Sungkyunkwan University · Energy
Professor Heechae Choi's research lab specializes in computational materials science with a focus on designing and understanding advanced functional materials for sustainable energy applications. The lab employs first-principles calculations, including density functional theory (DFT) and time-dependent DFT, to investigate defect engineering, doping strategies, and heterointerface effects in metal oxides and nitrides. Key research directions include enhancing photocatalytic and electrocatalytic performance for solar energy conversion, such as water splitting and nitrogen reduction to ammonia, as well as optimizing electronic and optical properties through controlled defect and doping control. The lab also explores the role of surface and interface phenomena in heterostructured materials to improve charge separation and catalytic selectivity.
Figures are computed from collected data and may differ slightly.
Tungsten–nitrogen (W–N) codoping has been known to enhance the photocatalytic activity of anatase TiO2 nanoparticles by utilizing visible light. The doping effects are, however, largely dependent on calcination or annealing conditions, and thus, the massive production of quality-controlled photocatalysts still remains a challenge. Using density functional theory (DFT) thermodynamics and time-dependent DFT computations (TDDFT), we investigate the atomic structures of N doping and W–N codoping in
The photoluminescence intensity of Bi-doped Y<sub>2</sub>O<sub>3</sub> is increased in a high oxygen partial pressure atmosphere due to the healed oxygen vacancy.
Abstract Electrochemical nitrogen reduction reaction (NRR) is a sustainable alternative to the Haber‒Bosch process for ammonia (NH 3 ) production. However, the significant uphill energy in the multistep NRR pathway is a bottleneck for favorable serial reactions. To overcome this challenge, we designed a vanadium oxide/nitride (V 2 O 3 /VN) hybrid electrocatalyst in which V 2 O 3 and VN coexist coherently at the heterogeneous interface. Since single‐phase V 2 O 3 and VN exhibit different surface
Vanadium pentoxide (V2O5) is known to have natural n-type conductivity but transitions from n- to p-type conductivity when grown in a hydrated amorphous phase via atomic layer deposition. Compared with the intrinsic n-type character of V2O5, the hydrated amorphous V2O5 with artificial p-type conductivity has an increased work function difference, which can build stronger interface electric fields in ZnO/V2O5 heterojunction structures. This increased internal electric field strengthens the electr
Brookite, the least studied crystalline phase of TiO2, recently has been found to have excellent photocatalytic activities, comparable to that of anatase TiO2. However, its activity is highly dependent on its defect levels. We systematically studied the equilibria of the native point defects of brookite, along with their effects on photocatalytic activities. From first-principles calculations and thermodynamics modeling, we predicted the formation of an interstitial defect (Tii4+) under weak red
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