bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Rational Design of Hybrid Photoelectrode Assemblies for Solar Fuel Generation
Authors: Janáky Csaba 
Published: February 2020

Given that CO2 is a greenhouse gas, using the energy of sunlight to convert CO2 to fuels (such as methanol or methane) or basic chemicals represents a value-added approach to the simultaneous generation of alternative fuels and environmental remediation of carbon emissions. Electrochemistry and photoelectrochemistry have been proven to be a useful avenue for solar water splitting. CO2 reduction, however, is multi-electron in nature (e.g., 6 e- to methanol) with considerable kinetic barriers to electron transfer. It therefore requires the use of carefully designed electrode surfaces to accelerate e- transfer rates to levels that make practical sense. In this talk I will present some collaborative work, carried out together with Prof. Rajeshwar, on hybrid photoelectrodes leading to enhanced efficiency, selectivity, and stability.
First, I will present the use of electrosynthetic (and photoelectrosynthetic) methods for preparing semiconductors on nanocarbon-modified electrode surfaces. Composites of nanocarbons with both inorganic and organic semiconductors represent an interesting class of new functional materials. Therefore, I will show how electrodeposition can be used to tune composition, crystal structure, and morphology of the nanocomposites for targeted applications.
In the second part of my talk, I will focus on how to use semiconductor/nanocarbon hybrid materials for the photoelectrochemical reduction of CO2. Carbon nanotubes and graphene (either alone, or as building blocks of organized 3-D superstructures) can facilitate enhanced charge transport property for the photoelectrodes. I will present examples for Cu2O, TiO2, and Fe2O3-based electrodes, where the nanocarbon-containing photoelectrodes outperformed the pure semiconductor counterparts, both in terms of the achieved current densities and stability. Taking these observations together, as a general model will be presented on the role of the nanocarbon scaffold.
Hydrogen PEC Supernode: Emergent Degradation Mechanisms with Integration and Scale up of PEC Devices
Authors: Young James L. , Deutsch Todd G , Danilovic Nemanja 
Published: February 2020

This talk will give an overview of the HydroGEN Photoelectrochemistry (PEC) Supernode and present recent progress. This Supernode project is collaboration of nine PEC capability nodes that are part of the HydroGEN Advanced Water Splitting Materials consortium. These nodes are contributing to a common objective of developing understanding of integration issues and emergent degradation mechanisms of PEC devices beyond the current research scales that typically does not exceed 1 cm2 active areas. Larger devices are expected to introduce new component integration challenges and pathways for degradation that this PEC Supernode project will identify and propose pathways for future progress.
The PEC Supernode project tasks include: 1) Photoreactor chassis fabrication and baselining, 2) development, fabrication, and testing of larger area PEC devices, 3) development of in-situ morphology and corrosion analysis techniques and characterization, and 4) analysis of durability mechanisms and impacts using modeling LCA and TEA. A new photoreactor chassis will be presented that has been designed to facilitate indoor and on-sun efficiency and durability benchmarking measurements. The design will be validated in a preliminary set of multi-institution round robin measurements toward understanding and harmonizing measurement conditions and protocol. This preliminary protocol and initial set of round robin results will be presented.
Solution Combustion Synthesis and Rapid Screening of Complex Oxides and Their Composites for Photoelectrochemical Solar Energy Conversion
Authors: Hossain mohammad Kabir , Rajeshwar Krishnan 
Published: February 2020

Photoelectrochemical (PEC) water splitting using inorganic semiconductors is an attractive route for renewable energy production. However, many scientific and engineering challenges need to be overcome before its commercialization. Screening of potential semiconductor material candidates falls tops the list. Oxide semiconductors offer many advantages such as stability in a variety of electrolytes, diverse range of bandgaps and their Earth-abundance in nature. In this respect many binary metal oxides have been investigated thoroughly; however, unfortunately, a suitable candidate has not been identified. Hence, ternary and quaternary oxides and their composites have emerged as promising alternatives to binary metal oxides. It is no easy task to screen 8000 ternary and 70000 quaternary combinations and this warrants a
time-efficient
route of synthesis.
Herein, we employed a rapid and energy-efficient method, solution combustion synthesis, to investigate the Cu-Bi-V-O complex system. In this way, we synthesized p-CuBi2O4 and a range of its composites with CuO and α-Bi2O3. As the Cu-V-O system consists of multiple ternary oxide compositions, we were able to synthesize CuV2O6, Cu2V2O7 and Cu3V2O8. Moreover, growth conditions for two polymorphs (low-temperature β-phase and high temperature α-phase) of Cu2V2O7 were identified. Rietveld refinements were performed to confirm phase purity as well as to deduce composition for mixed phases. Finally, the PEC performances of these oxides will be discussed under various electrolyte conditions.
(Invited) Electrochemical Ammonia Synthesis As Potential Alternative to the Haber-Bosch Process
Authors: Soloveichik Grigorii L. 
Published: February 2020

The Advanced Research Projects Agency (ARPA-E) funds high risk, high reward transformational research to reduce energy related emissions, reduce imports of energy from foreign sources, improve energy efficiency across all economic sectors, and ensure US technological lead in advanced energy technologies, including aiming sustainable fuels synthesis for energy storage.
Ammonia is considered to be a promising sustainable energy vector with zero carbon emissions in addition to its common use as a fertilizer. Conventional ammonia synthesis via the Haber-Bosch process requires high pressure and temperature that lead to high operational costs. Electrochemical ammonia synthesis via combined electrolysis of dinitrogen and water has a potential for lower energy consumption and simplified process flow. However this route has a fundamental issue of competing hydrogen evolution reaction (HER). Therefore, to realize this potential it necessary to develop electrocatalysts or conditions where HER is suppressed. Another approach combining electrochemical and chemical steps via reaction of lithium metal with N2 followed by protonolysis could provide high faradaic efficiency but consumes more energy.
Recent advances in the development of novel approaches to energy efficient ways to synthesize ammonia via electrochemical route that is being funded by ARPA-E via REFUEL and OPEN 2018 programs will be discussed.
(Invited) Electrochemical Nitrogen Fixation Under Ambient Conditions
Authors: Chen Gaofeng , Ding Liangxin , Luo Raru , Wang Haihui 
Published: February 2020

Ammonia is vital to life and industrial manufacture. The traditional technology of ammonia synthesis, Haber-Bosch process, has been plagued for decades with problems of the harsh conditions required (typically 300oC–500oC and 200–300 atm). The mechanism studies of nitrogenase enzymes have recently motivated an alternative electrochemical technology to reduce N2 to NH3 using renewable resources under ambient conditions. Unfortunately, the NRR has seriously subjected to an ultralow Faradaic efficiency and yield rate due to the inert triple bond of N2 molecule and competing hydrogen evolution reaction (HER). This talk will present our strategies focusing on the perspective of catalyst design to tackle challenges of electrochemical nitrogen reduction reaction (NRR), such as proposing a Li+ incorporation strategy to facilitate the N2 activation,[1] recommending a finding of the possibility of efficient NRR catalysts accompanied with vigorous HER,[2] disclosing the significance of sized and spatial effects of two-dimension materials (Ti3C2Tx MXene, black phosphorus) for NRR.[3] Moreover, considering electrochemical NRR as an immature field, rigorous control experiments to eliminate possible contaminations and standard ammonia detection methods to ensure data accuracy are proposed.[4]

References

[1] G. F. Chen, X. Cao, S. Wu, X. Zeng, L. X. Ding*, M. Zhu, H. Wang*, J. Am. Chem. Soc.
2017, 139, 9771-9774.
[2] H. Cheng, L.-X. Ding*, G.-F. Chen, L. Zhang, J. Xue, H. Wang*, Adv. Mater. 2018, 30, 1803694.
[3] Y. Luo, G.-F. Chen, L. Ding, X. Chen, L.-X. Ding*, H, Wang*, Joule
2019, 3, 1-11.
[4] G.-F. Chen, S. Ren, L. Zhang, H. Cheng, Y. Luo, K. Zhu, L.-X. Ding*, H. Wang*, Small Methods
2018, 1800337.
(Invited) Electrolytic Synthesis of Ammonia at Ambient Conditions from Nitrogen and Acidic Water By a Catalyst-Free, Plasma Process
Authors: Hawtof Ryan , Toth Joseph , Ghosh Souvik , Guarr Evan , Xu Cheyan , Renner Julie N. , Sankaran R. Mohan 
Published: February 2020

Industrially, nitrogen reduction to ammonia is performed via the Haber-Bosch process at high pressure and high temperature which makes it difficult to conduct at small scales, and uses hydrogen gas as a reactant that currently comes from steam methane reforming which results in significant carbon dioxide emission. Electrolytic synthesis of ammonia is attractive because it can take place at or near ambient conditions, enables remote operation and integration with renewable sources of energy such as solar and wind, and can rely on water (typically acidic) as the source of hydrogen atoms. However, to date, the selectivity for electrolytic ammonia formation has been low, mostly because of issues associated with the catalyst materials. Specifically, large overpotentials are required to reduce the stable nitrogen molecule, and at these potentials hydrogen preferentially adsorbs on the catalyst surface and leads to hydrogen gas evolution instead of ammonia formation.
In this talk, we will present a new electrolytic approach to ammonia synthesis in which the solid cathode is replaced by a gas discharge (plasma). Similar to the more typical electrochemical systems, ammonia is formed at ambient conditions from nitrogen and water using only electricity. However, nitrogen is reduced without a catalyst by the unique interactions of the plasma and water. Specifically, electrons in the plasma potentially excite or even dissociate the nitrogen molecule in the gas phase, and solvate to produce one of the strongest reducing agents known. Remarkably, we find that at certain processing conditions, ammonia is synthesized with 100% charge-transfer (faradaic) efficiency. Scavenger experiments show that solvated electrons and hydrogen radicals are key intermediates. The dependence of ammonia formation on current, time, and pH, as well as potential reasons for the highly selective synthesis of ammonia in our process will also be discussed.
(Invited) X-Ray Microscopy of Operating Electrochemical Energy Storage Systems
Authors: Weker Johanna Nelson 
Published: February 2020

Hard X-ray transmission X-ray microscopy (TXM) is an ideal tool for in situ and operando studies of functional materials and materials synthesis routes. The high energy X-rays provides relatively relaxed restrictions on in situ environments enabling high resolution 2D microscopy and tomography (3D microscopy)1 across a large range of pressures and temperatures and in varying gas or liquid environments. The full field geometry of TXM allows imaging at the sub-second time scale, allowing relevant dynamics to be captured during; for example, battery cycling,2,3 catalysis reactions,4 electrochemical synthesis,5 and corrosion.6 Moreover, by tuning the incident X-ray energy to specific absorption edges, TXM can capture elemental and chemical (spectro-microscopy) changes at 30 nm resolution within a few minutes (Figure).
Li-ion batteries promise the high specific capacity required to replace the internal combustion engine with a number of possible earth abundant electrode materials; however, setbacks such as capacity fading hinder the full capability of these rechargeable batteries. In the search for better electrode materials, high resolution X-ray microscopy during typical battery operation is vital in understand and overcoming the failure mechanisms of these materials. I will discuss the use of X-ray microscopy including spectro-microscopy and nano-tomography to track electrochemical and morphological changes in the electrode material in real time during typical battery operation.

N. Weker, N. Liu, S. Misra, J. C. Andrews, Y. Cui and M. F. Toney, Energy Environ. Sci.
2014, 7, 2771-2777.

Nelson Weker, Y. Li, R. Shanmugam, W. Lai and W. C. Chueh, ChemElectroChem
2015, 2, 1576-1581.

Nelson Weker, A. M. Wise, K. Lim, B. Shyam and M. F. Toney, Electrochim. Acta
2017, 247, 977-982.

D. Gonzalez-Jimenez, K. Cats, T. Davidian, M. Ruitenbeek, F. Meirer, Y. Liu, J. Nelson, J. C. Andrews, P. Pianetta, F. M. F. de Groot and B. M. Weckhuysen, Angew. Chem. Int. Ed.
2012, 51, 11986-11990.

E. R. Tay, A. E. Goode, J. Nelson Weker, A. A. Cruickshank, S. Heutz, A. E. Porter, M. P. Ryan and M. F. Toney, Nanoscale
2016, 8, 1849-1853.

A. Koronfel, A. E. Goode, J. Nelson Weker, S. E. R. Tay, C. A. Stitt, T. A. Simoes, J. F. W. Mosselmans, P. Quinn, R. Brydson, A. Hart, Michael F. Toney, A. E. Porter and M. P. Ryan accepted to npj Mater. Degrad., 2018, DOI: 10.1038/s41529-018-0029-2.

Figure 1
(Invited) Optimizing the Structure and Composition of PFSA/PVDF Fuel Cell Membranes
Authors: Pintauro Peter N. , Wycisk Ryszard , Powers Devon 
Published: February 2020

In order to control water uptake and improve the mechanical properties of a highly charged cation or anion exchange membrane, an uncharged polymer is often added to the membrane in one of two ways: (1) the uncharged polymer is added to the membrane casting solution to create a blended polymer film or (2) a composite membrane is made where ionomer is impregnated into a porous uncharged polymer network/support. Improvements in both approaches can be achieved by use of nanofiber electrospinning. Thus, one can electrospin a blended polymer solution of mutually incompatible charged and uncharged polymers, where good shear mixing at the spinneret tip and fast fiber drying minimizes phase separation and where hot-pressing of the resultant fiber mat results in a dense and defect free film. Similarly, dual fiber electrospinning of separate ionomer and uncharged polymer solutions followed by hot pressing/densification circumvents problems associated with impregnating an ionomer solution into a pre-formed reinforcing porous mat. In this talk, three methods of membrane fabrication will be described and contrasted: (1) solution-cast films of a blended polymer solution, (2) membranes from blended electrospun fibers, and (3) membranes from dual fiber electrospun mats. Membranes 20-25 μm in thickness were prepared using a perfluorosulfonic acid (PFSA) ionomer from 3M Co. (660, 725, or 825 EW) and poly(vinylidene fluoride) (PVDF). The effects of membrane composition, i.e., the EW of the PFSA and the PFSA/PVDF weight ratio, and the membrane preparation procedure on proton conductivity, water swelling (gravimetric and in-plane), and membrane mechanical properties will be discussed. In general, it was found that membranes prepared by separately electrospinning PFSA and PVDF exhibited the best combination of high proton conductivity and low in-plane water swelling – two properties relevant to membrane use in a H2/air fuel cell.
Acknowledgement: The authors thank the US DOE (EERE Cooperative Agreement No. DE-EE0006362) for funding this work, as well as Dr. Michael Yandrasits at 3M for providing the PFSA ionomers used in this study.
Synergistic Hybrid MoS2/Fe2O3 Composites for Efficient Hydrogen Evolution in Alkaline Media
Authors: Hu Jue , Zhang Chengxu 
Published: February 2020

It is highly desirable to generate H2 by splitting water (2H2O → O2 + 2H2), because the storage of a large amount of energy (4.92 eV) can be realized in the molecular transformation with no emission of greenhouse gases and other pollutants.(1) The hydrogen evolution reaction (HER) is the cathodic half reaction of water splitting, which is the actual process that produces H2 needed to fuel the purported "hydrogen-based economy".(2) HER on earth-abundant molybdenum disulfide (MoS2) in acidic media is a robust process, but it is kinetically retarded in alkaline media. Thus, improving the sluggish kinetics for HER in alkaline media is crucial for advancing the performance of water-alkali electrolyzers. Here, we demonstrate a dramatic enhancement of HER kinetics in base by judiciously hybridizing vertical MoS2 sheets with another earth-abundant material, iron oxide (Fe2O3). The field-emission scanning electron microscopy (FESEM) images in Figure 1a show that the MoS2/Fe2O3 composite is composed of a particle-like structure of Fe2O3 grown closely on the edge surfaces of the vertically aligned MoS2 sheets. The highly ordered lattice planes in the high-resolution TEM (HRTEM) image of MoS2/Fe2O3 composite are clearly visible in Figure 1b. The d-spacing of 0.63 nm and 0.37 nm, which are corresponds to the (002) and (012) facets of MoS2 and Fe2O3 crystals, respectively, suggests the formation of an interface between the (002) facet of MoS2 and the neighboring (012) facet of Fe2O3 in the composite. Benefiting from the desirable structural characteristics, the MoS2/Fe2O3 interfaces synergistically favor the chemisorption of H (on MoS2) and OH (on Fe2O3), and thus can effectively accelerate the water dissociation step and thus the overall HER catalysis. The resultant MoS2/Fe2O3 heterostructures exhibit much better HER performance than bare MoS2 and outstanding stability in base (Figure 1c and d). Our synergistic hybridization of MoS2 with metal oxide materials enlightens the design and fabrication of promising heterostructures for hydrogen evolution in alkaline media.
Figure Caption
Figure 1. (a) High- and (inset) low-magnification FESEM images of MoS2/Fe2O3 composite. (b) P High-magnification TEM image of the MoS2/Fe2O3 composite, showing their interfaces. (c) Polarization curves of the MoS2, Fe2O3 and MoS2/Fe2O3 composite catalysts in 1M KOH solution at a scan rate of 5 mV/s. (d) Chronopotentiometry responses (η ~ t) recorded from MoS2/NiCo-LDH composite at high current densities of -10 mA/cm2.

References

J. L. Dempsey, B. S. Brunschwig, J. R. Winkler, H. B. Gray, Hydrogen evolution catalyzed by cobaloximes. Acc. Chem. Res.
42, 1995-2004 (2009).

J. Hu et al., Hydrogen evolution electrocatalysis with binary-nonmetal transition metal compounds. J. Mater. Chem. A
5, 5995-6012 (2017).

Figure 1
A Protonic Biotransducer for Controlling ATP Synthesis in Mitochondria
Authors: Miyake Takeo , Li Chenliang , Ohta Toshiyuki 
Published: February 2020

Controlling the flow of ions and electrons at the device/biological interface has become an important challenge in broad fields such as bioelectronics and medical biology. These devices provide a new way to translate bidirectionally between the ionic language of biology and the electronic language of circuitry.
The current strategy to develop such ion and electron controlling devices is to use new functional materials at the device/biological interface. For example, silicon nanowire and carbon nanotube based transistors use ions to read out biological functions. Aluminum nanostraws and carbon nanotube porins can selectively deliver molecules such as cations, DNA, and nicotine into biological materials. Since conductive polymers allow the transport of both ions and electrons, there are many conductive polymer based examples including organic field effect transistors for biosensing and organic ion pumps for locally delivering ions and neurotransmitters into cells and the brain.
Along with ions and small molecules, protons (H+) play an important role in biology. Examples include the homeostatic pH regulation in body and bacteria, acid sensing ion channels activating in neuron cells, proton activated bioluminescence in dinoflagellates, and pH responsive flagella in bacteria. Mitochondria in particular are a noteworthy organelle that utilize the transport of protons and electrons across a membrane to synthesize adenosine triphosphate (ATP) molecules. To translate H+ signals from biological environments into measureable electronic signals, Rolandi and co-workers developed a prototype bioprotonic device using a Pd/PdHx protode. In his group, the metallic protode was used to measure the protonic conductivity in biological materials such as chitosan and jelly from in the ampullae of Lorenzini of sharks, and to integrate electronic signals with an enzymatic flip flop circuit, ion channels, and light-sensitive bacteriorhodopsin. Gorodestky and co-workers have separately demonstrated high proton conductivity in reflectin squid proteins and Pd/PdHx based transistors. All attempts however focused on the interfacing between Pd-based metal and biological materials, even though the Pd protode may occur side reactions such as oxygen conversion (PdO, PdO2 and Pd(OH)x) at the potentials beginning at 0.9 V vs. NHE and toxic hydrogen peroxide production. Here, we develop an organic biotransducer using a high H+-coupling conductive polymer of sulfonated polyaniline (SPA) that monitors and modulates the pH in the vicinity of the SPA electrode, even in solutions with the high buffering capacity typical of mitochondrial environments (Fig.1). We integrate this biotransducer with mitochondria isolated from pig hearts to translate the H+ signal from the activated mitochondria into a measureable protonic current, and also to control the activity of ATP synthase through electrochemical pH modulation at the SPA surface.

Figure 1
Four Probe Impedance and Transference Number Analysis on Polymer Electrolytes in Liquid Phase
Authors: Su Lin-Ya , Wu Nae-Lih 
Published: February 2020

To meet the ever increasing demand for high energy density storage devices, not only the high energy density materials are eagerly required, but also is there an increasing attention in achieving a high safety standard for lithium-ion batteries (LIBs). Recently, there have been paper that claimed PVDF coating on the anode is proved to effectively suppress the growth of Li dendrite, leading to high Coulombic efficiency even under large current densities, enhanced full-cell capacity density and improved safety for LIBs. This special coating is named artificial solid-electrolyte interphase (ASEI), which supposed to have the characteristic of flexible and high ionic conductivity.
In order to measure the specific ionic conductivity value of the polymer coating layer, we design a novel four-probe electrochemical impedance spectroscopy (EIS) measuring system, which is allowed to measure the impedance of various polymer membrane in a liquid electrolyte filled atmosphere. With the nature of four probe measurement, the impedance contributed by the electrodes can be ignored in this case, meaning the equivalent circuit is just a resistor, corresponding to the ionic resistance of the electrolyte between the two references. Moreover, the activation energies of each polymer film is also calculated under various temperatures statement applied.
A large transference number can reduce concentration polarization of electrolytes during charge–discharge steps, and thus produce higher power density. It is highly desirable that the transference number of lithium ions approaches 1 in an electrolyte system. In this work, we also set up a complete system to fully analyze the property of various polymers and to further reach to a best polymer for LIBs as an ASEI.

Figure 1