采用一步式阶跃电压加压方法,在NH4F/(NH4)2SO4电解质溶液中对W片进行阳极氧化处理制备了WO3多孔薄膜,通过后续热处理温度的控制,制备了性能规律性变化的WO3多孔纳米薄膜材料,用场发射扫描电镜(FE-SEM)、×射线衍射(XRD)分析等手段考察了热处理温度对氧化钨晶体结构和形貌影响的规律,在450.C以下的煅烧温度下,薄膜保持50-100 nm孔径:通过对光电化学性质、光催化降解甲基橙动力学行为的研究,考察了不同热处理温度对WO3多孔薄膜光电转换性能影响的规律.研究表明,450°C煅烧处理后的WO3薄膜在500W氙灯光源照射及1.2V偏压下,光电流密度达到5.11 mA.cm-2; 340及400 nm单色光辐射下光电转换效率(IPCE)值分别达到87.4％及22.1％.电化学交流阻抗谱显示,450°C煅烧处理后的WO3薄膜表现出最佳的导电率及最小的界面电荷转移电阻.实验结果证明,高结晶度的多孔结构足WO3溥膜具有高光电转换效率的主要因素,控制热处理温度是实现薄膜具有高孔隙率、完整结晶度、低电阻的重要手段.%Visible-light-responsive WO3 porous films were synthesized via step-voltage anodization in NH4F/(NH4)2SO4 solution and calcined at various temperatures.The crystalline phase and surface morphology were characterized using X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM).The as-anodized nanoporous films converted to a monoclinic phase with preferential orientation in the (020) planes,and the pore diameters of the films calcined below 450 °C were estimated to be in the region of 50-100 nm.The photocatalytic activity was evaluated via photodegradation of methyl orange.The film calcined at 450 °C showed the highest photocatalytic activity.Photoelectrochemical measurements showed that the incident photon-to-current conversion efficiency (IPCE) values of the film calcined at 450 °C were 87.4％ at 340 nm and 22.1％ at 400 nm.Under visible light (A>_400 nm),the photocurrent density in 0.5 mol·L-1 H2SO4 solution at 1.2 V (vs Ag/AgCI (KCI saturated)) was 5.11 mA.cm-2.Electrochemical impedance spectroscopy (EIS) measurements showed that the film calcined at 450 °C exhibited the smallest interface charge transfer resistance and optimal electroconductivity.Perfect crystallinity,high porosity and low resistance can therefore be obtained by controlling the calcination temperature.A large surface area and a porous structure are important factors in affecting photocatalytic activity.
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