bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Electrochemical CO2 Reduction to Formic Acid on Crystalline SnO2 Nanosphere Catalyst
Authors: Fu Yishu , Liu Yuyu , Li Yanan , Qiao Jinli , Zhou Xiao-Dong 
Published: February 2020

The electrochemical reduction of CO2 is a reaction of much current interest as a possible reaction for energy storage.1 To date, formic acid, carbon monoxide, methanol, and oxalic acid have been prepared by this way. However, the key technological challenge for electrochemical reduction of CO2 is the preparation of the electrode with high catalytic activity, high selectivity and long term stability. Considering these difficulties, developing new material synthesis technology to give innovative new catalysts with optimal performance is the priority.
Tin (Sn) and copper (Cu) are considered as promising electrocatalysts to convert carbon dioxide (CO2) to fuels (e.g. formate, methanol or hydrocarbons) because of their low cost, easy availability and reasonable overall Faradaic efficiency towards fuel production.2 However, the deactivation of Sn metal electrodes during CO2 reduction is very fast, and requires at least 0.86 V of overpotential to attain a CO2 reduction partial current density of 4−5 mA cm-2 in an aqueous solution saturated with 1 atm CO2.3 Combined with the advantages of metal tin, we here report a simple one step synthesis of crystalline SnO2 nanosphere with good electrochemical performance of high catalytic activity and high selectivity.
Effect of Acid Leaching on the Catalytic Activity of Co-Salen/C Non-Precious Metal Catalysts for Oxygen Reduction Reaction
Authors: Qiao Jinli , Xu Pan 
Published: February 2020

To overcome the barrier of high cost caused by the exclusive use of Pt-based catalysts, the development of non-precious metal catalysts (NPMCs) to replace Pt in polymer electrolyte membrane fuel cells has become the goal of intensive research in recent years.1,2 Some of these NPMCs have shown remarkable catalytic activity towards ORR. Among these NPMCs, carbon-supported transition metal/nitrogen ( M/N/C, M = Fe, Co, Mn, etc.) materials have gained increased attention due to their promising catalytic activity and high durability.3-5 However, the role of transition metal playing in the catalysts’ active sites is still a subject of controversy. In order to further clarify the nature of the active sites of NPMCs, in this, with Co(SO4)7H2O as the metal precursor and N,N-bis (salicylidene) ethylenediamine (Salen) as the nitrogen precursor, carbon-supported non-precious metal catalysts, Co-Salen/C, were synthesized using a facile thermal annealing approach. The catalysts were heat-treated at different temperatures (from 600- 1000oC) to optimize oxygen reduction reaction (ORR) activity. To clarify the significance of metal (Co) content for the ORR enhancement, the catalyst was further processed by acid leaching.
The electrocatalytic activity and electron transfer mechanism were demonstrated in oxygen-saturated alkaline electrolyte by cyclic voltammetry (CV), linear sweep voltammetry (LSV) as well as rotating disk electrode (RDE) techniques. Scanning electron microscope-energy dispersive spectrometer (SEM-EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) measurements were used to identify the structure and composition of the catalysts.
Synthesis and Conductive Property of Alkaline Anion-Exchange Membranes Based on Poly(vinyl alcohol)/Bis(2-chloroethyl) Ether-1,3-bis[3-(dimethylamino)propyl] Urea Copolymer Composite
Authors: Chen Shuli , Song Yanxi , Song Feifei , Zhao Xiaoxiang , Qiao Jinli , Zhou Xiao-Dong 
Published: February 2020

Anion-exchange membrane fuel cells (AEMFCs) researches have recently made a noticeable comeback from proton-exchange membrane fuel cells (PEMFCs) dominant era, since the AEMFCs can get faster electrokinetics, lower fuel crossover, reduced CO poisoning, and use of non-precious metal catalysts1,2. In the development of AEMFCs, the conductivity of alkaline anion-exchange membranes (AEMs) is considered to be the most chanellagen, since the mobility of OH- is only 1/4 of that of the H+ transportation (membranes that conduct H+ cations), the membranes that can have high OH- conductivity are highly desired for making a breakthrough in AEMFCs performances3. In cases where much effort has been undertaken for the above purpose and some promising candidates have been proposed such as quaternized polysulphane (PS)4, poly(ether imide) (PEI)5 and radiationgrafted PVDF and FEP6. However, these polymers were generally of high price and their quaternization is complex process.
Chitosan (CS) is a low-cost biopolymer, which has very good mechanical and chemical stability along with good film formation property7. However, since CS is just a weak alkaline conductivity, it cannot be directly used to fuel cell membrane. In this work, we report a novel series of alkaline anion-exchange membranes: Chitosan /Bis(2-chloroethyl)ether-1,3-bis[3-(dimethylamino)propyl]urea copolymer (PUB) membranes. By incorporation of PUB, the OH- conductivity of the CS/PUB membrane was found to be greatly improved and reached high up to 8.610×10-
3S cm-1 at 70oC.
Noble Metal Aerogel Design for Bio-/Fuel Cell Applications
Authors: Wen Dan , Zhu Chengzhou , Eychmüller Alexander 
Published: February 2020

The considerable interest in energy technology has sparked a sustained research effort on fuel cells because of their high energy efficiency and outstanding environmental compatibility.[1] Aerogels derived from noble metal nanoparticles (NPs) are a new kind of materials, which not only retain the inherent characteristics of the aerogels, including high surface area, interconnected porosity in the meso and macropore size range, and nanosized primary units, but also possess high electrical conductivity and intrinsic catalytic activity.[2] These unique properties endow them with an enormous potential in applications, such as electrocatalysis.
Our recent efforts have been focused on the design of noble metal aerogels with controllable morphologies or composition and their exploration in bio-/fuel cell applications. Via a cation-induced or a spontaneously running route, we realized the controlled growth of Pd aerogels with different porosities and surface areas and obtained aerogels composed of Pd-Ferrocene. They provided a three-dimensional matrix with high electrical conductivity and high surface area for enzyme loading, showing a promoted bioelectrocatalysis and biofuel cell application.[3,4] On the other hand, a series of highly efficient AuxPty bimetallic aerogel electrocatalysts derived via a host-guest interaction-induced method exhibited high activity, low overpotential, and high CO tolerance toward the direct oxidation of methanol, ethanol and glucose.[5] Additionally, PdxNiy aerogels from kinetically controlled synthesis displayed excellent performance toward the methanol oxidation.[6] Here the non-precious metal component was introduced to lower the cost of the fuel cell electrocatalyst and to increase its activity due to the bimetallic synergistic effect.
References
[1] M. Debe, Nature
2012, 486, 43–51.
[2] W. Liu, A.-K. Herrmann, N. Bigall, P. Rodriguez, D. Wen, M. Özaslan, T. Schmidt, N. Gaponik, A. Eychmüller, Acc.
Chem. Res.
2014, revised.
[3] D. Wen, A.-K. Herrmann, L. Borchardt, F. Simon, W. Liu, S. Kaskel, A. Eychmüller, J. Am. Chem. Soc.
2014, 136, 2727–2730.
[4] D. Wen, W. Liu, A.-K. Herrmann, A. Eychmüller, Chem. Eur. J.
2014, 20, 4380–4385.
[5] D. Wen, W. Liu, D. Haubold, A. Eychmüller, 2014, submitted.
[6] C. Zhu , D. Wen , M. Oschatz , M. Holzschuh , W. Liu , A.-K. Herrmann , F. Simon , S. Kaskel , A. Eychmüller, small
2014, accepted, DOI: 10.1002/smll.201401432.

Figure 1
Oxygen Reduction on Hafnium/Hafnium Carbide Nanoparticles
Authors: Baturina Olga A , Epshteyn Albert , Purdy Andrew 
Published: February 2020

Non-precious metal nanoparticles are attractive candidates for oxygen electrocatalytic reduction in electrochemical energy conversion devices, such as fuel cells and batteries. Here we report for the first time electrocatalytic activity of hafnium/hafnium carbide nanoparticles towards the oxygen reduction reaction (ORR). While activity of hafnium oxynitride nanoparticles towards the ORR in acid has previously been reported [1] a little was known about the ability of Hf/HfC nanoparticles to reduce molecular oxygen. Here we demonstrate that molecular oxygen can be reduced on Hf/HfC nanoparticles both in acidic and alkaline environment. However, the reaction mechanism changes from 4 - to 2 - electron pathway, when switching from acidic to alkaline environment. Although the ORR in base occurs through the two-electron parthway, this reaction has a potential for a practical application because Hf/HfC catalyst demonstrates an activity toward the disproportionation of hydrogen peroxide to O2 and H2O. Onset potential for the ORR in 0.1 M KOH for non-optimized catalyst (-0.10 V vs AgAgCl ) is superior to that of the best reported to date MnO2 catalyst (-0.13 V vs Ag/AgCl). In acid, moderate catalytic activity towards the ORR is observed. The results suggests that Hf nanomaterials can be considered as a promising candidate for replacing noble metal catalysts in alkaline air electrodes.

[1] CHISAKA, M. & MURAMOTO, H. 2014. Suppression and Evaluation of Hydrogen Peroxide Formation on Carbon-Supported Hafnium Oxynitride. ECS Electrochemistry Letters, 3, F1-F4.
Impregnation Based Electrodes for Solid Oxide Fuel and Electrolysis Cells, the State-of-the-Art and Perspectives
Authors: Boulfrad Samir , Da'as Eman Husni , Bi Lei , Traversa Enrico 
Published: February 2020

Increasing the density of the triple phase boundary (TPB) sites has been the main focus of the microstructural optimization of the electrodes in solid oxide fuel and Electrolysis Cells (SOCs). TPB is the interface between the catalyst/electronic conductor, the ionic conductor, and the gas phase where the electrode reactions occur. Better electrode performance is achieved with increasing the TPB surface. Classically, electrodes are prepared by mixing powders of the solid phases and then depositing them to form porous films after appropriate heat treatments. Optimizing the composition and particle size distribution of starting powders, as well as the deposition and sintering processes have led to a substantial increase in the TPB density. However, this has reached an optimum maturity. In the recent years impregnation based processes were developed to achieve larger TPB and better performance. In this scenario, one solid phase, usually the electrolyte, is sintered to form a porous backbone structure to be impregnated with a liquid precursor of the second phase. After drying and heating, the second solid phase is usually formed as a very fine structure on the top of larger particles of the porous backbone. This ensures a significant increase in the TPB, and good percolation of both solid phases. Very interesting results have been reported with a large number of cathode and anode materials in SOCs.
In this paper we will review the progress performed in our laboratories in impregnation based SOCs electrodes, including methods, materials, and results. In addition, the optimization of inkjet printing impregnation process will be presented and discussed in terms of controllability, reproducibility, and scalability.
(Invited) Measuring and Modeling Transport Processes in Porous Electrodes
Authors: Gostick Jeff T. 
Published: February 2020

The porous materials found inside fuel cells and other electrochemical devices differ substantially from the traditional porous media studied by geologists and reservoir engineers (i.e. rock, sand and soil). The list of challenging features of porous electrode materials is long: they can be extremely thin, nanoporous, electrically conductive, anisotropic, highly porous, fibrous, multilayered, fractured, compressible, and not self-supporting. As such, the standard set of experimental tools and modeling techniques are not always suitable or applicable. In this tutorial, progress made in porous materials characterization in the fuel cell field over the past decade will be summarized, but this tutorial will be of interest to workers in any application involving engineered porous materials. Specific topics will include pore phase measurements of effective diffusivity and permeability, solid phase measurements such as electronic and thermal conduction, multiphase flow related processes such as capillary pressure curves and breakthrough conditions, as well as pore space characterization techniques such as porosity, pore size distributions, and X-ray tomography. The role and value of the various transport parameters will also be discussed in relation to modeling and simulation.
(Invited) Mass Transport and Electrocatalysis: Experimental Techniques for Determining the Performance of Low Temperature Fuel Cell Electrocatalysts
Authors: Kucernak Anthony R. J. 
Published: February 2020

Gases are important reactants in low temperature fuel cells, comprising both the fuel (hydrogen) in many systems and the oxidant (oxygen in air) in most systems. The fast transport of these reactants through the gas phase provides a problem in accurately assessing the performance of electrocatalysts over the relevant potential range of operation. This comes about because most electrochemical methods involve provision of reactant dissolved in an electrolyte, and mass transport through a condensed phase is orders of magnitude slower than through the gaseous phase. In this paper, we consider the different approaches that can be used to determine the electrocatalytic performance of test fuel cell catalysts using liquid electrolytes, and assess how closely the different approaches mimic the mass transport conditions in a low temperature PEFC. In principle, we can adopt two different approaches, we can either (a) change (in a defined way) the electron transfer kinetics of our electrochemical reaction through changing the temperature, or poisoning our catalysts; or (b) we can increase mass transport of reactant to the electrode. In the latter case, our choices include either decreasing our measurement time (fast voltammetry); increasing convection in our system (Rotating disk, Wall-Jet, channel flow, etc); or change the geometry of our system (e.g. ultra microelectrode, floating electrode etc). There is a tradeoff between accuracy of results and ease of use, leading to some significant discrepancies in the literature.
Ordered Mesoporous Porphyrinic Carbons for Oxygen Reduction Reaction: Pt-like Activity in Acidic Media and Active Site
Authors: Joo Sang Hoon 
Published: February 2020

The high cost of polymer electrolyte fuel cell (PEFC) systems, predominantly dictated by the platinum-based cathode catalysts for the oxygen reduction reaction (ORR), has critically impeded the widespread application of PEFCs. Therefore, the quest for low-cost yet high-performance non-precious metal catalysts has been of prime importance in recent years. We present a new class of self-supported, transition metal-doped ordered mesoporous porphyrinic carbon (M-OMPC; M=transition metal) catalysts, which were prepared by nanocasting mesoporous silica templates with metalloporphyrin precursors [1]. The preparation of M-OMPC catalysts is simple, tunable, scalable, and highly reproducible. Among the M-OMPC catalysts, FeCo-OMPC exhibits a very high ORR activity in an acidic medium, which is one of the best performances among the non-precious M/N/C catalysts, and outperformed the carbon-supported commercial Pt/C catalyst. Furthermore, the FeCo-OMPC showed superior long-term durability in ORR, compared to Pt/C; after cycling 10,000 times under O2 bubbling, the FeCo-OMPC exhibited 6-fold higher ORR activity than the Pt/C. The weakening of the interaction between oxygen atom and the FeCo-OMPC compared to Pt/C as well as high surface area of the former could be responsible for its significantly high ORR activity. We also systematically investigated the potential active sites for the ORR in the FeCo-OMPC catalysts, and could correlate the local coordination structure around metal centers and corresponding ORR activities [2]. The M-OMPC catalysts could suggest a new concept for future design of non-precious metal-based high-performing ORR catalysts.
[1] J. Y. Cheon, T. Kim, Y. Choi, H. Y. Jeong, M. G. Kim, Y. J. Sa, J. Kim, Z. Lee, T.-H. Yang, K. Kwon, O. Terasaki, G.-G. Park, R. R. Adzic, S. H. Joo, Scientific Reports 3, 2715 (2013).
[2] J. Y. Cheon, M. G. Kim, G.-G. Park, S. H. Joo, manuscript in preparation.
Electrochemical Stress Development during CO and NO Oxidation on Pt
Authors: Ha Yeyoung , Cohen Yair , Gewirth Andrew A. 
Published: February 2020

The adsorption and oxidation of CO on Pt electrodes is among the most studied electrochemical reactions due to its fundamental importance as a simple model system and practical importance as CO is a well-known poison in fuel cells.1 We use in situ electrochemical surface stress measurements to monitor the surface stress development during the oxidation of CO on Pt electrodes where adsorbed CO reacts with oxygen-containing species on the surface via Langmuir-Hinshelwood mechanism.1-2 The nature of adsorbed CO layer and the role of oxygenated species are studied in both acid and alkaline media. Further, the effect of dissolved CO is examined. Another strong adsorbate, NO, is oxidized on Pt surface and the surface stress change is monitored. Despite the similarity in the electronic structure, the oxidation of NO follows a different mechanism where the complete oxidation of adsorbed NO is very difficult due to surface oxide formation.3The different role of oxygenated species on the surface can be seen from the surface stress response.
References
1. Garcia, G.; Koper, M. T., Carbon monoxide oxidation on Pt single crystal electrodes: understanding the catalysis for low temperature fuel cells. Chemphyschem : a European journal of chemical physics and physical chemistry
2011,
12(11), 2064-72.
2. Arenz, M.; Mayrhofer, K. J. J.; Stamenkovic, V.; Blizanac, B. B.; Tomoyuki, T.; Ross, P. N.; Markovic, N. M., The Effect of the Particle Size on the Kinetics of CO Electrooxidation on High Surface Area Pt Catalysts. J. Am. Chem. Soc.
2005,
127(18), 6819-6829.
3. de Vooys, A. C. A.; Beltramo, G. L.; van Riet, B.; van Veen, J. A. R.; Koper, M. T. M., Mechanisms of electrochemical reduction and oxidation of nitric oxide. Electrochim. Acta
2004,
49 (8), 1307-1314.
Voltage Asssisted Photocatalytic Flow through Cell for Inactivation of Biological Pathogens Using Titania Nanotube Arrays
Authors: Carlson Krista , Huber Jeff , Misra Mano , Mohanty Swomitra K. 
Published: February 2020

Diseases stemming from pathogen contaminated water kills 3.4 million people annually; despite our centralized water treatment facilities in the US, we are not immune to tainted drinking water. Aging infrastructure and natural disasters can cause limited access to potable water, making point-of-use (POU) disinfection devices critical for survival.
In this work, a POU device using a voltage assisted photocatalytic flow through cell, was designed and built for the disinfection of water under various conditions. Anodically formed titania nanotube arrays (TNAs) were used as the photocatalytic component of the cell. The TNAs were characterized via x-ray diffraction, scanning electron microscopy and photoelectrochemical measurements. Voltage assisted inactivation was examined under different light intensities, water chemistries and applied biases. Complete biocide (a 10-log reduction) of Escherichia coli (E. Coli) W3110, was achieved in 15 s of contact time under 25 mW/cm2 insolation and an anodic bais of 3 V. The presence of chloride ions was found to enhance disinfection as chlorine radicals participate in bacterial inactivation; however, sulfate and nitrate ions were found to inhibit inactivation. It was also determined that TNAs annealed in a reducing atmosphere performed significantly better than those annealed in air. Overall, this voltage assisted photocatalysis methodology proved to be highly effective in complete inactivation of E. Coli.

Figure 1
4A-Zeolite Enhanced Electrocatalytic Activity of Pt/C for Electrooxidation of Methanol in Alkaline Medium
Authors: Zhang Guangli , Feng Wanru , He Ping , Zhang Susu 
Published: February 2020

Pt-based electrocatalyst is considered to be the most efficient materials in direct methanol fuel cells [1]. However, the high cost of noble metals inhibits their application in fuel cells on a large scale. Therefore, the effort to finding out an abundant, inexpensive and efficient electrocatalytic material is of great significance. Zeolite, composed of silicon-aluminum oxides, is well known for its ion exchange property, adsorption with of acidic protonic entities and porosity on its surface, making it more hydrophilic and facilitating the diffusion of analytes into the film of electrode surface as well as the enhancement of active area [2,3]. Furthermore, the lower resistance and less ohmic power losses can be obtained when zeolite is used as electrode materials.
In this study, Pt/C catalyst was prepared by reducing H2PtCl6 with NaBH4 as reducer, and subsequently co-mixed with the porosity structured 4A-zeolite for the purpose of enhancing of the specific activity and reducing of the dosage of noble metal. The corresponding electrocatalytic activity for electrooxidation of methanol was evaluated in alkaline medium by cyclic voltammetry. It was shown that the electrocatalytic activity of the 4A-zeolite modified Pt/C catalyst was much better than that of Pt/C catalyst (Figure 1). This increased electrocatalytic activity could be attributed to that the micrometer 4A-zeolite with porosity structure could significantly increase the effective electrode surface and facilitate the diffusion of analytes into the film of electrode surface.

References

[1] Ziwu Liu, Qianqian Shi, Rufan Zhang, Quande Wang, Guojun Kang, Feng Peng. Phosphorus-doped carbon nanotubes supported low Pt loading catalyst for the oxygen reduction reaction in acidic fuel cells. Journal of Power Sources. 2014, 268: 171-175
[2] Zhengwei Xie, Ping He, Licheng Du, Faqin Dong, Ke Dai, Tinghong Zhang. Comparison of four different nickel-based electrodes for hydrogen evolution reaction. Electrochimica Acta. 2013, 88: 390-394
[3] Ping He, Wei Wang, Licheng Du, Faqin Dong, Yuequan Deng, Tinghong Zhang. Zeolite A functionalized with copper nanoparticles and graphene oxide for simultaneous electrochemical determination of dopamine and ascorbic acid. Analytica Chimica Acta. 2012, 739: 25-30

Figure 1