Ti-Fe_(2)O_(3)/Ni(OH)_(x) as an efficient and durable photoanode for the photoelectrochemical catalysis of PET plastic to formic acid

Photoelectrochemical(PEC) technology provides a promising prospect for the transformation of polyethylene terephthalate(PET) plastic wastes to produce value-added chemicals.The PEC catalytic systems with high activity,selectivity and long-term durability are required for the future up-scaling industrial applications.Herein,we employed the interfacial modification strategy to develop an efficient and stable photoanode and evaluated its PEC activity for ethylene glycol(EG,derived from PET hydrolysate) oxidation to formic acid.The interfacial modification between Fe_(2)O_(3)semiconductor and Ni(OH)xcocatalyst with ultrathin TiO_(x) interlayer not only improved the photocurrent density by accelerating the kinetics of photogenerated charge carriers,but also kept the high Faradaic efficiency(over 95% in 30 h) towards the value-added formic acid product.This work proposes an effective method to promote the PEC activity and enhance the long-term stability of photoelectrodes for upcycling PET plastic wastes.

A perspective on the PGM-free metal–nitrogen–carbon catalysts for PEMFC

Introduction Atomically dispersed transition metals embedded in nitrogendoped carbons(M–N–C) represent a typical kind of platinum group-free(PGM-free) catalyst which is considered as a potential candidate for the cathode of proton-exchange membrane fuel cells(PEMFCs) [1–3]. Apart from their low cost, the advantage of the M–N–C catalysts over PGM is further underlined by their good poisoning-resistance to impurities in fossil-derived hydrogen, such as carbon monoxide and sulfur-containing compounds [4,5].

Solution-processed all-inorganic lead halide perovskite/layered double hydroxides superlattices

Quantum wells and superlattices are key building blocks in the semiconductor industry,normally fabricated using epitaxial growth techniques,such as vapor phase epitaxy,metalorganic chemical vapor deposition and molecular beam epitaxy.However,these complicated preparation processes,as well as their high cost,limit their extensive applications.It is essential to develop a simple solution process for building superstructures.Here,we demonstrate an ion exchange strategy for synthesizing an allinorganic superlattice cesium lead bromide/layered double hydroxides(CsPbBr_3/LDH)in solution.At room temperature,the perovskite ions diffuse into the interlayer of LDH and assemble into layered perovskite with various thicknesses.Compared with traditional organic-inorganic hybrid perovskite superlattice,the all-inorganic perovskite superlattice CsPbBr_(3)/LDH has weak quantum confinement,which exhibits narrow emission line-widths of 20 nm,high quantum yields of 55%,and radiative lifetimes of several ns.Our findings offer a new route to synthesize novel perovskite superlattices and enrich the perovskite supercrystal platform for electronics,photonics and optoelectronics devices.

Temperature-insensitive KNN-based ceramics by elevating O-T phase transition temperature and crystal texture

The inferior temperature stability of piezoelectric response is the main drawback of KNN-based ceramics.Here,the Ba-doped 0.97(K0.48Na0.52)(Nb0.96Sb0.04)O3-0.03Bax(Bi0.5Ag0.5)1-xZrO3(abbreviated as KNNSBxBAZ)textured ceramics were prepared by the template grain growth(TGG)method.Excellent comprehensive properties(d33¼(406±15)pC/N,TC=274℃,strain is 0.17%)were achieved in KNNSBxBAZ textured ceramics with x=0.2.Meanwhile,its piezoelectric and strain properties also show superior temperature stability(d33 maintained within±20%change in awide temperature range from 25℃to 200℃and strain variation was less than 5%in the temperature range from room temperature to 165℃).The high O-T phase transition temperature(TO-T is 110℃)induced by incorporating Ba ions accounts for the enhanced temperature stability of piezoelectric properties.In addition,the crystal texture always maintains the contribution of piezoelectric anisotropy to the piezoelectric properties during elevated temperature,which significantly improved the temperature stability of piezoelectric properties.This work provides an effective strategy for simultaneously achieving high piezoelectric response and excellent temperature stability in KNN-based ceramics.

Observation of Refractive Index Line Shape in Ultrafast XUV Transient Absorption Spectroscopy

Ultrafast extreme ultraviolet (XUV) transient absorption spectroscopy measures the time- and frequencydependent light losses after light–matter interactions. In the linear region, the matter response to an XUV light field is usually determined by the complex refractive index ̃n. The absorption signal is directly related to the imaginary part of ̃n, namely, the absorption index. The real part of ̃n refers to the real refractive index, which describes the chromatic dispersion of an optical material. However, the real refractive index information is usually not available in conventional absorption experiments. Here, we investigate the refractive index line shape in ultrafast XUV transient absorption spectroscopy by using a scheme that the XUV pulse traverses the target gas jet off-center. The jet has a density gradient in the direction perpendicular to the gas injection direction, which induces deflection on the XUV radiation. Our experimental and theoretical results show that the shape of the frequency-dependent XUV deflection spectra reproduces the refractive index line profile. A typical dispersive refractive index line shape is measured for a single-peak absorption;an additional shoulder structure appears for a doublet absorption.Moreover, the refractive index line shape is controlled by introducing a later-arrived near-infrared pulse to modify the phase of the XUV free induction decay, resulting in different XUV deflection spectra. The results promote our understanding of matter-induced absorption and deflection in ultrafast XUV spectroscopy.

Performance enhancement of paper-based SERS chips by shell-isolated nanoparticle-enhanced Raman spectroscopy

Paper-based flexible surface-enhanced Raman scattering(SERS) chips have been demonstrated to have great potential for future practical applications in point-of-care testing(POCT) due to the potentials of massive fabrication, low cost, efficient sample collection and short signal acquisition time. In this work,common filter paper and Ag@Si O2 core-shell nanoparticles(NP) have been utilized to fabricate SERS chips based on shell-isolated nanoparticle-enhanced Raman spectroscopy(SHINERS). The SERS performance of the chips for POCT applications was systematically investigated. We used crystal violet as the model molecule to study the influence of the size of the Ag core and the thickness of the Si O2 coating layer on the SERS activity and then the morphology optimized Ag@Si O2 core-shell NPs was employed to detect thiram. By utilizing the smartphone as a miniaturized Raman spectral analyzer, high SERS sensitivity of thiram with a detection limit of 10^-9 M was obtained. The study on the stability of the SERS chips shows that a Si O2 shell of 3 nm can effectively protect the as-prepared SERS chips against oxidation in ambient atmosphere without seriously weakening the SERS sensitivity. Our results indicated that the SERS chips by SHINERS had great potential of practical application, such as pesticide residues detection in POCT.

Coupling the Xinanjiang model with geomorphologic instantaneous unit hydrograph for flood forecasting in northeast China

The Xinanjiang(XAJ)model has been successfully applied in humid and semi-humid regions.Considering the geomorphologic factors to accurately estimate floods,this study adopted the geomorphologic instantaneous unit hydrograph(GIUH)method to calculate the surface runoff instead of the experience unit hydrograph(EUH)in the original model.The geomorphologic factors of the case study basin were obtained by using a digital elevation model(DEM)and the Terrain analysis using Digital Elevation Models(TauDEM).Furthermore,the dynamic Muskingum model was used for the channel flood routing.This study focused on the simulation of heavy precipitation and floods over the Chong River,which is a tributary river to the Songhua River on the right bank in northeast China.The detailed steps of the method were shown,up to the estimated value of flood runoff discharges and flood peaks and their comparison with observed values.The average deterministic coefficients(DCs)of model calibration and validation were 0.89 and 0.83,respectively.The results show that the model precision is high and the model is feasible for flood forecasting.Lastly,some methodological perspectives to enhance the method are presented.

Studies of nanoparticle delivery with in vitro bio-engineered microtissues

A variety of engineered nanoparticles,including lipid nanoparticles,polymer nanoparticles,gold nanoparticles,and biomimetic nanoparticles,have been studied as delivery vehicles for biomedical applications.When assessing the efficacy of a nanoparticle-based delivery system,in vitro testing with a model delivery system is crucial because it allows for real-time,in situ quantitative transport analysis,which is often difficult with in vivo animal models.The advent of tissue engineering has offered methods to create experimental models that can closely mimic the 3D microenvironment in the human body.This review paper overviews the types of nanoparticle vehicles,their application areas,and the design strategies to improve delivery efficiency,followed by the uses of engineered microtissues and methods of analysis.In particular,this review highlights studies on multicellular spheroids and other 3D tissue engineering approaches for cancer drug development.The use of bio-engineered tissues can potentially provide low-cost,high-throughput,and quantitative experimental platforms for the development of nanoparticle-based delivery systems.

One-pot synthesis of CoO-ZnO/rGO supported on Ni foam for high-performance hybrid supercapacitor with greatly enhanced cycling stability

The high specific capacitance along with good cycling stability are crucial for practical applications of supercapacitors,which always demands high-performance and stable electrode materials.In this work,we report a series of ternary composites of CoO-ZnO with different fractions of reduced graphene oxide(rGO)synthesized by in-situ growth on nickel foam,named as CZG-1,2 and 3,respectively.This sort of binder-free electrodes presents excellent electrochemical properties as well as large capacitance due to their low electrical resistance and high oxygen vacancies.Particularly,the sample of CZG-2(CoO-ZnO/rGO 20 mg)in a nanoreticular structure shows the best electrochemical performance with a maximum specific capacitance of 1951.8 F/g(216.9 mAh/g)at a current intensity of 1 A/g.The CZG-2-based hybrid supercapacitor delivers a high energy density up to 45.9 Wh/kg at a high power density of 800 W/kg,and kept the capacitance retention of 90.1%over 5000 charge-discharge cycles.

Electric field-induced photoluminescence quenching in Pr-doped BNT ceramics across the MPB region

Piezophotonics is a great interesting field of physics that has led to a number of important technologies,such as light source,smart sensors,and mechatronics.In this work,we reported Pr-doped(Bi_(0.5)Na_(0.5))TiO_(3)-based lead-free ceramics with strong red photoluminescence emission and large strain response(d_(33)^(*)=460 pm/V,S=0.32%).The PL emission can be quenched by decreasing the intensity by 93%after electrical polarization(E=50 kV/cm).The local structure and electric field-induced structural changes were systematically investigated to reveal the significant distinction in photoluminescence properties caused by electrical polarization.The results indicated that polarization treatment eliminates the structural inhomogeneities and establishes a long-range ferroelectric tetragonal and rhombohedral distortion.The crystal structure transformed irreversibly from a non-ergodic to a normal ferroelectric state.PL quenching originated from the decreased distortion of octahedral due to the transition from a non-ergodic state to a highly ordered symmetrical structure.Meanwhile,the enlarged domain structure contributed to the photoluminescence quenching effect.Our findings demonstrate that an electric field can be a robust tool for adjusting the photoluminescence property and provide insights into the rela-tionship between the structure and PL properties of BNT-based ceramics under an external stimulus.