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101. Enabling interfacial stability of LiCoO2 batteries at an ultrahigh cutoff voltage ≥ 4.65 V via a synergetic electrolyte strategy.

Author

Fu, Ang, Xu, Chuanjing, Lin, Jiande, Su, Yu, Zhang, Haitang, Wu, De-Yin, Zhang, Xiaozheng, Xia, Meng, Zhang, Zhongru, Zheng, Jianming, and Yang, Yong

Abstract

Elevating the cutoff charge voltage (≥4.65 V) of LiCoO2 (LCO) arouses a big challenge between the pursuit of high energy density and long cycling life of LCO-based batteries. Herein, 2,3-dimethylmaleic anhydride (DMMA) as a novel electrolyte additive not only serves as a sacrificial agent to construct a robust and stabilized CEI film enriched with inorganic species (LiF, PO2−, etc.) but also removes the trace amounts of H2O in electrolytes and prevents further decomposition of carbonate-based electrolytes and erosion of LCO. Several advanced characterization techniques such as AFM, XPS, HRTEM, and TOF-SIMS combined with theoretical calculations were applied to reveal the functioning mechanism. It was shown that at a cutoff voltage of 4.65 V, LCO cathode retains 81.6% of its initial capacity (215 mA h g−1) after 300 cycles and 70.7% after 500 cycles at 1C in the presence of 1% DMMA. Moreover, fluoroethylene carbonate (FEC), 1,3,6-hexanetricarbonitrile (HTCN) and DMMA-containing electrolytes are able to further enhance the high-voltage stability of LCO. LCO delivers a high capacity retention of 75.9% after 300 cycles at 4.7 V using the upgraded electrolyte. The synergistic strategy of multiple additives paves a new way to promote the durability of LCO at ultrahigh voltages as well as LCO-based batteries with high energy density. [ABSTRACT FROM AUTHOR]

Published
2023
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103. Electrochemical and Plasmonic Photochemical Oxidation Processes of para-Aminothiophenol on a Nanostructured Gold Electrode

Author

Peng, Hui-Yuan, primary, Xiao, Yuan-Hui, additional, Yu, Huan-Huan, additional, Wang, Jia-Zheng, additional, Lin, Jian-De, additional, Devasenathipathy, Rajkumar, additional, Liu, Jia, additional, Zou, Pei-Hang, additional, Zhang, Meng, additional, Zhou, Jian-Zhang, additional, Wu, De-Yin, additional, and Tian, Zhong-Qun, additional

Published
2021
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106. Shell-isolated nanoparticle-enhanced Raman spectroscopy

Author

Li, Jian Feng, Huang, Yi Fan, Ding, Yong, Yang, Zhi Lin, Li, Song Bo, Zhou, Xiao Shun, Fan, Feng Ru, Zhang, Wei, Zhou, Zhi You, Wu, De Yin, Ren, Bin, Wang, Zhong Lin, and Tian, Zhong Qun

Subjects
Structure, Usage, Research, Properties, Nanoparticles -- Properties -- Structure -- Research, Atomic force microscopy -- Usage, Raman spectroscopy -- Usage
Abstract

The invention of TERS led to a breakthrough in the substrate and surface generalities of SERS (18,19). It uses a working mode that separates the probed substance from a Au [...], Surface-enhanced Raman scattering (SERS) is a powerful spectroscopy technique that can provide non-destructive and ultrasensitive characterization down to single molecular level, comparable to single-molecule fluorescence spectroscopy (1-15). However, generally substrates based on metals such as Ag, Au and Cu, either with roughened surfaces or in the form of nanoparticles, are required to realise a substantial SERS effect, and this has severely limited the breadth of practical applications of SERS. A number of approaches have extended the technique to non-traditional substrates (14,16,17), most notably tip-enhanced Raman spectroscopy (TERS) (18-20) where the probed substance (molecule or material surface) can be on a generic substrate and where a nanoscale gold tip above the substrate acts as the Raman signal amplifier. The drawback is that the total Raman scattering signal from the tip area is rather weak, thus limiting TERS studies to molecules with large Raman cross-sections. Here, we report an approach, which we name shell-isolated nanoparticle-enhanced Raman spectroscopy, in which the Raman signal amplification is provided by gold nanoparticles with an ultrathin silica or alumina shell. A monolayer of such nanoparticles is spread as 'smart dust' over the surface that is to be probed. The ultrathin coating keeps the nanoparticles from agglomerating, separates them from direct contact with the probed material and allows the nanoparticles to conform to different contours of substrates. High-quality Raman spectra were obtained on various molecules adsorbed at Pt and Au single-crystal surfaces and from Si surfaces with hydrogen monolayers. These measurements and our studies on yeast cells and citrus fruits with pesticide residues illustrate that our method significantly expands the flexibility of SERS for useful applications in the materials and life sciences, as well as for the inspection of food safety, drugs, explosives and environment pollutants.

Published
2010

112. Theoretical Insight into the Transition-Metal-Embedded Boron Nitride-Doped Graphene Single-Atom Catalysts for Electrochemical Nitrogen Reduction Reaction

Author

Xiao, Yuan-Hui, Ma, Zi-Wei, Wu, Xin-Wei, Chen, Lai-Ke, Sajid, Zubia, Devasenathipathy, Rajkumar, Lin, Jian-De, Wu, De-Yin, and Tian, Zhong-Qun

Abstract

Single-atom catalysts (SACs) have become attractive options for the efficient nitrogen reduction reaction (NRR) because of their unique properties in the activation of nitrogen molecules. As a novel two-dimensional material, boron nitride (BN)-doped graphene has attracted much attention due to its electronic structure, which can be regulated with boron nitride coverage. In the current work, we first screened potential SACs for NRR from various single transition metal atoms embedded in BN-doped graphene (BNC) by using density functional theory (DFT) calculations. Excellent catalytic activity for NRR is demonstrated by the V, Mo, Ru, and Os anchored on the B vacancy and generated SACs, with overpotentials of −0.56, −0.52, −0.60, and −0.61 V vs the standard hydrogen electrode (SHE). Taking advantage of BN-doped graphene electronic structures that can be modified, we further investigated the effect of boron nitride coverage on the SACs’ NRR performance. The electronic structure of the metal center can be altered by controlling the boron nitride coverage, which can further affect the catalytic performance. The potential determining step (PDS) and also the maximal free energy difference vary by modulating the boron nitride coverage. A larger energy range than the hydrogen evolution reaction (HER) is covered by the maximum energy shift between the PDSs, which can reach 0.29 eV. This indicates that by changing the coverage of the BN of the substrate, it is expected to improve the SACs’s catalytic activity and selectivity of NRR. Moreover, it is possible for a pathway to change from one that is adsorption favorable to another one that is thermodynamically favorable of the intermediate NNH. Our results help to clarify the structure–performance correlations and expedite the creation of SACs for ammonia synthesis.

Published
2025
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113. Adsorption, Stretching and Breaking Processes in Single‐Molecule Conductance of para‐Benzenedimethanethiol in Gold Nanogaps: A DFT‐NEGF Theoretical Study

Author

Guan, Si-Yuan, Cai, Zhuan-Yun, Liu, Jia, Pang, Ran, Wu, De-Yin, Ulstrup, Jens, Tian, Zhong-Qun, Guan, Si-Yuan, Cai, Zhuan-Yun, Liu, Jia, Pang, Ran, Wu, De-Yin, Ulstrup, Jens, and Tian, Zhong-Qun

Abstract

Electrical and mechanical properties of gold‐ para ‐benzenedimethanethiol (BDMT)‐gold molecular junctions with different binding configurations have been investigated using density functional theory (DFT) combined with a non‐equilibrium Green’s function (NEGF) approach. We first determined the most stable structure in total electronic energy by geometry optimization of the molecular junction. We then studied how different stretching processes affect the conductance and the stretching forces. Particularly two stretching modes can bring about different conductance behavior. When only a single‐end molecular contact in interfacial configurations at the top and bridge sites is stretched, the molecular conductance first decreases exponentially. This is followed by a flat platform, and finally produced an abrupt conductance drop from the fracture of interfacial chemical bond Au‐Au. In the junction with a double‐end stretching mode, the fracture of Au‐S bond occurs either between the sulfur‐bonded gold atom and the underlying Au surfaces, or at either of the two Au‐S bonds in the double‐end stretching mode at the top‐pyramidal site. The latter interfacial structure consists of a four‐Au‐atom pyramidal structure adsorbed on gold surface, resulting in a sharp conductance increase just before complete fracture. This is closely associated with resonance tunneling of beta spin electrons in the critical breaking state of interfacial Au‐S bonds in gold‐BDMT‐gold molecular junction.

Published
2021

119. An oxygen-blocking oriented multifunctional solid–electrolyte interphase as a protective layer for a lithium metal anode in lithium–oxygen batteries

Author

Lin, Xiao-Dong, primary, Gu, Yu, additional, Shen, Xiao-Ru, additional, Wang, Wei-Wei, additional, Hong, Yu-Hao, additional, Wu, Qi-Hui, additional, Zhou, Zhi-You, additional, Wu, De-Yin, additional, Chang, Jeng-Kuei, additional, Zheng, Ming-Sen, additional, Mao, Bing-Wei, additional, and Dong, Quan-Feng, additional

Published
2021
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121. Correction: An oxygen-blocking oriented multifunctional solid–electrolyte interphase as a protective layer for a lithium metal anode in lithium–oxygen batteries

Author

Lin, Xiao-Dong, primary, Gu, Yu, additional, Shen, Xiao-Ru, additional, Wang, Wei-Wei, additional, Hong, Yu-Hao, additional, Wu, Qi-Hui, additional, Zhou, Zhi-You, additional, Wu, De-Yin, additional, Chang, Jeng-Kuei, additional, Zheng, Ming-Sen, additional, Mao, Bing-Wei, additional, and Dong, Quan-Feng, additional

Published
2021
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126. Electronic Spillover from a Metallic Nanoparticle: Can Simple Electrochemical Electron Transfer Processes Be Catalyzed by Electronic Coupling of a Molecular Scale Gold Nanoparticle Simultaneously to the Redox Molecule and the Electrode?

Author

Shermukhamedov, Shokirbek A., primary, Nazmutdinov, Renat R., additional, Zinkicheva, Tamara T., additional, Bronshtein, Michael D., additional, Zhang, Jingdong, additional, Mao, Bingwei, additional, Tian, Zhongqun, additional, Yan, Jiawei, additional, Wu, De-Yin, additional, and Ulstrup, Jens, additional

Published
2020
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130. Electronic Spillover from a Metallic Nanoparticle:Can Simple Electrochemical Electron Transfer Processes Be Catalyzed by Electronic Coupling of a Molecular Scale Gold Nanoparticle Simultaneously to the Redox Molecule and the Electrode?

Author

Shermukhamedov, Shokirbek A, Nazmutdinov, Renat R, Zinkicheva, Tamara T, Bronshtein, Michael D, Zhang, Jingdong, Mao, Bingwei, Tian, Zhongqun, Yan, Jiawei, Wu, De-Yin, Ulstrup, Jens, Shermukhamedov, Shokirbek A, Nazmutdinov, Renat R, Zinkicheva, Tamara T, Bronshtein, Michael D, Zhang, Jingdong, Mao, Bingwei, Tian, Zhongqun, Yan, Jiawei, Wu, De-Yin, and Ulstrup, Jens

Abstract

Electrochemical electron transfer (ET) of transition metal complexes or redox metalloproteins can be catalyzed by more than an order of magnitude by molecular scale metallic nanoparticles (NPs), often rationalized by concentration enhancement of the redox molecules in the interfacial region, but collective electronic AuNP array effects have also been forwarded. Using DFT combined with molecular electrochemical ET theory we explore here whether a single molecular scale Au nanocluster (AuC) between a Au (111) surface and the molecular redox probe ferrocene/ferricinium (Fc/Fc+) can trigger an ET rate increase. Computational challenges limit us to Au n Cs (n up to 147), which are smaller than most electrocatalytic AuCs studied experimentally. AuC-coating thiols are addressed both as adsorption of two S atoms at the structural Au55 bridge sites and as superexchange of variable-size AuCs via a single six-carbon alkanethiyl bridge. Our results are guiding, but enable comparing many AuC surface details (apex, ridge, face, direct vs superexchange ET) with a planar Au(111) surface. The rate-determining electronic transmission coefficients for ET between Fc/Fc+ and AuC are highly sensitive to subtle AuC electronic features. The transmission coefficients mostly compete poorly with direct Fc/Fc+ ET at the Au(111) surface, but Fc/Fc+ 100 face-bound on Au79 and Au147 and ridge bound on Au19 leads to a 2- or 3-fold rate enhancement, in different distance ranges. Single AuCs can thus indeed cause rate enhancement of simple electrochemical ET, but additional, possibly collective AuNC effects, as well as larger clusters and more complete coating layers, also need to be considered.

Published
2020

131. Dense Crystalline–Amorphous Interfacial Sites for Enhanced Electrocatalytic Oxygen Evolution.

Author

Li, Dan, Qin, Yanyang, Liu, Jia, Zhao, Hongyang, Sun, Zongjie, Chen, Guangbo, Wu, De‐Yin, Su, Yaqiong, Ding, Shujiang, and Xiao, Chunhui

Subjects
HYDROGEN evolution reactions, OXYGEN evolution reactions, PHASE transitions, TRANSITION metals, RAMAN spectroscopy, ELECTRONIC structure
Abstract

The crystalline‐amorphous (c–a) heterostructure is verified as a promising design for oxygen evolution reaction (OER) catalysts due to the concerted advantages of the crystalline and amorphous phase. However, most heterostructures via asynchronous heterophase synthesis suffer from the limited synergistic effect because of the sparse c–a interfaces. Here, a highly efficient and stable OER electrocatalyst with dense c–a interfacial sites is reported by hybridizing crystalline Ag and amorphous NiCoMo oxides (NCMO) on the nickel foam (NF) via synchronous dual‐phase synthetic strategy. In 1 m KOH, the as‐obtained Ag/NCMO/NF catalyst exhibits a low OER overpotential of 243 mV to attain 10 mA cm−2 and a small Tafel slope of 67 mV dec−1. Theoretical calculations indicate that the c–a interface can efficiently modulate the electronic structure of the interfacial sites and lower the OER overpotential. Besides, in situ Raman spectroscopy results demonstrate that the c–a interfacial sites can promote the irreversible phase transition to the metal oxy(hydroxide) active phase, and the dense c–a interfaces can stabilize the active phase during the whole OER process. [ABSTRACT FROM AUTHOR]

Published
2022
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132. Adsorption and Co‐adsorption of Chlorine and Water‐Chlorine Complexes on Au(111) Surfaces: First‐Principles DFT Study.

Author

Xiao, Yuan‐Hui, Liu, Jia, Lin, Jian‐De, Yu, Huan‐Huan, Pang, Ran, Wu, De‐Yin, and Tian, Zhong‐Qun

Subjects
CHLORINE, ADSORPTION (Chemistry), HYDROGEN bonding interactions, DENSITY functional theory, FREQUENCIES of oscillating systems, METALLIC surfaces
Abstract

The adsorption of atomic chlorine (Cl) on perfect Au(111) surfaces has been investigated by employing extensive density functional theory calculations, including the Cl coverage range from 1/9 to 1 monolayer (ML) and the effect of water on the Cl adsorption. The structural, energetic, and electronic properties are calculated and compared with previously reported experimental studies towards adsorption of Cl on metal surfaces. We found that there is a significant difference in energy and electronic structures for adsorption of Cl at the top site, compared with adsorption of Cl on other sites of the Au surface. Surface coverage lower than 1/3 ML is enough for the adsorption of Cl atoms at an fcc hollow site, whereas the Cl adopts a mixed adsorption sites at higher coverage reaching 3/4 ML. The negatively charged Cl− ion increase the work function of the Au(111) surface at all coverage, and the Au−Cl interaction is dominated by a strong coupling between the d‐band of Au and the p state of Cl atoms. The appearance of water molecules makes Cl more stable for adsorbing on the top site of Au (111) through hydrogen bonding interaction, and also promotes interfacial charge transfer between Cl and Au(111). We emphasize here is that the Au−Cl stretching vibrational frequency at the top site is similar to the observed values in the experiment, while the Au−Cl stretching frequency redshifts as the coverage increases for Cl adsorped at the fcc site. The presence of water would cause a significant redshift of the Au−Cl stretching vibrational frequency because of the stretched bond length and the decrease of the covalent bonding component. These changes motivate us to rethink of the Au−Cl vibration frequency and the corresponding interfacial structure. [ABSTRACT FROM AUTHOR]

Published
2021
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137. Adsorption, Chemical Enhancement, and Low-Lying Excited States of p-Methylbenzenethiol on Silver and Gold Nanoparticle Surfaces: A Surface Enhanced Raman Spectroscopy and Density Functional Theory Study

Author

Wang, Rui, primary, Shen, Xiao-Ru, additional, Zhang, Meng, additional, Devasenathipathy, Rajkumar, additional, Pang, Ran, additional, Wu, De-Yin, additional, Zhang, Jingdong, additional, Ulstrup, Jens, additional, and Tian, Zhong-Qun, additional

Published
2019
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147. Surface Plasmon Enhanced Chemical Reactions on Metal Nanostructures

Author

Wu, De-Yin, Devasenathipathy, Rajkumar, and Tian, Zhong-Qun

Subjects
Technology & Engineering / Nanotechnology & Mems
Abstract

Noble metal nanomaterials as plasmonic photocatalysts can strongly absorb visible light and generate localized surface plasmon resonance (SPR), which in turn depends on the size, shape, and surrounding of the plasmonic metal nanomaterials (PMNMs). Remarkably, the high-efficiency conversion of solar energy into chemical energy was expected to be achieved by PMNMs. Therefore, researchers have chosen PMNMs to improve the photocatalytic activity toward targeted molecules. This enhancement can be achieved by the effective separation of photogenerated electrons and holes of the PMNMs in the presence of light. Surface-enhanced Raman spectroscopy (SERS) has been performed for obtaining information about the photochemically transformed surface species at molecular levels. A profound understanding of kinetic mechanisms is needed for the development of novel plasmonic catalysts toward various chemical transformations of targeted molecules. In this chapter, based on the above discussions, the participation of SPR excitation in PMNMs and photocatalysis toward chemical transformations of SERS-active organic molecules such as aromatic amino and nitro compounds based on PMNMs have been discussed in detail through theoretical and experimental studies. Eventually, a summary and the future directions of this study are discussed.

Published
2018

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