磷钼钒酸铯光催化剂的制备、表征及催化氧化解聚木质素研究

Preparation,Characterization of Cesium PhosphomolybvanadatePhotocatalyst and Its Catalytic Oxidative Depolymerization Ability on Lignin

以三氧化钼、五氧化二钒、磷酸、碳酸铯为原料制备了不同铯含量的磷钼钒酸铯光催化剂Cs_(x)H_(4-x)PAV(x=1、1.5、2、2.5),通过FTIR、N_(2)吸附-脱附、XRD、UV-Vis、SEM等对其结构进行了表征;在模拟可见光源下将其应用于催化氧化解聚木质素,通过单因素实验探讨了铯含量、反应时间、催化剂用量、木质素用量等对木质素解聚率的影响,获得了木质素光催化氧化解聚的最佳条件;并通过解聚前后木质素的FTIR和SEM表征,验证了磷钼钒酸铯光催化剂对木质素的催化氧化解聚能力。结果表明,光催化剂Cs_(2.5)H_(1.5)PAV呈球形,表面粗糙,具有最大的比表面积,催化活性最高;在模拟可见光源下,当反应温度为40℃、反应时间为2 h、Cs_(2.5)H_(1.5)PAV用量为15 mg时,木质素的解聚率达到96.3%,可解聚木质素的最大量为300 mg;在光催化氧化解聚过程中,木质素的致密三维网络结构转变为疏松短链线束状结构,表明催化剂Cs_(2.5)H_(1.5)PAV具有较强的催化氧化解聚木质素的能力。

Using molybdenum trioxide,vanadium pentoxide,phosphoric acid,and cesium carbonate as raw materials,we prepared cesium phosphomolybvanadate photocatalyst Cs_(x)H_(4-x)PAV(x=1,1.5,2,2.5),and characterized their structures by FTIR,N_(2)adsorption-desorption,XRD,UV-Vis,and SEM.Moreover,under simulated visible light sources,we applied them to the catalytic oxidative depolymerization of lignin,investigated the effects of cesium content,reaction time,catalyst amount,and lignin amount on the depolymerization rate of lignin by single-factor experiments,and obtained the optimal conditions for catalytic oxidative depolymerization of lignin.Furthermore,we verified the catalytic oxidative depolymerization ability of cesium phosphomolybvanadate photocatalyst on lignin by FTIR and SEM characterization of lignin before and after depolymerization.The results show that the photocatalyst Cs_(2.5)H_(1.5)PAV is spherical in shape,with a rough surface and the largest specific surface area,resulting in the highest catalytic activity.Under the simulated visible light sources,when the reaction temperature is 40℃,the reaction time is 2 h,and the Cs_(2.5)H_(1.5)PAV amount is 15 mg,the depolymerization rate of lignin reaches 96.3%,and the maximum amount of lignin that can be depolymerized is 300 mg.During the process of photocatalytic oxidative depolymerization,the compact three-dimensional network structure of lignin transforms into a loose short-chain harness structure,indicating that the catalyst Cs_(2.5)H_(1.5)PAV has the higher catalytic oxidative depolymerization ability on lignin.