In this work, Au@Cu2O core-shell nanoparticles (NPs) were synthesized by simple solution route and applied for CO sensing applications. Au@Cu2O core-shell NPs were formed by the deposition of 30-60 nm Cu2O shell layer on Au nanorods (NRs) having 10-15 nm width and 40-60 nm length. The morphology of Au@Cu2O core-shell NPs was tuned from brick to spherical shape by tuning the pH of the solution. In the absence of Au NRs, cubelike Cu2O NPs having ∼200 nm diameters were formed. The sensor having Au@Cu2O core-shell layer exhibited higher CO sensitivity compared to bare Cu2O NPs layer. Tuning of morphology of Au@Cu2O core-shell NPs from brick to spherical shape significantly lowered the air resistance. Transition from p- to n-type response was observed for all devices below 150 °C. It was demonstrated that performance of sensor depends not only on the electronic sensitization of Au NRs but also on the morphology of the Au@Cu2O core-shell NPs.

No abstract

Quantum dots (QDs) have emerged as an important class of material due to their excellent photonic properties and durability for diverse applications such as solid-state lighting, energy conversion, display, biomedicine,...

No abstract

In this study, an InP-cored quantum dot (InP-QD) material was prepared and physically immobilized on TiO 2 particles functionalized with an archetypical reduction catalyst, (4,4-Y 2bpy)Re I (CO) 3 Cl (ReP, Y = CH 2 PO(OH) 2 ), to form a new type of InP quantum dot-sensitized hybrid photocatalyst (InP-QD/TiO 2 / ReP) and evaluated as a lower-energy photosensitizer in this hybrid system. It was found that the TiO 2 heterogenization of the InP-QD material promotes the photoexcited electron transfer process from the photoexcited InP-QD* to the inorganic TiO 2 solid with rapid electron injection (by ∼25 ps) through oxidative quenching, resulting in efficient charge separation at the InP-QD/TiO 2 interface. With such an effective photosensitization, the stabilization of the structurally vulnerable InP-cored QDs by TiO 2 heterogenization resulted in highly efficient and durable photochemical CO 2 -to-CO conversion of the InP-QD/TiO 2 /ReP hybrid in a 10 times-repeated photolysis, giving a turnover number of ∼51,000 over a 420 h period without any damage to the InP-QD photosensitizer. The stability of TiO 2 -bound InP-QDs was confirmed by the comparative analysis of their photophysical and chemical structures before and after long-term photoreaction. This catalytic performance is the highest reported for QD-sensitized photocatalytic CO 2 conversion systems using sacrificial organic electron donors. This study provides useful design guidelines for photocatalysts using QD materials as photosensitizing components.