Physical Chemistry Commons^™

Rutile Tio2 Nanosheet Arrays Planted On Magnetron Sputtered Ti Metal Layers For Efficient Perovskite Solar Cells, Nang Zhang, Meidan Ye, Xiaoru Wen, Changjian Lin

Journal of Electrochemistry

In this work, vertical rutile titanium oxide (TiO₂) nanosheet arrays (NSAs) were firstly hydrothermally grown on the top of thin titanium (Ti) metal layers which were loaded on fluorine doped tin oxide (FTO) substrates by the DF magnetron sputtering deposition method. After an annealing post-treatment, the Ti metal layers were transformed into the compact TiO₂ layers with a strong connection between the rutile TiO₂ NSAs and the FTO substrates. For comparison, the rutile TiO₂ NSAs were similarly planted over two compact TiO₂ layers fabricated through atomic layer deposition (ALD) and spin coating (SC) methods, …

Electrodeposition Of Ruo2 Layers On Tio2 Nanotube Array Toward Co2 Electroreduction, Bei Jiang, Lina Zhang, Xianxian Qin, Wenbin Cai

Journal of Electrochemistry

RuO₂/TiO₂ composite materials have multitude of electrocatalytic applications including but not limited to CO₂ reduction reaction (CO₂RR). RuO₂/TiO₂ electrodes were previously prepared by repetitive coating and thermal decomposition (TD) of a Ru(III) precursor solution on Ti substrate. In this work, electrochemical potential cycling is applied to deposit amorphous RuO₂ (α-RuO₂) layers onto TiO₂ nanotube array (TNA) (RuO₂^CV/TNA) preformed on Ti foil. SEM, GIXRD, and voltammetry are applied to characterize the structures of the resulting RuO₂^CV/TNA. Ru loading on the RuO_{2 …}

Oxidation Of Substituted Catechols At The Air-Water Interface: Production Of Carboxylic Acids, Quinones, And Polyphenols, Elizabeth A. Pillar, Marcelo I. Guzman

Chemistry Faculty Publications

Anthropogenic activities contribute benzene, toluene, and anisole to the environment, which in the atmosphere are converted into the respective phenols, cresols, and methoxyphenols by fast gas-phase reaction with hydroxyl radicals (HO(•)). Further processing of the latter species by HO(•) decreases their vapor pressure as a second hydroxyl group is incorporated to accelerate their oxidative aging at interfaces and in aqueous particles. This work shows how catechol, pyrogallol, 3-methylcatechol, 4-methylcatechol, and 3-methoxycatechol (all proxies for oxygenated aromatics derived from benzene, toluene, and anisole) react at the air-water interface with increasing O3(g) during τc ≈ 1 μs contact time and contrasts their …

Environmentally Friendly Synthesis Of Transition Metalorganic Hybrid Nanocomposites, Aubrey N. Penn

Masters Theses & Specialist Projects

Research on metal nanoparticles (MNPs) synthesis and their applications for optoelectronic devices has been a recent interest in the fields of nanoscience and nanotechnology Photovoltaics are one of such systems in which MNPs have shown to be quite useful, due to unique physical, optical, magnetic, and electronic properties, including the metal nanoparticles synthesized in this research.

Owing to the challenges with the most common physical and chemical methods of preparing MNPs, including the use of high temperatures, toxic reducing agents, and environmentally hazardous organic solvents, there is a critical need for a benign synthesis procedure for MNPs. In this work, …

Performance Of Piperidine Ionic Liquid Based Mixed Electrolyte In Li/Licoo2 Cell, Hu Cheng, Xiao-Yan Nie, Ye-Dan Shen

Journal of Electrochemistry

The N-methyl-N-ethyl (propyl, butyl) piperidinium bis (trifluo romethanesulfonyl) imide (PP12(3,4)TFSI) ionic liquids were prepared, and their influences on the performances of Li/LiCoO₂ cells were investigated. The electrochemical performance and thermostability of ionic liquids based mixed electrolytes were characterized by electrochemical methods and thermogravimetric analysis. The results showed that the piperidine ionic liquids could improve the thermostability of organic electrolyte, and the size of their side chain had played an important role on the electrochemical performance of Li/LiCoO₂ cell. The Li/LiCoO₂ cell used the electrolyte mixed with PP13TFSI exhibited the best electrochemical performance among the three ionic liquids. …

The Problem Of The Anode Electrolyte In H-Type Electrolytic Cell For Electrochemical Reduction Of Carbon Dioxide, Rui Zhang, Wei-Xin Lv, Li-Xu Lei

Journal of Electrochemistry

Electrochemical reduction of carbon dioxide (CO₂) was studied in the H-type electrolytic cell. It was found that the voltage between the cathode and the anode would increase during the long time electrolysis process, for this reason the electrolytic process would be unsustainable. After the experimental investigations carried out by constant potential electrolysis, constant current electrolysis, pH test and KHCO₃ concentration analysis of anode electrolyte before and after the electrolysis, the increase in cell voltage might be caused by the following process: H⁺, that was generated from the anodic oxygen evolution reaction, reacted with HCO_{3 …}

Effects Of Flame Retardant On The Rate Capability And Safety Performances Of The Soft-Package 5ah Lithium Ion Battery, Yan-Zhuo Lv, Xiao-He Wang, Yi-Ming Qin, Zhen-Bo Wang, Ke Ke

Journal of Electrochemistry

The 5 Ah soft packed lithium ion batteries with LiNi _0.4Co_0.2Mn_0.4 O₂ as the positive electrode material and the organic electrolytes with different amounts of fire retardants as the electrolyte solution were prepared. The effects of the fire retardant amount (5 %,10 %,20 %) of the fire retardants on the rate performances, short-circuit characteristics and overcharged behaviors of the 5 Ah soft packed lithium ion battery were investigated by electrochemical methods. The results indicated that the best rate performances were obtained by adding 5 vol.% of the fire retardants in the electrolyte solution when the …

Application Of Composite Ionic Liquid In Electro-Oxidation Activation Of A C-H Bond, Zi-Ying Chen, Qian-Qian Wu, Jian-Qing Zhang, Ying-Hong Zhu, Chun-An Ma

Journal of Electrochemistry

In this paper, the ionic liquid/carbon nanotube composite material was prepared through modifying the ionic liquid 1-ethyl-3-methylimidazolium acetate to multi-walled carbon nanotubes. The electro-oxidation properties of p-methoxy toluene (p-MT) were studied using the composite as an electrolyte. The effects of scanning speed, temperature and substrate concentration were studied by cyclic voltammetry and chronoamperometry. The electrochemical kinetics of p-MT in this system was also studied. The results showed that the electrochemical oxidation of p-MT in the composite electrolyte solution was irreversible. The process was mainly controlled by diffusion, and the diffusion coefficient (D) was 7.69×10-10 cm²·s^-1. Increasing …

Electrochemical Nucleation Of Invar Alloy On Glassy Carbon Electrode, Xian-Jie Huang, Hui Yan, Shuai-Shuai Huang, Fang-Zu Yang, Zhong-Qun Tian, Shao-Min Zhou

Journal of Electrochemistry

The linear sweep voltammetry, cyclic voltammetry and potential step methods were used to study the electrodeposition mechanism of Invar nickel-iron alloy (the mass fraction of nickel was 32~36%) on glassy carbon electrode surface in the weak acidic bath. The results demonstrate that the electrodeposition is was a diffusion controlled irreversible electrode process in this system. The Scharifker-Hill (SH) theory theoritic model (SH) were was used employed to fitting the experimental data and the result shows that the codeposition of Invar alloy on glassy carbon electrode surface conformed to the diffusion controlled three-dimensional instantaneous nucleation mechanism. The kinetic parameters were obtained …

Electrochemical Synthesis Of Porous Polyaniline Electrodes Using Hkust-1 As A Template And Their Electrochemical Supercapacitor Property, Qiong Luan, Chun-Feng Xue, Hong-Ye Zhu, Fu-Juan Yang, Xu-Li Ma, Xiao-Gang Hao

Journal of Electrochemistry

Excellent electrode plays vital important role in the performance of supercapacitors. Polyaniline (PANI) with good conductivity is often used to prepare electrode. However, its available surface is limited and results in a poor supercapacitance in many cases. It is desirable to fabricate an electrode containing electroactive PANI with high surface area deriving from its porous structure. Here, the metal-organic framework (MOF) material with high surface area was selected as a hard template for synthesizing porous PANI. Microporous PANI composite electrodes (Micro-PANI/CC) were fabricated by depositing aniline on to carbon cloth (CC) pre-coated with MOF material of HKUST-1 using a unipolar …

Sn-Doped Α-Fe2O3 Photocatalyst Containing Oxygen Vacancy For Water-Splitting, Zu-Hua Wang, Dong-Fang Niu, Hui-Cheng Li, Rong-Bin Du, Heng Xu, Xin-Sheng Zhang

Journal of Electrochemistry

The α-Fe₂O₃ nanoparticles containing oxygen vacancies were synthesized in atmospheric N₂ by dip-dropping method without a high vacuum employed before annealing. The influences of annealing atmosphere and Sn-doping on the photocatalytic performance of α-Fe₂O₃ nanoparticles were studied by annealing the photocatalyst in N₂ or air and adding SnCl₄ to the precursor directly. The results showed that the current density of Sn-doping α-Fe₂O₃ annealed in N₂ at 550 °C and 1.23 V (vs. RHE) was 35 times greater than that of pristine α-Fe₂O₃ annealed in …

Preparation And Electrochemical Properties Of Attapulgite-Supported Nitrogen-Doped Carbon@Nico2O4 Composites For Supercapacitors, Hui Wan, Zong-Rong Ying, Xin-Dong Liu, Jian-Jian Lu, Wen-Wen Zhang

Journal of Electrochemistry

In this work, the attapulgite-supported nitrogen-doped carbon (ANC) was prepared by in-situ chemically polymerizing polyaniline coating upon attapulgite, followed by high temperature heat treatment, and then NiCo₂O₄was reacted onto the surface of ANC by a combination of hydrothermal reaction and calcination to synthesize ANC@NiCo₂O₄ composites. The chemical composition and morphology of the samples were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N₂ adsorption/desorption. The electrochemical properties were evaluated by means of constant current charge discharge (GCD) and cyclic voltammetry (CV). …

Preparations Of Mno2 Reference Electrodes For Corrosion Monitoring Of Reinforced Concrete, Li Yang, Bing Xu, Hai Wang, Ze-Hua Dong

Journal of Electrochemistry

In this work, the solid reference electrode was assemblied by using the electrochemically synthesized manganese dioxide (MnO₂) (EMD) powder, gel electrolyte and thin mortar layer for the durability evaluation of concrete. The EMD reference electrode exhibited higher potential stability (< 10 mV drift) than the chemically synthesied MnO₂ (CMD) based on half year potential tests in the saturated Ca(OH)₂ solution and hardened mortar. In addition, the EMD electrode was almost insensitive to the presences of chloride ion and corrosion inhibitor. Electrochemical impedance and polarization curves indicate that the EMD electrode had lower charge transfer resistance,higher exchange current density and lower temperature coefficient than the …

Aligning Electronic Energy Levels On The Anatase Tio2(101) Surface, Jun-Jie Zhao, Jun Cheng

Journal of Electrochemistry

As one of the most commonly-used materials for photocatalysis and solar energy conversion, titanium dioxide (TiO₂) has been extensively studied for more than 40 years. Its photoelectrochemical activity crucially depends on the band positions at the interface. In this work, the valence band maximum (VBM) and conduction band minimum (CBM) of a model TiO₂ surface are computed using the standard work function method at the level of Perdew-Burke-Ernzerhof (PBE) density functional, which are then converted to the scale of the standard hydrogen electrode (SHE) by subtracting the absolute SHE potential. Comparing with the rutile TiO₂(110) …

Effect Of Pressure On Ion Selectivity In Biomimetic Nanopores With Ph-Tunable Polyelectrolyte Brushes, Hui-Xia Shan, Zhen-Ping Zeng, Li-Xian Ye, Feng Shu

Journal of Electrochemistry

Biomimetic ionic channels of synthetic nanopores functionalized with pH-tunable polyelectrolyte (PE) brushes have significant application potentials for active transport control of ions, fluids, and bioparticles on the nanoscale. Ion selectivity is an important phenomenon of ion transport in nanofluidic devices, which has great theoretical significance and practical values. We propose a pressure control scheme to control the ion selectivity in biomimetic nano-systems with pH-tunable PE brushes. Effects of the solution properties (i.e., pH and background salt concentration), the applied voltage and pressure on ion selectivity are comprehensively investigated. The results show that ion selectivity is sensitive to pressure. Unlike the …

An Investigation In The Performance Of Lithium Sulfur Battery With A Tic Coated Separator, Jian-Hua Fang, Yong Cao, Mao-Ping Yang, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

To improve the specific capacity and cycle stability of lithium-sulfur (Li-S) battery, a TiC/Celgard coating separator was developed and its performance in Li-S battery was investigated. The electrochemical test results confirmed that the TiC coating layer could significantly increase the capacity and cycle stability. At a high rate of 2C, it still delivered the capacity of 650 mAh·g^-1. At 0.5C, the specific capacity was maintained at 841.3 mAh·g^-1 after 100 cycles.

Direct Electrochemistry Of Glucose Oxidase Based On Ws2 Quantum Dots And Its Biosensing Application, Chen-Lu Li, Hua-Ping Peng, Zhong-Nan Huang, Yi-Lun Sheng, Pei-Wen Wu, Xin-Hua Lin

Journal of Electrochemistry

In this study, a novel electrochemical glucose biosensor has been developed by immobilizing glucose oxidase (GOx) on tungsten disulfide quantum dots (WS₂ QDs) on the surface of glassy carbon electrode (GCE). Transmission electron microscopy, UV-vis spectroscopy and cyclic voltammetry were employed to characterize the morphology, structure, and electrochemical behaviors of the as-prepared WS₂ QDs and the biofilm modified electrode. The results suggested that the WS₂ QDs could accelerate the electron transfer between the electrode and the immobilized enzyme, which enabled the direct electrochemistry of GOx without any electron mediator. Besides, the immobilized GOx in WS₂ QDsfilm …

Application Of Adamantane Schiff Base Nickel Complexes/Graphene Oxide/Glassy Carbon Modified Electrode In Detection Of Carmine, Peng Guo, Zheng Liu, Hai-Ying Li, Li-Ming Ma

Journal of Electrochemistry

The Schiff base nickel complexes/graphene oxide/glassy carbon electrodes were prepared by embedded method and electrodeposition on which were used to quantitatively detect the contents of carmine. Cyclic voltammetry, chronoamperometry, scanning electron microscopy (SEM) and other methods were employed to characterize properties and morphologies of the modified electrodes. The results show that the adamantane double Schiff base nickel complexes/graphene oxide/glassy carbon electrode had high electric catalytic activity toward carmine oxidation reaction, and might provide an easy and quick way to detect carmine content with good reproducibility.

Nitrate Radicals And Biogenic Volatile Organic Compounds: Oxidation, Mechanisms And Organic Aerosol, Nga Lee Ng, Steven S. Brown, Alexander T. Archibald, Elliot Atlas, Ronald C. Cohen, John N. Crowley, Douglas A. Day, Neil M. Donahue, Juliane L. Fry, Hendrik Fuchs, Robert J. Griffin, Marcelo I. Guzman, Hartmut Hermann, Alma Hodzic, Yoshiteru Iinuma, José L. Jimenez, Astrid Kiendler-Scharr, Ben H. Lee, Deborah J. Luecken, Jingqiu Mao, Robert Mclaren, Anke Mutzel, Hans D. Osthoff, Bin Ouyang, Benedicte Picquet-Varrault, Ulrich Platt, Havala O. T. Pye, Yinon Rudich, Rebecca H. Schwantes, Manabu Shiraiwa, Jochen Stutz, Joel A. Thornton, Andreas Tilgner, Brent J. Williams, Rahul A. Zaveri

Chemistry Faculty Publications

Oxidation of biogenic volatile organic compounds (BVOC) by the nitrate radical (NO₃) represents one of the important interactions between anthropogenic emissions related to combustion and natural emissions from the biosphere. This interaction has been recognized for more than 3 decades, during which time a large body of research has emerged from laboratory, field, and modeling studies. NO₃-BVOC reactions influence air quality, climate and visibility through regional and global budgets for reactive nitrogen (particularly organic nitrates), ozone, and organic aerosol. Despite its long history of research and the significance of this topic in atmospheric chemistry, a number …

Charge Transport In Electronic-Ionic Composites, Long Zhang

Theses and Dissertations--Chemical and Materials Engineering

The goal of this thesis is to generate fundamental understandings of charge transport behaviors of composites consisting of garnet structured Al substituted Li₇La₃Zr₂O₁₂ (LLZO) electrolyte and LiCoO₂ electrode. In order to take full advantage of all-solid-state batteries, bulk type composite electrodes should be introduced to increase energy and power density. However, the charge utilization of bulk type composite electrodes is quite low. Understanding ionic conduction behavior is, therefore, important for improving the performance of all-solid-state batteries, because ion conduction within solids depends on effective pathways. Electronic conductivity can be easily compensated by …

A Study On The Oxidation Of Hydrogen Peroxide At Au(111) And Au(100) Electrodes, Yong-Li Zheng, Jie Wei, Yan-Xia Chen

Journal of Electrochemistry

The oxidation reactions of hydrogen peroxide (H₂O₂) at Au(111) and Au(100) electrodes in 0.1 mol·L^-1 HClO₄ were investigated by using rotating disk electrode system. It was found that H₂O₂ could be readily oxidized to O₂ at both Au(100) and Au(111) surfaces with the onset potential close to its equilibrium potential. In contrast, the onset overpotential for H₂O₂ reduction was above 0.4 V, while the onset overpotential for H₂O₂ oxidation at Au(100) was ca. 0.1 V more negative than that at Au(111), this is probably …

Lithium-Sulfur (Selenium) Batteries: Interface Issues And Solving Strategies, Nian-Wu Li, Ya-Xia Yin, Yu-Guo Guo

Journal of Electrochemistry

The stable interface is still a challenge for lithium-sulfur (selenium) batteries because of the low conductivity of sulfur (selenium), dissolution of polysulfide (polyselenide), volume expansion of sulfur (selenium), and lithium dendrite growth. This review describers some recent developments in lithium-sulfur (selenium) batteries and highlights our efforts in this field. The possible strategies for building stable interface in the lithium-sulfur (selenium) batteries including nano-restriction effect, chemical bonding, interface adsorption, surface coating, electrolyte optimization, and Lithium anode treatment have been discussed.

Stm Investigation Of Oxygen Reduction Reaction On Solid Interface In Fuel Cell, Zhen-Feng Cai, Bing Sun, Wen-Jie Jiang, Ting Chen, Dong Wang, Li-Jun Wan

Journal of Electrochemistry

An electrocatalyst for oxygen reduction reaction (ORR) is an important component for fuel cells. An investigation at interfacial electrochemical reactions toward ORR at a molecular scale benefits mechanistic understanding as well as rational design of catalysts. Scanning tunneling microscopy (STM) has been proven to be a powerful tool to monitor chemical reactions and to provide in-situ information about the interfacial electrochemical reactions at a molecular level. This review summarizes the recent STM studies in monitoring the interface processes such as morphological changes, molecular changes, reaction intermediates, and oxidation products. The prospects of future development in this field are outlined.

Electrochemical Behaviors And Determinations Of Terbutaline Sulfate At Poly Eriochrome Black T Modified Electrode, Yan-Jie Zheng, Hong Yao, Shao-Huang Weng, Hua-Ping Peng, Shi-Wen Gong, Li Huang, Qiang Dai, Xin-Hua Lin

Journal of Electrochemistry

The poly eriochrome black T modified electrode was prepared by electropolymerization. This modified electrode was characterized by scanning electron microscopy(SEM), electrochemical impedance spectroscopy(EIS) and cyclic voltammetry (CV). The electrochemical behaviors of terbutaline sulfate were studied by CV, while the recoveries were measured by differential pulse voltammetry (DPV). The modified electrode shows excellent electrocatalytic characteristics for terbutaline sulfate. In pH 7.0 phosphate buffer solution, the oxidation peak currents obtained by DPV were linear to the terbutaline sulfate concentrations over the range of 1.2x10^-7~2.0x10^-6 mol•L^-1. The detection limit was estimated to be 1.5x10^-8  mol•L^-1 and …

Chitosan/Nonahydrate Gel Derived Fe-N-Doped Porous Carbon Sheet As High-Efficient Orr Electrocatalyst, Fan-Lu Meng, Xin-Bo Zhang, Jun-Min Yan

Journal of Electrochemistry

The chitosan/nonahydrate gel was used as a precursor to realize the uniform mixture of N-polymer and metal salt. After lyophilization treatment, the gel went through heat treatment and acid etch. Accordingly, the Fe-N-doped porous carbon sheet with homogenous composition and microstructure was prepared. Compared with the commercial Pt/C catalyst, the Fe-N-doped porous carbon sheet exhibited more positive onset potential and half-wave potential, higher current density, and especially, excellent durability. The power density of 318 mW·cm^-2 was obtained in alkaline fuel cell with the Fe-N-doped porous carbon sheet as a cathode catalyst, which is higher than 267 mW·cm^-2 with …

Synthesis Of Ultrathin Co3O4 Nanoflakes Film Material For Electrochemical Sensing, Hui-Juan Wang

Journal of Electrochemistry

Ultrathin cobalt oxide (Co₃O₄) nanoflakes film material was synthesized by using an electro-deposited cobalt layer as a raw material through a simple oxidation method and followed by a heat treatment at 350 ^oC. The physical characterizations of the Co₃O₄ nanoflakes film were performed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM) technologies, and the electrochemical activity was measured by cyclic voltammetry (CV). As a promising material for electrochemical sensing, the as-synthesized ultrathin Co₃O₄ nanoflakes film material exhibited excellent electrochemical activity for H₂O …

Syntheses Of Ag@Pd@Pt Nanoparticles With Tunable Shell Thickness For Electrochemical Oxidation Of Formic Acid, Xiao-Dong Lin, Du-Hong Chen, Zhong-Qun Tian

Journal of Electrochemistry

In an effort to lower cost of a catalyst, the silver (Ag) core with palladium (Pd) layer then platinum (Pt) island (Ag@Pd@Pt) nanoparticles were synthesized and the electrocatalytic activity of Ag@Pd@Pt nanoparticles on formic acid was compared with that of Au@Pd@Pt nanoparticles reported previously. The results showed that the existence of a small amount of Pt could significantly improve the activity of the catalyst. When the surface coverage of Pt approached 0.5 monolayers, the activity of Ag@Pd@Pt nanoparticles reached the maximum. Though the onset potential of the electro-oxidation was slightly more positive (about 50 mV), the overall electrocatalytic activity of …

Investigation On Laser Induced Deposition Of Cu-Based Materials At [Bmim]Bf4/Pt Electrode Interface, Min-Min Xu, Jin-Hua Mei, Jian-Lin Yao, Ren-Ao Gu

Journal of Electrochemistry

By controlling the negative potential, Cu-based materials were deposited at the [BMIm]BF₄/Pt electrode interface under the laser irradiation. The effects of laser power and irradiation time on the yield of deposition products were studied by using different laser powers and different irradiation time. The product yield could be directly determined by the size of deposition point through the observation from the optical microscope. Further mechanism study combined with the formula deduced that the thermal effect of the laser could make the electrode surface temperature rise 110 degrees, which can promote the occurrence of electrodeposition. By SEM characterization, the …

Intrinsic Interfacial Property Between High-Voltage Lini0.5Mn1.5O4 Cathode And Electrolyte, Li Li, Jing-Jing Xu, Shao-Jie Han, Wei Lu, Li-Wei Chen

Journal of Electrochemistry

To obtain high energy density, developing high-voltage cathode materials is an effective approach. The cathode/electrolyte interface stability is the key factor for the cycle performance and safety performance of high-voltage lithium ion batteries. It is, therefore, of significant importance to study the stability of cathode/electrolyte interface. However, many reports have shown that at the cathode/electrolyte interface the cathodes were prepared by coating the mixture of active materials with a conductive additive and a binder on an Al current collector. The introduction of additives will interfere the surface morphology and component analyses, resulting in difficulty to acquire the intrinsic information at …

Hydrogen Evolution Properties On Individual Mos2 Nanosheets, Yu Gao, Juan Zhou, Yu-Wen Liu, Sheng-Li Chen

Journal of Electrochemistry

Molybdenum disulfide (MoS₂) has been acknowledged to play important roles in hydrogen evolution reaction (HER) for hydrogen energy technology. Both computational and experimental results have suggested that the promising catalytic activity of MoS₂ for the HER could be attributed to the sulfur edges of two-dimensional nanosheets, while their basal planes were catalytically inert. In order to verify this conclusion, we prepared single MoS₂ sheet electrodes which were made of individual MoS₂ sheets attached on the self-assembly monolayers (SAM) of SH(CH₂)₁₅COOH at Au ultramicroelectrodes (Au/SAM/MoS₂). The single MoS₂ sheet …