Energy and Materials Research

Biography

Biography: Hyoyoung Lee

Abstract

Low energy bandgap semicondunding metarials such as transtion metal chalcogenides (TMCs) including TiO₂, MoS₂, CoS₂ and so on have been paid attention for energy conversion and environmental issues. For the low energy semiconducting materials, we like to introduce new visible-light driven blue TiO₂ materials for photo-catalytic hydrogen evolving reaction (HER) and for a removal of algae from water. In addition, we like to report new layered ternary transition metal chalcogenides (TTMCs) material to overcome to the limitation of active sites which is challenging in binary transition metal chalcogenides (BTMC) such as MoS₂ towards electrochemical hydrogen production. We carefully designed the TTMC materials that contain two transition metals Cu and Mo with chalcogen S. Th e TTMC, Cu₂MoS₄ has been successfully synthesized by a facile solutionprocessed method. Moreover, by anion doping such as Se in as the synthesized Cu₂MoS₄, it has been found that TTMC can be exfoliated into single layer nanosheets. Furthermore, by controlling the number of layers, single layers TTMC exhibit the highest electrocatalytic activity towards HER because the single layers can provide more catalytic active sites than multilayers and bulk. As a result, our TTMC work can guide new strategy for the developments of applications of TMCs in HER. Finally, we like to demonstrate new strategy to satisfy all requirements for the development of a highly active and remarkably durable HER electrocatalyst in both acidic and alkaline media via anion-cation double substitution into a CoS2 moiety for preparing 3D mesoporous pyrite-metal vanadium-cobalt phosphorsulphide (Co_1-xV_xSP).