WO_(3)/碳点/TiO_(2)复合纳米材料的制备及其光致阴极保护作用研究

Preparation of a WO_(3)/carbon dots/TiO_(2) composite nanomaterial and its photocathodic protection

采用两步阳极氧化法制备了TiO_(2)纳米阵列(TNAs),然后分别采用浸泡法和电沉积法在TNAs表面负载碳点层和WO_(3)层,得到WO_(3)/碳点/TNAs复合纳米光阳极(TCW),并通过扫描电子显微镜(SEM)、X射线衍射仪(XRD)和X射线光电子能谱仪(XPS)对其进行了表征。采用紫外可见漫反射光谱法(UV-Vis DRS)和电化学方法测定了TCW光阳极的光吸收和电化学性能,并评价了在模拟海水溶液中TCW对Q235碳钢的光致阴极保护作用。结果显示:与TNAs相比,TCW的吸收边从紫外光区(384 nm)扩展至可见光区(426 nm),带隙宽度(E)从3.23 eV降低到2.91 eV,对光的吸收能力显著提升;可见光响应电流密度提高了6.85倍,达到157μA/cm~2。将TCW光阳极与Q235碳钢阴极耦合后,阴极表面的稳态光响应电流密度达到101μA/cm~2;与耦合前相比,其自腐蚀电位降低了0.41 V(vs.Ag/AgCl),电化学电流噪声(ECN)振幅增大,腐蚀过程受到明显抑制。以上结果表明TCW对Q235碳钢具有优异的光致阴极保护作用。

TiO_(2)nanoarrays(TNAs)have been prepared by a two-step anodization method.Carbon dots and WO_(3)layers were subsequently loaded on the surface of the TNAs by an immersion method and an electrodeposition method,respectively.The resulting WO_(3)/carbon dots/TNAs composite nanophotoanodes(TCW)were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).The light absorption and electrochemical properties of the TCW photoanodes were measured by UV-Vis diffuse reflectance spectroscopy(UV-Vis DRS)and electrochemical methods,and the photocathodic protection of Q235 carbon steel by TCW was evaluated in simulated seawater solution.The results showed that compared with pristine TNAs,the absorption edge of TCW was extended from the ultraviolet region(384 nm)to the visible region(426 nm),the band gap width(E)decreased from 3.23 eV to 2.91 eV,and the light absorption ability was significantly improved.The visible light response current density increased by 6.85 times to 157μA/cm~2.After coupling the TCW photoanode with a Q235 carbon steel cathode,the steady-state photoresponse current density on the cathode surface reached 101μA/cm~2.Compared with that before coupling,the self-corrosion potential decreased by 0.41 V(vs.Ag/AgCl),the amplitude of electrochemical current noise(ECN)increased,and the corrosion process was significantly inhibited.The above results show that TCW has an excellent photocathodic protection effect on Q235 carbon steel.