1T-Phase Tungsten Chalcogenides (WS₂, WSe₂, WTe₂) Decorated with TiO₂ Nanoplatelets with Enhanced Electron Transfer Activity for Biosensing Applications

Layered transition metal dichalcogenides (TMDs) have received a great deal of attention due to fact that they have varied band gap, depending on their metal/chalcogen composition and on the crystal structure. Furthermore, these materials demonstrate great potential application in a myriad of electrochemical technologies. Heterogeneous electron transfer (HET) abilities of TMD materials toward redox-active molecules occupy a key role in their suitability for electrochemical devices. Herein, we introduce a promising biosensing strategy based on improved heterogeneous electron transfer rate of WS₂, WSe₂, and WTe₂ nanosheets exfoliated using tert-butyllithium (t-BuLi) and n-butyllithium (n-BuLi) intercalators decorated with vertically aligned TiO₂ nanoplatelets. By comparison of all the nanohybrids, decoration of TiO₂ on t-BuLi WS₂ (TiO₂@t-BuLi WS₂) results in the fastest HET rate of 5.39 × 10^-3 cm s^-1 toward ferri/ferrocyanide redox couple. In addition, the implications of decorating tungsten dichalcogenides (WX₂) with TiO₂ nanoplatelets in enzymatic biosensor applications for H₂O₂ detection are explored. TiO₂@t-BuLi WS₂ outperforms all other nanohybrid counterparts and is demonstrated to be an outstanding sensing platform in enzyme-based biosensor with wide linear range, low detection limit, and high selectivity. Such conceptually new electrocatalytic detection systems shall find the way to the next generation biosensors.