Article
Chemistry, Multidisciplinary
Mojtaba Rezaei, Luis Francisco Villalobos, Kuang-Jung Hsu, Kumar Varoon Agrawal
Summary: This article reports a method for controlling graphene edges and vacancies, which is desired for various applications. The researchers found that CO2 can effectively control the etching rate without causing vacancy nucleation, showing great potential for practical applications.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Nanoscience & Nanotechnology
Esmaeil Zaminpayma, Payman Nayebi, Mohsen Emami-Razavi
Summary: The transport properties and rectification behavior of junctions containing armchair graphene nanoribbons with double vacancy defects or nitrogen doping in three different sizes were studied. Results showed that the presence of double vacancy defects and nitrogen doping can alter the behavior of the devices, with significant rectification observed in the 9-atom size devices.
Article
Chemistry, Physical
K. Rajendran, N. Pandurangan, C. P. Vinod, Tuhin S. Khan, Shelaka Gupta, M. Ali Haider, D. Jagadeesan
Summary: CuO is utilized as a reusable solid reagent for hydrogenation of nitroarenes to aminoarenes with high efficiency, facilitating the reaction by forming oxygen vacancies on its surface in reducing environment.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2021)
Review
Chemistry, Physical
Ankit Kumar Verma, Anand Mohan Verma, Ananth Govind Rajan
Summary: This review focuses on the theoretical basis of classical and quantum confinement effects in two-dimensional (2D) electrode materials and discusses the recent experimental advances in this area. It covers topics such as ion transport, mass and electron transport mechanisms, and the impact of step edges, defects, and dopants on electron transport in 2D electrode materials. Opportunities for further research involving first-principles calculations, molecular dynamics simulations, and the development of analytical theories are also identified.
CURRENT OPINION IN ELECTROCHEMISTRY
(2022)
Article
Multidisciplinary Sciences
Luis Francisco Villalobos, Cedric Van Goethem, Kuang-Jung Hsu, Shaoxian Li, Mina Moradi, Kangning Zhao, Mostapha Dakhchoune, Shiqi Huang, Yueqing Shen, Emad Oveisi, Victor Boureau, Kumar Varoon Agrawal
Summary: The study achieved a high density of molecular-sieving nanopores in the graphene lattice through controlled synthesis of nanocrystalline graphene. The porous nanocrystalline graphene films improve mechanical robustness while allowing large gas transport, with gas permeance and gas pair selectivity comparable to nanoporous SLG membranes prepared by state-of-the-art postsynthetic lattice etching.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Chemistry, Multidisciplinary
Yuanyuan Wang, Donghai Wu, Peng Lv, Bingling He, Xue Li, Dongwei Ma, Yu Jia
Summary: The electrocatalytic reduction of nitrate to ammonia on graphene-based single atom catalysts (SACs) was studied using first-principles calculations. It was found that FeN4-doped graphene exhibited excellent eNO(3)RR performance due to effective adsorption and activation of NO(3)(-) and moderate binding. The activity of eNO(3)RR was found to be correlated with the intrinsic properties of the metal centers and their local environments. This study provides atomic-level insights into the catalytic mechanism and activity origin of eNO(3)RR on graphene-based SACs.
Article
Chemistry, Physical
Tongfei Yang, Pengrong Ren, Xiangcheng Qi, Xin Wang, Qingnan Meng, Zhiyong Liu, Shu Yang
Summary: In this study, NaNbO3 powders were prepared using a hydrothermal method. The particle size of NaNbO3 decreased unexpectedly with increasing reaction temperature, indicating a nucleation-dominated growth mechanism. The sample reacted at 210 degrees C for 12 h showed the highest piezoelectric catalytic efficiency. The annealing of NaNbO3 powders in N2 increased the concentration of oxygen vacancy, as confirmed by impedance and XPS spectra. Simulation results showed that under the influence of oxygen vacancies, valence electrons of A-site Na cations on the surface were more easily excited to the conduction band compared to Nb cations, resulting in a more than 6 times increase in piezoelectric catalytic efficiency.
APPLIED SURFACE SCIENCE
(2023)
Article
Nanoscience & Nanotechnology
Shimin Huang, Shenggong He, Haiqing Qin, Xianhua Hou
Summary: This study focuses on a new type of 3D spongy hydrated vanadium dioxide composite with superior electrochemical performance in aqueous electrolyte, which is further applied in flexible zinc ion batteries, demonstrating excellent flexibility and cycling stability.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Physical
Cheng-May Fung, Boon-Junn Ng, Chen-Chen Er, Wei-Kean Chong, Jingxiang Low, Xuecheng Guo, Xin Ying Kong, Hing Wah Lee, Lling-Lling Tan, Abdul Rahman Mohamed, Siang-Piao Chai
Summary: A homo-hetero architecture consisting of oxygen-defective ultrathin BiVO4 (BiVO4-Ov) and red/black phosphorus (RP/BP) homojunction with a built-in nanoscale dual Z-scheme electronic configuration is developed to address the sluggish charge kinetics and rapid carrier recombination in CO2 photoreduction. The BiVO4-Ov@RP/BP system demonstrates a remarkably high CH4 yield after 6 h of visible light illumination, resembling a leading-edge photocatalytic performance among the existing semiconductors.
Article
Engineering, Environmental
Xixi Chen, Wanyi Fu, Zhichao Yang, Yulong Yang, Yanjun Li, Hui Huang, Xihui Zhang, Bingcai Pan
Summary: This study demonstrates the preparation of a Ti-doped Mn3O4/Fe3O4 ternary catalyst, which creates abundant oxygen vacancies, enhances electrical conductivity, and accelerates the activation of O2 to produce H2O2. The catalyst achieved a 100% removal of tiamulin with a high H2O2 utilization efficiency, and demonstrated excellent stability and resistance to leaching.
Article
Physics, Applied
Phillip Weinberg, Adrian E. Feiguin
Summary: In this study, a novel quantum gate architecture is proposed to control the exchange interactions between magnetic impurities in nanoscale graphene flakes, allowing for the tuning from ferromagnetic to antiferromagnetic by changing the carrier density. By exact calculations and analysis of many-body mechanisms, different operation regimes of this device are explored. Arrays of these devices are discussed as potential quantum simulators for quantum many-body Hamiltonians.
APPLIED PHYSICS LETTERS
(2021)
Article
Engineering, Environmental
Yikui Zeng, Jinping Zhong, Huangbin Wang, Mingli Fu, Daiqi Ye, Yun Hu
Summary: A series of Co3O4/rGO nanocomposites with tunable oxygen vacancy defect concentrations were synthesized via alkali etching, with Co3O4/rGO-N0.64 exhibiting the highest photothermal catalytic performance due to the synergistic effect of oxygen vacancy defects and the thermal auxiliary effect of rGO.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Materials Science, Ceramics
Chao Zhang, Ying Li, Guifang Liu, Kewei Liu, Kaidi Wu
Summary: This article introduces a method for preparing ZnO1-alpha by hydrogen heat treatment and studies its sensing properties in monitoring NO2 concentration. The results show that the ZnO1-alpha coating heat-treated in a reduced atmosphere for 1 hour exhibits the best performance at room temperature under blue light irradiation.
CERAMICS INTERNATIONAL
(2021)
Article
Materials Science, Multidisciplinary
Leonie Koch, Sebastian Steiner, An-Phuc Hoang, Arne J. Klomp, Karsten Albe, Till Froemling
Summary: Solid solutions of sodium bismuth titanate (NBT) are the most performant lead-free dielectric ceramics for energy storage. The defect chemistry of NBT is complex, and acceptor doping can result in unexpected and extraordinarily high oxygen ionic conductivity. This study elucidates the interaction between acceptors and oxygen vacancies and rationalizes the observed differences in conductivity through experiments and calculations.
Article
Engineering, Environmental
Congcong Ni, Yifan Li, Xianzhe Meng, Shuliang Liu, Siyi Luo, Jing Guan, Bo Jiang
Summary: The electron-trapped oxygen vacancy and [001] facets of TiO2 have a synergistic effect on the electrochemical activity towards p-nitrophenol (p-NP) reduction. The introduction of [001] facets and electron-trapped oxygen vacancy on TiO2 can improve electron transfer and indirect reduction efficiency for p-NP electrochemical reduction. Modulating the reduction temperature can affect the electron-trapped oxygen vacancy extent on TiO2, with the Ti/TiO2-x-001 cathode prepared at 350 degrees Celsius showing the highest p-NP reduction efficiency.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Engineering, Environmental
Abhishek Meena, Pandiarajan Thangavel, Arun S. Nissimagoudar, Aditya Narayan Singh, Atanu Jana, Da Sol Jeong, Hyunsik Im, Kwang S. Kim
Summary: The self-supported oxovanadate-doped cobalt carbonate (VCoCOx@NF) on nickel foam (NF) is a high-performance catalyst for overall water splitting in alkaline-anionexchange-membrane-water-electrolyzer (AAEMWE). It shows excellent activity for both hydrogen and oxygen evolution reactions, reducing overpotentials and achieving overall water splitting at low cell voltages. The doping of V species enhances the HER and OER at the Co site, providing potential for large-scale hydrogen production utilizing V- and Co-based bimetallic oxide materials.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Materials Science, Multidisciplinary
In Young Choi, Sung-Doo Baek, Ashkan Vakilipour Takaloo, Seung Yong Lee, Amir Hajibabaei, Kwang S. Kim, Jae-Min Myoung
Summary: This study demonstrates a highly efficient pure-blue light-emitting diode (PeLED) by using a novel nanocomposite perovskite film as an emissive layer. The nanocomposite effectively reduces nonradiative recombination and enhances luminescence efficiency. The optimized nanocomposite layer also possesses a shallower valence band maximum, which is advantageous for hole injection in device operation.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Chemistry, Physical
Muhammad Umer, Sohaib Umer, Mohammad Zafari, Miran Ha, Rohit Anand, Amir Hajibabaei, Ather Abbas, Geunsik Lee, Kwang S. Kim
Summary: This study highlights a new perspective for the rational design of transition metal single-atom catalysts (SACs) using density functional theory (DFT) and machine learning (ML) approaches. By embedding single atoms of 3d/4d/5d transition metals in different substrates, the electronic properties of 364 catalysts were tuned. Machine learning analysis identified stable and high-performance catalysts for hydrogen evolution reaction (HER) based on various descriptors. The study provides a fundamental understanding for the efficient rational design of TM-SACs for H-2 production through water-splitting.
JOURNAL OF MATERIALS CHEMISTRY A
(2022)
Article
Chemistry, Physical
Abhishek Meena, Pandiarajan Thangavel, Da Sol Jeong, Aditya Narayan Singh, Atanu Jana, Hyunaik Im, Duc Anh Nguyen, Kwang S. Kim
Summary: Developing low-cost, efficient, and stable electrocatalysts are crucial for industrial high-purity hydrogen production. This study introduces an active pre-electrocatalyst that achieves high current density at low overpotential, meeting the commercial requirements for oxygen evolution reaction. Additionally, by combining with a non-noble metal-based HER catalyst, complete water-splitting is achieved in a highly corrosive alkaline environment, and an economically viable alkaline-anion-exchange-membrane water-electrolyzer is fabricated.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2022)
Article
Chemistry, Physical
Mohammad Zafari, Muhammad Umer, Arun S. Nissimagoudar, Rohit Anand, Mirah Ha, Sohaib Umer, Geunsik Lee, Kwang S. Kim
Summary: In this study, various transition metals implanted on boron-arsenide, boron-phosphide, and boron-antimony were investigated as single-atom catalysts for nitrogen reduction reaction (NRR) using density functional theory. W-BAs showed high catalytic activity and selectivity, while W-BSb and Mo-BSb exhibited high performances. Through the analysis of charge transfer and protonation steps, a crucial obstacle in NRR was successfully overcome. Machine learning descriptors were also introduced to reduce computational cost.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
So-Dam Sohn, Yohan Kim, Sungchul Jung, Jeong Su Kang, Huijun Han, Kwang S. Kim, Kibog Park, Hyung-Joon Shin
Summary: We report the dark catalysis of water dissociation on a TiO2 surface using C-60 molecules as molecular electron acceptors. This method is simple and can be widely applied for tuning and enhancing the catalytic activity of various photocatalytic systems.
Article
Physics, Condensed Matter
Amir Hajibabaei, Muhammad Umer, Rohit Anand, Miran Ha, Kwang S. Kim
Summary: This study applies on-the-fly machine learning potentials (MLPs) and sparse Gaussian process regression (SGPR) algorithm to optimize atomic structures quickly. The acceleration achieved is significant even for a single local optimization. It is found that, while MLPs have limited accuracy and may require switching to another algorithm for finding the exact local minimum, the algorithm is highly suitable for global optimization methods such as random or evolutionary structure searching or basin hopping, particularly due to the highly transferable MLPs.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Chemistry, Physical
Miran Ha, Amir Hajibabaei, Dong Yeon Kim, Aditya Narayan Singh, Jeonghun Yun, Chang Woo Myung, Kwang S. Kim
Summary: This study investigates the anion redox reaction in high-energy-density cathode materials using density functional theory and machine learning methods. The voltage/capacity fadings are suppressed by Al-doping, which enhances the structural stability and diminishes safety concerns. This research contributes to the design of stable reversible layered cathode materials.
ADVANCED ENERGY MATERIALS
(2022)
Article
Engineering, Environmental
Sandeep Kajal, Jaeki Jeong, Jongdeuk Seo, Rohit Anand, YeonJu Kim, Bangaru Bhaskararao, Chan Beom Park, Jiwoo Yeop, Anders Hagdfeldt, Jin Young Kim, Kwang S. Kim
Summary: Despite the recent increase in efficiency, perovskite solar cells (PSCs) still suffer from surface defects and ion migration, affecting their stability. In this study, we synthesized new materials with high binding energy and investigated their effects on defect passivation, ion migration, and device stability. The passivation treatment significantly improved the power conversion efficiency of PSCs, reduced hysteresis, and enhanced long-term stability, even without encapsulation.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Physical
Haiyan Jin, Miran Ha, Min Gyu Kim, Jong Hoon Lee, Kwang S. Kim
Summary: In this study, a novel atomically dispersed catalyst Pt@VNC consisting of Pt single atoms, Pt-Pt/V dual atoms, and small clusters supported on a vanadium and nitrogen co-doped carbon (VNC) surface is synthesized. By introducing atomically dispersed V sites and V2O5 clusters, the coordination structures of Pt atoms are modulated, showing extraordinary activity for the hydrogen evolution reaction. The synergistic effect of single atoms and clusters contributes to the low charge transfer resistance, fast reaction kinetics, superior catalytic efficiency, and robust durability of Pt@VNC.
ADVANCED ENERGY MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Miran Ha, Pandiarajan Thangavel, Ngoc Kim Dang, Dong Yeon Kim, Siraj Sultan, Jae Sung Lee, Kwang S. Kim
Summary: Researchers have developed a high-quality catalyst for chlorine evolution reaction (ClER) with near 100% selectivity, long-term durability, significant chlorine production, and vastly improved mass activity compared to industrial electrodes. The catalyst, composed of single platinum atoms dispersed in N-doped graphene, also exhibits ultra-low overpotential at typical operating temperatures in the chlor-alkali industries, consistent with theoretical calculations.
Article
Chemistry, Physical
Sandeep Kajal, Hyungsu Jang, Rohit Anand, Yun Seop Shin, Jung Geon Son, Jae Woong Jung, Jin Young Kim, Kwang S. Kim
Summary: Poor crystallization and nonradiative recombination are challenges faced by mixed-halide perovskite solar cells. Passivation is needed to suppress surface defects and improve charge carrier lifetime, but it must be done without disrupting the 3D symmetry. By using secondary amine passivation, the bulk phase of the perovskite material can be stabilized, leading to improved performance.
ACS APPLIED ENERGY MATERIALS
(2023)
Article
Chemistry, Physical
Rohit Anand, Babu Ram, Muhammad Umer, Mohammad Zafari, Sohaib Umer, Geunsik Lee, Kwang S. Kim
Summary: Designing efficient bifunctional and multifunctional catalysts is crucial for the development of clean and renewable energy technologies. By incorporating non-noble metal atoms onto the surface of MXenes, their properties can be modified. Using machine learning and density functional theory, we systematically screened and investigated different MXene combinations to explore their catalytic abilities.
JOURNAL OF MATERIALS CHEMISTRY A
(2022)
Article
Chemistry, Multidisciplinary
Atanu Jana, Chang Woo Myung, Vijaya Gopalan Sree, Kwang S. Kim
Summary: In this study, non-toxic, zero-dimensional bulk organic-inorganic hybrid materials were developed, which exhibited upconversion and multiexciton generation along with a long lifetime. The multiexciton generation in these materials contributed to a high photoluminescence quantum yield, the highest among any other materials. This research provides a pathway for designing and synthesizing lead-free materials with upconversion and multiexciton generation properties, thus improving the performance of optoelectronic devices.
MATERIALS CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Physical
Miran Ha, Amir Hajibabaei, Saeed Pourasad, Kwang S. Kim
Summary: Universal machine learning interatomic potentials for saturated, olefinic, and aromatic hydrocarbons are generated using the Sparse Gaussian process regression algorithm. These potentials combine previously trained systems and cross-terms between new systems. The ML-IAPs, trained using density functional theory, accurately predicted various molecular structures and energies in testing.
ACS PHYSICAL CHEMISTRY AU
(2022)
