Tri-profit electrolysis for energy-efficient production of benzoic acid and H_(2)

Electrosynthesis has recently attracted intensive research attentions and holds great potential in implementing scalable green synthesis thanks to more and more readily accessible renewable electric energy.

Fabrication of WO3/TiO2 Heterostructures for Efficiently Photocatalytic Gaseous Hydrocarbons Degradation:Origin of Photoactivity and Revisit the Role of WO3 Decoration

Efficient oxidation of gaseous small molecular hydrocarbons under mild conditions remains a significant but challenging task to date. Here we report that WO3 decoration can obviously improve the performance of TiO2 （P25） toward the photocatalytic oxidation of several small molecular hydrocarbons （C2H6, C3H8 and C2H4） under simulated solar light irradiation. Among the WO3/TiO2 heterostructures, the 10wt%WO3/TiO2 nanocomposite shows the best photoactivities, which can efficiently oxidize C2H6, C3H8 and C2H4 within 15, 9 and 8 minutes, respectively under simulated sunlight with a light intensity of 200 mW/cm2. By strong contrast, a decreased photoactivity of TiO2 by coupling with WO3 is observed when investigating the performance of photocatalysts toward the degradation of methylene blue （MB） in liquid phase. The opposing effect of WO3 decoration on the performance of TiO2 is thoroughly investigated, and it is found that the improved photoactivities for gaseous hydrocarbon degradation is ascribed to the enhanced oxygen adsorption, resulting from WO3 decoration rather than efficient charge separation within the WO3/TiO2 heterostructures.

Defect engineering of single-walled carbon nanohorns for stable electrochemical synthesis of hydrogen peroxide with high selectivity in neutral electrolytes

Hydrogen peroxide(H_(2)O_(2))is one of the most important chemicals,which are commonly used in the paper and pulp industry,water purification and environmental protection[1-3].Most of the commercial available H_(2)O_(2) is produced by the anthraquinone oxidation process,which is environment unfriendly.

Novel 2D bifunctional layered rare-earth hydroxides@GO catalyst as a functional interlayer for improved liquid-solid conversion of polysulfides in lithium-sulfur batteries

The detrimental“shuttle effect”of lithium polysulfides(LiPSs)together with sluggish multi-order reaction kinetics are the main drawbacks hindering lithium-sulfur(Li-S)batteries from commercial success.Here,we first propose the implementability of layered rare-earth hydroxides(LREHs)in Li-S batteries to optimize electrochemical performance.In this work,a two-dimensional(2D)rare-earth-based composite constructed by the layered gadolinium hydroxy chloride[Gd_(2)(OH)_(5)(H_(2)O)_(n)]Cl nanoplates(LGdH NPs)and graphene oxide(GO)was designed as a sulfur immobilizer for Li-S batteries.Combining the experimental results and density functional theory(DFT)calculations,it is revealed that the LGdH@GO composite not only provides a strong anchoring of the intermediates during cycling,but also acts as an effective catalyst to accelerate the liquid-solid conversion of polysulfides.The Li-S batteries assembled by LGdH@GO modified separators delivered a superior rate performance with a specific capacity of 605.34 mAh/g at 5 C,as well as excellent cycle stability with a decay rate of 0.087%over 500 cycles at 2 C.This study provided a deep understanding of the mechanism to suppress the“shuttle effect”by the LREHs,and a guide to design effective functional interlayers for high-performance Li-S batteries with excellent electrocatalytic activity.

Bifunctional Mn-doped CoSe_(2) nanonetworks electrode for hybrid alkali/acid electrolytic H_(2) generation and glycerol upgrading

Electrolytic water splitting,as a promising route to hydrogen(H_(2))production,is still confronted with the sluggish anodic oxygen evolution reaction(OER)and its less value-added O2 production.Herein,we report a bifunctional electrode fabricated by in situ growth of Mn-doped CoSe_(2)nanonetworks on carbon fiber cloth(Mn-CoSe_(2)/CFC),which shows attractive electrocatalytic properties toward glycerol oxidation reaction(GOR)in alkali and hydrogen evolution reaction(HER)in acid.A flow alkali/acid hybrid electrolytic cell(fA/A-hEC)was then developed by coupling anodic GOR with cathodic HER with the Mn-CoSe_(2)/CFC bifunctional electrode.Such fA/A-hEC enables a rather low voltage of 0.54 V to achieve 10 mA cm^(-2),and maintain long-term electrolysis stability over 300-h operation at 100 mA cm^(-2)with Faraday efficiencies of over 99%for H_(2)and 90%for formate production.The designed bifunctional electrode in such innovative fA/A-hEC device provides insightful guidance for coupling energy-efficient hydrogen production with biomass upgradation.

A strategy for accurate detection of glucose in human serum and whole blood based on an upconversion nanoparticles-polydopamine nanosystem

The accurate detection of blood glucose is of critical importance in the diagnosis and management of diabetes and its complications. Herein, we report a novel strategy based on an upconversion nanoparticles-polydopamine （UCNPs-PDA） nanosystem for the accurate detection of glucose in human serum and whole blood through a simple blending of test samples with ligand-free UCNPs, dopamine, and glucose oxidase （GOx）. Owing to the high affinity of lanthanide ions exposed on the surface of ligand-free UCNPs, dopamine monomers could spontaneously attach to the UCNPs and further polymerize to form a PDA shell resulting in a remarkable upconversion luminescence （UCL） quenching （97.4%） of UCNPs under 980-nm excitation. Such UCL quenching can be effectively inhibited by H2O2 produced from the GOx/glucose enzymatic reaction, thus enabling the detection of H2O2 or glucose based on the UCL quenching/inhibition bioassay. Owing to the highly sensitive UCL response and background-free interference of the UCNPs-PDA nanosystem, we achieved a sensitive, selective, and high-throughput bioassay for glucose in human serum and whole blood, thereby revealing the great potential of the UCNPs-PDA nanosystem for the accurate detection of blood glucose or other HRO2-generated biomolecules in clinical bioassays.

Boosting single-band red upconversion luminescence in colloidal NaErF_4 nanocrystals:Effects of doping and inert shell

Single-band red upconversion luminescence(UCL) is vital to in vivo bioimaging as well as "see and treat" biomedicines. Herein, starting with the previously reported β-NaErF4:Tm UCNPs, we examined the effects of both Yb^(3+) doping and inert shell coating on the red-to-green(R/G) ratio for Er3+ based UCL. The doping of Yb^(3+) into the β-NaErF4:Tm3+ core not only enhances the whole UCL intensity, but also raises the R/G ratio by 1.25 times. In addition, the coating of an inert NaYF4 shell, which is usually adopted for the enhancement of UCL intensity, further boosts the R/G value up to as high as 77.92. This work may benefit the potential bioimaging application of single-band red UCL.

Recovery of thorium and rare earths from leachate of ion-absorbed rare earth radioactive residues with N1923 and Cyanex■572

Ion-absorbed rare earth ores radioactive residues(IREORR)are a class of waste residue from the production of rare earth elements(REEs).Because of its radioactive dose,IREORR are usually stored in waste warehouses.IREORR are difficult to be disposed of.However,it contains relatively high concentrations of REEs,which can be considered as a valuable secondary resource.In this paper,a novel process is developed for the separation of thorium(Th)and recovery of REEs from IREORR hydrochloric acid leachate with primary amine N1923 and Cyanex?572,respectively.The effects of sulfate concentration,extractant concentration and pH on N1923 extraction in hydrochloric acid solution were investigated in detail.The results show that the extraction capacity of N1923 can be improved by adding sulfate to the solution and increasing the concentration of N1923.Acidity has little effect on the extraction of Th when pH is higher than 1.As for the stripping,REEs are more easily stripped from loaded organic phase than Th,and nitric acid is a better stripping agent than hydrochloric acid.Combined with the extraction of Cyanex■572 for REEs,a fractional extraction experiment for separating Th and enriching of REEs was performed.The yield of Th is higher than 99.9%and the concentration of REEs is enriched to 183.84 g/L.

In-situ Growth of Carbon Nanosheets Intercalated with TiO_(2) for Improving Electrochemical Performance and Stability of Lithium-ion Batteries

In situ growth of carbon nanomaterials on active substance is a very favorable strategy for the preparation of electrode in lithium-ion batteries with excellent electrochemical performance and high stability.Small-sized TiO_(2) nanoparticles intercalated into carbon nanosheets(CNS@TiO_(2)SNP-600)were successfully synthesized via in-situ polymerization-carbonization method,utilizing layered H_(2)Ti_(4)O_(9)(HTO)as template and benzidine as carbon source.The morphology and size of TiO_(2) are greatly influenced by carbonization temperature.The coin cell with the CNS@TiO_(2)SNP-600 electrode demonstrates a discharge specific capacity of 430.4 mAh·g^(-1) at a current density of 0.1 A·g^(-1),and the capacity retention rate is 88.1%after 100 cycles;and it also displays a high discharge specific capacity of 101.8 mAh·g^(-1) at a high current density of 12.8 A·g^(-1).The excellent electrochemical performances can be ascribed to the capacitance effect originated from the intercalated structure of in-situ grown CNS and TiO_(2) nanoparticles.We believe this type of materials can be widely used in the lithium-ion batteries and other related green chemical fields.

Separation and recovery of rare earth from waste nickel-metal hydride batteries by phosphate based extraction-precipitation

A novel type of extraction-precipitation strategy based on phosphate was developed to recover rare earth(RE,i.e.,La,Ce,Nd,and Pr)from waste nickel-metal hydride(NiMH)batteries.This method does not require saponification and organic solvents.The novel phosphates,i.e.,dibenzyl phosphate(DBP),diphenyl phosphate(DPP),triphenyl phosphate(TPP)were studied as extraction-precipitants.DBP has high precipitation efficiencies for RE^(3+),which can reach 97.84%,100%,100%and 99.77%,respectively.In addition,the precipitation efficiencies of Mn^(2+),Co^(2+)and Ni^(2+)are less than 1.75%.DBP-RE has the largest particle size(D10=52.6μm,D50=135.35μm,D90=296.08μm),which is much larger than the precipitations formed by NH_(4)HCO_(3),H_(2)C2O_(4),CaO and MgO.The larger precipitation particle sizes contribute to improving the solid-liquid separation efficiency.With 3 mol/L hydrochloric acid,the stripping efficiency of DBP-RE reaches 98.60%,and the purity of recovered RE is 99.85%.The regenerated DBP can be directly used for the recycling extraction.Therefore,the novel extraction-precipitation strategy is a green and sustainable separation method.

Synthesis of NaYF_(4):20% Yb^(3+),2% Er^(3+),2% Ce^(3+)@NaYF_(4) nanorods and their size dependent uptake efficiency under flow condition

Lanthanide doped fluorescent nanoparticles have gained considerable attention in biomedical applications.However,the low uptake efficiency of nanoparticles by cells has limited their applications.In this work,we demonstrate how the uptake efficiency is affected by the size of nanoparticles under flow conditions.Using the same size NaYF_(4):20%Yb^(3+),2%Er^(3+),2%Ce^(3+)(the contents of rare earths elements are in molar fraction)nanoparticles as core,NaYF_(4):20%Yb^(3+),2%Er^(3+),2%Ce^(3+)@NaYF_(4) core-shell structured nanorods(NRs)with different sizes of 60-224 nm were synthesized by thermal decomposition and hot injection method.Under excitation at 980 nm,a strong upconversion green emission(541 nm,^(2)H_(11/2)→^(4) I_(15/2) of Er^(3+))is observed for all samples.The emission intensity for each size nanorod was calibrated and is found to depend on the width of NRs.Under flow conditions,the nanorods with 96 nm show a maximum uptake efficiency by endothelial cells.This work demonstrates the importance of optimizing the size for improving the uptake efficiency of lanthanide-doped nanoparticles.

Organic polystyrene and inorganic silica double shell protected lead halide perovskite nanocrystals with high emission efficiency and superior stability

The practical application of all-inorganic semiconductor lead halide perovskite nanocrystals(LHP NCs)has been limited by their poor stability.Recently,a lot of research on core-shell structure has been done to improve the stability of perovskite NCs,but the effect was far from the application requirements.Herein,we,for the first time,report a convenient approach to synthesize organic-inorganic double shell CsPbBr_(3)@SiO_(2)@polystyrene(PS)NCs with an inter-core of CsPbBr_(3),the intermediate layer of SiO_(2)shell,and outmost PS shell.Particularly,the CsPbBr_(3)@SiO_(2)@PS NCs maintained more than 90%of their initial photoluminescence(PL)intensity under one month's ultraviolet lamp irradiation or in 85℃ and 85%relative humidity(RH)condition.The white-light-emitting-diodes(WLEDs)were fabricated by encapsulating commercial InGaN chip with CsPbBr_(3)@SiO_(2)@PS NCs and K2SiF6:Mn^(4+)(KSF:Mn^(4+))phosphor with a luminous efficacy of~100 lm/W at 20 mA current and a color gamut of 128%of the National Television Standards Committee(NTSC)standard.In addition,these WLEDs still maintain 91%of the initial luminous efficacy after 1200 h of continuous lighting.These results demonstrated that double shell-protected CsPbBr_(3)perovskite NCs have great potential in the field of WLEDs.

Precipitation transformation of rare earth sulfate into chloride with p-dodecylphenoxy carboxylic acids

Methods for transforming rare earth(RE)sulfate into chloride mainly include extraction process with organophosphonic mono-acids or aliphatic acids and precipitation process with ammonium bicarbonate(NH4 HCO3).In this paper,alkylphenoxy carboxylic acids(HAs)ofp-dodecylphenoxy acetic acid(HA-Ⅰ),pdodecylphenoxypropanoic acid(HA-Ⅱ)and p-dodecylphenoxybutyric acid(HA-Ⅲ),which were liquid at room temperature were synthesized and characterized.The precipitation mechanisms of RE elements with the HAs were investigated and the HA/RE molar ratios of the solid complexes were determined as3:1 by equi-molar series method which accord with the principle of charge balance.Applicability of HAs for the transformation of RE sulfate from concentrated sulfuric acid roasted RE concentrate into chloride via precipitation method was discussed.100%HA-Ⅱwas selected as the liquid organic precipitant without dilution of volatile solvent soracceleration of phase separation by phase-modifiers.The RE sulfate solution can be precipitated by HA-Ⅱafter neutralization with liquid NaOH and stripped with concentrated HCl at room temperature.High concentration of RE chloride of 218.1 g/L with low residue of sulfate radical of 0.536 g/L was obtained.The residual organic precipitant in the raffinate solution was tested to be lower than 8 mg/L at 25℃and the chemical oxygen demand(COD)in wastewater was less than 50 mg/L.

"Chameleon-like" optical behavior of lanthanide-doped fluoride nanoplates for multilevel anti-counterfeiting applications

Lanthanide-based luminescent anti-counterfeiting materials are widely used in various kinds of products.However,the emission color of traditional lanthanide-based luminescent materials usually remains nearly unaltered upon different excitation lights,which may only work for single-level anti-counterfeiting.Herein,the NaYbF4∶2%Er@NaYF4 core/shell nanoplates (NPs) with "chameleon-like" optical behavior are developed.These NPs display single-band red or green downshifting (DS) emission upon excitation at 377 or 490 nm,respectively.Upon 980 nm excitation,the color of upconversion (UC) emission can be finely tuned from green to yellow,and to red with increasing the excitation power density from 0.1 to 4.0 W/cm^2.The proposed materials readily integrate the advantages of excitation wavelength-dependent DS single-band emissions and sensitive excitation power-dependent UC multicolor emissions in one and the same material,which has never been reported before.Particularly,the proposed NPs exhibit excellent performance as security labels on trademark tag and security ink on painting,thus revealing the great potential of these lanthanide-doped fluoride NPs in multilevel anti-counterfeiting applications.

Preface to the Special Issue of Rare Earth Luminescent Materials

Lanthanide photonics,and more particularly lanthanide luminescence,is at the heart of applications as diverse as lighting devices,displays,lasers,optical fibers and associated telecommunication networks,security markings,solar energy conversion and photocatalysis,or bioanalysis and bioimaging.

Precise Construction of Stable Bimetallic Metal–Organic Frameworks with Single-Site Ti(IV) Incorporation in Nodes for Efficient Photocatalytic Oxygen Evolution

Assembling the reactive low-cost Co clusters and photoresponsive ligands in the form of metal–organic frameworks(MOFs)is a promising strategy to construct efficient water-oxidizing photocatalysts,but it is restricted by poor water stability.Introducing high valent cations in the clusters to build heterometallic Co-MOFs might be a solution,yet a precise fabrication strategy is still challenging.

Stress-induced CsPbBr3 nanocrystallization on glass surface:Unexpected mechanoluminescence and applications

In this work,we discovered an unexpected mechanoluminescence (ML) phenomena occurring when transforming amorphous into crystalline,due to the stress-induced precipitation of CsPbBr3 perovskite nanocrystals on glass surface.It is revealed that,unlike the conventional thermal-induced phase transformation mechanism,the breakage of bonding of glass network provides the energy for nucleation and growth,and the shear stress avoids the long-range migration of structural units for crystallization.Such unique ML phenomenon enables the visualization of dynamical force that is inaccessible by common strategy,and so,opens up some novel applications,such as the pressure-sensitive "glassy pencil" to learn people's writing habits,and the pb^2+-detection with good sensitivity and selectivity.These findings not only demonstrate an effective route for the preparation of perovskite materials in a green,time-saving,low cost,and scalable way,enrich the knowledge of glass crystallization mechanism,but also exploit a useful avenue to quantitatively visualize the dynamical force.

TiO2-Ti3C2 Composites with Pt Decoration as Efficient Photocatalysts for Ethylene Oxidation under Near Infrared Light Irradiation

Efficient utilization of solar energy is highly desirable in the field of photocatalysis. However, the near-infrared part of the solar spectrum, which constitutes about 44% of sunlight, has rarely been used. Herein, we report that the TiO2 coupled with MXene Ti3C2 nanosheets shows promising photoactivity for ethylene oxidation under near infrared light（NIR） irradiation. Moreover, the Pt nanoparticle decoration can dramatically improve the performance of TiO2–Ti3C2 nanocomposites. Within 15 minutes irradiation of the NIR light, 444 ppm of C2 H4 is completely removed over 1 wt%Pt–TiO2–Ti3C2 and the catalyst exhibits excellent stability. It is expected that our work could provide useful information for the design and synthesis of efficient and stable NIR active photocatalyst for the target applications.

Precursor chemistry towards highly efficient and phase-stable red emitting CsPbI_(3) perovskite nanocrystals

All-inorganic cesium lead halide perovskite nanocrystals(CsPbX_(3),X=Cl,Br,I)have attracted considerable scientific and technological interest due to their precise bandgap tunability,high color purity and efficient luminescence.Nevertheless,their poor stability in harsh conditions such as moisture,ultraviolet(UV)light irradiation and high temperature,is a major obstacle for their further commercial applications.Herein,by simply using a new type of precursor,namely“HPbX_(3)”(X=Cl,Br,I),we can achieve the coordination equilibrium for Pb precursors during reaction and obtain high-quality perovskite nanocrystals with tremendously enhanced luminous efficiency and chemical stability based on hot-injection method.The prepared a-CsPbb nanocrystals exhibit an extremely high photoluminescence quantum yield of 96%and keep stable in air for more than two months without any post-synthesis treatment.Moreover,stability evaluations under UV light irradiation,water or thermal impact are also performed and the results show substantially improved stability of these nanocrystals as compared with the samples prepared using traditional Pbl_(2) as precursor.Through temperature-dependent(10-300 K)steady and transient spectral analysis combined with compositional measurements,it is revealed that the lower structural defect density,which is guaranteed by abundant halogen when using HPbX3 as precursor,is the most important reason for such performance enhancement.

Inorganic-organic Hybrid Cathodes for Fast-charging and Long-cycling Zinc-ion Batteries

Here we report the utilization of inorganic-organic hybrid(IOH)as a new type of cathode material for aqueous Zn-ion batteries.The IOH possessing a unique lattice-water-rich layered structure achieves high long-term cycling stability(81.5%capacity retention over 1500 cycles)and ultrafast charging capability(~90%state of charge about 1 minute).