on the surface of oxidized coconut shell activated carbon(OBAC)to prepare Ti1Li3Al2-LDHs@OBAC photocatalyst,which was further characterized by XRD,FT-IR,SEM,TEM,N2 adsorption-desorption isotherms,XPS,CO2 static adsorption isotherms,CO2-TPD,UV-Vis and EIS.The structural model of Ti1Li3Al2-LDHs@OBAC was constructed based on Ti1Li3Al2-LDHs,and the photocatalytic CO2 reduction characteristics of the photocatalyst were studied using CO2-water reaction system.The results indicate that Ti4+and Li+ions in Ti1Li3Al2-LDHs replace Mg2+in MgAl-LDHs,thus forming a composite octahedron structure with Ti4+and Li+at the center;a 2D layered structure is formed in an orthorhombic stacking(3R)manner,and the interlayer anions are CO32-.Ti1Li3Al2-LDHs@OBAC presents a coated spherical morphology,and Ti1Li3Al2-LDHs with a hexagonal lamellar structure are vertically grown on the surface of OBAC.The yields of CO,CH4 and yield rate of CO/CH4 of Ti1Li3Al2-LDHs@OBAC after photocatalytic CO2 reduction are 42.62,1.18 μmol/g and 36,respectively at the temperature of 80 ℃ and reaction time of 8 h.The carbon defects of OBAC enhance its adsorption and activation ability to CO2,thus significantly improving the photocatalytic CO2 reduction activity of Ti1Li3Al2-LDHs@OBAC.
hydrotalcite-likephotocatalysisCO2 reductionactivated charcoalstructurecomposite material
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