Article
Materials Science, Multidisciplinary
Yeonsig Nam, Hao Li, Jin Yong Lee
Summary: The study demonstrates that nitrogen/fluorine doping of TiO2 nanoparticles plays a crucial role in suppressing electron-hole recombination. The trapping of electrons and holes varies depending on the doping site, with different trapping times observed. Nanoparticles doped in different domains exhibit diverse charge recombination pathways.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Review
Materials Science, Multidisciplinary
Guanxing Li, Ke Fang, Yang Ou, Wentao Yuan, Hangsheng Yang, Ze Zhang, Yong Wang
Summary: The anatase TiO2 (001) surface, known for its excellent performance, undergoes reconstruction to a (1 x 4)-(001) surface due to its high reactivity, potentially altering its properties. Recent advances in surface science have elucidated the intrinsic physical and chemical properties of this surface. Studying the structure, formation mechanism, stability, and surface chemistry of the reconstructed TiO2 (001) surface is crucial for understanding its behavior.
PROGRESS IN NATURAL SCIENCE-MATERIALS INTERNATIONAL
(2021)
Article
Chemistry, Multidisciplinary
Pu Zhang, Haihua Zeng, Decai Wen, Xiaoyu Sui, Zhuan Wang, Ying Wang, Hailong Chen, Yuxiang Weng, Jinlin Long
Summary: This study demonstrates the efficient photocatalytic hydrogen evolution reaction (HER) by constructing well-defined single-site Ni-grafted TiO2 photocatalysts with unique coordination environments. The T-Ni Bpy catalyst exhibits high catalytic activity, with a rate and turnover frequency 260 times higher than those of Ni-O-TiO2. The electron paramagnetic resonance and femtosecond transient IR absorption measurements indicate that the presence of fewer electron trapped oxygen vacancies and a larger portion of long-lived photogenerated electrons are essential for achieving excellent HER activity.
Article
Chemistry, Physical
Yiqing Wu, Feng Gao, Huamin Wang, Libor Kovarik, Berlin Sudduth, Yong Wang
Summary: This study investigates the surface acid-base properties of anatase TiO2 nanomaterials with {101} and {001} facets via methanol titrations. It was found that adsorption and desorption of methanol differ significantly between TiO2(101) and TiO2(001), with surface defects playing an important role in the reaction process.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Cong Fu, Fei Li, Zongfang Wu, Feng Xiong, Junfa Zhu, Xue-Qing Gong, Weixin Huang
Summary: A trace amount of potassium dopant is found to restructure the surface of anatase TiO2(001) single crystal, changing the termination from molecule termination to oxygen termination. The molecule-terminated surface shows (photo)catalytic activity, while the oxygen-terminated surface is inert.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Shanshan Dong, Jinyuan Hu, Shucai Xia, Binli Wang, Zhiqiang Wang, Tianjun Wang, Wei Chen, Zefeng Ren, Hongjun Fan, Dongxu Dai, Jun Cheng, Xueming Yang, Chuanyao Zhou
Summary: Methanol has been used as a hole scavenger in photocatalysis to improve charge separation. Study revealed that methoxy anions on TiO2 facilitate charge transfer more effectively than methanol, enhancing photocatalytic activity.
Article
Chemistry, Multidisciplinary
Saif M. H. Qaid, Hamid M. Ghaithan, Huda S. Bawazir, Abrar F. Bin Ajaj, Khulod K. AlHarbi, Abdullah S. Aldwayyan
Summary: This study aims to synthesize various TiO2 nanocrystals, including nanosheets, nanorods, and nanoparticles, using a rapid hydrothermal method. The synthesized TiO2 nanocrystals exhibit high purity and exposed high-energy facets, resulting in high reactivity and large surface area. The {001} facets dominate in the nanosheets and nanorods, accounting for approximately 80% and 85% of the outer surface area, respectively.
Article
Chemistry, Physical
Lan Jiang, Gongbing Zhou
Summary: The study revealed that the interaction between Ru nanoparticles and TiO2 crystal surfaces in Ru/ATCs catalysts contributes to enhancing activity and selectivity in benzene semi-hydrogenation reactions. Among different support facets, Ru/ATCs-101 showed the lowest density of coordinatively unsaturated atoms and exhibited the best catalytic performance.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Physical
Hanggara Sudrajat, Sri Hartuti, Sandhya Babel
Summary: Anatase TiO2 doped with tantalum cations through hydrothermal route exhibits higher photocatalytic activity, with the optimal performance observed in samples doped with 2 mol% tantalum. Tantalum doping results in an increased population of photoexcited electrons and prolonged electron lifetime, attributed to the formation of Ti3+ defect states, leading to enhanced mineralization efficiency and electron population compared to pristine TiO2. The fundamental question of why proper metal doping into TiO2 enhances photocatalytic activity is discussed in this study.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Kasidid Yaemsunthorn, Wiktoria Adamowicz, Marcin Kobielusz, Wojciech Macyk
Summary: The photocatalytic selective reduction of 3-nitrophenol to 3-aminophenol was studied using titanium dioxide in different compositions. Both intrinsic and extrinsic parameters were found to affect the reaction progress, with intrinsic factors related to the chemical, structural, and electronic properties and extrinsic factors related to the reaction conditions. The analysis revealed that the performance of anatase and rutile materials varied due to differences in interfacial electron transfer, charge recombination, reduction driving force, and methanol photooxidation efficiency. The understanding of these factors could lead to the rational design of efficient and selective photocatalysts.
Article
Engineering, Environmental
Wenjin Ni, Dejian Yan, Shangjun Fu, Yanan Wei, Hongyun Yang, Xiaowen Zhang, Fangfang Zhao, Kuiyi You, He'an Luo
Summary: This study developed an environmentally friendly and efficient method for the selective oxidation of cyclohexylamine to cyclohexanone oxime by preparing TiO2 nanocrystals with different facets ratios. The dominant anatase TiO2 (001) catalyst showed promising results with 51.3% conversion of cyclohexylamine and 86.3% selectivity to cyclohexanone oxime, along with excellent stability. The TiO2 (001) facet provided abundant surface hydroxyl groups as catalytic active sites. DFT calculations revealed that the energy barriers for the rate determining steps in the oxidation of N-H bond on TiO2 (001) facet were lower than those on (101) facet, indicating better catalytic performance. This work offers new insights into the design of catalytic active sites for the selective oxidation of amines to oximes.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Nanoscience & Nanotechnology
Kasidid Yaemsunthorn, Marcin Kobielusz, Wojciech Macyk
Summary: The low-temperature synthesis of TiO2 nanocomposites allows precise tuning of the anatase/rutile ratio. Different phase compositions have varying impacts on water oxidation, hydrogen peroxide reduction, and water reduction reactions, with the A series showing higher activity in oxidation-controlled reactions and the B series facilitating reduction-controlled processes. The design of optimal photocatalysts should consider both intrinsic and extrinsic factors for improved catalytic activity.
ACS APPLIED NANO MATERIALS
(2021)
Article
Chemistry, Physical
Giuseppe Zollo, Kersti Hermansson, Lorenzo Agosta
Summary: The study emphasizes the importance of considering the thermodynamic state of the surrounding liquid in finding interface structures in real systems. The research addresses the issue of reconstruction symmetry on the anatase surface and shows the different stable states of WIR surfaces in vacuum and bulk water, depending on the thermodynamic state of the system. Surface phase transitions between (2x4) and (2x3) symmetries are thermally activated and lead by the surface relaxation caused by molecular adsorption and release phenomena.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Jian Wang, Wei Lin, Shulan Zhou, Zheng Li, Hao Hu, Yinglong Tao, Shijian Zhou, Xian Zhao, Yan Kong
Summary: This work presents a novel method for synthesizing TiO2 with Ti3+ defects exclusively embedded in the bulk lattice near the surface. The presence of both ethanol and HF is essential for precise location control of the formed Ti3+ defects. Extensive analysis using various techniques and theoretical simulation clarify the mechanism behind the precise control of the Ti3+ defect sites.
NEW JOURNAL OF CHEMISTRY
(2021)
Article
Chemistry, Physical
Shuyang Wu, Kana Ishisone, Yuan Sheng, Manoel Y. Manuputty, Markus Kraft, Rong Xu
Summary: Controlling the stoichiometry of reduced titanium dioxide to modulate its surface chemistry and improve charge separation is an effective strategy. Defective TiO2-x nanoparticles with moderate defects and more grain boundary oxygen vacancies have shown improved charge separation and high degradation efficiency for gaseous isopropanol. The study sheds more light on the structure-activity correlations and benefits the design of photocatalysts for efficient gaseous pollutant removal.
CATALYSIS SCIENCE & TECHNOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Xiaochuan Ma, Yongliang Shi, Jianyi Liu, Xintong Li, Xuefeng Cui, Shijing Tan, Jin Zhao, Bing Wang
Summary: The hydrogen-bond network plays a crucial role in water splitting by facilitating the transfer of proton and hole. Through controlling the coverage of water, a hydrogen-bond network is formed, which opens a channel for the transfer of photoexcited hole and leads to the formation of surface hydroxyl groups. This study provides important insights into the water splitting process in photocatalysis.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Zhengwang Cheng, Aobo Wang, Huating Bo, Mei Wang, Jing He, Wei Zou, Xinguo Ma
Summary: This study prepared molybdenum (Mo) films on CMOS compatible Si/SiO2 wafers through a magnetron sputtering method and systematically investigated the effect of several process parameters on film thickness nonuniformity and other structural properties. The optimized process parameters resulted in films with unified <110> preferred orientation, excellent thickness nonuniformity of 0.46%, surface roughness of 0.83 nm, and low X-ray diffraction (110) rocking curve of 0.47 degrees. These results provide an efficient reference for the preparation of uniform metal films and improving the quality and yield in filter device manufacturing.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Physics, Multidisciplinary
Minghu Pan, Xin Zhang, Yinong Zhou, Pengdong Wang, Qi Bian, Hang Liu, Xingyue Wang, Xiaoyin Li, Aixi Chen, Xiaoxu Lei, Shaojian Li, Zhengwang Cheng, Zhibin Shao, Haoxuan Ding, Jianzhi Gao, Fangsen Li, Feng Liu
Summary: In this study, we report the surface growth of a self-assembled monolayer of 2D hydrogen-bond organic frameworks (HOFs) on an Au(111) substrate and the observation of flat bands (FBs). The highly ordered THPB HOF domains and the FB over the whole Brillouin zone were observed through high-resolution scanning tunneling microscopy or spectroscopy and angle-resolved photoemission spectroscopy, respectively. Density functional theory calculations and analyses showed that the observed FB arises from a hidden electronic breathing-kagome lattice without atomically breathing bonds.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Physical
Miaomiao Xiang, Xiaochuan Ma, Chang Gao, Ziyang Guo, Chenxi Huang, Yue Xing, Shijing Tan, Jin Zhao, Bing Wang, Xiang Shao
Summary: In this study, the electronic structures at the atomically flat interface of single-layer MoS2 (SL-MoS2) on rutile TiO2 surface were investigated using high-resolution angle-resolved photoemission spectroscopy. The valence band maximum and the conduction band minimum of SL-MoS2 at the K point were directly visualized, indicating a direct bandgap of approximately 2.0 eV. Detailed analyses and density functional theory calculations confirmed that the conduction band minimum of MoS2 is formed by trapped electrons at the MoS2/TiO2 interface coupling with longitudinal optical phonons in the TiO2 substrate through an interfacial Frohlich polaron state. This interfacial coupling effect may provide a new route for tuning free charges in hybridized systems of two-dimensional materials and functional metal oxides.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Zhengya Wang, Ruoting Yin, Jie Meng, Jianing Wang, Yifan Liang, Chuanxu Ma, Shijing Tan, Qunxiang Li, Jinlong Yang, Bing Wang
Summary: In this study, a cascade reaction from periodic hydrogenated divacancies to alternating 585-ringed divacancies and Ag atoms on the Ag(111) surface was successfully developed. The evolution of the structural and electronic properties in the reaction intermediates was in situ monitored using various characterization techniques combined with theoretical calculations. The observation of embedded Ag atoms and the analysis of the reaction pathway provided evidence for Ag adatom-mediated C-H activation. This research opens up a new avenue for introducing periodic impurities in on-surface synthesis and has potential implications in the fabrication of multifunctional graphene nanostructures.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Xiang Zhu, Jiayu Xu, Yao Zhang, Bin Li, Yishu Tian, Yingying Wu, Zhiwei Liu, Chuanxu Ma, Shijing Tan, Bing Wang
Summary: Isotope substitution not only changes the vibrational frequencies but also the vibrational distributions in real-space of a molecule. Measuring isotope effects in a polyatomic molecule at the single-bond level with energy and spatial resolutions has been challenging. By achieving angstrom resolution in tip-enhanced Raman spectroscopy (TERS), the isotope effect of each vibrational mode in pentacene and its fully deuterated form is identified and measured. The frequency ratio ν(H)/ν(D) varies from 1.02 to 1.33, indicating different isotopic contributions of H/D atoms, which can be distinguished and described by TERS maps and potential energy distribution simulations. This study demonstrates that TERS can be a non-destructive and highly sensitive method for isotope detection and recognition with chemical-bond precision.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Chuanxu Ma, Jufeng Wang, Huanhuan Ma, Ruoting Yin, Xin-Jing Zhao, Hongjian Du, Xinyong Meng, Yifan Ke, Wei Hu, Bin Li, Shijing Tan, Yuan-Zhi Tan, Jinlong Yang, Bing Wang
Summary: We demonstrate the direct growth of topologically nontrivial graphene nanoribbons (GNRs) in the second layer by annealing designed precursor molecules over one monolayer on the Au(111) surface. The second-layer GNRs undergo domino-like cyclodehydrogenation reactions that are remotely triggered at the link.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Engineering, Electrical & Electronic
Wei Zou, Lei Li, Zhengwang Cheng, Li Zhang, Mei Wang, Xinguo Ma, Xuecheng Zou
Summary: This paper proposes a high frequency resolution digitally controlled oscillator (DCO) for wireless transceivers, which utilizes an optimized cascaded differential switched-capacitor (SC) ladder and a low-coupled eight-shaped transformer. The frequency resolution is further enhanced by reducing the electromagnetic coupling effect between the primary and secondary coils of the on-chip transformer, thereby reducing quantization noise and phase noise. The DCO achieves a tuning range of 36.7% from 3.83 to 5.55 GHz with a frequency resolution of 17 kHz, and exhibits a phase noise of -120.29 dBc/Hz at 1 MHz offset from the carrier frequency of 3.83 GHz. The power consumption of the DCO is 9.26 mA from a 1.8 V supply, and the figure of merit with tuning range is -191 dBc/Hz. The chip size is 0.294 mm².
INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Mei Wang, Huating Bo, Aobo Wang, Zhengwang Cheng, Shengjia Li, Wei Zou, Jing He, Xinguo Ma
Summary: To adapt to the upgrading of wireless communication system, research on thin film bulk acoustic resonator (FBAR) has gained attention. This study focuses on the core functional layer, the piezoelectric film, particularly aluminum nitride (AlN) and scandium-doped AlN films, examining their characteristics and quality changes. The results show that doping with scandium significantly improves the uniformity, roughness, and stress of AlN films, making it promising for improving the performance of FBAR filters and device yield.
Article
Chemistry, Physical
Miaomiao Xiang, Xiaochuan Ma, Chang Gao, Ziyang Guo, Chenxi Huang, Yue Xing, Shijing Tan, Jin Zhao, Bing Wang, Xiang Shao
Summary: In this work, the electronic structures at the interface of single-layer MoS2 on rutile TiO2 surface were investigated using high-resolution angle-resolved photoemission spectroscopy. The experiments directly observed the valence band maximum and the conduction band minimum (CBM) of single-layer MoS2 at the K point, defining a direct bandgap of approximately 2.0 eV. Detailed analysis and density functional theory calculations showed that the CBM of MoS2 is formed by trapped electrons at the MoS2/TiO2 interface that couple with longitudinal optical phonons in the TiO2 substrate through an interfacial Frohlich polaron state. This interfacial coupling effect may provide a new route for tuning free charges in hybridized systems of two-dimensional materials and functional metal oxides.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Gang Yuan, Zhengwang Cheng, Yuehuan Cheng, Wangyang Duan, Hui Lv, Zhifeng Liu, Changcun Han, Xinguo Ma
Summary: The influence of interlayer spacing and external electric field on the GR/MoSi2N4 heterojunction was systematically investigated. The study found that both the type and height of the Schottky barrier can be tuned by altering the interlayer spacing or applying external electric field. These findings are of great importance for the design of next-generation field-effect transistors.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Gang Yuan, Zhengwang Cheng, Yuehuan Cheng, Wangyang Duan, Hui Lv, Zhifeng Liu, Changcun Han, Xinguo Ma
Summary: This study systematically investigates the influence of the combination of graphene and monolayer MoSi2N4 on the interfacial characteristic and electronic structure, and finds that the type and height of the Schottky barrier can be tuned by altering the interlayer spacing or applying an external electric field.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Physics, Multidisciplinary
Ju-Feng Wang, Ming-Yang Tian, Hong-Jian Du, Chuan-Xu Ma, Bing Wang
Summary: This study reports a new low-temperature phase of Pb-Bi alloy thin film, namely PbBi3. Through in situ characterization of surface structure and superconducting properties, it is found that the superconducting transition temperature of PbBi3 is about 6.13K. By studying the heterojunctions of non-superconducting and superconducting regions with different structures, the lateral superconducting penetration length is found to be influenced by atomic connection, Josephson junctions, and external magnetic field. Furthermore, the observed topological superconducting behaviors on the PbBi3 surface may occur in the vortex regions under magnetic fields or near the topological superconducting Bi(110) islands considering the proximity effect.
ACTA PHYSICA SINICA
(2022)
Article
Materials Science, Ceramics
Yuan Gang, Ma Xinguo, He Hua, Deng Shuiquan, Duan Wangyang, Cheng Zhengwang, Zou Wei
Summary: This study investigates the effect of plane strain on the band structure and photoelectric properties of two-dimensional MoSi2N4. The results show that strain can modify the band gap and effective mass of photogenerated carriers in MoSi2N4, expanding its potential applications in the field of optoelectronic devices.
JOURNAL OF INORGANIC MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Jufeng Wang, Xia Sun, Hongjian Du, Chuanxu Ma, Bing Wang
Summary: The electronic and topological properties of ultrathin Bi(110) films on a Cu(111) substrate are studied using experimental and computational methods. It is found that the stacking modes and atomic buckling heights have significant effects on the properties of the films. In 2-BL films, the electronic and topological properties are independent of the substrate and surface atomic buckling height. In 1-BL films, the properties are influenced by the stacking modes between the bilayer and substrate.
