bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Surface Chemistry of Gap in Solar-Driven Pyridine-Catalyzed CO2 Reduction
Authors: Chen Zhu , Kronawitter Coleman X. , Koel Bruce E. 
Published: February 2020

Atypical high selectivity for the conversion of CO2 to methanol has been reported when pyridine is dissolved in the electrolyte of a photoelectrochemical cell employing a p-type gallium phosphide (GaP) photocathode.[1] Despite considerable electrochemical characterization and theoretical consideration, there is no consensus on the mechanism by which pyridine catalyzes CO2-to-methanol conversion. A fundamental understanding of the origin of high selectivity in this system is important for continued optimization of solar-driven CO2 reduction. Our research combines a surface science approach with in situ and operando spectroscopy to investigate GaP surface chemistry and determine the role of heterogeneous processes in this catalysis.
Ambient pressure photoemission spectroscopy (APPES) was used to study the adsorption of H2O [2] on GaP(110) and pyridine (Py) on clean and hydrided GaP(110). The stable adsorption of both H and pyridine on GaP(110) characterizes the precursor state for the formation of adsorbed dihydropyridine (DHP), which could be a key hydride-shuttling catalyst for heterogeneous CO2 reduction. Using APPES we also observed dissociative adsorption of methanol on GaP(111), which leads to the formation of surface-bound methoxy (CH3O) species, while simultaneous formation of surface-bound formate (HCOO) and methoxy occurs on the more reactive GaP(110) surface. Low temperature scanning tunneling microscopy (LT-STM) was used to observe orbital-resolved bonding of adsorbed pyridine on the GaP(110) surface.[3] By examining the distribution of unoccupied molecular orbitals with high spatial and energy resolution, we have identified the sites on pyridine susceptible to nucleophilic attack that lead to the formation of hydrogenated species such as dihydropyridine. O
perando FTIR studies of pyridine hydrogenation at a Pt electrode under relevant electrochemical conditions was used to observe the formation of a hydrogenated piperidinium (PyH7
+) near-surface species, which implies that dihydropyridinium (PyH3
+), the protonated form of dihydropyridine, must exist transiently during CO2 reduction.[4]
1. Barton, E. E.; Rampulla, D. M.; Bocarsly, A. B., J. Am. Chem. Soc.
130, 6342 (2008)
2. Kronawitter, C. X.; Lessio, M.; Zhao, P.; Riplinger, C.; Boscoboinik, A.; Starr, D. E.; Sutter, P.; Carter, E. A.; Koel, B. E., J. Phys. Chem. C
119, 17762 (2015)
3. Kronawitter, C. X.; Lessio, M.; Zahl, P.; Muñoz-García, A. B.; Sutter, P.; Carter, E. A.; Koel, B. E., J. Phys. Chem.
C
119, 28917 (2015)
4. Kronawitter, C.; Chen, Z.; Zhao, P.; Yang, X.; Koel, B. E., Catal. Sci. Tech., 7, 831 (2017)
(Invited) Solar-Driven Electrochemical Conversion of Carbon Dioxide to Hydrocarbons and Oxygenates
Authors: Ager Joel W. 
Published: February 2020

Sustainable solar to fuel conversion could provide an alternative to mankind’s currently unsustainable use of fossil fuels [1]. Solar fuel generation by photoelectrochemical (PEC) and electrochemical methods is a potentially promising approach to address this fundamental challenge. To date, solar to fuel research efforts have been mostly focused on solar water splitting, which produces hydrogen [2]. In contrast, the conversion of CO2 to hydrocarbons that could displace currently used fossil fuels is considerably less well developed [3].
Achieving a viable solar-driven EC CO2 reduction energy conversion efficiency requires minimizing potential losses in all aspects of the device including the cathode, anode, electrolyte, and membrane. Achieving selective products requires management of multi-electron transfer reactions [4]. Strategies to optimize each component (anode, cathode, electrolyte, cell design) of our CO2 electrolyzer cell to obtain high selectivity and energy conversion efficiency at low overpotential will be described. An overall cell design which has efficient gas to liquid mass transfer of CO2 is employed [5]. Use of a CsHCO3 buffered electrolyte increases selectivity to C2+ products such as ethylene and ethanol [6]. A nanostructured anode is used which shows superior stability and high performance for oxygen evolution in the pH range of interest for CO2 reduction. Finally, a cathode design has been developed which enables selectivity to hydrocarbons and oxygenates over a wide range of pH and cell voltage conditions.
Solar-driven CO2 reduction is accomplished by coupling the optimized electrolysis device to solar cells. 1 sun efficiencies of over 4% for the production of hydrocarbons and oxygenates are achieved. Notably, the overall system also functions at >1% conversion efficiency at illumination intensities down to 0.3 suns.

Chu, S.; Cui, Y.; Liu, N. The Path towards Sustainable Energy. Nat. Mater.
2016, 16, 16–22.

Ager, J. W.; Shaner, M. R.; Walczak, K. A.; Sharp, I. D.; Ardo, S. Experimental Demonstrations of Spontaneous, Solar-Driven Photoelectrochemical Water Splitting. Energy Environ. Sci. 2015, 8, 2811–2824.

Goeppert, A.; Czaun, M.; Jones, J.-P.; Surya Prakash, G. K.; Olah, G. A. Recycling of Carbon Dioxide to Methanol and Derived Products – Closing the Loop. Chem. Soc. Rev.
2014, 43, 7995–8048.

Y. Hori, in Mod. Asp. Electrochem., (Springer New York, New York, NY, 2008), pp. 89–189.

Lobaccaro, P.; Singh, M. R.; Clark, E. L.; Kwon, Y.; Bell, A. T.; Ager, J. W. Effects of Temperature and Gas–liquid Mass Transfer on the Operation of Small Electrochemical Cells for the Quantitative Evaluation of CO 2 Reduction Electrocatalysts. Phys. Chem. Chem. Phys.
2016, 18, 26777–26785.

Singh, M. R.; Kwon, Y.; Lum, Y.; Ager, J. W.; Bell, A. T. Hydrolysis of Electrolyte Cations Enhances the Electrochemical Reduction of CO2 over Ag and Cu. J. Am. Chem. Soc.
2016, 138, 13006–13012.
Efficient Electrochemical Reduction of CO2 to Ethylene
Authors: Kenis Paul J.A. , Gewirth Andrew A 
Published: February 2020

A significant reduction in atmospheric carbon dioxide (CO2) emissions as well as in the development of alternative energy sources will be critical to curb the unwanted effects of climate change (e.g., global warming, erratic weather patterns) and to reduce our dependence on fossil fuels. A number of strategies will need to be pursued simultaneously to indeed reduce anthropogenic CO2 emissions. One such strategy is the use of CO2 as a feedstock for the production of useful chemicals (formic acid, carbon monoxide, hydrocarbons, or alcohols) via electrochemical reduction. This type of electrolysis processes can be driven in a cost effective and sustainable manner if otherwise-wasted renewable energy produced in excess of grid demand is used.
Over the past decade, significant advances have been made in the efficient electrocatalytic conversion of CO2 to carbon monoxide (to be used for dense energy carrier production) with scale up and commercialization activities now ongoing. The production of other interesting chemicals such as methanol and ethylene via electroreduction of CO2 has been lagging.
This presentation will report on our recent progress to in developing ever more active and especially selective catalysts for the production of ethylene and ethanol. Many researchers are pursuing Cu-based catalysts for this task. While reasonable conversion rates can be achieved (overall current densities exceeding 100 mA/cm2), the main challenge has been achieving selectivity for the desired products of ethylene and ethanol. Typically, other gaseous products such as CO, hydrogen and methane are formed in significant amounts, in addition to ethylene and ethanol. Here we will report our work on the development of Cu-based catalysts that produce 70-80% ethylene and ethanol, at a combined rate exceeding 170 mA/cm2. The presentation will also include an analysis of economic feasibility for the production of ethylene from CO2.
Eutectic Ionic Liquid Mixture for Lithium Batteries
Authors: Huang Qianwen , Gurkan Burcu 
Published: February 2020

Lithium-ion batteries (LIBs) are widely used in portable electronic devices. However, LIBs are reaching their fundamental limits and new battery chemistries become essential for wider applications. Lithium metal batteries offer an order of magnitude increase in energy density in theory, compared to LIBs. However, the high reactivity and the related safety hazard of the metallic lithium hinder its application in electrochemical energy storage devices. Ionic liquid (IL) electrolytes due to their unique properties including lack of flammability, negligible volatility, wide electrochemical window and high thermal stability are capable of resolving safety and stability issues in lithium metal batteries, thus enabling high-energy storage devices. The ionic conductivity of ILs, however, need to be improved to achieve practical charge/discharge rates in batteries. We investigate the non-idealities in physical and electrochemical properties of eutectic ILs and their lithium salt mixtures. Here, we will present the ionic interactions that can lead to increased conduction pathways for lithium ion in eutectic mixtures.
ILs consist of ions and their interactions with small charged ions such as Li+ create heterogeneities in the solvation shell of these solutes. Eutectic IL mixtures including the [PYR13][TFSI] with high electrochemical stability, and imidazolium and sulfonium based ILs with low viscosities but lower stabilities were studied. Improved conductivities were obtained for the eutectic IL mixtures, compared to the parent ILs. When examined on a Walden plot, the eutectic IL electrolyte demonstrate moderate ionicity. Surface Enhanced Raman Spectroscopy (SERS) was used to investigate the Li+ interaction and coordination in the bulk and near electrode surface via confocal capability of SERS. Li+ coordination is observed to increase with increasing lithium salt concentration in the range of 0 – 1 M, as expected. Increasing the concentration further to 2 M, however, shows no further changes in coordination suggesting that there are free Li+. Our in-situ electrochemical SERS indicate that the coordination condition did not completely reverse to initial state after polarization. Measured electrochemical windows, thermal analysis results and conductivities will be presented for the eutectic systems studied. Further performance analysis of these electrolytes are being conducted for lithium metal batteries.
(Invited) Ion Transport in Polymerized Ionic Liquids: Structure-Morphology-Property Relationships
Authors: Sangoro Joshua R , Heres Maximilian Ferdinand , Liu Hongjun , Paddison Stephen , Strehmel Veronika 
Published: February 2020

Polymerized ionic liquids (PolyILs) are a novel class of functional polymers that combine the unique physicochemical properties of molecular ionic liquids with the outstanding mechanical characteristics of polymers. This special mix of features might help to circumvent the key limitations of low molecular weight ionic liquids, namely, leakage and poor mechanical properties while utilizing their outstanding characteristics such as low vapor pressures, wide liquidus ranges, high thermal stability, high ionic conductivity, and wide electrochemical windows. PolyILs have shown remarkable advantages when employed in electrochemical devices such as dye-sensitized solar cells, lithium batteries, actuators, field-effect transistors, light emitting electrochemical cells, and electrochromic devices, among others. Despite their promising prospects as ideal polymer electrolytes, the role of molecular structure, morphology, and polymer dynamics on charge transport in PolyILs remains poorly understood. According to classical theories, the self-diffusion and ion transport in electrolytes are controlled by structural relaxation. These approaches predict similar temperature dependence for the dc conductivity and structural dynamics. Although this prediction has been shown to hold reasonably well for low molecular weight aprotic ionic liquids, it fails for PolyILs. In addition, the impact of morphology on charge transport is not considered within the framework of these theories.
This talk will focus on new insights obtained from experimental studies employing broadband dielectric spectroscopy, temperature-modulated differential scanning calorimetry, rheology, and scattering techniques to elucidate the impact of morphology on charge transport and structural dynamics in systematic series of polymerized ammonium- and imidazolium- based ionic liquids. Detailed analyses reveal strong decoupling of these processes in the PolyILs, implying the limitation of the classical theories in describing charge transport and molecular dynamics in these materials, in contrast to low molecular weight systems. In addition, the strong correlation observed between ionic conductivity from dielectric experiments and morphologies from scattering and computational studies will be discussed.
(Invited) Monitoring Endogenous Opioid Neuropeptide Dynamics in Real Time Using Multiple Scan Rate Voltammetry Coupled with Carbon Nanotube Yarn Microelectrodes
Authors: Sombers Leslie A , Lee Christie A , Calhoun Sarah E , Meunier Carl J , Smith Samantha K , McCarty Gregory S 
Published: February 2020

Opioid peptides are critically involved in a variety of physiological functions necessary for adaptation and survival, and as such they show tremendous promise as therapeutic targets. However there is a critical gap in understanding when and where these molecules are released, because there is a paucity of detection methods for monitoring opioid peptides in the extracellular space. We have designed a novel waveform that employs two distinct scan rates in each voltammetric sweep to detect enkephalin dynamics in live tissue with sub-second temporal resolution using carbon fiber microelectrodes. Combining two scan rates in a single voltammetric scan is unprecedented in molecular monitoring. It exploits fundamental principles to offer a combination of temporal and spatial resolution, sensitivity, and chemical selectivity that has the potential to advance the voltammetric detection of many classes of molecules. Electrochemical detection is further enhanced by combining this approach with a microelectrode sensing substrate engineered entirely of multi-walled carbon nanotubes spun into a yarn, replacing the standard carbon fiber altogether. The high aspect ratio and distinct electronic properties of the nanotubes result in markedly improved selectivity, sensitivity, and spatial resolution, as well as faster electron transfer kinetics that are manifested as sharper voltammetric peaks when compared to conventional carbon-fiber microelectrodes. By combining a groundbreaking voltammetric approach with a novel tool engineered from nanoscale materials, we are enabling a shift from interferential measures of endogenous opioid activity to direct molecular measurements.
(Keynote) Detecting the Elusive Adsorbed CO2
·- Intermediate on a Copper Electrode Using Operando Raman Spectroscopy and Pyridine As a Promoter: Implication for CO2 Electroreduction
Authors: Chernyshova Irina , Somasundaran Ponisseril , Goldman Mark , Ponnurangam Sathish 
Published: February 2020

Electrochemical conversion of the abundant CO2 to fuels, polymers, drugs, and other materials using renewable energy is one of the most promising approaches that can help deploy this energy and reduce our dependence on fossil fuels. However, the rational development of a viable CO2 electroreduction system is hampered by a daunting lacunae in the mechanistic knowledge of this reaction. This is especially true with respect to the knowledge derived from experimental (electrochemical and operando spectroscopic) data. The problem stems from the complexity of both CO2 electroreduction per se and the great technical challenges to detect and identify the key reaction intermediates in operandi
exactly on the same catalyst that is employed in the preparative electrolysis studies.
We address this technical challenge by employing advantages of the electrochemical surface-enhanced Raman scattering (SERS) method, which have been neglected in the earlier attempts to gain mechanistic insights into CO2 electroreduction. These advantages include the outstanding sensitivity of SERS to the species adsorbed on the ‘hot spots’ and the ability of this method to detect these species on real electrocatalysts in real time. Specifically, combining this method with Density Functional Theory (DFT) simulations and employing pyridine as the reaction promoter, we resolve the long-standing controversies about the mechanism of the formate and CO synthesis on a polycrystalline copper electrode in aqueous electrolytes, as well as on the promoting effects of pyridine. Correlating the microscopic results with the electrolysis and electrochemical data, we conclude that the formation of the CO2
•
d- intermediate is the rate-determining step of the formate synthesis on Cu, while formate and CO share the same route.
Hierarchical and Selective Systems for Photoelectrochemical and Electrocatalytic Reduction of Carbon Dioxide
Authors: Kulesza Pawel J , Rutkowska Iwona Agnieszka , Solarska Renata , Szaniawska Ewelina , Wadas Anna , Bienkowski Krzysztof 
Published: February 2020

There has been growing interest in the photoelectrochemical conversion of carbon dioxide (a potent greenhouse gas and a contributor to global climate change) to useful carbon-based fuels or chemicals. The reaction products are of potential importance to energy technology, food research, medical applications and fabrication of plastic materials. Given the fact that the CO2 molecule is very stable, its electroreduction processes are characterized by large overpotentials. It is often postulated that, during electroreduction, the rate limiting step is the protonation of the adsorbed CO product to form the CHO adsorbate. In this respect, the proton availability and its mobility at the photo(electro)chemical interface has to be addressed. On the other hand, competition between such parallel processes as hydrogen evolution and carbon dioxide reduction has also to be considered.
Recently, we have concentrated on the development of hybrid materials by utilizing combination of metal oxide semiconductors thus capable of effective photoelectrochemical reduction of carbon dioxide. For example, the combination of titanium (IV) oxide and copper (I) oxide has been considered before and after sunlight illumination. Application of the hybrid system composed of both above-mentioned oxides resulted in high current densities originating from photoelectrochemical reduction of carbon dioxide mostly to methanol (CH3OH) as demonstrated upon identification of final products. Among important issue is intentional stabilization, activation, and functionalization of the mixed-metal-oxide-based photoelectrochemcal interface toward better long-term performance and selectivity production of small organic molecules (C1-C4) and other chemicals. In this respect, ultra-thin films of conducting polymers (simple or polyoxometallate-derivatized) and supramolecular complexes (with nitrogen containing ligands and certain transition metal sites), sub-monolayers of metals (Cu, Au), networks of noble metal (Au, Ag) nanoparticles or layers of robust bacterial biofilms have been considered.
The photo-biocathode with Cu-containing enzyme has induced the reduction of not only oxygen but carbon dioxide as well, under illuminations with photon energies higher than silicon band gap.
In the presentation, special attention will be paid to mechanistic aspects of electroreduction of carbon dioxide, fabrication and characterization of highly selective and durable semiconductor photoelectrode materials and to importance of the reaction conditions.
(Invited) Specific Metal-Metal Oxide Interactions in Efficient Electroreduction of Carbon Dioxide
Authors: Rutkowska Iwona Agnieszka , Kulesza Pawel J 
Published: February 2020

Of particular interest to the preparation of advanced catalytic materials is efficient utilization of carbon nanostructures and noble metal nanoparticles, their stabilization and intentional activation, as well as organization into two-dimensional arrays, ultra-thin films or three-dimensional networks (e.g. through sequential attraction) on electrode surfaces. They can form nanosized materials with well-defined composition, structure and thickness that exhibit desirable electrocatalytic properties (e.g. toward reduction of CO2). We explore here the ability of polynuclear inorganic systems to stabilize and derivatize metal and carbon nanostructures. Here certain nanostructured metal oxides of zirconium, titanium, zinc or tungsten have been demonstrated to influence supported metal centers in ways other than simple dispersion over electrode area. Evidence is presented that the support can modify activity (presumably electronic nature) of catalytic metal nanoparticles (e.g. Cu, Ag, Au, Pd, Pt or Ru) thus affecting their chemisorptive and catalytic properties. Metal oxide nanospecies can generate –OH groups at low potentials that induce proton mobility at the photo(electro)chemical interface.
Our research interests concern development of systems for the reduction (conventional/electrocatalytic or photoelectrochemical) of carbon dioxide. For example, nanosized Cu or Au naoparticles immobilized within ultra-thin films of tungsten oxide or zirconia have been considered. Reduction of carbon dioxide begins now at less negative potentials and is accompanied by significant enhancement of the CO2-reduction current densities.
When it comes to photoelectrochemical reduction, we are also going to demonstrate utility of zirconia or zinc oxide over-layers on copper(I) oxide photocathodes irradiated with visible light in aqueous solutions. The possibility of generation of localized surface plasmons with use of gold or silver nanoparticles, will also be considered. Special attention will be paid to stability and controlled reactivity of the proposed systems.