Publications by authors named "Hao-Bo Li"

15 Publications

  • Page 1 of 1

Dehydration of Electrochemically Protonated Oxide: SrCoO with Square Spin Tubes.

J Am Chem Soc 2021 Oct 14;143(42):17517-17525. Epub 2021 Oct 14.

Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan.

Controlling oxygen deficiencies is essential for the development of novel chemical and physical properties such as high- superconductivity and low-dimensional magnetic phenomena. Among reduction methods, topochemical reactions using metal hydrides (e.g., CaH) are known as the most powerful method to obtain highly reduced oxides including NdSrNiO superconductor, though there are some limitations such as competition with oxyhydrides. Here we demonstrate that electrochemical protonation combined with thermal dehydration can yield highly reduced oxides: SrCoO thin films are converted to SrCoO by dehydration of HSrCoO at 350 °C. SrCoO forms square (or four-legged) spin tubes composed of tetrahedra, in contrast to the conventional infinite-layer structure. Detailed analyses suggest the importance of the destabilization of the SrCoO precursor by electrochemical protonation that can greatly alter reaction energy landscape and its gradual dehydration (HSrCoO) for the SrCoO formation. Given the applicability of electrochemical protonation to a variety of transition metal oxides, this simple process widens possibilities to explore novel functional oxides.
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http://dx.doi.org/10.1021/jacs.1c07043DOI Listing
October 2021

High-sensitive sensor for the simultaneous determination of phenolics based on multi-walled carbon nanotube/NiCoAl hydrotalcite electrode material.

Mikrochim Acta 2021 Aug 27;188(9):308. Epub 2021 Aug 27.

College of Chemical Engineering, Xiangtan University, Xiangtan, 411105, Hunan, China.

The ternary NiCoAl hydrotalcite (NiCoAl-LDH) was combined with carboxylic multi-walled carbon nanotube (MWCNT) to fabricate a novel electrochemical sensor for simultaneously determining the co-existing trace phenolic substances. The morphology, structure, and electrochemical behavior of the as-prepared materials were characterized by various techniques. Benefitting from the great conductivity of MWCNT and high electrocatalytic activity of NiCoAl-LDH for phenolic substances, the advanced MWCNT/NiCoAl-LDH sensor presented a fast response, high sensitivity, excellent stability, and satisfactory replicability. The sensor offered good linear responses in the ranges1.50~600 μM to hydroquinone (HQ), 5.00~1.03 × 10 μM to catechol (CC), and 6.00 × 10~250 μM to bisphenol A (BPA). The detection limits of HQ, CC, and BPA were 0.4, 0.8, and 6. × 10 μM (S/N = 3), respectively. In environmental water, the sensor achieved satisfactory recoveries for the simultaneous detection of HQ (98.6~101%), CC (98.0~101%), and BPA (97.5~101%), with relative standard deviations less than 4.4%.
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http://dx.doi.org/10.1007/s00604-021-04948-1DOI Listing
August 2021

Controllable architecture of the [email protected] layered double hydroxide coral-like structure for high-performance supercapacitors.

Dalton Trans 2021 Sep 5;50(33):11542-11554. Epub 2021 Aug 5.

College of Chemical Engineering, Xiangtan University, Xiangtan 411105, Hunan, China.

The rational design of the morphological structure of electrode materials is considered as an important strategy to obtain high-performance supercapacitors. So, NiCoZnS materials with different Ni/Co/Zn molar ratios on Ni foam (NF) were synthesized, in which the Ni/Co/Zn molar ratio plays a key role in the morphological structure and electrochemical performances. Furthermore, the pre-prepared NiCoZnS materials act as substrates to guide the self-assembling of NiCoFe layered double hydroxide (LDH) nanosheets on the substrate surface to form core-shell electrode materials ([email protected]) with a 3D mesoporous hierarchical network structure for further improving electrochemical performances. The unique interconnected coral-like [email protected] with a large specific surface area (93.1 m g) and high specific capacitance is achieved at the Ni/Co/Zn molar ratio of 1 : 1 : 1. Benefiting from the unique structural feature and respective merits of the NiCoZnS and NiCoFe-LDH, the [email protected] demonstrates an ultrahigh specific capacitance of 1524.0 C g (3386.7 F g) at 1.0 A g and excellent 95.0% capacitance retention at 10 A g after 5000 cycles. As for practical application, the assembled [email protected]//AC delivers a favorable energy density of 66.25 W h kg at 1500 W kg and a long-term cycling lifetime (86.04% retention at 5.0 A g after 10 000 cycles), which suggests promising potential in energy storage and conversion.
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http://dx.doi.org/10.1039/d1dt01329gDOI Listing
September 2021

Preparation of a [email protected] Composite for High-Performance Supercapacitors.

Chem Asian J 2019 Dec 6;14(23):4337-4344. Epub 2019 Nov 6.

College of Chemical Engineering, Xiangtan University, Xiangtan, 411105, Hunan, China.

A core-shell [email protected] composite ([email protected]) with a 3D "sand rose"-like morphology was prepared via a facile in situ oxidative polymerization of pyrrole monomer, where the role of PPy coating thickness was investigated for high-performance supercapacitors. Microstructure analyses indicated that the PPy was successfully coated onto the NiAlO surface to form a core-shell structure. The [email protected] exhibited a better electrochemical performance than pure NiAlO, and the moderate thickness of the PPy shell layer was beneficial for expediting the electron transfer in the redox reaction. It was found that the [email protected] prepared at 5.0 mL L addition amount of pyrrole monomer demonstrated the best electrochemical performance with a high specific capacitance of 883.2 F g at a current density of 1 A g and excellent capacitance retention of 91.82 % of its initial capacitance after 1000 cycles at 3 A g . The outstanding electrochemical performance of [email protected] were due to the synergistic effect of NiAlO and PPy, where the uniform network-like PPy shell with the optimal thickness made electrolyte ions more easily accessible for faradic reactions. This work provided a simple approach for designing organic-inorganic core-shell materials as high-performance electrode materials for electrochemical supercapacitors.
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http://dx.doi.org/10.1002/asia.201901299DOI Listing
December 2019

Electric Field-Controlled Multistep Proton Evolution in H SrCoO with Formation of H-H Dimer.

Adv Sci (Weinh) 2019 Oct 15;6(20):1901432. Epub 2019 Aug 15.

State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics Tsinghua University Beijing 100084 China.

Ionic evolution-induced phase transformation can lead to wide ranges of novel material functionalities with promising applications. Here, using the gating voltage during ionic liquid gating as a tuning knob, the brownmillerite SrCoO is transformed into a series of protonated H SrCoO phases with distinct hydrogen contents. The unexpected electron to charge-neutral doping crossover along with the increase of proton concentration from = 1 to 2 suggests the formation of exotic charge neutral H-H dimers for higher proton concentration, which is directly visualized at the vacant tetrahedron by scanning transmission electron microscopy and then further supported by first principles calculations. Although the H-H dimers cause no change of the valency of Co ions, they result in clear enhancement of electronic bandgap and suppression of magnetization through lattice expansion. These results not only reveal a hydrogen chemical state beyond anion and cation within the complex oxides, but also suggest an effective pathway to design functional materials through tunable ionic evolution.
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http://dx.doi.org/10.1002/advs.201901432DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6794722PMC
October 2019

Manipulate the Electronic and Magnetic States in NiCo O Films through Electric-Field-Induced Protonation at Elevated Temperature.

Adv Mater 2019 Apr 27;31(16):e1900458. Epub 2019 Feb 27.

State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, China.

Ionic-liquid-gating- (ILG-) induced proton evolution has emerged as a novel strategy to realize electron doping and manipulate the electronic and magnetic ground states in complex oxides. While the study of a wide range of systems (e.g., SrCoO , VO , WO , etc.) has demonstrated important opportunities to incorporate protons through ILG, protonation remains a big challenge for many others. Furthermore, the mechanism of proton intercalation from the ionic liquid/solid interface to whole film has not yet been revealed. Here, with a model system of inverse spinel NiCo O , an increase in system temperature during ILG forms a single but effective method to efficiently achieve protonation. Moreover, the ILG induces a novel phase transformation in NiCo O from ferrimagnetic metallic into antiferromagnetic insulating with protonation at elevated temperatures. This study shows that environmental temperature is an efficient tuning knob to manipulate ILG-induced ionic evolution.
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http://dx.doi.org/10.1002/adma.201900458DOI Listing
April 2019

Publisher Correction: Electric-field control of ferromagnetism through oxygen ion gating.

Nat Commun 2018 02 5;9(1):580. Epub 2018 Feb 5.

State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, 100084, Beijing, China.

In the original version of this Article, Figs. 4c and 4d contained incorrectly sized error bars. This has now been corrected in both the PDF and HTML versions of the Article.
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http://dx.doi.org/10.1038/s41467-018-02960-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5799163PMC
February 2018

Electric-field control of ferromagnetism through oxygen ion gating.

Nat Commun 2017 12 18;8(1):2156. Epub 2017 Dec 18.

State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, 100084, Beijing, China.

Electric-field-driven oxygen ion evolution in the metal/oxide heterostructures emerges as an effective approach to achieve the electric-field control of ferromagnetism. However, the involved redox reaction of the metal layer typically requires extended operation time and elevated temperature condition, which greatly hinders its practical applications. Here, we achieve reversible sub-millisecond and room-temperature electric-field control of ferromagnetism in the Co layer of a Co/SrCoO system accompanied by bipolar resistance switching. In contrast to the previously reported redox reaction scenario, the oxygen ion evolution occurs only within the SrCoO layer, which serves as an oxygen ion gating layer, leading to modulation of the interfacial oxygen stoichiometry and magnetic state. This work identifies a simple and effective pathway to realize the electric-field control of ferromagnetism at room temperature, and may lead to applications that take advantage of both the resistance switching and magnetoelectric coupling.
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http://dx.doi.org/10.1038/s41467-017-02359-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5735161PMC
December 2017

Electric-Field-Controlled Phase Transformation in WO Thin Films through Hydrogen Evolution.

Adv Mater 2017 Dec 23;29(46). Epub 2017 Oct 23.

State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, China.

Field-effect transistors with ionic-liquid gating (ILG) have been widely employed and have led to numerous intriguing phenomena in the last decade, due to the associated excellent carrier-density tunability. However, the role of the electrochemical effect during ILG has become a heavily debated topic recently. Herein, using ILG, a field-induced insulator-to-metal transition is achieved in WO thin films with the emergence of structural transformations of the whole films. The subsequent secondary-ion mass spectrometry study provides solid evidence that electrochemically driven hydrogen evolution dominates the discovered electrical and structural transformation through surface absorption and bulk intercalation.
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http://dx.doi.org/10.1002/adma.201703628DOI Listing
December 2017

Electric-field control of tri-state phase transformation with a selective dual-ion switch.

Nature 2017 06 31;546(7656):124-128. Epub 2017 May 31.

State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China.

Materials can be transformed from one crystalline phase to another by using an electric field to control ion transfer, in a process that can be harnessed in applications such as batteries, smart windows and fuel cells. Increasing the number of transferrable ion species and of accessible crystalline phases could in principle greatly enrich material functionality. However, studies have so far focused mainly on the evolution and control of single ionic species (for example, oxygen, hydrogen or lithium ions). Here we describe the reversible and non-volatile electric-field control of dual-ion (oxygen and hydrogen) phase transformations, with associated electrochromic and magnetoelectric effects. We show that controlling the insertion and extraction of oxygen and hydrogen ions independently of each other can direct reversible phase transformations among three different material phases: the perovskite SrCoO (ref. 12), the brownmillerite SrCoO (ref. 13), and a hitherto-unexplored phase, HSrCoO. By analysing the distinct optical absorption properties of these phases, we demonstrate selective manipulation of spectral transparency in the visible-light and infrared regions, revealing a dual-band electrochromic effect that could see application in smart windows. Moreover, the starkly different magnetic and electric properties of the three phases-HSrCoO is a weakly ferromagnetic insulator, SrCoO is a ferromagnetic metal, and SrCoO is an antiferromagnetic insulator-enable an unusual form of magnetoelectric coupling, allowing electric-field control of three different magnetic ground states. These findings open up opportunities for the electric-field control of multistate phase transformations with rich functionalities.
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http://dx.doi.org/10.1038/nature22389DOI Listing
June 2017

Postoperative Evaluation of Reduction Loss in Proximal Humeral Fractures: A Comparison of Plain Radiographs and Computed Tomography.

Orthop Surg 2017 May 30;9(2):167-173. Epub 2017 May 30.

Department of Orthopaedic Trauma, East Hospital, Tongji University School of Medicine, Shanghai, China.

Objective: To compare postoperative CT images with plain radiographs for measuring prognostic factors of reduction loss of fractures of the proximal part of the humerus.

Methods: A total of 65 patients who sustained fractures of the proximal humerus treated with locking plates from June 2012 to October 2015 were retrospectively analyzed. There were 24 men and 41 women, with a mean age of 60.0 years (range, 22-76 years). According to the Neer classification system of proximal humeral fracture, there were 26 two-part, 27 three-part and 12 four-part fractures of the proximal part of the humerus, and all fractures were treated with open reduction and internal fixation (ORIF) using locked plating. All postoperative CT images and plain radiographs of the patients were obtained. Prognostic factors of the reduction loss were the change of neck shaft angle (NSA) and the change of humeral head height (HHH). The change of NSA and HHH were evaluated by the difference between postoperative initial and final follow-up measurement. Reduction loss was defined as the change ≥10° for NSA or ≥5 mm for HHH. The NSA and HHH were measured using plain radiographs and 3-D CT images, both initially and at final follow-up. The paired t-test was used for comparison of NSA, change of NSA, HHH, and change of HHH between two image modalities. The differences between two image modalities in the assessment of reduction loss were examined using the χ -test (McNemar test). Intraclass correlation coefficients (ICC) were used to assess the intra-observer and inter-observer reliability.

Results: 3-D CT images (ICC range, 0.834-0.967) were more reliable in all parameters when compared with plain radiographs (ICC range, 0.598-0.915). Significant differences were found between the two image modalities in all parameters (plain radiographs: initial NSA = 133.6° ± 3.8°, final NSA = 130.0° ± 1.9°, initial HHH = 17.9 ± 0.9 mm, final HHH = 15.8 ± 1.5 mm; 3-D CT: initial NSA = 131.4° ± 3.4°, final NSA = 128.8° ± 1.7°, initial HHH = 16.8 ± 1.2 mm, final HHH = 14.5 ± 1.1 mm; all P < 0.05). In the assessment of reduction loss, the percentage was 16.9% (11/65) for the plain radiographs and 7.7% (5/65) for the 3-D CT scans (P < 0.05). For the 5 patients with reduction loss, which were observed by two imaging modalities, the mean Constant-Murley score was 61.0 ± 1.6. The patients with reduction loss, observed only in plain radiographs but not CT images, had good shoulder function (Constant-Murley score: 82.7 ± 1.0).

Conclusions: Our data reveal that 3-D CT images are more reliable than plain radiographs in the assessment of the prognostic factors of reduction loss of fractures of the proximal part of the humerus with treatment of locking plates; this reliable CT technique can serve as an effective guideline for the subsequent clinical management of patients.
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http://dx.doi.org/10.1111/os.12332DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6584099PMC
May 2017

Heteroepitaxy of FeO/Muscovite: A New Perspective for Flexible Spintronics.

ACS Appl Mater Interfaces 2016 Dec 1;8(49):33794-33801. Epub 2016 Dec 1.

Department of Materials Science and Engineering, National Chiao Tung University , Hsinchu 30010, Taiwan.

Spintronics has captured a lot of attention since it was proposed. It has been triggering numerous research groups to make their efforts on pursuing spin-related electronic devices. Recently, flexible and wearable devices are in a high demand due to their outstanding potential in practical applications. In order to introduce spintronics into the realm of flexible devices, we demonstrate that it is feasible to grow epitaxial FeO film, a promising candidate for realizing spintronic devices based on tunneling magnetoresistance, on flexible muscovite. In this study, the heteroepitaxy of FeO/muscovite is characterized by X-ray diffraction, high-resolution transmission electron microscopy, and Raman spectroscopy. The chemical composition and magnetic feature are investigated by a combination of X-ray photoelectron spectroscopy and X-ray magnetic circular dichroism. The electrical and magnetic properties are examined to show the preservation of the primitive properties of FeO. Furthermore, various bending tests are performed to show the tunability of functionalities and to confirm that the heterostructures retain the physical properties under repeated cycles. These results illustrate that the FeO/muscovite heterostructure can be a potential candidate for the applications in flexible spintronics.
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http://dx.doi.org/10.1021/acsami.6b11610DOI Listing
December 2016

Electronic Structure and Ferromagnetism Modulation in Cu/Cu2O Interface: Impact of Interfacial Cu Vacancy and Its Diffusion.

Sci Rep 2015 Oct 19;5:15191. Epub 2015 Oct 19.

Department of Electronics and Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, Nankai University, Tianjin, 300071, China.

Cu/Cu2O composite structures have been discovered to show sizable ferromagnetism (FM) with the potential applications in spintronic devices. To date, there is no consensus on the FM origin in Cu/Cu2O systems. Here, first principles calculations are performed on the interface structure to explore the microscopic mechanism of the FM. It is found that only the Cu vacancy (V(Cu)) adjacent to the outermost Cu2O layer induces a considerable magnetic moment, mostly contributed by 2p orbitals of the nearest-neighbor oxygen atom (O(NN)) with two dangling bonds and 3d orbitals of the Cu atoms bonding with the O(NN). Meanwhile, the charge transfer from Cu to Cu2O creates higher density of states at the Fermi level and subsequently leads to the spontaneous FM. Furthermore, the FM could be modulated by the amount of interfacial V(Cu), governed by the interfacial Cu diffusion with a moderate energy barrier (~1.2 eV). These findings provide insights into the FM mechanism and tuning the FM via interfacial cation diffusion in the Cu/Cu2O contact.
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http://dx.doi.org/10.1038/srep15191DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4609911PMC
October 2015

GaN as an interfacial passivation layer: tuning band offset and removing fermi level pinning for III-V MOS devices.

ACS Appl Mater Interfaces 2015 Mar 25;7(9):5141-9. Epub 2015 Feb 25.

College of Electronic Information and Optical Engineering, Nankai University , 300071 Tianjin, P. R. China.

The use of an interfacial passivation layer is one important strategy for achieving a high quality interface between high-k and III-V materials integrated into high-mobility metal-oxide-semiconductor field-effect transistor (MOSFET) devices. Here, we propose gallium nitride (GaN) as the interfacial layer between III-V materials and hafnium oxide (HfO2). Utilizing first-principles calculations, we explore the structural and electronic properties of the GaN/HfO2 interface with respect to the interfacial oxygen contents. In the O-rich condition, an O8 interface (eight oxygen atoms at the interface, corresponding to 100% oxygen concentration) displays the most stability. By reducing the interfacial O concentration from 100 to 25%, we find that the interface formation energy increases; when sublayer oxygen vacancies exist, the interface becomes even less stable compared with O8. The band offset is also observed to be highly dependent on the interfacial oxygen concentration. Further analysis of the electronic structure shows that no interface states are present at the O8 interface. These findings indicate that the O8 interface serves as a promising candidate for high quality III-V MOS devices. Moreover, interfacial states are present when such interfacial oxygen is partially removed. The interface states, leading to Fermi level pinning, originate from unsaturated interfacial Ga atoms.
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http://dx.doi.org/10.1021/am507287fDOI Listing
March 2015

Expression of human DNA mismatch-repair protein, hMSH2, in patients with oral lichen planus.

Exp Ther Med 2015 Jan 6;9(1):203-206. Epub 2014 Nov 6.

Oral Surgery Department, Central Hospital of Cangzhou, Cangzhou, Hebei 061000, P.R. China.

hMSH2 is one of the human DNA mismatch repair genes that plays an important role in reducing mutations and maintaining genomic stability. The aim of the present study was to detect the expression and significance of hMSH2 protein in patients with oral lichen planus (OLP). The expression levels of hMSH2 in the OLP group (n=51) and control group with normal oral mucosa (NM; n=40) were detected using an immunohistochemical method and subsequently assessed. The positive rate of hMSH2 expression in the OLP group was 52.94%, while the rate was 80% in the control group, exhibiting a statistically significant difference (χ=7.1993; P<0.05). However, the expression of hMSH2 in the OLP tissues was not shown to significantly correlate with the patient gender, age and type of OLP (P>0.05). In conclusion, the protein expression levels of hMSH2 in the OLP tissues were significantly reduced as compared with that in the NM tissues, indicating that hMSH2 plays a role in the development of OLP. Therefore, hMSH2 may be used as a biomarker for evaluating the cancer risk of patients with OLP.
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http://dx.doi.org/10.3892/etm.2014.2053DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4247292PMC
January 2015
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