In this work, visible light driven enzyme-free glucose PEC sensor was developed by electrochemically deposited CoO x nanosheets on graphene-CdS nanocomposites modified electrode to achieve both the electrocatalytic and photoelectrocatalytic oxidation of glucose at the resultant CoO x /graphene-CdS nanocomposites modified electrode. Scanning electron microscopy, electrochemical impedance spectroscopy and cyclic voltammetry were used to characterize the morphology and electrochemical properties of the resultant CoO x /graphene-CdS nanocomposites. The CV results demonstrated that decoration of CoO x nanosheets largely enhanced the photoelectrocatalytic activity of graphene-CdS composites toward glucose oxidation in alkaline solution. The glucose detection sensitivity under visible light irradiation is dramatically improved compared to dark condition. Good performance was obtained for the CoO x /graphene-CdS nanocomposites based glucose sensor. The feasibility of the present method was confirmed by good recovery results for glucose detection in human urine samples.
Jinming Feng,Jincheng Mu,Qiong Peng,Yang Xiao,Baojun Liu
Cobalt-based oxides have attracted extensive attention in heterogeneous catalytic peroxymonosulfate (PMS) activation towards emerging pollutants degradation, while the improvement of their catalytic performance is still a severe challenge. Herein, a CoO x ultrathin nanosheet composed of in situ interfacial Co 3 O 4 and CoO (CoO x -Ar-350) was synthesized and employed in PMS activation for micro-contaminates removal. The catalyst shows 100 % bisphenol A (BPA) conversion within 2 min ([BPA] = 20 mg/L, [Catalyst] = 20 mg/L, [PMS] = 200 mg/L) with a remarkable reaction rate of 2.69 min −1 , which is 3.84 and 2.66 times of pure Co 3 O 4 and CoO, respectively. Characterization and theoretical calculation results indicates that the interfacial synergy between Co 3 O 4 and CoO could modulate the adsorption behavior and enhance the electron acceptance of PMS, which boosts the breaking of O-O bonds and the generation of reactive oxygen species (ROS) and thereby the pollutant removal efficiency. The ROS quenching and capture experiments demonstrate that the enhanced OH and 1 O 2 play significant contribution during the degradation process. This work provides a novel in situ interfacial engineering for the development of highly efficient catalyst and reveals the activity enhancement mechanism for PMS activation.
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