Article
Chemistry, Multidisciplinary
Ding Zhang, Constantine Tsounis, Zhipeng Ma, Dominique Djaidiguna, Nicholas M. Bedford, Lars Thomsen, Xunyu Lu, Dewei Chu, Rose Amal, Zhaojun Han
Summary: A metal-free edge-rich vertical graphene catalyst has been synthesized and exhibits superior performance for hydrogen peroxide production in alkaline media. By tailoring oxygen-containing functional groups and developing a vacuum-based method to enhance surface wettability, gas diffusion rate has been greatly improved without compromising Faradaic efficiency.
Article
Chemistry, Physical
Taisuke Ochi, Masahiro Kamada, Takamoto Yokosawa, Kozo Mukai, Jun Yoshinobu, Tomohiro Matsui
Summary: Edge engineering is crucial for both fundamental research and applications, especially in the case of graphene, where the electronic properties of the edge depend on the atomic structure and termination. This study investigates the termination of edges created by hydrogen (H) plasma etching, revealing that the edge is sp2 bonded with only one H atom terminating the edge carbon atom. The results suggest that an ideal atomically precise and sp2 bonded zigzag edge can be achieved through H-plasma etching. Additionally, scanning tunneling microscopy studies show that deuterium (D) plasma anisotropically etches graphite less efficiently but can create defects more efficiently than H-plasma.
Article
Chemistry, Multidisciplinary
Constantine Tsounis, Bijil Subhash, Priyank Kumar, Nicholas M. Bedford, Yufei Zhao, Joel Shenoy, Zhipeng Ma, Ding Zhang, Cui Ying Toe, Soshan Cheong, Richard D. Tilley, Xunyu Lu, Liming Dai, Zhaojun Han, Rose Amal
Summary: Graphene edges possess a localized density of states that leads to increased reactivity. This study demonstrates that Pt single atom catalysts (SACs) can be anchored at the edges of graphene, resulting in enhanced catalytic performance by improving the coupling between Pt SACs and graphene.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Bo Tian, Junzhu Li, Abdus Samad, Udo Schwingenschlogl, Mario Lanza, Xixiang Zhang
Summary: This study demonstrates a method for controlled production of wafer-scale high-quality nucleus-free graphene-mesh metamaterial films and evaluates the carrier mobility of the fabricated films. These findings contribute to the large-scale production of high-quality low-dimensional graphene-mesh metamaterials and provide insights for the application of integrated circuits based on graphene and other 2D metamaterials.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Neubi F. F. Xavier Jr, Anthony J. R. Payne, Glauco F. Bauerfeldt, Marco Sacchi
Summary: The viability of catalytic methane decomposition (CMD) on carbon-based materials, specifically graphene nanoribbons, was investigated. The bare carbon edges of graphene nanoribbons were found to exhibit comparable performance to commonly used metallic and bi-metallic catalysts for methane decomposition.
FRONTIERS IN CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Xuelin Yao, Wenhao Zheng, Silvio Osella, Zijie Qiu, Shuai Fu, Dieter Schollmeyer, Beate Mueller, David Beljonne, Mischa Bonn, Hai Wang, Klaus Muellen, Akimitsu Narita
Summary: Graphene nanoribbons (GNRs), as a new family of semiconductors, offer promising opportunities for tuning optical and electronic properties. The novel fjord-edged GNR (FGNR) with nonplanar geometry was synthesized and characterized through various spectroscopic analyses, providing insights into its structural and photophysical properties.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
James Lawrence, Alejandro Berdonces-Layunta, Shayan Edalatmanesh, Jesus Castro-Esteban, Tao Wang, Alejandro Jimenez-Martin, Bruno de la Torre, Rodrigo Castrillo-Bodero, Paula Angulo-Portugal, Mohammed S. G. Mohammed, Adam Matej, Manuel Vilas-Varela, Frederik Schiller, Martina Corso, Pavel Jelinek, Diego Pena, Dimas G. de Oteyza
Summary: This study demonstrates two chemical protection/deprotection strategies for chiral graphene nanoribbons, allowing them to survive exposure to air and regain their original electronic properties through hydrogenation and annealing.
Article
Chemistry, Multidisciplinary
Maria Grazia Betti, Ernesto Placidi, Chiara Izzo, Elena Blundo, Antonio Polimeni, Marco Sbroscia, Jose Avila, Pavel Dudin, Kailong Hu, Yoshikazu Ito, Deborah Prezzi, Miki Bonacci, Elisa Molinari, Carlo Mariani
Summary: By exposing fully free-standing nanoporous samples of graphene to atomic hydrogen in ultrahigh vacuum, the researchers achieved an unprecedented level of hydrogenation, converting conductive graphene into a wide gap semiconductor. The experimental results confirmed the theoretical predictions of a stable, double-sided fully hydrogenated configuration without pi states.
Article
Chemistry, Physical
Yan Gao, Dan Xu, Tian Cui, Da Li
Summary: Hydrogen passivation leads to energetically more stable hydrogen-terminated graphene edges compared to bare graphene edges. Hydrogen-terminated graphene edges with six-membered carbon rings exhibit better overall stability. The effects of experimental temperatures and hydrogen partial pressures on the stability are fully investigated.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Nanoscience & Nanotechnology
Kenan Elibol, Toma Susi, Clemens Mangler, Dominik Eder, Jannik C. Meyer, Jani Kotakoski, Richard G. Hobbs, Peter A. van Aken, Bernhard C. Bayer
Summary: The presence of metal atoms at the edges of graphene nanoribbons (GNRs) allows for tailoring their physical properties. In this study, indium (In) chains were formed on the edges of graphene-supported GNRs through laser heating and physical vapor deposition. Aberration-corrected scanning transmission electron microscopy (STEM) revealed that multiple In atoms preferred to decorate the edges of the GNRs. Electron-beam irradiation induced the migration of In atoms along the edges and the formation of longer chains. Theoretical calculations confirmed the metallic character of these structures. This research provides insights into the formation and properties of long linear metal atom chains at graphitic edges.
NPJ 2D MATERIALS AND APPLICATIONS
(2023)
Review
Materials Science, Multidisciplinary
Yu Liu, Huy Q. Ta, Xiaoqin Yang, Yue Zhang, Junhua Zhou, Qitao Shi, Mengqi Zeng, Thomas Gemming, Barbara Trzebicka, Lei Fu, Mark H. Ruemmeli
Summary: This review focuses on the fabrication and characterization of free-standing nanostructures suspended in graphene using transmission electron microscopy, which enables the observations with atomic resolution and investigations of the dynamic behavior of atoms/structures in such materials. Additionally, the review discusses the influence of novel metal/nonmetal dopants in graphene vacancies with varying bond configurations and the catalytic activities of single atoms/clusters located at the graphene edges. Moreover, the dynamic forming process of freestanding single-atom-thick two-dimensional (2D) clusters/metal/metallenes and 2D clusters/metal/metallenes oxides is discussed.
SCIENCE CHINA-MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Md Shahjahan Kabir Chowdury, Young Jin Cho, Sung Bum Park, Min Hwan Lee, Yong-il Park
Summary: High-performance conventional proton exchange membrane fuel cells (PEMFCs) often use expensive Pt/C as catalysts, but they are susceptible to CO poisoning. Graphene, as a precious metal-free alternative, has high catalytic activity and tolerance against poisoning. In this study, nitrogen-doped reduced graphene oxide (N-rGO), a low-cost and precious metal-free electrocatalyst, was synthesized and a safe method for Pt/C-free electrocatalyst application in graphene oxide-hydrogen membrane fuel cells (GOHMFCs) was developed.
MATERIALS TODAY CHEMISTRY
(2023)
Article
Chemistry, Physical
Yulia G. Polynskaya, Irina V. Lebedeva, Andrey A. Knizhnik, Andrey M. Popov
Summary: Ab initio calculations were conducted to study consecutive reconstruction of a zigzag graphene edge. It was found that the formation of the first pentagon-heptagon pair is the slowest step, while the growth of an already nucleated reconstructed edge domain occurs at a much higher rate. The merging of domains is not guaranteed, and residual defects may be left behind. Additionally, the probability of spontaneous formation of pairs of residual defects is low.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
Article
Nanoscience & Nanotechnology
Zhe Chen, Arash Khajeh, Ashlie Martini, Seong H. Kim
Summary: The high friction at step edges on graphite surfaces is due to stick-slip behavior facilitated by topographical changes and atomic interactions, rather than the buckling or peeling deformation of graphene. Experimental results and simulations show that the mechanisms proposed have identifiable features in lateral force and vertical height profiles, with the stick-slip behavior being the main cause of high friction.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Multidisciplinary Sciences
Ravi Kumar, Saurabh Kumar Srivastav, Christian Spanslatt, K. Watanabe, T. Taniguchi, Yuval Gefen, Alexander D. Mirlin, Anindya Das
Summary: Graphene has recently been used as a new platform for studying quantum Hall states. Noise measurements have provided evidence for the presence and ballistic nature of the upstream mode in the hole-conjugate fractional quantum Hall state in bilayer graphene. The existence of upstream modes moving against the charge current flow direction is crucial for the emergence of renormalized modes with exotic quantum statistics, with excess noise at the edge serving as a smoking gun for their presence.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Mengmeng Yang, Rupeng Huo, Huidong Shen, Qineng Xia, Jieshan Qiu, Alex W. Robertson, Xi Li, Zhenyu Sun
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2020)
Article
Chemistry, Physical
Wenshuo Xu, Sha Li, Gyeong Hee Ryu, Peng Tang, Mauro Pasta, Jamie H. Warner
CHEMISTRY OF MATERIALS
(2020)
Article
Nanoscience & Nanotechnology
Gyeong Hee Ryu, Sungwoo Lee, Jung Hwa Kim, Gun-Do Lee, Zonghoon Lee
Summary: The study reveals that oxygen and hydrogen atoms can participate in the formation of point defects in freestanding graphene monolayers. The theoretical calculations demonstrate that these participating atoms can stabilize 13-5 ring pairs under electron beam irradiation.
Article
Nanoscience & Nanotechnology
Yung-Chang Lin, Sungwoo Lee, Yueh-Chiang Yang, Po-Wen Chiu, Gun-Do Lee, Kazu Suenaga
Summary: This study demonstrates the unambiguous observation of a two-dimensional IF bilayer grown on the surface of WSe2, showing a clear hexagonal lattice and robust epitaxial relationship with the substrate. Despite the known instability of IF at room temperature, it was found stabilized on a suitable substrate, pointing to the possibility of producing unexpected crystalline structures.
NPJ 2D MATERIALS AND APPLICATIONS
(2021)
Article
Chemistry, Physical
Geosan Kang, Deokgi Hong, Ji-Yong Kim, Gun-Do Lee, Sungwoo Lee, Dae-Hyun Nam, Young-Chang Joo
Summary: The study presents a method for achieving polymorphic conversion of VIB TMDs using gas-solid reactions, with process conditions predicted by thermodynamic calculations and the mechanism triggered by the formation of S vacancy (V-S).
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Materials Science, Multidisciplinary
S. Sinha, H. Kim, A. W. Robertson
Summary: For two-dimensional materials, forming heterostructures or hybrids with other nanomaterials is a key strategy to control and enhance their overall performance.
MATERIALS TODAY ADVANCES
(2021)
Article
Chemistry, Multidisciplinary
Di Wang, Lifen Li, Qineng Xia, Song Hong, Leiduan Hao, Alex W. Robertson, Zhenyu Sun
Summary: Selective cathodic CO2 conversion to C2+ chemicals has been achieved by optimizing the surface charge of Cu. The stabilization of Cu+ and adjusting the surface content of Cu+ enables the regulation of C2+ selectivity, resulting in high C2+ FE and current density.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2022)
Article
Chemistry, Multidisciplinary
Zhibo Yao, Shiqiang Liu, Honghong Liu, Yukun Ruan, Song Hong, Tai-Sing Wu, Leiduan Hao, Yun-Liang Soo, Pei Xiong, Molly Meng-Jung Li, Alex W. Robertson, Qineng Xia, Liang-Xin Ding, Zhenyu Sun
Summary: By utilizing catalysts composed of In2O3 and CdO5, as well as elucidating the reaction mechanism, surface hydrogenation-facilitated NRR for NH3 synthesis has been successfully achieved, which is of great significance for sustainable and decentralized green ammonia production.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Matthew J. Coupin, Yi Wen, Sungwoo Lee, Anshul Saxena, Colin Ophus, Christopher S. Allen, Angus I. Kirkland, Narayana R. Aluru, Gun-Do Lee, Jamie H. Warner
Summary: Defects in crystalline lattices cause modulation of the atomic density, leading to variations in the associated electrostatics at the nanoscale. Four-dimensional scanning transmission electron microscopy (4D-STEM) was used to measure electric fields near point dislocations in a monolayer, overcoming the challenges of traditional phase contrast imaging. The increased electric field magnitude near the (1,0) edge dislocation core in graphene is shown to arise from long-range interactions beyond the nearest atomic neighbor. These results provide insights into using 4D-STEM for quantifying electrostatics and mapping potential variations in thin materials.
Review
Electrochemistry
Zixuan Li, Alex W. Robertson
Summary: Rechargeable aqueous zinc-ion batteries are promising candidates for next-generation energy storage due to their high theoretical capacity, low cost, safety, and environmental friendliness. However, the physical and chemical instability of the zinc anode hinders the electrochemical performance. Regulating the electrolyte can improve the performance of the zinc anode, making it important to gain an in-depth understanding of the electrolyte-dependent regulation mechanisms.
Review
Chemistry, Physical
Yukun Ruan, Zhen-Hong He, Zhao-Tie Liu, Weitao Wang, Leiduan Hao, Liang Xu, Alex W. Robertson, Zhenyu Sun
Summary: This review summarizes the important progress in the electroreduction of N2 to NH3 using state-of-the-art two-dimensional (2D) electrocatalysts. Several reaction mechanisms of nitrogen reduction reaction (NRR) are explained, and recent experimental progress regarding these unique 2D NRR electrocatalysts is reported. Furthermore, concepts proposed from high-throughput computations and machine learning are described. By understanding the N2 conversion to NH3 process on 2D electrocatalysts, novel 2D materials that could potentially serve as viable NRR electrocatalysts are presented. The future perspectives and challenges of N2 electrolysis using 2D materials are also discussed.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Chemistry, Multidisciplinary
Xin Li, Lifen Li, Lijun Wang, Qineng Xia, Leiduan Hao, Xinyu Zhan, Alex W. Robertson, Zhenyu Sun
Summary: We have achieved significantly enhanced electrochemical CO2 reduction to C2H4 by tuning the interface of a metal oxide composite (CuOx/HfO2). The CuOx-HfO2 interface greatly strengthens CO2 adsorption and the binding of *CO, leading to higher C2H4 production.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Yeji Baek, Hakhyeon Song, Deokgi Hong, Suneon Wang, Sungwoo Lee, Young-Chang Joo, Gun-Do Lee, Jihun Oh
Summary: The electrochemical conversion of CO2 to ethanol and ethylene is a promising method for addressing global climate change. CuZn alloys as catalysts enhance the ethanol selectivity and achieve high ethanol production efficiency.
JOURNAL OF MATERIALS CHEMISTRY A
(2022)
Article
Multidisciplinary Sciences
Zhenqing Zhao, Jongseo Park, Changhyeok Choi, Song Hong, Xiangchao Hui, Hao Zhang, Tsz Woon Benedict Lo, Alex W. Robertson, Zengxiang Lv, Yousung Jung, Zhenyu Sun
Summary: This study successfully increased the efficiency of ambient NRR for ammonia production by tuning the Te vacancies and surface hydrophobicity of two-dimensional TaTe2 nanosheets. It achieved remarkable NH3 faradic efficiency and maintained high stability, with the edge plane of TaTe2 and VTe identified as the main active sites for NRR.
Article
Nanoscience & Nanotechnology
Sungwoo Lee, Deokgi Hong, Ji-Yong Kim, Dae-Hyun Nam, Sungwoo Kang, Seungwu Han, Young-Chang Joo, Gun-Do Lee
Summary: The study presents a detailed atomic-scale mechanism of structural phase transition of MoS2 nanocrystals under reaction with CO gas molecules. The research findings suggest that the evaporation of S atoms at the edge induces the structural change from 2H to 1T/1T' in the basal plane of nanocrystals.
ACS APPLIED NANO MATERIALS
(2021)