bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Influence of Nanoscale Surface Structure of TiO2 Single Crystal Electrode on Water Photooxidation Reaction Process
Authors: Imanishi Akihito 
Published: February 2020

The oxygen photoevolution reaction on TiO2 and related metal oxides has attracted strong attention from the point of view of solar water splitting. In our previous study, we have proposed a new reaction model in which generated holes are consumed not only by the O2 evolution reaction but also by three competitive paths possibly occur at different surface sites; photoluminescence, surface roughening (i.e. photocorrosion), and nonradiative recombination [1,2]. Actually, we found that the branch ratio for these paths on TiO2 (110) changed by the density and the direction of steps (i.e. atomic leveled surface structure) [3]. On the other hand, it is expected that the nano-sized structure of the TiO2 surface also affect the branch ratio of 4 competitive photooxidation reactions. Thus, in this study, we investigated oxygen photoevolution efficiency on a nanostructured TiO2 electrode that exposes different facets.
A Pt wire and an Ag/AgCl/sat.KCl electrode were used as a counter and a reference electrode, respectively. An n-type TiO2 (110) doped with 0.05wt% Nb was used as a working electrode. The j−U curves were measured in 0.1 M HClO4 (pH 1.1) under UV irradiation.
Nanostructured TiO2(110) surfaces were prepared by photoetching in 0.05 M H2SO4 [4]. We obtained the nanostructured surfaces on which shallow grooves are regularly arranged. We should note that formed surface of the nanostructure is composed by (100) facet faces [4]. Photocurrent generated along with the O2 evolution from H2O on the nanostructured TiO2 (110) was apparently different from that on the flat TiO2 (100). The onset potential of nanostructured TiO2 electrode was shifted toward negative voltage, indicating that the activation energy of oxygen evolution reaction was smaller than that on the flat surface. In addition, the consumption ratio of the photogenerated holes by above mentioned 4 competitive reactions was largely different from that on the atomically flat (100) surface. Considering the fact that the photoetched TiO2(110) surface is composed by (100) microfacets[4], this result can be attributed to the nanostructuring effect. We also carried out the same experiment using the some other TiO2 electrode those have different nanostructure on their surfaces, and found that the nanostructuring effect (1. Branch ratio of 4 competitive photooxidation reactions, 2. Activation energy of O2 evolution reaction) depends on the nano-sized surface morphology of the TiO2 electrode.
[1] A. Imanishi, T. Okamura, N. Ohashi, R. Nakamura, Y. Nakato, J. Am. Chem. Soc., 129 (2007) 11569.
[2] A. Imanishi, K. Fukui, J. Phys. Chem. Lett., 5 (2014) 2108.
[3] M. Kadono, Master’s thesis, Osaka Univ. (2013).
[4] A. Imanishi, H. Suzuki, K. Murakoshi, Y. Nakato, J. Phys. Chem. B, 110 (2006) 21050.
(Invited) Fast CO2 Sorption Kinetics Using Nanowire Based Materials
Authors: Sunkara Mahendra Kumar , Nambo Apolo , Atla Veerendra , Zain Muhammed 
Published: February 2020

Capture and utilization of carbon dioxide is one of the important strategies for reducing greenhouse gas emissions. The capture of CO2 onto solid sorbents is receiving increasing attention. In recent years, different lithium ceramics have been tested as possible CO2 adsorbents. However, majority of materials systems exhibit sorption capacities much lower than the corresponding theoretical capacities and slow kinetics necessary for practical use. Here, nanowire forms of several lithiated ceramics have been tested for their carbon dioxide sorption capacities and kinetics. The nanowire morphology provides smaller length scale in diameter for complete lithium utilization for carbon dioxide capture.
Li4SiO4 nanowire (NWs) powders exhibited an uptake of 0.35 g g–1 of CO2 at an ultrafast adsorption rate of 0.22 g g–1 min–1 at 650–700 °C.1 The time scales for CO2 sorption using nanowires are approximately 3 min and two orders magnitude faster compared to those obtained using lithium silicate powders with spherical morphologies and aggregates. Furthermore, Li4SiO4 nanowire powders showed reversibility through sorption–desorption cycles indicating their suitability for CO2 capture applications.
The presentation will also highlight our recent results with other nanowire materials with CO2 sorption at temperatures around 100 C.
Acknowledgements: Support from National Science Foundation (NSF) EPSCoR program (1355438).

References:

Nambo, J. He, V. Atla, T. Q. Nguyen, T. Druffel, and M. Sunkara, “Ultrafast carbon dioxide sorption kinetics using lithium silicate nanowires”, 17 (6), 3327–3333, Nano Letters (2017).
Quantum-Interference-Enhanced Thermoelectricity in Single-Molecule Junctions
Authors: Lambert Colin John 
Published: February 2020

Experimental evidence of the effect of quantum interference on the room-temperature electrical conductance of single-molecules 1 opens the possibility of manipulating quantum interference in single molecules and self-assembled molecular layers.
In this talk, I will present a brief outline of current understanding of quantum interference in single-molecules2 and then discuss our recent works3 demonstrating how quantum interference can be exploited to increase the thermoelectric performance of single molecules and assemblies of molecules connected to nano-gap electrodes. Results will be presented for the thermoelectric properties of metallo-porphyrins, endohedral fullerenes and oligoynes.

Am. Chem. Soc., 2011, 133, 11426; Nature Nano. 2012, 7, 305; Nat. Nano., 2012, 7, 663, Phys. Rev. Lett. 2012, 109, 056801;
Nano. Lett. 2012, 6, 1643-1647; JACS 2012, 134, 5262; Beil
stein J. Nanotech. 2011, 2, 699 and refs. therein

Lambert C.J., Soc. Rev.
44, 875-888 (2015); Geng, et al., J. Am. Chem. Soc. 137, 4469 (2015); Sangtarash et al., J. Am. Chem. Soc. 137 11425 (2015); D. Manrique, et al., Nature Comm. 6 6389 (2015); Berritta et al, Nanoscale 7 1096 (2015)

Evangeli et al., Nano Letters
13, 2141-2145 (2013); Garcia-Suarez et al, Nanotechnology
25, 205402 (2014); Sadeghi et al, Nano Lett. 15, 7467-7472 (2015); Manrique et al., Lett.
16, 1308−1316 (2016); Ismael et al, Nanoscale 7 17338 (2015); Rincón-García at al, Nature Materials, 15, 289–293 (2016); Han et al., Nature Comm.
7 11281 (2016); M. Noori et al, Nanoscale 9 (16), 5299-5304 (2017); Q. Al-Galiby et al, Nanoscale 9 (14), 4819-4825 (2017)
Hydrogen and Oxygen Evolution Reactions Catalyzed By Single Site Metal Porphyrins and Corroles
Authors: Cao Rui 
Published: February 2020

Catalytic hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are key steps involved in artificial photosynthesis for solar-energy conversion for the production of clean, carbon-free, and renewable energy sources, and thus they are considered to be appealing ways to eliminate the energy and environmental problems caused by burning fossil fuels. Extensive efforts have been made to develop efficient and robust catalysts for these two processes. Research on mononuclear metal complexes has attracted increasing attention recently because not only they are capable of catalyzing HER and OER as efficiently as multinuclear metal complexes, but also there are several advantages in synthesis and mechanism studies by using single site catalysts. In this talk, we will introduce hydrogen and oxygen evolution reactions catalyzed by single site metal porphyrins and corroles.1-6

References

(1) Zhang, W.; Lai, W. Z.; Cao, R. Energy-Related Small Molecule Activation Reactions: Oxygen Reduction and Hydrogen and Oxygen Evolution Reactions Catalyzed by Porphyrin- and Corrole-Based Systems. Chem. Rev.
2017, 117, 3717-3797.
(2) Han, Y. Z.; Fang, H. Y.; Jing, H. Z.; Sun, H. L.; Lei, H. T.; Lai, W. Z.; Cao, R. Singly Versus Doubly Reduced Nickel Porphyrins for Proton Reduction: Experimental and Theoretical Evidence for a Homolytic Hydrogen-Evolution Reaction. Angew. Chem. Int. Ed.
2016, 55, 5457-5462.
(3) Lei, H. T.; Fang, H. Y.; Han, Y. Z.; Lai, W. Z.; Fu, X. F.; Cao, R. Reactivity and Mechanism Studies of Hydrogen Evolution Catalyzed by Copper Corroles. ACS Catal.
2015, 5, 5145-5153.
(4) Lei, H. T.; Liu, C. Y.; Wang, Z. J.; Zhang, Z. Y.; Zhang, M. N.; Chang, X. M.; Zhang, W.; Cao, R. Noncovalent Immobilization of a Pyrene-Modified Cobalt Corrole on Carbon Supports for Enhanced Electrocatalytic Oxygen Reduction and Oxygen Evolution in Aqueous Solutions. ACS Catal.
2016, 6, 6429-6437.
(5) Han, Y. Z.; Wu, Y. Z.; Lai, W. Z.; Cao, R. Electrocatalytic Water Oxidation by a Water-Soluble Nickel Porphyrin Complex at Neutral pH with Low Overpotential. Inorg. Chem.
2015, 54, 5604-5613.
(6) Sun, H. L.; Han, Y. Z.; Lei, H. T.; Chen, M. X.; Cao, R. Cobalt Corroles with Phosphonic Acid Pendants as Catalysts for Oxygen and Hydrogen Evolution from Neutral Aqueous Solution. Chem. Commun.
2017, 53, 6195-6198.

Figure 1
Synthesis of Carbazole-Based Porphyrin Oligomers
Authors: Maeda Chihiro 
Published: February 2020

Fused porphyrins show NIR absorption because they have larger p-conjugation system than regular porphyrins. General fused porphyrins have been synthesized by the peripheral oxidative fusion reaction of the porphyrin skeleton. On the other hand, we successfully synthesized carbazole-based porphyrin via the annulation reaction of butadiyne-bridged carbazole dimer and the subsequent oxidation of the isophlorin. The carbazole-based porphyrin shows strong NIR absorption due to the effect of the quadruple benzo-fusion.
We have synthesized several carbazole-based porphyrins, and effective substituent effect was observed at the carbazole moieties. Therefore, we then tried to oligomerize the carbazole-based porphyrin at the carbazole moieties. Four kinds of carbazole-based diporphyrins were synthesized, and their photophysical properties were investigated. As a result, thiophene-bridged diporphyrin was found to show strong intramolecular electron coupling. Furthermore, cyclic porphyrin trimer and tetramer with thiophene linkages were synthesized.
All the molecules show NIR absorption. It is worth to note that the spectra of oligomers show broad and red-shifted NIR band as compared to the monomer, which indicates strong intramolecular electronic interaction.

Figure 1
Assemblies of Expanded and Contracted Oligopyrroles: On-Surface Synthesis, Reactions, and Electronic Properties
Authors: Gottfried J. Michael 
Published: February 2020

Oligopyrroles and their metal complexes are versatile materials for surface and interface functionalization [1]. While monolayers of these molecules can sometimes be prepared by physical vapor deposition under vacuum conditions, this approach is limited to chemically and thermally stable species. An interesting alternative is the on-surface synthesis, which provides access to monolayers of species that are too fragile for vapor deposition or that cannot be made by solution-based synthesis at all. In this contribution, I introduce several strategies for the on-surface synthesis of oligopyrroles: (1) On-surface metalation of pre-deposited free-base porphyrin, phthalocyanine, or corrole ligands. With this approach, surface-stabilized complexes with metal centers in unusual oxidation states can be prepared. The attachment of additional ligands on the metal center can lead to bonding competition such as the surface trans effect. (2) Phthalocyanines, naphthalocyanines and their expanded homologs can be prepared by template-directed on-surface synthesis from suitable dinitrile-based precursors. (3) On-surface synthesis also gives access to linear open-chain counterparts of phthalocyanines, which represent a novel class of non-cyclic oligopyrroles. Structure, electronic properties and reactivities of the oligopyrrole monolayers will be discussed on the basis of extensive experimental and theoretical results.
[1] J.M. Gottfried, Surface Chemistry of Porphyrins and Phthalocyanines, Surf. Sci. Rep. 70 (2015) 259-379.
In-Vivo and In-Vitro Metabolomics with Porphyrins Based Sensor Arrays
Authors: Capuano Rosamaria , Paolesse Roberto , Di Natale Corrado 
Published: February 2020

Porphyrins have been used in the last two decades to prepare sensor arrays for a diversity of applications. The wide chemical interactivity of porphyrins sustains these applications making possible the measurement of complex patterns of volatile compounds.
The interplay between the metal ion, the aromatic ring and the peripheral compounds establishes unique selectivity patterns which are fundamental elements for sensor array design and development.
Porphyrin films can be adequately applied to inorganic surfaces making possible the preparation of different kinds of chemical sensors. Among them mass transducers, such as Quartz Microbalances (QMBs), have been found particularly suitable for several applications. The moderate sensitivity of the transducer avoids unpleasant effects of signal saturation. Furthermore, QMBs do not operate any selection among the interaction mechanisms giving the unique chance to appreciate and to use the whole bouquet of interactions occurring among the volatile compounds and the sensitive layers.
The combination of the intrinsic porphyrins sensitivity and the transduction operated by QMB makes porphyrins sensor array able to discriminate among subtle changes in patterns of volatile compounds produced by living organisms. In-vivo, these sensors have been applied to the measure of volatile compounds released by various body compartments such as skin, breath, and urines.
In breath, the identification of lung cancer has been carried out since 2003 and more recently the relationship between sensor signals and tuberculosis has been studied.
In-vitro applications were concerned with the identification of cancer cells and, more recently, with the identification of the steps of stem cells differentiation has been shown. Finally, it has to be mentioned the use of sensors to study the evolution of xenografted tumors and malaria infection in animal models.
All these results evidence the capability of porphyrin sensor array to capture the differences in volatile compounds patterns elicited by living organisms.
Similar results can be obtained by other sensors technologies; however, porphyrin sensors show a unique character of universal approach to the identification of metabolic volatiles.
A suggestive explanation of this behavior considers the role of oxidative stress to the production of cancer related volatile metabolites and in particular on the role played by natural porphyrins in the oxidative stress promoted by the Cytochrome p450. In practice, a porphyrin may be active in the synthesis of the relevant compounds and other porphyrins are used to detect them.
In this paper, a rationale for the development of porphyrin sensors for metabolomics is presented together with a thorough discussion about the evidences collected so far.
Ion-Pairing Assemblies and Materials Comprising Charged Porphyrins
Authors: Maeda Hiromitsu 
Published: February 2020

π-Electronic ions with appropriate geometries and peripheral substituents would provide assemblies through interactions between building subunits, resulting in fascinating electronic properties. Diverse ion-responsive π-electronic systems and π-electronic ions were prepared, affording dimension-controlled ion-pairing assemblies as crystals, supramolecular gels, and thermotropic liquid crystals (LCs).[1] Structures and properties of the assemblies can be controlled by the combined negatively and positively charged species in the assemblies. Highly ordered arrangement of charged species, not only the ion complexes but also charged π-systems, has been found to be a key factor to exhibit the enhanced performance as fascinating electronic materials.[2] Recently, ion pairs based on porphyrin-AuIII complexes as π-electronic cations were prepared with the combination of various anions including a π-electronic anion. Porphyrin-AuIII complexes possessing aliphatic alkyl chains formed dimension-controlled ion-pairing assemblies as thermotropic liquid crystals, whose ionic components were highly organized by electrostatic and π–π stacking interactions.[3,4]
References

A recent review: Haketa, Y.; Maeda, H. Chem. Commun.
2017, 53, 2895.

As an example of an anionic porphyrin: Sasano, Y.; Yasuda, N.; Maeda, H. Dalton Trans.
2017, 46, 8924.

Haketa, H.; Bando, Y.; Yasuda, N.; Hisaki, I.; Maeda, H. to be submitted.

Sasano, Y.; Yasuda, N.; Maeda, H. to be submitted.
C-MEMS Device for Plasma Separation from Whole Blood
Authors: Pramanick Bidhan , Pakira Victor , Chakraborty Suman 
Published: February 2020

In this work, we report the fabrication of carbon-microelectromechanical system (C-MEMS) based contactless dielectrophoresis chip for the separation of Red Blood Cell (RBC) and plasma from whole blood. Blood is the most important functional body fluid and it is necessary to separate plasma and RBC for common disease diagnosis. Use of centrifugal force and microfilters are the conventional methods for this separation. To make a portable and cost effective device, researchers found a method of geometry driven separation by means of changing the blood flow channel shapes. This method was not popular because of the pressure driven flow of blood in the channel and the need of the apparatus including syringe pump, tubing, etc. Dielectrophoresis is one of the best methods for this application. But the contact dielectrophoresis (sample is in contact with the electrodes) damages the RBC because of the use of high voltage (more than 100V). It may also cause electrochemical effect, bubble formation and joule heating in the sample.
In our development, one Indium Tin Oxide (ITO) coated glass was used as the bottom substrate. ITO coated side was used as the bottom electrode and microchannel was made in SU-8 by UV photolithography on the other side of the substrate. In a separate process, SU-8 derived carbon electrode was fabricated on Si/SiO2 substrate using the conventional C-MEMS process and transferred to 200µm thick PDMS layer. This polydimethylsiloxane (PDMS) layer was used to cover the microchannel in such a way that the carbon electrode was on the upper side of the device, aligned with the microchannel. These two electrodes (ITO and carbon) were capacitively coupled with the microchannel. The eletrostatic force is induced in the blood cells flow in the channel upon applying high frequency (1MHz) electric field to the electrodes. When blood flows in the channel, the electrostatic force combines with the capillary force and produces velocity difference between RBC and plasma resulting in their separation. In the preliminary experiment, we observed the separation of RBC and plasma at less than 1Vp-p with 1MHz frequency.

Figure 1
Transient Changes of Corrosion Potentials and Their Correlations with Metal Release During Stagnation and Flow Episodes in Drinking Water Systems
Authors: Korshin Gregory V , Fabbricino Massimiliano 
Published: February 2020

Corrosion and metal release in drinking water systems are affected by the chemistry of ambient water (e.g., pH, concentrations of carbonate and other ions), stagnation/flow transitions associated with diurnal and seasonal changes of water consumption as well as the introduction of alternative water sources, for instance desalinated water. Control of metal release in drinking water is mandated by the EPA within the Lead and Copper Rule (LCR). The current LCR paradigm of copper and lead monitoring is based on measurements of metal concentrations at the end of a predetermined stagnation time (e.g., > 6 hours). While this approach is suitable for the general evaluation of LCR compliance, it does not provide any information concerning metal release in short-term stagnation episodes nor does it allow evaluating effects of short-term changes of water chemistry.
The goal of this study was to address these deficiencies based on the quantitation of transient changes of open circuit corrosion potentials (Ecorr) of metal surfaces during stagnation/flow episodes and examining relationships between such changes and attendant metal release at varying water chemistries. Experimental data demonstrate that Ecorr transients for copper, lead and iron are characterized by several consistently present features. Theoretical interpretation shows that the Ecorr transients are associated with the concurrent processes of release of metal solutes and consumption of oxidants (dissolved oxygen, chlorine species). The former process is dominant in the case of copper or lead while the latter effect is more significant for higher corrosion rates typical for iron. Further modeling shows the presence of the phase of rapid quasi-exponential consumption of the oxidants at the surface followed by a slower phase associated with the development of diffusion controlled fluxes.
These results show that the monitoring of Ecorr transients allows quantitating corrosion and metal release rates in conditions characteristic for drinking water systems, notably when other methods either do not provide relevant data or cannot be deployed.
Microstructure and Corrosion Behavior of Fe-Cr-Ni-Co-Mn High Entropy Alloys
Authors: Chang Jun-Kai , Hsu Kuo-Min , Lin Chao-Sung 
Published: February 2020

High entropy alloys (HEAs) consisting of five or more principle elements are known as an emerging novel material because of superior properties resulting from the alloy effects of mixing elements. Several HEAs systems have been developed by adjusting the compositions. Among them, an equiatomic Fe-Cr-Ni-Co-Mn alloy (also known as the Cantor alloy) is a single FCC structure and has good resistance against brittleness at low temperatures. Several HEAs studies have detailed the microstructure, processing, and related mechanical properties. However, the materials scales only limit in the laboratory. The knowledge of microstructure and corrosion resistance of the Fe-Cr-Ni-Co-Mn alloy for industry application scales is still absent nowadays.
In this study, a 50-kg-bulk Fe-Cr-Ni-Co-Mn alloy was melted and casted. The alloy was homogenized, forged, and rolled. The as-cast bulk and deformed bulk alloys had different microstructures. The as-cast ingot with a diameter of approximately 120 mm was sliced using wire electrical discharge machining. The as-cut disk showed brown color on the rim of the disk and dark len-shaped in the middle. The XRD results showed different patterns from the distinct regions. The microstructure and the related corrosion properties of the specific was compared. The effect of segregation of the as-cast bulk was re-constructed with the related corrosion resistance. The in-situ corrosion observation system was also built and employed to study the corrosion behavior of the Fe-Cr-Ni-Co-Mn alloy in comparison to 316 stainless steel.
Key Words: high-entropy alloys, Fe-Cr-Ni-Co-Mn alloys, corrosion, segregation, as-casted