Muhammad Hussain

Enhanced photocatalytic and electrochemical properties of Au nanoparticles supported TiO2 microspheres

Au/TiO2 composites were synthesized by a two-step hydrothermal approach and their photocatalytic and electrochemical properties were investigated. It is found that Au/TiO2 composites with a large specific surface area, stability and catalytic activity of Au nanoparticles (NPs) demonstrate enhanced photocatalytic activity compared to pure TiO2 microspheres. Furthermore, the electrochemical properties of the Au/TiO2 composite electrode demonstrate its ability to electrocatalyze the oxidation of hydrogen peroxide and substantially increase the response current. In addition, this modified electrode also exhibits a very rapid and sensitive response towards glucose detection at the low operating potential. The modified electrode shows a linear response from 1.0 to 15 mM with a reproducible sensitivity of 1350 μA mM−1 cm−2 within a response time of less than 6 s. The photocatalytic and electrochemical activity of Au/TiO2 composites provides a new platform for environmental remediation and biomedical applications. All these results reveal that Au/TiO2 composites exhibit great prospects for developing efficient non-enzymatic biosensors.

Bipolar tri-state resistive switching characteristics in Ti/CeOx/Pt memory device

Highly repeatable multilevel bipolar resistive switching in Ti/CeOx/Pt nonvolatile memory device has been demonstrated. X-ray diffraction studies of CeO2 films reveal the formation of weak polycrystalline structure. The observed good memory performance, including stable cycling endurance and long data retention times (> 104 s) with an acceptable resistance ratio (~102), enables the device for its applications in future non-volatile resistive random access memories (RRAMs). Based on the unique distribution characteristics of oxygen vacancies in CeOx films, the possible mechanism of multilevel resistive switching in CeOx RRAM devices has been discussed. The conduction mechanism in low resistance state is found to be Ohmic due to conductive filamentary paths, while that in the high resistance state was identified as Ohmic for low applied voltages and a space-charge-limited conduction dominated by Schottky emission at high applied voltages.