Construction of an Ultrasensitive AFP Photoelectrochemical Analysis Based on the Efficient Carrier Separation Capability of p-n Heterojunction CuO/TiO2 Complexes
The p-n type composite materials are considered valuable materials to improve their photoelectrochemical(PEC)performance.In this paper,TiO2 nanoparticles were composited with Cu(pta)MOFs,and the CuO/TiO2 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/TiO2-modified ITO electrodes exhibited significant enhancement of the PEC response signal,with the photocurrent value(59.4 µA)15.5 and 7.4 times higher than that of single-component TiO2,and CuO particles,respectively.Linear scanning voltammetry(LSV)result confirmed that the CuO/TiO2/ITO electrode had a greater LSV response intensity than the CuO and TiO2 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/TiO2 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/TiO2/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/TiO2/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.
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