Cobalt-Doping Induced Formation of Five-Coordinated Nickel Selenide for Enhanced Ethanol Assisted Overall Water Splitting.

To overcome the low efficiency of overall water splitting, highly effective and stable catalysts are in urgent need, especially for the anode oxygen evolution reaction (OER). In this case, nickel selenides appear as good candidates to catalyze OER and other substitutable anodic reactions due to their high electronic conductivity and easily tunable electronic structure to meet the optimized adsorption ability. Herein, an interesting phase transition from the hexagonal phase of NiSe (H-NiSe) to the rhombohedral phase of NiSe (R-NiSe) induced by the doping of cobalt atoms is reported. The five-coordinated R-NiSe is found to grow adjacent to the six-coordinated H-NiSe, resulting in the formation of the H-NiSe/R-NiSe heterostructure. Further characterizations and calculations prove the reduced splitting energy for R-NiSe and thus the less occupancy in the t2g orbits, which can facilitate the electron transfer process. As a result, the Co2 -NiSe/NF shows a satisfying catalytic performance toward OER, hydrogen evolution reaction, and (hybrid) overall water splitting. This work proves that trace amounts of Co doping can induce the phase transition from H-NiSe to R-NiSe. The formation of less-coordinated species can reduce the t2g occupancy and thus enhance the catalytic performance, which might guide rational material design.

Highly efficient photosynthesis of hydrogen peroxide in ambient conditions.

Photosynthesis of hydrogen peroxide (H2O2) in ambient conditions remains neither cost effective nor environmentally friendly enough because of the rapid charge recombination. Here, a photocatalytic rate of as high as 114 µmol⋅g-1⋅h-1 for the production of H2O2 in pure water and open air is achieved by using a Z-scheme heterojunction, which outperforms almost all reported photocatalysts under the same conditions. An extensive study at the atomic level demonstrates that Z-scheme electron transfer is realized by improving the photoresponse of the oxidation semiconductor under visible light, when the difference between the Fermi levels of the two constituent semiconductors is not sufficiently large. Moreover, it is verified that a type II electron transfer pathway can be converted to the desired Z-scheme pathway by tuning the excitation wavelengths. This study demonstrates a feasible strategy for developing efficient Z-scheme photocatalysts by regulating photoresponses.

An Effective Approach to Enhance Hydrogen Evolution Reaction and Hydrogen Oxidation Reaction by Ni Doping to MoO3.

The development of bifunctional catalysts that facilitate both the hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR) in alkaline environment is crucial for realizing unitized regenerative anion-exchange membrane fuel cells. In this study, a novel strategy to modulate the electron density of MoO3 through Ni doping (sample named Nix Mo1- x O3 ) is reported. Ni is incorporated to replace Mo atoms in MoO3 . Specifically, Nix Mo1- x O3 is combined with optimal adsorption energy, along with MoO2 /Mo2 N hybrid with high conductivity. The resulting Nix Mo1- x O3 supported on MoO2 /Mo2 N hybrid (sample named as Nix Mo1- x O3 -H) exhibits excellent alkaline HER activity, with an overpotential of only 16 mV at 10 mA cm-2 and a Tafel slope of 54 mV dec-1 . In addition, the Nix Mo1- x O3 -H demonstrates an ultrahigh HOR performance with a high exchange current density (3.852 mA cm-2 ). The catalyst's breakdown potential of 0.23 V indicates its ability to withstand higher voltages without breaking down. As evidenced by the results, this characteristic leads to improved stability. These results are higher than those of the other catalysts reported, which indicates that the electron density of MoO3 can be effectively modulated through Ni doping, leading to excellent HER and HOR performance.

Electronic Structure Modulation of Nickel Sites by Cationic Heterostructures to Optimize Ethanol Electrooxidation Activity in Alkaline Solution.

It is a good idea for efficient production of hydrogen to use ethanol oxidation reaction (EOR) in place of oxygen evolution reaction (OER) in water electrolysis process. Ni-based non-precious electrocatalysts are widely used in the conversion of ethanol to acetic acid. Here, different selenide heterostructures (NiCoSe, NiFeSe, and NiCuSe) are prepared in which Ni sites are regulated by transition metal. The valence state of Ni is NiCuSe < NiCoSe < NiFeSe in the three heterojunctions. NiCoSe shows the optimized charge distribution of Ni sites and outstanding catalytic activity. The effective modulations lead to optimized d-band center and facilitates both adsorption and desorption of reaction intermediates, which improves the kinetics of EOR. The results of this work prove that with appropriate designed catalyst it is possible to replace kinetically slow OER with faster EOR in water electrolysis to produce hydrogen.

Electrocatalytic Synthesis of Pyridine Oximes using in Situ Generated NH2 OH from NO species on Nanofiber Membranes Derived from NH2 -MIL-53(Al).

Pyridine oximes produced from aldehyde or ketone with hydroxylamine (NH2 OH) have been widely applied in pharmaceutics, enzymatic and sterilization. However, the important raw material NH2 OH exhibits corrosive and unstable properties, leading to substantial energy consumption during storage and transportation. Herein, this work presents a novel method for directly synthesizing highly valuable pyridine oximes using in situ generated NH2 OH from electrocatalytic NO reduction with well-design nanofiber membranes (Al-NFM) derived from NH2 -MIL-53(Al). Particularly, 2-pyridinealdoxime, the precursor of antidote pralidoxime (2-PAM) for nerve agents suffering from scarcity and high cost, was achieved with a Faraday efficiency up to 49.8 % and a yield of 92.1 %, attributing to the high selectivity of NH2 OH production on Al-NFM, further easily reacted with iodomethane to produce 2-PAM. This study proposes a creative approach, having wide universality for synthesizing pyridine and other oximes with a range of functional groups, which not only facilitates the conversion of exhaust gas (NO) and waste water (NO2 - ) into valuable chemicals especially NH2 OH production and in situ utilization through electrochemistry, but also holds significant potential for synthesis of neuro detoxifying drugs to humanity security.

Transition Metal d-band Center Tuning by Interfacial Engineering to Accelerate Polysulfides Conversion for Robust Lithium-Sulfur Batteries.

Although lithium-sulfur batteries (LSBs) promise high theoretical energy density and potential cost effectiveness, their applications are severely impeded by the shuttling and sluggish redox kinetics of lithium polysulfides (LiPSs). In this context, a Co9 S8 @MoS2 heterostructure is sophisticatedly designed as an efficient catalytic host to boost the sulfur reduction reaction/evolution reaction (SRR/SER) kinetics and suppresses the LiPSs shuttling in LSBs. The results indicate that the electronic structure is manipulated in the Co9 S8 @MoS2 heterostructure, where the built-in electric fields (BIEFs) within the heterointerfaces enable the sufficient adsorption sites to accelerate the ionic diffusion/charge transfer kinetics for LiPSs redox, thus enhancing the sulfur conversion. By tuning the electronic structure, the metal d-band of Co9 S8 @MoS2 heterostructure plays an important role in adsorbing and catalyzing the conversion of LiPSs, thus promoting the reaction kinetics of the corresponding LSBs. This work unlocks the potential of heterostructures as promising catalysts to the design of high-energy and stabilized LSBs.

Versailles Project on Advanced Materials and Standards interlaboratory study on intensity calibration for x-ray photoelectron spectroscopy instruments using low-density polyethylene.

We report the results of a Versailles Project on Advanced Materials and Standards interlaboratory study on the intensity scale calibration of x-ray photoelectron spectrometers using low-density polyethylene (LDPE) as an alternative material to gold, silver, and copper. An improved set of LDPE reference spectra, corrected for different instrument geometries using a quartz-monochromated Al Kα x-ray source, was developed using data provided by participants in this study. Using these new reference spectra, a transmission function was calculated for each dataset that participants provided. When compared to a similar calibration procedure using the NPL reference spectra for gold, the LDPE intensity calibration method achieves an absolute offset of ∼3.0% and a systematic deviation of ±6.5% on average across all participants. For spectra recorded at high pass energies (≥90 eV), values of absolute offset and systematic deviation are ∼5.8% and ±5.7%, respectively, whereas for spectra collected at lower pass energies (<90 eV), values of absolute offset and systematic deviation are ∼4.9% and ±8.8%, respectively; low pass energy spectra perform worse than the global average, in terms of systematic deviations, due to diminished count rates and signal-to-noise ratio. Differences in absolute offset are attributed to the surface roughness of the LDPE induced by sample preparation. We further assess the usability of LDPE as a secondary reference material and comment on its performance in the presence of issues such as variable dark noise, x-ray warm up times, inaccuracy at low count rates, and underlying spectrometer problems. In response to participant feedback and the results of the study, we provide an updated LDPE intensity calibration protocol to address the issues highlighted in the interlaboratory study. We also comment on the lack of implementation of a consistent and traceable intensity calibration method across the community of x-ray photoelectron spectroscopy (XPS) users and, therefore, propose a route to achieving this with the assistance of instrument manufacturers, metrology laboratories, and experts leading to an international standard for XPS intensity scale calibration.

FeOOH Nanocubes Anchored on Carbon Ribbons for Use in Li/O2 Batteries.

A composite of FeOOH nanocubes anchored on carbon ribbons has been synthesized and used as a cathode material for Li/O2 batteries. Fe2+ ion-exchanged resin serves as a precursor for both FeOOH nanocubes and carbon ribbons, which are formed simultaneously. The as-prepared FeOOH cubes are proposed to have a core-shell structure, with FeOOH as the shell and Prussian blue as the core, based on information from XPS, TEM, and EDS mapping. As a cathode material for Li/O2 batteries, FeOOH delivers a specific capacity of 14816 mA h g-1 cathode with a cycling stability of 67 cycles over 400 h. The high performance is related to the low overpotential of the oxygen reduction/evolution reaction on FeOOH. The cube structure, the supporting carbon ribbons, and the -OOH moieties all contribute to the low overpotential. The discharge product Li2 O2 can be efficiently decomposed in the FeOOH cathode after a charging process, leading to higher cycling stability. Its high activity and stability make FeOOH a good candidate for use in non-aqueous Li/O2 batteries.

Noncontact Detection of Respiration Rate Based on Forward Scatter Radar.

Bioradar-based noncontact breathing detection technology has been widely studied due to its superior detection performance. In this paper, a breath detection mechanism based on the change in radar cross section (RCS) is proposed by using a forward scatter radar and the deduction of the mathematical model of the received signal. Furthermore, we completed human breathing detection experiments in an anechoic chamber and in an ordinary chamber; we obtained the breathing rate through envelope detection in cases where the human orientation angle was 0, 30, 60, and 90°. The analysis of the measured data shows that the theoretical model fits well with the measured results. Compared with the existing single-base radar detection schemes, the proposed scheme can detect human respiratory rates in different orientations.

[Surface Enhanced Spectroscopy Based on Lab-on-a-Chip Technology and Its Applications in Analytical Science].

In integrating lab-on-a-chip (LOC) technologies facilitated with a series of microfluidic units, microfluidic channels, with substrates put into metal nanoparticles, especially when gold, silver or copper nanoparticles, were prepared and pumped into µl or nl analytes. This sample preparation methods have important significance in real time, in-situ trace- or processing reaction analysis jointing with surface enhanced spectroscopies (SES).This combined technologies would integrate the mertis of the two technologies of lab-on-a-chip LOC and SES. LOC has the advantages of minuming the amount of analytes and stable test environments for step by step processing operations to achieve screening samples, segmentating, real-time detecting and so on, whiel SES has the characteristics of fast spectral response, high sensitivemess and selectivness,and in-situ detectoring. On the base of Drude medol and appropriate boundary conditions, external electric field induces localizing plasmon oscillation of valence electron of metal nano particles, then which derivates the mechannisms of resonant localized suface plasmon enhancement and electromagnetic enhancement mechanism of the surface enhanced Raman scattering by dipole polarization. In this paper, combined LOC and localized surface plasmon resonance technologies analysed in biological, pharmaceutical and food safety fileds with additional channels prompting detecting efficiencies and the limits of trace detections further being broken out. This paper also summarizes the application of chip laboratory technology in the fields of public safety testing, biomedical medicine detecting, electrochemical or biological sensors with surface enhanced Raman spectroscopieswhich were capable of high sensitivitiness and molecular spectral fingerprint. LOC technologies have gotten great develoment in their respective fileds, especially combinning with 3D fingerprint technologies, which could precisely control the sizes of 3D structures and high-accuracy manufacture 3D structures according to the special purpose. LSPR and SERS have been more maturing in some applications of near filed imaging and Tip-enhanced Raman spectroscopies (TERS), which have the ability to break through the optical limit of conventional microscopes and do that the width and depth of the SES technologies have been greatly extended in the micro and nano scales. So The jointed technologies would have a bright prospects in the practical applications for the qualitative and semi quantitative determination of trace analysis.

Structural evolution analysis and cold-crystallization kinetics of spherical crystals in poly(trimethylene terephthalate) film using Raman spectroscopy.

Dynamic processes and the structural evolution of cold-crystallized poly(trimethylene terephthalate) (PTT) film were investigated using Raman spectroscopy. Raman scattering of C[double bond, length as m-dash]O stretching vibration was related to the molecular chain movement and structure evolution in PTT during cold crystallization. In particular, information about each phase of crystallization, including induction, nucleation, nucleus growth, and secondary crystallization, was thoroughly revealed. The experimental results indicated that the kinetic parameters measured by the Raman method were in good agreement with those obtained by differential scanning calorimetry (DSC) and infrared spectroscopy. The blue-shifted C[double bond, length as m-dash]O stretching vibration resulting from the crystallization process is a popular phenomenon and may therefore have many potential applications in a wide range of areas.

Interaction at the silicon/transition metal oxide heterojunction interface and its effect on the photovoltaic performance.

The interfacial reaction and energy level alignment at the Si/transition metal oxide (TMO, including MoO3-x, V2O5-x, WO3-x) heterojunction are systematically investigated. We confirm that the interfacial reaction appears during the thermal deposition of TMO, with the reaction extent increasing from MoO3-x, to V2O5-x, and to WO3-x. The reaction causes the surface oxidation of silicon for faster electron/hole recombination, and the reduction of TMO for effective hole collection. The photovoltaic performance of the Si/TMO heterojunction devices is affected by the interface reaction. MoO3-x are the best hole selecting materials that induce least surface oxidation but strongest reduction. Compared with H-passivation, methyl group passivation is an effective way to reduce the interface reaction and improve the interfacial energy level alignment for better electron and hole collection.

Hierarchical Li electrochemistry using alloy-type anode for high-energy-density Li metal batteries.

Exploiting thin Li metal anode is essential for high-energy-density battery, but is severely plagued by the poor processability of Li, as well as the uncontrollable Li plating/stripping behaviors and Li/electrolyte interface. Herein, a thickness/capacity-adjustable thin alloy-type Li/LiZn@Cu anode is fabricated for high-energy-density Li metal batteries. The as-formed lithophilic LiZn alloy in Li/LiZn@Cu anode can effectively regulate Li plating/stripping and stabilize the Li/electrolyte interface to deliver the hierarchical Li electrochemistry. Upon charging, the Li/LiZn@Cu anode firstly acts as Li source for homogeneous Li extraction. At the end of charging, the de-alloy of LiZn nanostructures further supplements the Li extraction, actually playing the Li compensation role in battery cycling. While upon discharging, the LiZn alloy forms just at the beginning, thereby regulating the following Li homogeneous deposition. The reversibility of such an interesting process is undoubtedly verified from the electrochemistry and in-situ XRD characterization. This work sheds light on the facile fabrication of practical Li metal anodes and useful Li compensation materials for high-energy-density Li metal batteries.

Orbital Occupancy Modulation to Optimize Intermediate Absorption for Efficient Electrocatalysts in Water Electrolysis and Zinc-Ethanol-Air Battery.

Spin engineering is a promising way to modulate the interaction between the metal d-orbital and the intermediates and thus enhance the catalytic kinetics. Herein, an innovative strategy is reported to modulate the spin state of Co by regulating its coordinating environment. o-c-CoSe2-Ni is prepared as pre-catalyst, then in situ electrochemical impedance spectroscopy (EIS) and in situ Raman spectroscopy are employed to prove phase transition, and CoOOH/Co3O4 is formed on the surface as active sites. In hybrid water electrolysis, the voltage has a negative shift, and in zinc-ethanol-air battery, the charging voltage is lowered and the cycling stability is greatly increased. Coordinated atom substitution and crystalline symmetry change are combined to regulate the absorption ability of reaction intermediates with balanced optimal adsorption. Coordinated atom substitution weakens the adsorption while the crystalline symmetry change strengthens the adsorption. Importantly, the tetrahedral sites are introduced by Ni doping which enables the co-existence of four-coordinated sites and six-coordination sites in o-c-CoSe2-Ni. The dz2 + dx2-y2 orbital occupancy decreases after the atomic substitution, while increases after replacing the CoSe6-Oh field with CoSe6-Oh/CoSe4-Td. This work explores a new direction for the preparation of efficient catalysts for water electrolysis and innovative zinc-ethanol-air battery.

Fe Cluster Modified Co9 S8 Heterojunction: Highly Efficient Photoelectrocatalyst for Overall Water Splitting and Flexible Zinc-Air Batteries.

Designing bifunctional low-cost photo-assisted electrocatalysts for converting solar and electric energy into hydrogen energy remains a huge challenge. Herein, a heterojunction (Fe cluster modified Co9 S8 loaded on carbon nanotubes, Co9 S8 -Fe@CNT) for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is demonstrated. Benefiting from the good electronic conductivity and spatial confinement of the carbon skeleton, as well as the electronic structure regulation of the Fe cluster, Co9 S8 -Fe@CNT exhibits excellent catalytic performance with a low overpotential of 150 mV for OER and 135 mV for HER at 10 mA cm-2 . Upon light irradiation, holes and electrons are generated in the valence band and conduction band of the Co9 S8 , respectively. Part of the charges are transferred to the interface to facilitate the catalytic reaction, while the remaining are transferred by the electrode. When working as a bifunctional catalyst for overall water splitting, the performance can reach 1.33 V at under light conditions, which is significantly better than 1.52 V in a dark environment. Theoretical calculations revealed lowered Gibbs free energy (∆GH *) of the heterojunction with the effect of Fe modification of Co9 S8 . This work sheds a new light in designing novel photoelectrochemical materials to convert solar and electric energy into chemical energy.

[XRD, FTIR and XPS analysis of oxidized particles from Dongshengmiao pyrite-polymetallic sulfide deposit, inner Mongolia].

In the present paper, characteristics of material compositions, phase structures, surface element states, and transformation mechanism of oxidized particles from Dongshengmiao pyrite-polymetallic sulfide deposit were studied using modern analytical testing technology including XRD, FTIR and XPS. The results show that the samples consist of gypsum, calcite, quartz, muscovite, goethite, organic matter, etc. Primary ore in deep oxidation zone mainly under went such processes as oxidization, hydrolysis, dehydration and carbonation. Compared to the surface oxidation zone of arid and extremely arid regions in the northwestern China, the oxidation process and oxidizing condition of the deep oxidation zone were less complex. New mineral type was also not found, and extensively developed sulfate minerals were rare to be seen. The research results can not only be applied to mineral identification of oxidized particles from this type of ore deposit but also play an important role in ore exploration, mining, mineral processing, etc.

Enhanced ethanol oxidation reaction of CoSeO3 by Ni-doping for water electrolysis and an innovative zinc-ethanol-air battery.

By doping Ni into m-CoSeO3, the structure of the catalyst was modified to improve the Ethanol Oxidation Reaction (EOR) catalytic performance. The catalyst exhibited excellent EOR catalytic activity (j10 = 1.35 V) and high stability. Therefore, this catalyst is used in an innovative zinc-ethanol-air battery, which is more efficient and stable than the traditional zinc-air battery.

Quasi-In Situ XPS Insights into the Surface Chemistry of Garnet-Type Li6.4La3Zr1.4Ta0.6O12 Solid-State Electrolytes: The Overlooked Impact of Pretreatments and a Direct Observation of the Formation of LiOH.

Garnet-type Li6.4La3Zr1.4Ta0.6O12 (LLZTO) is a highly promising solid-state lithium metal battery electrolyte due to its exceptional ionic conductivity and electrochemical stability. However, when exposed to air, a passivation layer can be spontaneously formed on the garnet-type electrolyte, deteriorating its wettability with metallic lithium (Li) and impeding the lithium ion transfer at the Li-garnet electrolyte interface. The passivation layer is considered a critical issue for garnet-type solid electrolytes. Despite intensive research, the formation mechanism of the passivation film remains poorly understood. The key to elucidating the formation mechanism is to obtain a pristine garnet electrolyte surface and study how the pristine garnet electrolyte interacts with air. In this study, different passivation layer removal pretreatments were performed to expose pristine garnet electrolytes, and their impacts on the samples were systematically studied. The results reveal the overlooked negative impacts of vacuum annealing and acid treatment on LLZTO, which are indicated by the severe loss of Li and O and the formation of additional Li-depleted metal oxides. It was confirmed that argon annealing is the only viable approach to remove the passivation layer without introducing concomitant contaminations to LLZTO. Based on this method, we directly evidenced the formation of LiOH on LLZTO under rarefied air using quasi-in situ X-ray photoelectron spectroscopy. It was confirmed that the loss of Li and O ions, rather than Li+/H+ exchange, drives the formation of LiOH in the passivation layer. These results not only provide a better understanding of the surface and interface chemistry of LLZTO but also reveal a reliable surface treatment for the LLZTO sample.

Construction of Schottky contact by modification with Pt particles to enhance the performance of ultra-long V2O5 nanobelt photodetectors.

Schottky-contacted nanosensors have attracted extensive attention due to their high sensitivity and fast response time. In this article, we proved that the construction of Schottky contact by Pt nanoparticles (NPs) decoration can effectively improve the performance of V2O5 nanobelts photodetectors. After modified by Pt NPs, the photocurrent of V2O5 nanobelts is increased by more than two orders of magnitude, and the photoresponse speed is improved by at least three orders of magnitude. Detailed studies have shown that the performance enhancement is attributed to the formation of the Schottky contact at the electrode-semiconductor interface due to the decrease of surface gas adsorption and the increase of V2O5 work function after Pt NPs modification. The strong built-in field in the Schottky barrier region will quickly separate photogenerated carriers, thereby reducing the electron-hole recombination rate, resulting in the fast response time and an increase in the free carrier density. Moreover, it is found that this enhancement effect can be regulated by controlling the pressure to modulating the Schottky barrier height at the interface. Overall, the Pt NPs-modified V2O5 nanobelts photodetector exhibits a broad response spectrum (visible to near infrared), fast rise/fall response time (less than 6.12/6.15 ms), high responsivity (5.6 A/W), and high specific detectivity (6.9 × 108 Jones). This study demonstrates the feasibility of building a Schottky barrier to enhance the photodetection performance, which provides a general and effective strategy towards the construction and its practical application of supersensitive and fast-response nanosensors.

Janus bimetallic materials as efficient electrocatalysts for hydrogen oxidation and evolution reactions.

The development of hydrogen energy is limited by the high cost of platinum group metals (PGM). There is an urgent need to design efficient PGM-free electrocatalysts in the hydrogen electrode. Herein, Janus Ni/W bimetallic materials are proposed as an effective PGM-free bifunctional hydrogen electrocatalyst. By constructing the bimetallic materials, a synergistic effect is realized to enhance the reaction kinetics and improve the catalytic performance. In general, Ni can provide excellent Had sites, and W serves as OHad sites. Therefore, the synergistic effect of Ni and W can improve the kinetics of hydrogen evolution reaction and the hydroxide oxidation reaction. Ni/W@NF can obtain the hydrogen evolution reaction current density of 10 mA cm-2 with an overpotential of only 62.6 mV, and the exchange current density of hydroxide oxidation reaction can reach 1.83 mA cm-2. This work provides a new idea for the design of high-efficiency and low-cost PGM-free bifunctional hydrogen electrocatalysts.