bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reduction Induced Surface Amorphization Enhances Oxygen Evolution Reaction Activity in Co3O4
Authors: Leng Xue , Zeng Qingcong , Wu Kuang-Hsu , Gentle Ian , Wang Dawei 
Published: February 2020

Oxygen evolution reaction (OER) is one of the paramount steps in sustainable energy conversion and storage technologies.1-3
Spinel oxide Co3O4 has long been recognized as a promising alternative non-precious OER electrocatalyst for its good activity and low cost. Numerous nanostructured Co3O4 materials have been developed in order to acquire better OER performance.4-6 Herein, we have adopted thermal H2 annealing and air exposure to modify the surfaces of crystalline Co3O4. Our results demonstrate the remarkably enhanced OER activity of the surface modified Co3O4 electrocatalyst despite its increased crystal size and reduced surface area. The improved OER performance is believed to be relevant to the very surficial amorphous layer consisting of mixed hydrated cobalt oxyhydroxide/carbonate species on the reduced Co3O4.
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110, 6446-6473 (2010).
3. H. Wang, H. Dai, Chem. Soc. Rev.
42, 3088-3113 (2013).
4. M. Hamdani, R. N. Singh, P. Chartier, Int. J. of Electrochem. Sc
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5. H. Tüysüz, Y. Hwang, S. Khan, A. Asiri, P. Yang, Nano Res., 6, 47-54 (2013).
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133, 5587-5593 (2011).
Fabrication of Multi-Metallic Frameworks with Specific Surface Areas Tailored for Catalysis of Surface Based Reactions
Authors: Oppedisano Daniel Keith Joseph , Jones Lathe A , Bhargava Suresh Kumar 
Published: February 2020

Fabrication of catalysts is important with regards to the extraction of energy from future fuel sources. In order to enhance the understanding and improve reactions associated with this extraction, the control of size, shape, morphology and composition is crucial. Noble metals such as platinum, palladium, gold, and ruthenium are active for both electrocatalysis and heterogeneous catalysis, however the price of materials containing these metals is high, hence the creation of catalysts with large specific surface areas is essential.
Electrodeposition at high overpotential is able to create open surfaces of a 3-D high surface area nature. Here we use the dynamic hydrogen bubble templating method to fabricate highly porous and stable multi-metal frameworks. By using, copper, a relatively cheap metal, as the major component and incorporating precious noble metals, frameworks of both varying compositions and morphologies can be produced. Most importantly the porous and nanostructured nature results in increased roughness factors and therefore increases in the specific surface area and material utilisation. Through variation in the deposition parameters composition, shape and pore size is able to be controlled.
These frameworks of materials were tested for surface based catalysis reactions and have shown enhanced ability towards the hydrogen evolution reaction (HER) and the oxygen reduction reaction (ORR). It is shown that subtle variations in surface chemistry greatly affect catalytic activity. This is linked to both structural and electronic effects from the combination of the metals.

Figure 1
Patterned Electrodeposition of Cobalt Selenide Nanostructure Arrays As a Highly Efficient Bifunctional Catalyst for Oxygen Reduction Reaction (ORR) and Oxygen Evolution Reaction (OER)
Authors: Masud Jahangir , Swesi Abdurazag , Nath Manashi 
Published: February 2020

There is a growing interest in oxygen electrode catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), as they play a key role in a wide range of renewable energy technologies such as fuel cells, metal-air batteries, and water splitting. Nevertheless, the development of highly-active bifunctional catalysts at low cost for both ORR and OER still remains a huge challenge [1]. Herein, we report, a cost effective alternative, viz. cobalt selenide Co­x­Se­­y nanotube and nanorod arrays which shows considerable catalytic activity afor OER and/or ORR., The CoxSey nanostructure arrays were produced by a protocol developed recently in the Nath laboratory [2] which involves confined electrodeposition on lithographically created nanoelectrodes. ORR activity of catalysts were evaluated in acidic medium (Fig. 1). Coating the CoxSey nanostructures with a thin layer of Pt (CoxSey-Pt) also exhibits enhanced catalytic efficiency. ORR current densities of CoxSey and CoxSey-Pt are comparable with Pt which indicate the four electron reduction process of all catalysts. Besides ORR, CoxSey exhibits excellent activity towards OER. The polarization curve (inset of Fig. 1) for CoxSeyin linear sweep voltammetry (LSV) conditions show higher current and earlier onset (ca. 330 mV) of catalytic current in comparison with Pt in 1M KOH solution. Detailed characterization and analysis of ORR/OER activity of catalyst will be presented along with structural and morphological characterization of the active catalyst surface and the relationship between morphology and the observed catalytic activity.
References:

N.I. Andersen, A. Serov, P. Atanassov Applied Catalysis B: Environmental, 2015, 163, 623.

S. Mishra and Manashi Nath, Nano Energy, 2013, 2, 1207

Figure 1
Confinement of Platinum Catalysts in Carbon Nanocontainers to Control the Durability in the Oxygen Reduction Reaction
Authors: Kurtoglu Abdullah , Walsh Darren , Khlobystov Andrei N , Gimenez-Lopez Maria del Carmen 
Published: February 2020

Platinum and platinum alloys are widely used as catalysts for hydrogen fuel cells. However, several challenges need to be over come in order for Pt catalysts to reach their full potential. These include the high intrinsic costs, the fairly poor durability, wide nanoparticle size distributions, and a the lack of understanding of the precise nature of the contact between the catalyst and support materials.1 Moreover carbon black, which is the most commonly used support material in fuel cells is thermo chemically unstable under acid conditions which drastically limits its use. Recently, carbon nanotubes (CNTs) and graphitised carbon nanofibres (GNFs), both of which have a number of exciting properties including; high specific surface areas, high electrical conductivity and relatively good stability in acid and alkaline media, have been proposed as alternative catalyst supports.2 In addition, confinement of metal nanoparticles (NPs) inside these tubular structures potentially offers enhanced stability against sintering. As a consequence of this stabilisation the resultant catalysts will remain highly catalytically active for a significantly higher number of cycles making fuel cells financially more viable.3

In this study we have developed a series of GNF supported platinum composites for use as catalysts in the cathode side of the hydrogen fuel cell. Preformed free-standing platinum NPs (PtNPs) were deposited on either the external and internal surfaces of the GNFs using different conditions.4High resolution transmission electron microscopy (HRTEM) was used to characterise the composites, verifying the location of the PtNPs in each material (Figure1). The electrochemical active surface area of the composites materials, turn over numbers and the lifetime/stability of the materials was quantified using cyclic voltammetry, and the electrocatalytic activity of the catalyst towards the oxygen reduction reaction was assessed. It was found that depositing the PtNPs inside the GNFs (PtNPs@GNFs) rather than outside (PtNPs/GNF) resulted in a catalyst with higher catalytic activity, stability, and an increased electrochemical active surface area.
Figure 1: TEM images of the PtNPs@GNF (left) and Pt/GNFs (right) composites studied.

H. A. Gasteiger, S. S. Kocha, B.Sompalli, F. T. Wagner, Catal. B-Environ., 2005, 56, 9-35.

L. Li, Yangchuan Xing, J.Electrochem. Soc., 2006, 153, 1823-1828.

G. A. Rance, W. A. Solomonsz, A. N. Khlobystov, Chem. Commun., 2013, 49, 1067.

A. La Torre, M. C. Gimenez-Lopez, M. W. Fay, G. A. Rance, W. A. Solomonsz, T. W. Chamberlain, P. D. Brown, A. N. Khlobystov, ACS Nano, 2012, 6, 2000-2007.

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Self-Assembled Monolayer Experiments in Undergraduate Laboratories
Authors: Suroviec Alice H 
Published: February 2020

This talk will describe a junior/senior level undergraduate laboratory for analytical or physical chemistry that can be used to demonstrate how self-assembled monolayers (SAM) form and pack onto a surface. The laboratory experiment will also introduce students to electrochemical techniques, instrumentation and surface analysis techniques. This experiment uses both chronocoulometry to determine the surface area of an electrode as well as using reductive desorption to determine the surface coverage and packing of the SAM. Discussion of how molecules interact with the monolayers will also be discussed.
Structure and Dynamics at Ionic Liquid/Electrode Interfaces
Authors: Parr Daniel , Zibart Christina , Egan Bryce , Malik Kasim , Shadley Tyler , Haverhals Luke M. 
Published: February 2020

Ionic liquids (ILs) are potentially ‘game changing’ electrolytes for energy conversion applications such as capacitors
[i]

,[ii]
, batteries
[iii]

,[iv]
, fuel cells
[v]

,[vi]
, and solar cells.
[vii]

,[viii]
Significant progress has been made towards utilizing these remarkably adaptable materials for specific applications however, much work remains to generate technologically and economically relevant devices and processes.[ix] Characterizations of interfaces between IL-based electrolyte/electrode systems are crucial to continued development for these enterprises. In specific, detailed descriptions and understanding of structure and dynamics at electrolyte/electrode interfaces are necessary to realize engineered progress because device efficiencies are often largely determined by processes that occur at the interface.
[x]

,[xi]
Our presentation will focus on initial efforts to employ spectroscopic techniques that characterize interfacial structure and dynamics between ionic liquid media and electrode surfaces during simultaneous electrochemical perturbation. In specific, we will present surface enhanced infrared absorption (SEIRA) spectroscopy data for ILs composed of imidazolium-based cations with bis(trifluoromethylsulfonyl)imide anions at nanostructured noble metal electrodes (i.e, Au).

[i]. T. Sato, G. Masuda, K. Takagi, Electrochim. Acta, 2004, 49, 3603-3611.
[ii]. A. Orita, K. Kamijima, M. Yoshida, J. Power Sources, 2010, 195, 7471-7479.
[iii]. A. S. Best, A. I. Bhatt, A. F. Hollenkamp, J. Electrochem. Soc., 2010, 157, A903-A911.
[iv]. J.-K. Kima, A. Matica, J.-H. Ahnb, P. Jacobsson, J. Power Sources, 2010, 195, 7639-7643.
[v]. S.-Y. Lee, A. Ogawa, M. Kanno, H. Nakamoto, T. Yasuda, M. Watanabe, J. Am. Chem. Soc., 2010, 132, 9764-9773.
[vi]. M. Guo, J. Fang, H. Xu, W. Li, X. Lu, C. Lan, K. Li, J. Membr. Sci., 2010, 362, 97-104.
[vii]. P. K. Singh, N. A. Jadhav, S. K. Mishra, U. P. Singh, B. Bhattacharya, Ionics, 2010, 16, 645-648.
[viii]. C.-P. Lee, P.-Y. Chen, R. Vittal, K.-C. Ho, J. Mater. Chem., 2010, 20, 2356-2361.
[ix]. M. Armand, F. Endres, D. R. MacFarlane, H. Ohno, B. Scrosati, Nature Materials, 2009, 8, 621-629.
[x]. A. J. Bard, L. R. Faulkner, Electrochemical Methods: Fundamentals and Applications, 2nd ed., 2002, John Wiley & Sons, Inc., New York, NY.
[xi]. M. Yoshida, A. Yamakata, K. Takanabe, J. Kubota, M. Osawa, K. Domen, J. Am. Chem. Soc., 2009, 131, 13218-13219.
Electrocatalytic CO2 Reduction with Homogeneous Transition Metals: Early Metals
Authors: Grice Kyle A , Saucedo Cesar , Sovereign Mark 
Published: February 2020

Homogeneous electrocatalysts for CO2 reduction have been explored by many groups. However, the focus has been on systems based on groups 7 or later in the periodic table. Recently, a few examples of catalytic CO2 reduction have been observed at group 6 metals (Cr, Mo, and W) or earlier groups. Group 6 is notable as it is present in biological oxoreductase enzymes such as Formate Dehydroganse, which can convert between CO2 and formate. The electrochemical response of the homoleptic group 6 carbonyls was explored at a glassy carbon electrode. In addition, other “early” metal systems were examined. The complexes were examined under aprotic conditions as well as in the presence of proton donors under argon and carbon dioxide. The results of the work with undergraduate researchers will be discussed. The integration of research and teaching chemistry concepts to undergraduates using electrochemistry will also be discussed.
Stimuli-Responsive Hydrogel Films Based on Crosslinked Chitosan
Authors: Zhang Yongchao 
Published: February 2020

Electrochemical research has been particularly difficult at primarily undergraduate institutions (PUIs) because students entering a research lab in their freshman and sophomore years have no or little knowledge of analytical chemistry or physical chemistry, let alone electrochemistry. However, considering the limited resources and amount of time faced by students at PUIs, electrochemistry presents a great opportunity to expose the students to multi-disciplinary research that encompasses chemistry, biology, material science and engineering. Here we report the development of a stimuli-responsive hydrogel film based on crosslinked chitosan on the surface of an electrode. The film shows a pH-responsive, switch-like behavior. The negatively charged redox probe, Fe(CN)6
3-/4-, is found to be trapped and enriched in the catechol-crosslinked chitosan film under acidic conditions, and released into solution by either increasing pH or applying a negative voltage. The release of negative species from the film can be controlled by the amplitude and duration of the applied voltage. This pH- and voltage-responsive material has promising applications in biofabrications, biosensors and drug delivery systems. Future studies and incorporation of similar research in undergraduate curriculum will also be discussed.

Figure 1
Probing the Film Formation Mechanisms at the Slurry/Substrate Interface Relevant to the Chemical Mechanical Planarization Process
Authors: Janes Lisa M. , Keleher Jason J 
Published: February 2020

Chemical Mechanical polishing (CMP) has emerged as a critical technology for achieving global planarization of substrates used in advanced technologies such as integrated circuits and data storage media. CMP has been described as a kinetic/thermodynamic balance between the formation of a chemically modified layer and its subsequent abrasion via nanoparticles. While the nanoparticle in the slurry plays a key role it has been proposed that the chemically modified surface layer is the key activation barrier to achieving desired removal and surface quality. Therefore it is necessary to optimize and balance the rates of chemical modification and mechanical abrasion in the system, which is dependent on the nature of the complexing/passivation chemistry in the slurry. This presentation will provide insight into the key reaction mechanisms that occur at the slurry/substrate interface relevant to integrated circuit (copper) and data storage substrate (nickel phosphorous) CMP processes. This worked explored the use of electrochemical techniques (static/dynamic open circuit potential (OCP) and Tafel analysis) to probe the impact of organic additives on the surface redox and film forming mechanisms. More specifically, through monitoring the OCP (under both abrasive and non-abrasive conditions) versus time the film removal rate and subsequent passivation film formation kinetics can be determined as a function of slurry additives (complexing agents). These results can be correlated to macroscopic performance metrics such as static/dynamic etch rates and overall polishing rates. Additionally, the surface quality will be measured using atomic force microscopy (AFM) and a correlation between surface roughness and the film formation kinetics will be presented.
Structure and Electroactivity of Tungsten Oxides in Acid Medium: Enhancement of Charge Propagation Rates through Nanostructuring and Formation of Mixed-Metal Oxide Systems
Authors: Rutkowska Iwona Agnieszka , Wadas Anna , Kulesza Pawel J 
Published: February 2020

Electrochromism in tungsten oxides and related systems has been recognized for long time and has been still of interest for display applications. Redox transitions and related reversible coloration of thin WO3 films are believed to be controlled by simultaneous injection or removal of electrons and protons. The dynamics of partial reduction (in acid medium) of transparent tungsten(VI) oxides to blue hydrogen tungsten(VI,V) oxide bronzes or lower tungsten(VI,IV) oxides is largely dependent of the oxide morphology, nanostructuring, degree of hydration, or population of colored W(VI,V) or W(VI,IV) sites. For example, by depositing nanorods of tungsten oxide, rather than conventional tungsten oxide, on the ITO conducting glass (or the inert glassy carbon) substrate, the enhancement in the degree of the system's voltammetric reduction in acid medium (0.5 M H2SO4) has been observed. Tungsten oxide nanorods seem to be partially and reversibly reduced not only to nonstoichiometric hydrogen tungsten(VI,V) oxide bronzes (HxWO3, 0<x<1) but also substoichiometric lower tungsten (VI,IV) oxides (WO3-y, 0<y<1).
Another important issue is the mobility and availability of protons within the tungsten oxide film. We have found that by controlled admixing of tungsten oxide with zirconia nanoparticles both nanostructured morphology and high mobility of protons can be adjusted. The resulting mixed (hybrid or composite) system is well-behaved: redox reactions (which are characteristics of WO3) are fast and reversible despite the presence of semiconducting zirconia (ZrO­2). While ZrO2 is not electroative, WO3 undergoes redox reactions leading to formation of partially reduced hydrogen bronzes (H
x
WO3) in which mobility of H+ is coupled to electron transfers. The composite material is stabilized through electrostatic attraction between positively charged zirconium oxo cations (ZrO2+, ZrOH3+, [Zr3(OH)4]3+) and anionic tungstates (WO4
2- in WO3*H2O or H2WO4). Among important issues are: high population of hydroxyl groups and high mobility of protons at surfaces of zirconia (ZrO2) nanostructures in addition to the existence of fast electron transfers coupled to proton displacements in partially reduced tungsten oxides (HxWO3). In a different series of chronocoulometric experiments, diffusion coefficients (for charge propagation) have been determined, and they have been found typically higher for hybrid mixed metal (tungsten(VI)/zirconium(IV) oxide films (close to 10-7 cm s-1). Mechanistic considerations and the results of spectroelectrochemical and diagnostic spectroscopic (e.g. FTIR) experiments will also be provided.
We acknowledge collaboration with Christian Perruchot and Mohamed Jouini from ITODYS, Université Paris Diderot, France.
The Preparation and Electrochromic Properties of the Polyurethanes Containing Triphenylamine Moiety
Authors: Niu Haijun 
Published: February 2020

Electrochromism is a phenomenon that optical changes of chemical materials occur in a reversible electrochemical process. For electrochromic polymers, the electrochromism is related to the changing of band gaps during the doping-dedoping process. The color changes are commonly between a transparent state, where the chromophore only absorbs in UV region and colored state, or between two colored states in a given electrolyte solution.
Two series of novel triphenylamine-containing aromatic polyurethanes (PUs) were synthesized via polycondensation of N, N-bis (4 - diisocyanate) -4 -N'- carbazolyl-1,4-aniline, and N, N-bis (4 - diisocyanate) -4 -N'- carbazolyl-1,4-phenylenediamine with various dihydroxy such as phenolphthalein, bisphenol A, 4,4'-dihydroxybiphenyl, 4,4'-bishydroxybenzophenone, bisphenolfluorene. The variation of the backbone structure significantly affected the dihedral angles and changed the electronic properties, solubility, molecular weight and thermal stability of PUs. The obtained PUs exhibited stable and reversible electrochromic properties. The color of PUs can be varied from initial colorless to green, then to blue via electro-oxidation. Considering the sensitive chromic properties of PUs, they will have potential applications for eletrochomic materials.

C.J. Chen, Y.C. Hu and G.S. Liou, Polym.Chem, 2013, 4,4162-4171.

H.J. Niu, J.W. Cai and P Zhao, Dyes Pigments, 2013, 96, 158-169.

H.M. Wang and S.H. Hsiao, Polymer, 2009, 50, 1692-1697.

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In Situ Optical Studies of Carbon Accumulation with Different Molecular Weight Alkanes on SOFC Ni Anodes
Authors: McIntyre Melissa D. , Walker Robert A 
Published: February 2020

The addition of steam to carbon containing fuels is a common method for minimizing carbon accumulation on anodes in solid oxide fuel cells (SOFCs). The required steam to fuel ratio depends on fuel type where higher molecular weight hydrocarbons require higher steam concentrations. The mechanism(s) responsible for carbon suppression with humidified fuels remain speculative, however, and motivate the need for direct observation of the surface chemistry on SOFC anodes during operation. Experiments presented in this work utilize in situ Raman spectroscopy coupled with voltammetry measurements to examine the extent of carbon accumulation on Ni-based anodes of electrolyte supported SOFCs exposed to dry and humidified fuels (methane, propane and n-hexane) at 700ᵒC. Vibrational Raman spectra show that highly ordered graphite forms on the anodes exposed to methane and propane while disordered graphite forms during exposure to hexane. The carbon structure was unaffected when 3% steam was added to the fuel and the amount of carbon accumulation was reduced for humidified methane (figure 1). Electrochemical data showed rapidly diminishing performance and continued cell degradation for anodes exposed to propane and hexane compared to experiments with methane. From these data, we quantify carbon induced degradation of SOFC anodes exposed to the various fuels.
Figure 1. Representative Raman spectra collected on SOFC anodes exposed to (a) dry and (b) humidified methane (red), propane (green) and n-hexane (blue) at 700ᵒC. The G and 2D peaks at 1561 cm-1 and 2695 cm-1, respectively, are associated with the vibrational modes of highly ordered graphite. The D peak at 1346 cm-1 is associated with the vibrational mode of disordered graphite. The Raman feature at 2915 cm-1 corresponds to the C-H vibrational mode and is present for spectra recorded during fuel exposure with methane. The spectrum recorded on a pristine anode that has been fully reduced with hydrogen (black) is shown as a reference. Spectra have been off set on the y-axis for clarity.

Figure 1