정유성 교수

A molecular origin of the striking rate increase observed in a reaction on water is studied theoretically. A key aspect of the on-water rate phenomenon is the chemistry between water and reactants that occurs at an oil-water phase boundary. In particular, the structure of water at the oil-water interface of an oil emulsion, in which approximately one in every four interfacial water molecules has a free ("dangling") OH group that protrudes into the organic phase, plays a key role in catalyzing re

Nitrogen (N)-doped carbon materials were shown in recent studies to have promising catalytic activity for oxygen reduction reaction (ORR) as a metal-free alternative to platinum, but the underlying molecular mechanism or even the active sites for high catalytic efficiency are still missing or controversial both experimentally and theoretically. We report here the results of periodic density functional theory (DFT) calculations about the ORR at the edge of a graphene nanoribbon (GNR). The edge st

We studied electrochemical nitrogen reduction reactions (NRR) to ammonia on single atom catalysts (SACs) anchored on defective graphene derivatives by density functional calculations. We find significantly improved NRR selectivity on SACs compared to that on the existing bulk metal surface due to the great suppression of the hydrogen evolution reaction (HER) on SACs with the help of the ensemble effect. In addition, several SACs, including Ti@N4 (0.69 eV) and V@N4 (0.87 eV), are shown to exhibit

A simplified approach to treating the electron correlation energy is suggested in which only the alpha-beta component of the second order Møller-Plesset energy is evaluated, and then scaled by an empirical factor which is suggested to be 1.3. This scaled opposite-spin second order energy (SOS-MP2), where MP2 is Møller-Plesset theory, yields results for relative energies and derivative properties that are statistically improved over the conventional MP2 method. Furthermore, the SOS-MP2 energy can

Abstract Considering the promising electrochemical performance of the recently reported pyrophosphate family in lithium ion batteries as well as the increasing importance of sodium ion batteries (SIBs) for emerging large‐scale applications, here, the crystal structure, electrochemical properties, and thermal stability of Na 2 FeP 2 O 7 , the first example ever reported in the pyrophosphate family for SIBs, are investigated. Na 2 FeP 2 O 7 maintains well‐defined channel structures (triclinic fram

Abstract Aqueous zinc ion batteries (AZIBs) are steadily gaining attention based on their attractive merits regarding cost and safety. However, there are many obstacles to overcome, especially in terms of finding suitable cathode materials and elucidating their reaction mechanisms. Here, a mixed‐valence vanadium oxide, V 6 O 13 , that functions as a stable cathode material in mildly acidic aqueous electrolytes is reported. Paired with a zinc metal anode, this material exhibits performance metric

Abstract Electrochemical reduction of carbon dioxide (CO 2 ) to fuels and value‐added industrial chemicals is a promising strategy for keeping a healthy balance between energy supply and net carbon emissions. Here, the facile transformation of residual Ni particle catalysts in carbon nanotubes into thermally stable single Ni atoms with a possible NiN 3 moiety is reported, surrounded with a porous N‐doped carbon sheath through a one‐step nanoconfined pyrolysis strategy. These structural changes a

Achieving the 2016 Paris agreement goal of limiting global warming below 2 °C and securing a sustainable energy future require materials innovations in renewable energy technologies. Machine learning has demonstrated many successes to accelerate the discovery renewable energy materials.

[Image: see text] The constant demand for novel functional materials calls for efficient strategies to accelerate the materials discovery, and crystal structure prediction is one of the most fundamental tasks along that direction. In addressing this challenge, generative models can offer new opportunities since they allow for the continuous navigation of chemical space via latent spaces. In this work, we employ a crystal representation that is inversion-free based on unit cell and fractional ato

The development of highly selective, low cost, and energy-efficient electrocatalysts is crucial for CO₂ electrocatalysis to mitigate energy shortages and to lower the global carbon footprint. Herein, we first report that carbon-coated Ni nanoparticles supported on N-doped carbon enable efficient electroreduction of CO₂ to CO. In contrast to most previously reported Ni metal catalysts that resulted in severe hydrogen evolution during CO₂ conversion, the Ni particl

Fast transport of water inside nanoscale graphitic surfaces, namely carbon nanotubes and graphene, forms the basis of aqueous carbon nanofluidic phenomena for which there are numerous applications in energy and environmental fields. In this tutorial review, we provide the basic principles of nanofluidics using carbon materials. We also address thermodynamic and structural aspects of favourable water confinement between hydrophobic carbon surfaces. We outline the experimental and theoretical hist