bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanoporous Au-Cu-Pt As a Superior Electro-Catalyst for the Methanol Oxidation Reaction
Authors: Xie Yunxiang , Dimitrov Nikolay 
Published: December 2020

Among fuel cells, the direct methanol fuel cell (DMFC) has attracted great attention and has been considered a very promising power source because of the ease of methanol transportation and its high energy density. A major limiting factor hindering DMFC’s commercial application is the poor catalytic performance in the anode (methanol oxidation reaction). The methanol oxidation reaction (MOR) requires (OH-) from water dissociation as an oxygen donor for the reaction; however, the slow water dissociation on Pt limits the rate of MOR. In addition to the sluggish catalytic activity, the other major impediment for Pt catalysts is the generation of carbon monoxide (CO) during the MOR process.In order to improve the catalytic performance of MOR catalysts, a variety of catalyst design strategies have been devised. The interesting way of carrying out the MOR catalytic process is the non-CO pathway which takes place on Pt-Au bimetallic catalysts, thus eliminating CO poisoning. However, the overall activity of Pt-Au alloys in MOR is relatively low, which ultimately limits the application of Pt-Au catalysts.
In this study, a nanoporous (np) Au-Cu-Pt thin-film catalyst with a fine structure and tunable composition is synthesized by using a facile method involving successive electrodeposition and de-alloying. SEM, SEM-EDX and ICP have been used for morphology characterization and composition assessment. Pb under-potential deposition (UPD), H UPD and CO stripping tests have been employed to determine the electrochemical active surface area (ECSA) and to probe the Pt active sites specifically. Also, cyclic voltammetry (CV) tests have been performed to assess the catalytic performance in MOR. Finally, long-term CV and chronoamperometry (constant potential) tests have been used to study and evaluate the durability of accordingly synthesized catalyst for MOR.
The prepared np Au-Cu-(8% in the precursor alloy)Pt catalyst exhibits outstanding mass and specific activity toward the MOR, which is approximately six- and nine-times higher than the activity of a commercial Pt/C(40%) counterpart, respectively. A negative 75 mV onset potential shift upon the MOR anodic scan on the np Au-Cu-(8 %)Pt catalyst in comparison with Pt/C(40%) corroborates its higher catalytic activity. Furthermore, the alloy catalyst demonstrates better durability than the Pt/C(40%) counterpart in a three-hour constant potential test and exhibits full post-factum recovery of its cycling activity. In addition, it retains more than 60% of its original activity after 3000 cycles of an accelerated degradation test.
Reference:
Xie, Y., Li, C., Razek, S.A., Fang, J. and Dimitrov, N., 2020. Synthesis of Nanoporous Au− Cu− Pt Alloy as a Superior Catalyst for the Methanol Oxidation Reaction. ChemElectroChem, 7(2), pp.569-580.
(Keynote) Halide-Based Solid-State Batteries: Electrolyte, Stability, Interface and Electrode
Authors: Sun Xueliang 
Published: December 2020

All-state-state lithium batteries (ASSLBs) have gained worldwide attention because of intrinsic safety and increased energy density. Compared with other types of solid-state electrolytes including oxide-based, polymer-based and sulfide-based electrolytes, recently-developed halide-based solid-state electrolytes (SSEs) have garnered considerable attention for all-solid-state lithium batteries (ASSLBs) due to the high ionic conductivity, high oxidation voltage and good stability toward oxide cathode materials [1]. However, there are still many challenges in halide-based solid-state electrolytes for ASSLBs including controllable and mass-production synthesis, achieving high humidity tolerance and demonstrate high-performance of ASSLBs; in particular, increased understanding of mechanisms during synthesis and tuning their properties of the electrolytes as well as interface with electrode materials[1].
In this talk, (i) I will demonstrate synthesis strategy [2-3], in particular, new and salable water-mediated synthesis method [2]. (ii) I will report a systematic study on the correlations among structural evolution, Li+ migration properties, and humidity stability resulting of the halide-based electrolytes, along with in-situ characterization for understanding of the mechanisms [4], (iii) Full cell battery performance will be optimized [5], and (iv) humidity ability [6]. In the end, energy densities of ASSLBs using different solid-state electrolytes in ASSLBs will be discussed.
References:
1. X. Li, J. Liang, X. Yang, K. Adair, C. Wang, F. Zhao, X. Sun. Progress and Perspectives of Halide-based Lithium Conductors for All-Solid-State Batteries. Energy Environ. Sci., 13, 1429-1461 (2020).
2. X. Li, J. Liang, X. Sun, et al., H2O-Mediated Synthesis of Superionic Halide Solid Electrolyte. Angewandte Chemie International Edition, 58,1-7(2019).
3. X. Li, J. Liang, X. Sun, et al.,. Air-Stable Li3InCl6 Electrolyte with High Voltage Compatibility for All-Solid-State Batteries. Energy Environ. Sci., 12, 2665 - 267 (2019).
4. X. Li, J. Liang, X. Sun, et al.,. Origin of Superionic Halide Solid Electrolytes with High Humidity Tolerance, 2020, J. Am. Chem. Soc. 142, 7012-7022 (2020).
5. C. Wang, X. Li, J. Liang, X. Sun, et al., Eliminating Interfacial Resistance in All-Inorganic Batteries by In-situ Interfacial Growth of Halide-based Electrolyte. Nano Energy, 2020, in press.
X. Li, J. Liang, X. Sun, et al., Origin of Superionic Li3Y1-xInxCl6 Halide Solid Electrolytes with High
6. Humidity Tolerance, Nano Letters, in press, 2020.
High Pressure in-Situ X-Ray CT Measurement of Sulfide Solid Electrolyte for All-Solid-State Lithium Ion Battery
Authors: Kodama Manabu , Ohashi Akinari , Horikawa Naoki , Kawamura Katsuyuki , Hirai Shuichiro 
Published: December 2020

The sulfide solid electrolyte has a high ionic conductivity and is a candidate for use as the solid electrolyte in lithium ion batteries used for electrical vehicles [1]. A previous study showed that high ionic conductivity is achieved with compression of solid electrolyte powder by suppressing the void between the solid electrolyte particles as the structure of the solid electrolyte has a strong correlation with the ionic conductivity. However, this correlation has not been discussed directly.
In this study, the solid electrolyte three dimensional structure is measured with high pressure in-situ X-ray CT measurement and its ionic conductivity measured by EIS to elucidate the correlation between the structure and ionic conductivity. Moreover, three dimensional electromagnetic field numerical simulations based on the Maxwell and Nernst-Prank equations are conducted with the X-ray CT images to build a numerical model of the ionic conduction in a compressed sulfide solid electrolyte. The solid electrolyte used in this experiment is Li6PS5Cl [2].
Figure 1 illustrates the X-ray CT images of the sulfide solid electrolyte with various applied pressures. With a low applied pressure of 10.5 MPa (Fig.1 (a)), solid electrolyte particles exist independently, and there are many voids between them. The ionic conductivity with this structure is 0.35 mS/cm. With the increase in applied pressure to 95.0 MPa, the voids between the solid electrolyte particles disappear as shown in Fig.1 (b). This disappearance is owing to the room temperature sintering with creeping of solid electrolyte with high pressure [3]. The ionic conductivity with this structure is 1.15 mS/cm. The three dimensional electromagnetic numerical results for each X-ray CT image is 0.21 mS/cm and 1.16 mS/cm and these numerical results almost agree with the experimental results. In the numerical simulation, contact resistance, inhomogeneity of the ionic conductivity, and anisotropy of the ionic conductivity are not considered and only the distribution of the solid electrolyte and voids are inputted. Therefore, this numerical result suggests that the contact resistance between solid electrolyte particles can be neglected for numerical simulation of sulfide solid electrolytes.
Acknowledgement
This study is partially supported by the Japan Keirin Autorace Foundation (JKA).
References
[1] F. Zheng, M. Kotobukia, S. Song, M. O. Lai, L. Lu, J. Power Sources 389 (2018) 198–213.
[2] A. Sakuda, A. Hayashi, M. Tatsumisago, Sci. Rep., 3 (2013), 2261.
[3] S. Boulineau, M. Courty, J. M. Tarascon, V. Viallet, Solid State Ionics, 221 (2012) 1–5.

Figure 1
Carbon Supported Ni-Mo Catalysts for Reversible Alkaline Hydrogen Electrochemistry
Authors: Patil Rituja , House Stephen D , Yang Judith C , McKone James 
Published: December 2020

Alkaline anion exchange membrane (AAEM) electrolyzers are attractive for cost-effective production of hydrogen using carbon-free electricity as the energy input. These devices facilitate the use of non-precious metal catalysts and ancillary components, which together offer significant reduction in capital cost. When combined with the low and still rapidly decreasing cost of renewable electricity, AAEM electrolyzers have the potential to meet the cost target of $2/kg for hydrogen production set by the US Department of Energy. Despite this promise, considerable work remains to develop efficient and stable catalysts and membranes for use under alkaline operating conditions. In this context, non-precious Ni-based catalysts are among the most promising for use as hydrogen-evolving cathodes. Our focus is on Ni-Mo composites, which have been studied and deployed for decades as alkaline hydrogen evolution catalysts, but the associated reaction mechanism remains relatively less explored.
We recently showed that Ni-Mo catalysts comprise a Ni-rich metallic core surrounded by Mo-rich oxide shell, where the electrically resistive shell limits the overall catalytic activity in unsupported thin films. By contrast, incorporation of conductive carbon black supports significantly enhances catalyst mass activity toward the alkaline hydrogen evolution reaction (HER) without measurably altering the composition and structure of the active Ni-Mo composite. More recently, we have directly observed the evolution of the core-shell architecture in Ni-Mo catalysts using in situ environmental transmission electron microscopy (ETEM). These measurements suggest that thermal reduction of NiMoO4 precursors proceeds in at least two sequential events. When combined with HER catalytic activity measurements, the ETEM data show that the most competent Ni-Mo catalyst requires intimate contact between a metallic, Ni-rich face-centered cubic alloy phase and a Mo-rich suboxide phase. Carbon supported Ni-Mo catalyst composites were also found to be active for the alkaline hydrogen oxidation reaction (HOR), which lends to their potential use in unitized reversible fuel cell systems. Preliminary results suggest that the Ni-Mo mass loading relative to the carbon support has a stronger influence of its HOR activity than for the HER, suggesting that mass transfer plays a significant role in the practical HOR activity.
Electrochemical Behaviour of Steel in Aqueous Alkanolamines for CO2 capture
Authors: Sadeek Samara , Kelsall Geoff , Sedransk Campbell Kyra , Hankin Anna 
Published: December 2020

Carbon dioxide capture using absorption-desorption by alkanolamines can mitigate carbon dioxide emissions, but corrosion of the steel reactor systems remains a limitation that depends on the amine type. The primary amine, monoethanolamine (MEA), a commonly used solvent for this process, forms carbamate ions (CH2CH2OHNHCOO-)when it absorbs CO2 and has been reported to corrode carbon steel. CO2 absorption in another popular solvent, the tertiary amine, methyldiethanolamine (MDEA), does not form carbamate, but rather hydrogen carbonate ions (HCO3
-), which facilitate FeCO3 formation on steel surfaces (Fig.1), limiting their corrosion rates.
The surface reactions on iron in CO2-aqueous alkanolamine solutions were investigated by measuring current transients at an applied potential of -0.350 V vs. SHE at temperatures of 25 – 80 °C, concentrations of 5 and 3 M and various pHs. In aqueous 5 M MDEA solutions, an electrically resistive film formed on iron, evidenced from the sharp decrease in current density to ca. zero (Fig.2); similar behaviour was exhibited in 3 M MDEA(aq). By contrast, current transients measured in aqueous MEA solutions did not decrease sharply. Ex-situ surface characterisation by SEM and EDX detected FeCO3 (Fig.1) on the iron exposed to MDEA, but not on the iron sample exposed to MEA.
We shall explain the formation mechanisms of films, if present, and report impedance spectra used to define conditions corresponding to electrically resistive, stable film formation that could be used to inhibit steel corrosion in carbon capture plants.

Figure 1
A General Theory of Electrochemistry
Authors: Nilsson Bruno 
Published: December 2020

The electrochemical charge transfer reaction at an electrode/electrolyte interface occurs within close distance from the electrode surface. There is a delicate balance of forces between electrons in the electrode and electrode ions within the electrolyte, and forces between the ions themselves, in this region. Since ions have an electrical charge, a corresponding electrical field is present, which in turn gives rise to the electrode potential. An external current applied to the electrode will affect the distribution of ions, the electric field, and, ultimately, the electrode potential.
This report presents a new electrochemical theory that provides a detailed and accurate description of the electric field and charge distributions associated with the charge transfer reaction, together with their relation to time, electrode voltage, and electrode current. With this foundation, it is possible to establish and formulate the basic electrochemical properties of the electrochemical cell.
The core of the theory is a partial differential equation that models the electric field in close vicinity of the electrode surface based on fundamental natural constants and specific boundary conditions. The underlying basic equation was initially derived in an attempt to explain and describe the phenomenon of Induced Polarization, which technique is effectively employed by mining companies in the large-scale search for mineral deposits.
To demonstrate the general validity of the theory the well-known Butler/Volmer and Nernst’s equations are derived.
The theory also permits the accurate modeling of dynamic, or non-equilibrium properties, like the voltage variation with time from the moment an electrode is dipped into an inert electrolyte. To assess the accuracy of the modeling, experiments were carried out where a zinc electrode was dipped into a sodium sulfate electrolyte. The electrode voltage was measured over a 5 to 640 sec time span and would typically be within 5 mV of the predicted value.
The electrode voltage was also derived from initial contact with an electrolyte containing the electrode ions until equilibrium was fully established - ending up in agreement with the predictions of Nernst’s equation.
The theory also permitted the derivation of the complex impedance of the electrode/electrolyte interface reaction. A comparison with experimental data was carried out, whereby the complex impedance of a copper electrode in contact with nine different concentrations of copper sulfate/sulfuric acid electrolytes was measured. The fit with the theory was typically within 2% over the entire 0.07 to 2400 Hz measurement range. The best fit with the experimental data allowed in turn the exchange current and the electric field distribution thickness to be determined as functions of concentration.
(Preprint full report: https://ecsarxiv.org/8njbr/ )
Magnéli Phase Ti9O17- Catalyst Support Materials for ORR
Authors: Masud Jahangir , Thakare Jivan , Aulich Ted , Mann Michael , Zhao Julia Xiaojun 
Published: December 2020

The durability of catalysts in polymer electrolyte membrane fuel cells (PEMFCs) is an important issue that must be addressed before their commercialization since catalyst durability directly reflects the life and cost of fuel cell power-generation systems [1]. Although many factors could play a role in the mechanism of catalyst degradation, the major contributors are believed to be i) dissolution of Pt and re-deposition (Ostwald ripening), ii) coalescence via crystal migration, and iii) detachment of Pt particles from the carbon support [2]. Among these, Pt detachment is strongly affected by the corrosion of the carbon support materials. Conventional carbon blacks, such as Vulcan XC72, are superior catalyst-support materials because of their cost and physicochemical properties. However, carbon is not stable based on thermodynamic considerations under the cathode conditions in a PEMFC:
C + 2H2O → CO2 + 4H+ + 4e− E0 = 0.207 V vs. RHE
Although this reaction proceeds slowly at potentials <0.8 V in a PEMFC [3], corrosion reactions are significantly accelerated under high potential conditions. Therefore, alternative catalyst-support materials that are highly oxidation-resistant are necessary. In order to improve the stability of the catalyst support, considerable work has been done over the past few decades on non-carbon support materials [4].
In this presentation, we have focused on oxygen-deficient, sub-stoichiometric titanium oxide (TinO2n−1, known as Magnéli phase) as a potential oxidation-resistant cathode catalyst support in PEFCs. This leads to improving specific activity for the oxygen reduction reaction (ORR) due to the formation of Pt–Ti alloy particles on the TiOx support, as well as the improve dispersion of Pt due to the deposition of smaller catalyst particles. The Magnéli phase Ti9O17 is synthesized and characterized (Fig. 1) by XRD. The Pt/Ti9O17 will be synthesized, and the ORR activity and stability will be investigated. A comparative study will be performed to those of a conventional Pt/C catalyst.
References:

Chem. Rev., 107, 3904 (2007)

Top. Catal., 46,285(2007)

ECS Trans., 1 (8), 3 (2006)

J. Mater. Chem., 19, 46 (2009)

Figure 1
High-Throughput Screening of Hydrogen Peroxide (Electro)Catalysts Using Scanning Electrochemical Microscopy (SECM)
Authors: Zhao Yuanya , Kromer Matthew , Adams Jason , Flaherty David , Rodríguez-López Joaquín 
Published: December 2020

Hydrogen peroxide (H2O2) is a powerful, versatile and environmentally benign oxidant that has gained relevance in industrial settings. Direct synthesis of H2O2 from O2 and H2, which is a method with low pollution and on-site production at potentially low cost, has attracted great interest. To realize this synthetic process, catalysts of high efficiency need to be developed to facilitate the reaction. In this study, scanning electrochemical microscopy (SECM) methods were used to conduct high-throughput screening of bimetallic nanoparticle catalysts (consisting of Au, Pt, Ni, etc.) for H2O2 generation from direct synthesis. In order to achieve high-throughput analysis, samples with multiple catalysts were fabricated. We used photolithography to produce wells that confined catalyst spots of a library of materials. Gold nanoparticles (AuNPs) were dispensed into these wells with a microdispenser, leaving the same amount of AuNPs at each spot. Droplets of corresponding metal salt solutions were added into the wells and then annealed to form bimetallic catalyst spots. The morphology and composition of fabricated spot arrays were characterized with SEM, TEM and EDS.
SECM measurements were performed to study the catalytic reactivity of the catalyst spots for H2O2 direct synthesis. From an electrochemical point of view, the entire process of H2O2 direct synthesis from H2 and O2 can be split into two half reactions, oxygen reduction and hydrogen oxidation. The first half reaction, oxygen reduction reaction (ORR), is a two-electron process reducing O2 into H2O2. The second half reaction, hydrogen oxidation reaction (HOR), converts H2 to protons. Only when a catalyst exhibits outstanding catalytic reactivity towards both two reactions, does it catalyze H2O2 direct synthesis efficiently in a thermocatalytic system. The catalytic reactivity for the two half reactions was investigated separately in a high throughput manner by SECM as the technique acquired information from the entire spot array in one scan and revealed catalytic performance for each spot in the array. SECM images were obtained to visualize catalytic reactivity of the spot array.
Finite element analysis simulation was done in COMSOL Multiphysics to acquire theoretical values for SECM experiments. The ultimate goal of this study is to identify a catalyst of a specific composition with the best catalytic reactivity for overall H2O2 direct synthesis. Such catalyst can be used in industrial H2O2 production to improve production efficiency and to reduce cost.
Theoretical Analysis of Photo- and Electrochemical Properties of Anatase-Type TiO2 Nanoparticles
Authors: Juhasz Gergely 
Published: December 2020

Oxide nanoparticles, like TiO2 nanoparticles are often applied in electrodes and photocatalytic systems. The morphology and shape of these nanoparticles can be easily tuned with experimental conditions, which raises the question how much the electro- and photochemical properties are affected by the nanoparticle geometry.
We studied the electronic states around the bandgap in anatase-type TiO2 nanoparticles of different shapes with (101) and (001) facets using Density Functional-based Tight Binding (DFTB) method. Previous calculation has already shown that most orbitals of the valence and conduction bands forms delocalized band-like orbitals, however there are a significant number localized states at the lower at edge of conduction band, too. These trapping sites may play important role in electrochemistry when located on the surface of the nanoparticle.
Photochemical properties however depend on optical transitions between electronic states with proper symmetry, and mostly dominated by delocalized states of atoms in the bulk. In this talk we analyze the optical spectra (see Figure 1) on the nanoparticles and compare it to the electrochemically important surface trapping

Figure 1