‪Sang Hyun Ahn 교수

Different shapes of various nickel structures, including dendrite, particle and film are fabricated by electrodeposition under various conditions. The shape of nickel structures is definitely dependent on the deposition potential, leading to different electrochemical surface area and edge facets. The nickel particle which has a polycrystalline center and edge is obtained at high negative potential. On the other hand, the nickel dendrite deposited by relatively low negative potential exhibits lar

The electrochemical reduction of CO₂ to diverse value-added chemicals is a unique, environmentally friendly approach for curbing greenhouse gas emissions while addressing sluggish catalytic activity and low Faradaic efficiency (FE) of electrocatalysts. Here, zeolite-imidazolate-frameworks-8 (ZIF-8) containing various transition metal ions-Ni, Fe, and Cu-at varying concentrations upon doping are fabricated for the electrocatalytic CO₂ reduction reaction (CO₂ RR) t

Environmental problems such as global warming are one of the most prominent global challenges. Researchers are investigating various methods for decreasing CO₂ emissions. The CO₂ reduction reaction via electrochemical, photochemical, and photoelectrochemical processes has been a popular research topic because the energy it requires can be sourced from renewable sources. The CO₂ reduction reaction converts stable CO₂ molecules into useful products such

Abstract Recently, hydrogen energy has been significantly investigated by numerous technologies. To date, noble platinum group metals have often been employed to fabricate working electrodes for hydrogen evolution reaction (HER). Therefore, the demand of highly active HER catalysts based on effective and lower‐cost materials is becoming more and more critical. Transition metal dichalcogenide (TMD) materials could be one of the most suitable materials for these requirements because they possess n

The development of electrocatalysts for energy conversion systems is essential for alleviating environmental problems and producing useful energy sources as alternatives to fossil fuels. Improving the catalytic performance and stability of electrocatalysts is a major challenge in the development of energy conversion systems. Moreover, understanding their electrode structure is important for enhancing the energy efficiency. Recently, binder-free self-supported electrodes have been investigated be

Metal-organic frameworks (MOFs) and MOF-derived materials have been used for several applications, such as hydrogen storage and separation, catalysis, and drug delivery, owing to them having a significantly large surface area and open pore structure. In recent years, MOFs have also been applied to thin-film solar cells, and attractive results have been obtained. In perovskite solar cells (PSCs), the MOF materials are used in the form of an additive for electron and hole transport layers, interla

The use of noble-free materials to convert atmospheric CO2 into energy-rich fuels has gained a significant amount of attention in an effort toward decreasing global warming due to high concentrations of CO2. Metallic catalysts, two-dimensional materials (such as graphene and graphene based), metal oxides, and metal-organic frameworks have been used as catalysts in the CO2 reduction reaction and recently recognized as promising platforms due to their excellent electrical and thermal conductivity,

Self-terminating electrodeposition was used to grow ultrathin Pt overlayers on 111 textured Au thin films. The Pt thickness was digitally controlled by pulsed potential deposition that enabled the influence of overlayer thickness on electrocataytic reactions, such as methanol and formic acid oxidation, to be examined. Bimetallic and ensemble effects associated with submonolayer coverage of Pt on Au yield enhanced catalysis. For films grown using one deposition pulse, the peak rate of CH3OH oxida

Abstract Electrochromism is a unique phenomenon based on the ability to change the optical properties or color of a material when an external potential is applied. Conventional electrochromic materials are based on inorganic materials. In particular, transition metal oxides, such as tungsten oxide and molybdenum oxide, are extensively investigated for use in commercial electrochromic devices (ECDs). However, these devices have several drawbacks including single color change, expensive materials,

This study details a “wet” atomic layer deposition process that uses potential modulation and H adsorption to terminate Ir deposition at high deposition overpotentials. The ultrathin Ir films match or exceed the best reported electrocatalytic activity for the oxygen evolution reaction (OER) and hydrogen production and oxidation reaction (HER and HOR) on bulk Ir electrodes.

CsPbI3 perovskite quantum dots (QDs) are more unstable over time as compared to other perovskite QDs, owing to ligand loss and phase transformation. The strong red emission from fresh CsPbI3 QDs gradually declines to a weak emission from aged QDs, which PLQY dropped by 93% after a 20 day storage; finally, there is no emission from δ-phase CsPbI3. The present study demonstrated a facile surface treatment method, where a sulfur–oleylamine (S-OLA) complex was utilized to passivate the defect-rich s