Fluorophore Metal-Organic Complexes: High-Throughput Optical Screening for Aprotic Electrochemical Systems.

Combinatorial optical screening of aprotic electrocatalysts has not yet been achieved primarily due to H-associated mechanisms of fluorophore modulation. We have overcome this problem by using fluorophore metal-organic complexes. In particular, eosin Y and quinine can be coordinated with various metallic cations (e.

Highly Efficient, Selective, and Stable CO2 Electroreduction on a Hexagonal Zn Catalyst.

Electrocatalytic CO2 conversion into fuel is a prospective strategy for the sustainable energy production. However, still many parts of the catalyst such as low catalytic activity, selectivity, and stability are challenging. Herein, a hierarchical hexagonal Zn catalyst showed highly efficient and, more importantly, stable performance as an electrocatalyst for selectively producing CO.

Hierarchical Cu pillar electrodes for electrochemical CO2 reduction to formic acid with low overpotential.

To achieve high performance of electrochemical CO2 reduction, a series of Cu pillar electrodes (Cu-2.5 h, Cu-5 h) were fabricated by using an electrodeposition method, and then their catalytic activities and reaction mechanisms were investigated. The series of Cu pillar electrodes exhibited improved electrocatalytic activities toward CO2 reduction to formic acid (HCOOH) as Cu pillars on electrodes developed.

Rational Design of a Hierarchical Tin Dendrite Electrode for Efficient Electrochemical Reduction of CO2.

Catalysis is a key technology for the synthesis of renewable fuels through electrochemical reduction of CO2 . However, successful CO2 reduction still suffers from the lack of affordable catalyst design and understanding the factors governing catalysis. Herein, we demonstrate that the CO2 conversion selectivity on Sn (or SnOx /Sn) electrodes is correlated to the native oxygen content at the subsurface.

Combinatorial high-throughput optical screening of high performance Pd alloy cathode for hybrid Li-air battery.

Combinatorial high-throughput optical screening method was developed to find the optimum composition of highly active Pd-based catalysts at the cathode of the hybrid Li-air battery. Pd alone, which is one-third the cost of Pt, has difficulty in replacing Pt; therefore, the integration of other metals was investigated to improve its performance toward oxygen reduction reaction (ORR). Among the binary Pd-based catalysts, the composition of Pd-Ir derived catalysts had higher performance toward ORR compared to other Pd-based binary combinations.

Novel Mn-Ce-Ti mixed-oxide catalyst for the selective catalytic reduction of NOx with NH₃.

Mn-Ce-Ti mixed-oxide catalyst prepared by the hydrothermal method was investigated for the selective catalytic reduction (SCR) of NOx with NH3 in the presence of oxygen. It was found that the environmentally benign Mn-Ce-Ti catalyst exhibited excellent NH3-SCR activity and strong resistance against H2O and SO2 with a broad operation temperature window, which is very competitive for the practical application in controlling the NOx emission from diesel engines. On the basis of the catalyst characterization, the dual redox cycles (Mn(4+) + Ce(3+) ↔ Mn(3+) + Ce(4+), Mn(4+) + Ti(3+) ↔ Mn(3+) + Ti(4+)) and the amorphous structure play key roles for the high catalytic deNOx performance.

Long-range electron transfer over graphene-based catalyst for high-performing oxygen reduction reactions: importance of size, N-doping, and metallic impurities.

N-doped carbon materials are considered as next-generation oxygen reduction reaction (ORR) catalysts for fuel cells due to their prolonged stability and low cost. However, the underlying mechanism of these catalysts has been only insufficiently identified, preventing the rational design of high-performing catalysts. Here, we show that the first electron is transferred into O2 molecules at the outer Helmholtz plane (ET-OHP) over a long range.

A superior catalyst with dual redox cycles for the selective reduction of NO(x) by ammonia.

An environmentally benign Cu-Ce-Ti oxide catalyst exhibited excellent NH3-SCR activity, high N2 selectivity and strong resistance against H2O and SO2 with a broad operation temperature window. The dual redox cycles (Cu(2+) + Ce(3+) ↔ Cu(+) + Ce(4+), Cu(2+) + Ti(3+) ↔ Cu(+) + Ti(4+)) play key roles for the superior catalytic deNOx performance.

Designed synthesis of well-defined Pd@Pt core-shell nanoparticles with controlled shell thickness as efficient oxygen reduction electrocatalysts.

Improving the electrocatalytic activity and durability of Pt-based catalysts with low Pt content toward the oxygen reduction reaction (ORR) is one of the main challenges in advancing the performance of polymer electrolyte membrane fuel cells (PEMFCs). Herein, a designed synthesis of well-defined Pd@Pt core-shell nanoparticles (NPs) with a controlled Pt shell thickness of 0.4-1.

Additional doping of phosphorus and/or sulfur into nitrogen-doped carbon for efficient oxygen reduction reaction in acidic media.

Phosphorus and/or sulfur are additionally doped into N-doped carbon (NDC) using phosphoric acid and cysteine. The resulting catalysts demonstrate excellent oxygen reduction activities coupled with high stabilities in acidic media. Specially, additional S-doping in NDC reveals nearly 2.

Binary and ternary doping of nitrogen, boron, and phosphorus into carbon for enhancing electrochemical oxygen reduction activity.

N-doped carbon, a promising alternative to Pt catalyst for oxygen reduction reactions (ORRs) in acidic media, is modified in order to increase its catalytic activity through the additional doping of B and P at the carbon growth step. This additional doping alters the electrical, physical, and morphological properties of the carbon. The B-doping reinforces the sp(2)-structure of graphite and increases the portion of pyridinic-N sites in the carbon lattice, whereas P-doping enhances the charge delocalization of the carbon atoms and produces carbon structures with many edge sites.

Sustainable production of syngas from biomass-derived glycerol by steam reforming over highly stable Ni/SiC.

The production of syngas was investigated by steam reforming glycerol over Ni/Al(2)O(3), Ni/CeO(2), and Ni/SiC (which have acidic, basic, and neutral properties) at temperatures below 773 K. The complete and stable conversion of glycerol with a yield (higher than 90 %) of gaseous products (mainly syngas) was achieved over Ni/SiC during a 60 h reaction, whereas the conversion of glycerol continually decreases over Ni/Al(2)O(3) (by 49.8 %) and Ni/CeO(2) (by 77.

Oxygen reduction activity of Pd-Mn3O4 nanoparticles and performance enhancement by voltammetrically accelerated degradation.

Electrochemical properties of Pd-Mn3O4 nanoparticles toward oxygen reduction reaction (ORR) in acidic media were investigated. The catalysts were prepared by polyol reduction of Pd(acac)2 and thermal decomposition of Mn2(CO)10. Surface composition and structure of the particles vary depending on the injection temperature of Mn2(CO)10 and are closely related to the electrochemical properties.

Thermoelectric properties of nanocomposite thin films prepared with poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) and graphene.

Carbon nanotubes (CNTs), either single wall carbon nanotubes (SWNTs) or multiwall carbon nanotubes (MWNTs), can improve the thermoelectric properties of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT : PSS), but it requires addition of 30-40 wt% CNTs. We report that the figure of merit (ZT) value of PEDOT : PSS thin film for thermoelectric property is increased about 10 times by incorporating 2 wt% of graphene. PEDOT : PSS thin films containing 1, 2, 3 wt% graphene are prepared by solution spin coating method.

Chemiluminescence analyzer of NO as a high-throughput screening tool in selective catalytic reduction of NO.

A chemiluminescence-based analyzer of NO gas species has been applied for high-throughput screening of a library of catalytic materials. The applicability of the commercial NO analyzer as a rapid screening tool was evaluated using selective catalytic reduction of NO gas. A library of 60 binary alloys composed of Pt and Co, Zr, La, Ce, Fe or W on AlO substrate was tested for the efficiency of NO removal using a home-built 64-channel parallel and sequential tubular reactor.

Combinatorial screening of highly active Pd binary catalysts for electrochemical oxygen reduction.

Electro-catalysts omitting platinum are of interest to reduce the cost of fuel cells. The development of non-Pt alloys for this purpose would require a large number of experiments. Palladium-based bimetallic electro-catalysts using eight different metals were computationally evaluated for the oxygen reduction reaction (ORR) and were made and tested in acidic media using combinatorial methods.

On the mechanism of enhanced oxygen reduction reaction in nitrogen-doped graphene nanoribbons.

Nitrogen (N)-doped carbon materials were shown in recent studies to have promising catalytic activity for oxygen reduction reaction (ORR) as a metal-free alternative to platinum, but the underlying molecular mechanism or even the active sites for high catalytic efficiency are still missing or controversial both experimentally and theoretically. We report here the results of periodic density functional theory (DFT) calculations about the ORR at the edge of a graphene nanoribbon (GNR). The edge structure and doped-N near the edge are shown to enhance the oxygen adsorption, the first electron transfer, and also the selectivity toward the four-electron, rather than the two-electron, reduction pathway.

Optimum concentration gradient of the electrocatalyst, Nafion® and poly(tetrafluoroethylene) in a membrane-electrode-assembly for enhanced performance of direct methanol fuel cells.

A combinatorial library of membrane-electrode-assemblies (MEAs) which consisted of 27 different compositions was fabricated to optimize the multilayer structure of direct methanol fuel cells. Each spot consisted of three layers of ink and a gradient was generated by employing different concentrations of the three components (Pt catalyst, Nafion® and polytetrafluoroethylene (PTFE)) of each layer. For quick evaluation of the library, a high-throughput optical screening technique was employed for methanol electro-oxidation reaction (MOR) activity.

Enhancement in electro-oxidation of methanol over PtRu black catalyst through strong interaction with iron oxide nanocluster.

One of the major issues in direct methanol fuel cell research is to develop a new catalyst for methanol electro-oxidation reaction (MOR) with high activity and low cost. In this study, a new, simple, and economic way was introduced to improve the catalytic activity of commercial PtRu black catalyst for the MOR. A nanocomposite electrode was fabricated by mixing the PtRu catalyst with Fe(2)O(3) nanoclusters.

Combined micro-Raman/UV-visible/fluorescence spectrometer for high-throughput analysis of microsamples.

Combined micro-Raman/UV-visible (vis)/fluorescence spectroscopy system, which can evaluate an integrated array of more than 10,000 microsamples with a minimuma size of 5 microm within a few hours, has been developed for the first time. The array of microsamples is positioned on a computer-controlled XY translation microstage with a spatial resolution of 1 mum so that the spectra can be mapped with micron precision. Micro-Raman spectrometers have a high spectral resolution of about 2 cm(-1) over the wave number range of 150-3900 cm(-1), while UV-vis and fluorescence spectrometers have high spectral resolutions of 0.

Quantitative structure-property relationship in a combinatorial Bi4-xLaxTi3O12 (0

A ferroelectric Bi4-xLaxTi3O12 (BLT) thin film library was fabricated from Bi2O3/La2O3/TiO2 multilayers using a multitarget RF-sputtering system equipped with an automated shutter. The polarization-electric field and structure were mapped as a function of the La content from x=0 to 1. Remnant polarization (Pr) increased as the La content decreased, and it reached a maximum 2Pr of 20 microC/cm2 at x=0.

Discovery of new heterogeneous catalysts for the selective oxidation of propane to acrolein.

Combinatorial synthesis and screening technique have been applied to investigate the catalytic activity and selectivity of ternary and quaternary mixed-metal oxide catalysts for the selective oxidation of propane. The catalyst libraries were prepared via a modified sol-gel method using a synthesis robot and library design software, and examined for the catalytic activities in a simple high-throughput reactor system connected to a mass spectrometer for product analysis. Ternary Mo-Cr-Te, V-Cr-Sb, and Mo-V-Cr catalysts have been selected for potential candidate by composition spread approach.

Combinatorial approach for ferroelectric material libraries prepared by liquid source misted chemical deposition method.

Combinatorial approach for discovering novel functional materials in the huge diversity of chemical composition and processing conditions has become more important for breakthrough in thin film electronic and energy-conversion devices. The efficiency of combinatorial method depends on the preparation of a reliable high-density composition thin-film library. The physico-chemical properties of each sample on the library should be similar to those of the corresponding samples prepared by one-by-one conventional methods.