CdS quantum dots modified CuO inverse opal electrodes for ultrasensitive electrochemical and photoelectrochemical biosensor

Abstract

The CuO inverse opal photonic crystals (IOPCs) were synthesized by the sol-gel method and modified with CdS quantum dots by successive ionic layer adsorption and reaction (SILAR). CdS QDs modified CuO IOPCs FTO electrodes of different SILAR cycles were fabricated and their electrochemical properties were studied by cyclic voltammetry (CV) and chronoamperometry (I–t). Structure and morphology of the samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), high-resolution TEM (HRTEM), Energy-dispersive X-ray analysis (EDX) and X-ray diffraction pattern (XRD). The result indicated that the structure of IOPCs and loading of CdS QDs could greatly improve the electrochemical properties. Three SILAR cycles of CdS QDs sensitization was the optimum condition for preparing electrodes, it exhibited a sensitivity of 4345 μA mM-1 cm-2 to glucose with a 0.15 μM detection limit (S/N= 3) and a linear range from 0.15 μM to 0.5 mM under a working potential of +0.7 V. It also showed strong stability, good reproducibility, excellent selectivity and fast amperometric response. This work provides a promising approach for realizing excellent photoelectrochemical nonenzymatic glucose biosensor of similar composite structure.

3D macroporous TiO2inverse opal binary and ternary composite materials and their photocatalytic activity

“…The obtained IO-TiO 2 composite materials were soaked in a NaAuCl 4 solution, and the adsorbed anions containing Au 3+ were further reduced to AuNPs with ascorbic acid thereby generating IO-TiO 2 -AuNPs. Finally, SILAR method 43,44 was used with slight modication of the literature method to incorporate CdS thin lm into IO-TiO 2 and IO-TiO 2 -AuNPs and plain glass slide creating IO-TiO 2 -CdS, IO-TiO 2 -AuNPs-CdS, and CdS lm on glass slide.…”

“…Due to the presence of AuNPs, the color turned reddish-purple from white. IO-TiO 2 -CdS is formed by depositing CdS on IO-TiO 2 by SILAR method 43,44 and the color of the slide turned yellow. Finally, the ternary system IO-TiO 2 -AuNPs-CdS was shown in Fig.…”

“…43,44 50 mM solutions of Cd(CH 3 COO) 2 $2H 2 O and Na 2 S$9H 2 O were prepared in ethanol and 25% : 75% water-tomethanol, respectively. The CdS deposition proceeded as followed.…”

3D Cathodes of Cupric Oxide Nanosheets Coated onto Macroporous Antimony‐Doped Tin Oxide for Photoelectrochemical Water Splitting

“…[1] In many candidate materials, such as TiO 2 and ZnO, the generation of electron-hole pairs under visible light irradiation is impeded due to aw ide bandgap, which limits practical applications. This has led to much attention in recent years, with promise for applicationsi nw ater splitting, [4] water disinfection, [5] photodegradation, [6] biosensors, [7] electrocatalysts, [8] and photovoltaic applications. [2] CuO, being ap -type semiconductor with an arrow bandgap of 1.2-1.8 eV, [3] has severala dvantageous properties:i ti sc heap, comprised of earth-abundant elements, has high solara bsorbance, shows lowt hermale mittance,a nd is simple to manufacture.…”

“…[2] CuO, being ap -type semiconductor with an arrow bandgap of 1.2-1.8 eV, [3] has severala dvantageous properties:i ti sc heap, comprised of earth-abundant elements, has high solara bsorbance, shows lowt hermale mittance,a nd is simple to manufacture. This has led to much attention in recent years, with promise for applicationsi nw ater splitting, [4] water disinfection, [5] photodegradation, [6] biosensors, [7] electrocatalysts, [8] and photovoltaic applications. [9] CuO has at heoretical maximum photocurrent of 35 mA cm À2 under standard AM 1.5 irradiation.…”