Full Oxidation Research Articles

Measurements and simulations on effects of elevated pressure and strain rate on NOx emissions in laminar premixed NH3/CH4/air and NH3/H2/air flames

Efforts to reduce NOx emissions by utilizing ammonia-fired combustors are made through various methods; this work investigates the possibility of combining the effects of pressure and stretch rate to reduce NOxemissions in laminar premixed flames. NOx emissions, including NO, NO2, N2O, NH3,and HCN, from NH3/CH4/air and NH3/H2/air unstrained and strained laminar premixed flames were separately measured and simulated with a high-pressure heat flux burner and CHEMKIN software. The key points are that increasing the pressure can decrease most NOx emissions, including NO, N2O, and HCN. However, it slightly increases the unburnt ammonia emissions and largely increases the NO2 formation. Medium XNH3 conditions are the most favorable for reducing NO emissions by increasing pressure. High strain rates can reduce NO emissions, but only in stoichiometric and rich conditions; they reversely increase NO emissions for lean equivalence ratios before the NO peak equivalence ratio (ϕ). The reason is explained by kinetic and reaction pathway analyses, which showed that in high-strain flames, more fuel-N species participated in the reaction to form N2 instead of NO for higher ϕ, while O and OH increased for lower ϕ, promotingNO formation. The combination of increasing pressure and strain rate can efficiently reduce NO emissions but ensure full ammonia oxidation for the medium ammonia content at ϕ = 0.9 ∼ 1.1. This sheds light on the utilization of highly strained ammonia-blend flames in more practical high-pressure burners to reduce NOx emissions.

MXene-derived composite catalyst with micro-holes by a solvothermal method with tiny amount of solvent for high-efficiency catalytic hydrogen production

A strategy is reported here to introduce micro-holes in the two-dimensional layered Ti3C2 by the tiny-solve-thermal method. TiO2 grows situ either in holes and between or on layers of Ti3C2 using this method meanwhile. The special micro-holes morphology on Ti3C2 enhances the specific surface area and increases the channels for oxygen, enabling full oxidation between layers and generating more TiO2 and more in-situ generated Ti3C2–TiO2 interfaces, which is conducive to TiO2 distribution and uniformity and provides more active sites. This hydrothermal method using tiny solvents can also produce porous morphology in other MXene materials (such as NbC), and photocatalysts with the special morphology will have a broader application prospect. Moreover, a fine interface connection between Ti3C2 and the in-situ grown TiO2 and the lower work function of Ti3C2 achieve an efficient electron-hole transfer. The hydrogen production performance of the Ti3C2–TiO2 photocatalyst prepared by this simple hydrothermal method has been greatly improved, which is up to 7.28 mmol/h/g with 3 wt% Pt and is 109 times and 7 times the Ti3C2–TiO2 catalyst with no holes and P25, respectively.

Evaluation of air oxidation and internal stresses induced by quenching of partially Cr-coated and uncoated optimized ZIRLO part I: Materials characterization

It is critical to develop technologies that minimize risk of nuclear reactor failure. Coated claddings present an opportunity to preserve fuel rod integrity in the case of a loss of coolant accident. In this work, the material evolution of quenched Optimized ZIRLO (OPZ) rings and Cr-coated OPZ rings is studied at temperatures up to 1000 °C, until full oxidation in air is uncovered through a variety of microstructural characterization techniques, including optical analysis and X-ray diffraction. A number of microstructural reorienting and complex, multi-stage oxidation mechanisms are found to play a role in the structural and material changes. At 1000 °C, the primary failure mode of uncoated ZIRLO is breakaway oxidation; however, the introduction of a single-sided Cr coating protects ZIRLO from oxygen penetration through the exterior surface. The material is seen to undergo several microstructural reorientations from 315° to 900°C while remaining in the α-Zr phase. At 900 °C, Cr-coated OPZ begins the α to β phase transition, and the chromium diffuses into the substrate layer. When both events are present, the Cr phase change can lead to the formation of a Cr-β-Zr eutectoid, and subsequent eutectic temperature at 1332 °C. For uncoated samples, a new phenomenon of iron-rich oxide (rust) development along the ring center in air at 1000 °C is unveiled and explained as an extension of spinodal decomposition. This study is Part I of a two-part series regarding the behavior of Cr-coated and uncoated OPZ at high temperatures. Part II investigates the internal stresses and other mechanical behaviors induced by metallic restructuring and oxide development.

Occurrence of anionic redox with absence of full oxidation to Ru5+ in high-energy P2-type layered oxide cathode

The anionic redox has been widely studied in layered-oxide-cathodes in attempts to achieve high-energy-density for Na-ion batteries (NIBs). It is known that an oxidation state of Mn4+ or Ru5+ is essential for the anionic reaction of O2−/O− to occur during Na+ de/intercalation. However, here, we report that the anionic redox can occur in Ru-based layered-oxide-cathodes before full oxidation of Ru4+/Ru5+. Combining studies using first-principles calculation and experimental techniques reveals that further Na+ deintercalation from P2-Na0.33[Mg0.33Ru0.67]O2 is based on anionic oxidation after 0.33 mol Na+ deintercalation from P2-Na0.67[Mg0.33Ru0.67]O2 with cationic oxidation of Ru4+/Ru4.5+. Especially, it is revealed that the only oxygen neighboring 2Mg/1Ru can participate in the anionic redox during Na+ de/intercalation, which implies that the Na–O–Mg arrangement in the P2-Na0.33[Mg0.33Ru0.67]O2 structure can dramatically lower the thermodynamic stability of the anionic redox than that of cationic redox. Through the O anionic and Ru cationic reaction, P2-Na0.67[Mg0.33Ru0.67]O2 exhibits not only a large specific capacity of ∼172 mA h g−1 but also excellent power-capability via facile Na+ diffusion and reversible structural change during charge/discharge. These findings suggest a novel strategy that can increase the activity of anionic redox by modulating the local environment around oxygen to develop high-energy-density cathode materials for NIBs.

Comparison of Carbon Deposition and Removal from Ni-YSZ and Ni-BCZY Composites Using Operando Optical Methods

In this study, 50%-50% Ni-8YSZ and Ni-BCZY27 composites were exposed to CH4 in the absence and presence of H2O. Carbon deposition at 750 °C and carbon removal were estimated by exposure to steam using operando vibrational emission spectroscopy and thermal imaging. Carbon removal reveals more CO2 + CO formation from Ni-8YSZ compared to Ni-BCZY27, suggesting more carbon on the surface of the former. Carbon removal from composites exposed to CH4 alone indicates limited formation and fast depletion of CO over Ni-BCZY27. Over Ni-8YSZ, CO and CO2 depletion is gradual and sustained, suggesting carbon formation over Ni-BCZY27 is restricted and full oxidation readily occurs. Methane cracking over Ni-8YSZ is accompanied by more cooling compared to Ni-BCZY27. Wet reforming results in similar cooling over Ni-8YSZ and Ni-BCZY27. The results are discussed in the context of recent work using operando spectroscopies of fuel utilization over Ni-8YSZ SOFCs.

A Spin-Dependent Model for Multi-Heme Bacterial Nanowires.

The electrical properties of conductive heme-based nanowires found in Geobacter sulfurreducens bacteria were investigated using spin-dependent density functional theory (DFT). Molecular orbitals were generated using a restricted open-shell model which was solved by applying constraints to the spin-separated unrestricted open-shell model. Charge transport was simulated at different length scales ranging from individual heme sites up to the monomer unit of the nanowire, looking at hopping and tunneling between neighboring heme porphyrins with different Fe oxidation states. The resulting spin-dependent DFT results indicate that tunneling rates between heme sites are highly dependent on oxidation state and transport pathway modeled. The model demonstrates the importance of spin dependence for electron hopping, oxidation state, and decoherence transport in cytochromes. Applying non-equilibrium's Green's function to the system confirmed a substantial decrease in decoherent charge transport for the oxidized molecule at lower Fermi energies. In addition, partial or full oxidation of the heme sites in the nanowire created conditions for spin-dependent transport that can be exploited for spin-filtering effects in nanodevices.

Subnanoscale Dual-Site Pd-Pt Layers Make PdPtCu Nanocrystals CO-Tolerant Bipolar Effective Electrocatalysts for Alcohol Fuel Cell Devices.

Finding a high-performance low-Pt bipolar electrocatalyst in actual direct alcohol fuel cells (DAFCs) remains challenging and desirable. Here, we developed a crystalline PdPtCu@amorphous subnanometer Pd-Pt "dual site" layer core-shell structure for the oxygen reduction reaction (ORR) and alcohol (methanol, ethylene glycol, glycerol, and their mixtures) oxidation reaction (AOR) in an alkaline electrolyte (denoted D-PdPtCu). The prepared D-PdPtCu/C achieved a direct 4-electron ORR pathway, a full oxidation pathway for AOR, and high CO tolerance. The ORR mass activity (MA) of D-PdPtCu/C delivered a 52.8- or 59.3-fold increase over commercial Pt/C or Pd/C, respectively, and no activity loss after 20000 cycles. The D-PdPtCu/C also exhibited much higher AOR MA and stability than Pt/C or Pd/C. Density functional theory revealed the intrinsic nature of a subnanometer Pd-Pt "dual site" surface for ORR and AOR activity enhancement. The D-PdPtCu/C as an effective bipolar electrocatalyst yielded higher peak power densities than commercial Pt/C in actual DAFCs.

Chemical Influence of Carbon Interface Layers in Metal/Oxide Resistive Switches.

Thin layers introduced between a metal electrode and a solid electrolyte can significantly alter the transport of mass and charge at the interfaces and influence the rate of electrode reactions. C films embedded in functional materials can change the chemical properties of the host, thereby altering the functionality of the whole device. Using X-ray spectroscopies, here we demonstrate that the chemical and electronic structures in a representative redox-based resistive switching (RS) system, Ta2O5/Ta, can be tuned by inserting a graphene or ultrathin amorphous C layer. The results of the orbitalwise analyses of synchrotron Ta L3-edge, C K-edge, and O K-edge X-ray absorption spectroscopy showed that the C layers between Ta2O5 and Ta are significantly oxidized to form COx and, at the same time, oxidize the Ta layers with different degrees of oxidation depending on the distance: full oxidation at the nearest 5 nm Ta and partial oxidation in the next 15 nm Ta. The depth-resolved information on the electronic structure for each layer further revealed a significant modification of the band alignments due to C insertion. Full oxidation of the Ta metal near the C interlayer suggests that the oxygen-vacancy-related valence change memory mechanism for the RS can be suppressed, thereby changing the RS functionalities fundamentally. The knowledge on the origin of C-enhanced surfaces can be applied to other metal/oxide interfaces and used for the advanced design of memristive devices.

AMORE-Isoprene v1.0: a new reduced mechanism for gas-phase isoprene oxidation

Abstract. Gas-phase oxidation of isoprene by ozone (O3) and the hydroxyl (OH) and nitrate (NO3) radicals significantly impacts tropospheric oxidant levels and secondary organic aerosol formation. The most comprehensive and up-to-date chemical mechanism for isoprene oxidation consists of several hundred species and over 800 reactions. Therefore, the computational expense of including the entire mechanism in large-scale atmospheric chemical transport models is usually prohibitive, and most models employ reduced isoprene mechanisms ranging in size from ∼ 10 to ∼ 200 species. We have developed a new reduced isoprene oxidation mechanism using a directed-graph path-based automated model reduction approach, with minimal manual adjustment of the output mechanism. The approach takes as inputs a full isoprene oxidation mechanism, the environmental parameter space, and a list of priority species which are protected from elimination during the reduction process. Our reduced mechanism, AMORE-Isoprene (where AMORE stands for Automated Model Reduction), consists of 12 species which are unique to the isoprene mechanism as well as 22 reactions. We demonstrate its performance in a box model in comparison with experimental data from the literature and other current isoprene oxidation mechanisms. AMORE-Isoprene's performance with respect to predicting the time evolution of isoprene oxidation products, including isoprene epoxydiols (IEPOX) and formaldehyde, is favorable compared with other similarly sized mechanisms. When AMORE-Isoprene is included in the Community Regional Atmospheric Chemistry Multiphase Mechanism 1.0 (CRACMM1AMORE) in the Community Multiscale Air Quality Model (CMAQ, v5.3.3), O3 and formaldehyde agreement with Environmental Protection Agency (EPA) Air Quality System observations is improved. O3 bias is reduced by 3.4 ppb under daytime conditions for O3 concentrations over 50 ppb. Formaldehyde bias is reduced by 0.26 ppb on average for all formaldehyde measurements compared with the base CRACMM1. There was no significant change in computation time between CRACMM1AMORE and the base CRACMM. AMORE-Isoprene shows a 35 % improvement in agreement between simulated IEPOX concentrations and chamber data over the base CRACMM1 mechanism when compared in the Framework for 0-D Atmospheric Modeling (F0AM) box model framework. This work demonstrates a new highly reduced isoprene mechanism and shows the potential value of automated model reduction for complex reaction systems.

Phosphorous incorporation into palladium tin nanoparticles for the electrocatalytic formate oxidation reaction

The deployment of direct formate fuel cells (DFFCs) relies on the development of active and stable catalysts for the formate oxidation reaction (FOR). Palladium, providing effective full oxidation of formate to CO2, has been widely used as FOR catalyst, but it suffers from low stability, moderate activity, and high cost. Herein, we detail a colloidal synthesis route for the incorporation of P on Pd2Sn nanoparticles. These nanoparticles are dispersed on carbon black and the obtained composite is used as electrocatalytic material for the FOR. The Pd2Sn0.8P-based electrodes present outstanding catalytic activities with record mass current densities up to 10.0 A mgPd-1, well above those of Pd1.6Sn/C reference electrode. These high current densities are further enhanced by increasing the temperature from 25 °C to 40 °C. The Pd2Sn0.8P electrode also allows for slowing down the rapid current decay that generally happens during operation and can be rapidly re-activated through potential cycling. The excellent catalytic performance obtained is rationalized using density functional theory (DFT) calculations.

Investigation of asphalt oxidation kinetics aging mechanism using molecular dynamic simulation

Asphalt oxidative aging leads to pavement to become harder and brittle, resulting in the complex cracking and other diseases. However, the microscopic causes of oxidative aging and these changes are not clear. It is meaningful to investigate the complex aging process of asphalt from virgin state to aged state from a microscopic perspective. Molecular dynamics (MD) simulation was used to investigate the oxidation kinetic aging process from the microscopic point of view. Asphalt binders were aged in the oven at five different aging times to simulate the oxidative aging. Saturates, asphaltene, resin, and aromatic (SARA) fraction weights of binders as well as carbonyls and sulfoxides at different aging states were determined using the four fractions separation test and Fourier Transform Infrared Spectroscopy (FTIR). The virgin, fast-rate reaction, constant-rate reaction and full oxidation asphalt molecular models were established corresponded to the proportions of SARA fractions, carbonyl index and sulfoxide index. These models were simulated to investigate the microscopic properties, and the oxidation kinetic aging mechanism of asphalt were revealed.

A mechanic insight into low-temperature catalytic combustion toward ethylene oxide over Pt-Ru/CuCeOx bimetallic catalyst

The catalytic oxidation performance toward ethylene oxide (EO) and the consequent mechanism were investigated on the Pt-Ru/CuCeOx bimetallic catalyst, which was prepared by a distinct method combining stepwise adsorption and subsequent impregnation. The catalytic tests show that the introduction of Ru into the Pt catalyst, so as to form Pt-Ru bimetallic active sites, can greatly increase the oxidation activity of the catalyst, as evidenced by the extremely lower full oxidation temperature (120 °C) when compared with that of the Pt/CeO2 catalyst (160 °C). The XPS spectra show that the Ru species (mainly RuOx) have strong interaction with the CuCeOx support, which can therefore affect the electron transfer between the Pt species and the support. As a result, the oxygen activation on Pt species is obviously facilitated and catalytic activity is enhanced. Finally, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) was used to track the reaction mechanism. It is found that the catalytic oxidation process follows the MvK catalytic mechanism at low temperature and the L-H catalytic mechanism when the temperature moves to higher range.

Peak-fitting of Cu 2p photoemission spectra in Cu0, Cu1+, and Cu2+ oxides: A method for discriminating Cu0 from Cu1+

The photoemission spectra of Cu 2p are one of the most studied. Its analysis is especially challenging because, among others, the peaks for Cu0 and Cu1+ overlap, and Cu1+ and Cu2+ coexist under many conditions. The chemical state determination of metallic copper and the initial oxidation mechanism of copper require state-of-the-art peak fitting analysis and background modeling. This work presents a detailed and quantitative analysis of the Cu 2p photoemission spectra for a metallic ultra-thin film and the initial oxidation stages. Additionally, annealed films at 200 °C for up to 5 min were analyzed to assess the full oxidation of the copper oxides and assert the validity of the proposed peak-fitting procedures. For the initial oxidation, it was possible to accurately identify Cu1+ and Cu2+ states and, alongside, quantify the corresponding O 1s species, resulting in compositions close to stoichiometric values. Using the active background, it was possible to achieve close reproduction of all the photoemission spectra; three coexisting copper species were resolved during the fitting procedure. An accurate peak-fitting analysis allowed for quantifying the relative proportion of Cu1+ to Cu0 states despite their strong overlap.

Adsorption and Photo-Degradation of Organophosphates on Sulfate-Terminated Anatase TiO2 Nanoparticles

The adsorption and photocatalytic degradation of trimethyl phosphate (TMP) and triethyl phosphate (TEP), two environmentally relevant model pollutants, have been studied on commercial anatase TiO2 and sulfate-terminated anatase TiO2 nanoparticles by means of operando diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and 2D correlation spectroscopy (2D COS). It is concluded that both TMP and TEP adsorb dissociatively on anatase TiO2, while on the sulfate-terminated anatase TiO2, TMP and TEP adsorb associatively. Upon UV illumination, TMP and TEP are completely oxidized on sulfate-terminated anatase TiO2, as evidenced by the evolution of the IR bands characteristic for water and carbon dioxide. In contrast, on anatase TiO2, UV illumination leads to the formation of stable surface-coordinated carboxylate products, which impedes complete oxidation. 2D COS analysis suggests that parallel reaction pathways occur during oxidation under UV illumination, viz. methoxide/ethoxide (ads) → carboxylates (ads) and methoxide/ethoxide (ads) → aldehydes (ads) → carboxylates (ads). A parallel reaction occurs on sulfated TiO2 that yields CO2 and H2O by direct radical reactions with the methoxide groups with little, or no, formation of surface-coordinated intermediates. Sulfated TiO2 favor the formation of aldehyde intermediates, with reaction rates 10 times and 30 times faster for TMP and TEM, respectively, compared with commercial anatase TiO2. About 37% (33%) and 32% (24%) of TMP (TEP) were degraded on sulfated-terminated TiO2 and pure TiO2, respectively, after the first 9 min of UV illumination. We show that the sulfate-functionalization of TiO2 has two main functions. First, it prevents the formation of strongly bonded bridging carboxylates, thereby alleviating deactivation. Second, it promotes full oxidation of the organic side-chains into carbon dioxide and water. Improved electron-hole separation by the electrophilic S(VI) in combination with the blocking of bridging reaction intermediates is proposed to contribute to the improved activity. The presented results give insights into how acidic surface modifications change adsorbate surface chemistries, which can be used to increase the sustained activity of low-temperature photocatalysts.

Synthesis and Characterization of Stable Cu-Pt Nanoparticles under Reductive and Oxidative Conditions.

We report a synthesis method for highly monodisperse Cu-Pt alloy nanoparticles. Small and large Cu-Pt particles with a Cu/Pt ratio of 1:1 can be obtained through colloidal synthesis at 300 °C. The fresh particles have a Pt-rich surface and a Cu-rich core and can be converted into an intermetallic phase after annealing at 800 °C under H2. First, we demonstrated the stability of fresh particles under redox conditions at 400 °C, as the Pt-rich surface prevents substantial oxidation of Cu. Then, a combination of in situ scanning transmission electron microscopy, in situ X-ray absorption spectroscopy, and CO oxidation measurements of the intermetallic CuPt phase before and after redox treatments at 800 °C showed promising activity and stability for CO oxidation. Full oxidation of Cu was prevented after exposure to O2 at 800 °C. The activity and structure of the particles were only slightly changed after exposure to O2 at 800 °C and were recovered after re-reduction at 800 °C. Additionally, the intermetallic CuPt phase showed enhanced catalytic properties compared to the fresh particles with a Pt-rich surface or pure Pt particles of the same size. Thus, the incorporation of Pt with Cu does not lead to a rapid deactivation and degradation of the material, as seen with other bimetallic systems. This work provides a synthesis route to control the design of Cu-Pt nanostructures and underlines the promising properties of these alloys (intermetallic and non-intermetallic) for heterogeneous catalysis.

Dynamic oxygen migration and reaction over ceria-supported nickel oxides in chemical looping partial oxidation of methane

The oxygen species over oxygen carriers determine the reaction performance in chemical looping partial oxidation of methane (CLPOM). This paper describes the dynamic migration and reaction of oxygen species over ceria-supported NiO oxygen carrier for CLPOM. At initial reaction stage, Ni-O species could be consumed rapidly and cause the full oxidation of methane to CO2. Afterwards, the active Ni-O-Ce species dominates the methane partial oxidation to promote the syngas yield. It is found that CO formation rate is linearly related with the content of oxygen species over Ni-O-Ce. Furthermore, the lattice oxygen from CeO2 would migrate through the bulk to complement the consumed Ni-O-Ce oxygen species. Eventually, 5NiO/(40CeO2-Al2O3) exhibit nearly three times as high as methane reaction rate of CeO2/Al2O3 and two times as high as CO formation rate of 5NiO/Al2O3. This work provides the comprehensive understanding of transport and reaction mechanism of oxygen species for chemical looping processes.

A numerical simulation investigation on low permeability reservoirs air flooding: Oxidation reaction models and factors

A precise oxidation reaction model determines the reliability of numerical simulation results and the prediction of field performance of air injection-based enhanced oil recovery (EOR). By reviewing the classical oxidation reaction model and combining with geological characteristics of a low permeability reservoir, this work creatively divides pseudo-components and temperature regions and further proposes the improved low temperature oxidation (LTO), middle temperature oxidation (MTO), and high temperature oxidation (HTO) numerical models with chemical reaction coefficients. The EOR effects of reservoir temperature, permeability, air flow rate and bottom hole pressure during LTO and full temperature regions are determined on the basis of a 3D reservoir simulation model via CMG STARS. The results show that peak oil production rates of N2 flooding and LTO are 17.70 and 29.97 m3/d, respectively. The cumulative oil production in LTO stage is about 35%, which is higher than that in N2 flooding. The oxygen addition reaction in LTO stage can release much heat and increase sweep efficiency from thermal expansion and viscosity reduction. The peak oil production rates of LTO and full temperature oxidation (FTO) reactions are 42.16 and 44.34 m3/d, respectively, and the cumulative oil production of the FTO model was about 17% higher than that of LTO. The FTO model could more truly reflect the production performance during air flooding of low permeability oil reservoir. Strong oxygen consumption capacity and significant heat release effects can be observed under higher initial temperature, permeability, air flow rate, and lower bottom hole pressure. Thermal flooding and flue gas flooding are the main EOR mechanisms in FTO process. Considering the inescapable field problem of gas channeling, thorough contact between oil and air can be promoted by artificially preheating oil reservoir and adjusting air injection rate and pressure. Thus, oil recovery can be further improved under the premise of ensuring the safety of field application of air flooding technique.

Making Heterometallic Metal–Metal Bonds in Keggin-Type Polyoxometalates by a Six-Electron Reduction Process

Polyoxometalates (POMs) represent a promising class of molecular electron reservoirs. However, their multielectron reduction gives rise to intricate physical-chemical phenomena that must be fully understood for their future use in energy-storage devices. Herein, we show that bulk electrolysis of the archetypal Keggin-type POM [Si(WVI2MoVIO10)(WVI3O10)3]4- in aqueous solution leads to the six-electron-reduced derivative [Si(WIV2MoIVO7(H2O)3)(WVI3O10)3]4- (notated SiW11Mo-VI') in which the mixed-metal triad acts as a storage unit for six electrons and six protons. X-ray diffraction analysis and multinuclear NMR (183W and 95Mo) studies reveal that this electron-rich species represents the first example of POMs containing heterometallic metal-metal bonds between addenda centers. This electron-rich POM can be further reduced through multielectronic events, while its full oxidation restores the structure of the oxidized parent ion. Remarkably, the formation of SiW11Mo-VI' results from a fast clustering process compared to that observed for the entirely W-based analogue, revealing that the formation of metal-metal bonds in the mixed-metal Mo/W POM is facilitated because the reaction rate is not limited by a slow disproportionation step. Last, we evaluate the supramolecular properties of SiW11Mo-VI' using a method based on the cloud-point measurement of a nonionic surfactant. This investigation demonstrates that the clustering process has dramatic consequences on the solution behavior of the POM, canceling its superchaotropic character due to a local structuring effect of the hydration shell. These fundamental results pave the way for applications using the massive electron-storage properties of mixed-metal POMs.

Multifunctional Amorphous Co Phosphosulfide-Coated Fe-Co Carbonate Hydroxide for Highly Efficient Overall Water Splitting

Non-noble metal electrocatalysts current represent an appealing alternative to noble metal electrocatalysts for water oxidation reaction in alkaline conditions. However, the poor water reduction reaction activities limit their performance in driving overall water splitting in alkaline electrolytes. Here, we report the preparation of bifunctional amorphous Co phosphosulfide-doped Fe-Co carbonate hydroxide on the surface of Ni foam (Co-S-P/Fe1Co1COH/NF) through hydrothermal and electrochemical techniques. The efficient full water oxidation and reduction properties of the Co-S-P/Fe1Co1COH/NF were verified in pH = 14 medium. The results proved that a phosphorus and sulfur co-depositing catalyst could exhibit excellent anodic oxidation and cathodic reduction activity for full water splitting. Furthermore, the optimal electrocatalyst can afford a current density of 10 mA cm−2 at an overpotential of only 73 mV for hydrogen evolution from water reduction and 50 mA cm−2 at 160 mV for oxygen evolution from water oxidation in 1.0 M KOH solution, showing better activities than most non-noble metal materials. The improved electrocatalytic activities could be attributed to the increased number of active sites and the synergetic cooperation in the prepared material. Additionally, the Co-S-P/Fe1Co1COH/NF catalyst as both cathode and anode only needs a voltage of 1.5 V to achieve 10 mA cm−2 in 1 M KOH solution for full water splitting, which lays a good foundation for full water splitting in practical applications.

Oxidized β-Carotene Is a Novel Phytochemical Immune Modulator That Supports Animal Health and Performance for Antibiotic-Free Production.

Oxidized β-carotene (OxBC), a phytochemical that occurs naturally in plants, is formed by the spontaneous reaction of β-carotene with ambient oxygen. Synthetic OxBC, obtained by full oxidation of β-carotene with air, shows considerable promise as an in-feed antimicrobial alternative additive that enhances health and performance in livestock. OxBC is predominantly composed of β-carotene-oxygen copolymers that have beneficial immune-modulating effects that occur within the innate immune system by priming it to face microbial challenges and by mitigating the inflammatory response. OxBC does not have any direct anti-bacterial activity. Further, unlike traditional immune stimulants, OxBC modulates but does not stimulate and utilize the animal's energy stores unless directly stress-challenged. These immune effects occur by mechanisms distinct from the provitamin A or antioxidant pathways commonly proposed as explanations for β-carotene's actions. Trials in poultry, swine, and dairy cows with low parts-per-million in-feed OxBC supplementation have shown performance benefits over and above those of feeds containing regular vitamin and mineral premixes. Through its ability to enhance immune function, health, and performance, OxBC has demonstrated utility not only as a viable alternative to in-feed antimicrobials but also in its ability to provide tangible health and performance benefits in applications where antimicrobial usage is precluded.