基于p-n异质结CuO/TiO_(2)复合物高效的载流子分离能力构建超灵敏AFP光电化学分析

Construction of an Ultrasensitive AFP Photoelectrochemical Analysis Based on the Efficient Carrier Separation Capability of p-n Heterojunction CuO/TiO_(2) Complexes

将TiO_(2)纳米粒子与Cu(pta)MOFs复合,通过高温煅烧策略制得CuO/TiO_(2)复合物.在最优实验条件下,基于复合物对可见光更强的吸收利用效率,CuO/TiO_(2)修饰的ITO电极展现出显著的光电化学(PEC)响应信号,其光电流值(59.4μA)分别是单组分TiO_(2)和CuO粒子的15.5和7.4倍.线性扫描伏安法(LSV)测试结果证实CuO/TiO_(2)/ITO电极比CuO和TiO_(2)材料具有更大的LSV响应强度.这可归因于获得的薄片层状CuO粒子及其兼有的多孔隙特征促进了光的多重散射/反射效应,同时CuO/TiO_(2)复合材料具有的典型p-n异质结构(能级带隙匹配)大幅促进了光生电荷载流子(e^(-)/h^(+))的分离与转移.选用戊二醛(GA)作为交联手臂分子,通过温和的醛胺反应将壳聚糖(CS)和anti-AFP抗体组装于CuO/TiO_(2)/ITO电极表面,再用牛血清蛋白(BSA)封闭活性位点,构建出PEC传感平台(BSA/anti-AFP/GA-CS/CuO/TiO_(2)/ITO),实现了对不同浓度甲胎蛋白(AFP)的高灵敏检测(检出限达到2.63×10^(-4) ng/mL).制备的传感电极同时展示出良好的稳定性和选择性.

The p-n type composite materials are considered valuable materials to improve their photoelectrochemical(PEC)performance.In this paper,TiO_(2) nanoparticles were composited with Cu(pta)MOFs,and the CuO/TiO_(2) complex materials were prepared by the high-temperature calcination strategy.Under the optimal experimental conditions,based on the stronger absorption and utilization efficiency of visible light by the complexes,the CuO/TiO_(2)-modified ITO electrodes exhibited significant enhancement of the PEC response signal,with the photocurrent value(59.4μA)15.5 and 7.4 times higher than that of single-component TiO_(2),and CuO particles,respectively.Linear scanning voltammetry(LSV)result confirmed that the CuO/TiO_(2)/ITO electrode had a greater LSV response intensity than the CuO and TiO_(2) materials.It was attributed to the obtained lamellar layered CuO particles with porous features promoting the multiple scattering/reflection effect of light,while the typical p-n heterostructure(energy level band gap matching)of CuO/TiO_(2) composites substantially facilitated the separation and transfer of photo-generated charge carriers(e^(-)/h^(+)).GA was chosen as the crosslinking arm molecule to assemble CS and anti-AFP on the surface of CuO/TiO_(2)/ITO electrodes through a simple aldolamine reaction,and then the active sites were closed with BSA,for which to construct a PEC sensing platform(BSA/anti-AFP/GA-CS/CuO/TiO_(2)/ITO)and had achieved the high sensitivity detection of different concentrations of α-fetoprotein AFP(the detection limit reached to 2.63×10−4 ng/mL).This prepared sensing electrode demonstrated both good stability and satisfactory selectivity.