Novel synthetic route to Ce-Cu-W-O microspheres for efficient catalytic oxidation of vinyl chloride emissions

The solubility of ammonium tungstate in a special hydrothermal condition is exploited to synthesize uniform microspheres of Ce-Cu-W-O oxides.Compared to their W-undoped counterparts,they possess more Ce^3+ and oxygen vacancies,thereby promoting oxygen mobility.The formed rich WO3 surface can effectively provide acid sites,which is helpful for adsorption of vinyl chloride and interrupting the C-Cl bond.In addition,the presence of WO3 induces the formation of finer CuO nanoparticles with respect to the traditional coprecipitation method,thereby resulting in a better reducibility.Benefiting from both the enhanced acidity and reducibility,the Ce-Cu-W-O microspheres deliver excellent low-temperature vinyl chloride oxidation activity(a reaction rate of 2.01×10^-7 mol/(gcat·s)at 250℃)and high HCl selectivity.Moreover,subtle deactivation occurs after the three cycling activity tests,and a stable vinyl chloride conversion as well as mineralization are observed during the 72-h durability test at 300℃,which demonstrates good thermal stability.Our strategy can provide new insights into the design and synthesis of metal oxides for catalytic oxidation of chlorinated volatile organic compounds.

Closed Loop Recycling of Chlorine for Sustainable Development of Polyurethane Industry

Increasing demand is fueling the booming polyurethane industry worldwide. An impeding issue for poly- urethane industry is how to handle the large quantity of hydrogen chloride byproduct generated from the synthesis of intermediates, i.e., isocyanates. In the meantime, the traditional chloro-alkaline process sufibrs both from the high en- ergy intensity of electrolysis method and the disparity in the chlorine and caustic soda market. To solve these prob- lems, the state-of-the-art chlorine recycling technologies are reviewed and compared. Approaches for cost-effective utilization of chlorine in polyurethane industry are investigated. Chinese academies and enterprises＇ on-going effort on the development of a novel hydrogen chloride oxidation process for the synthesis of chlorine is presented. With this process, the closed loop recycling of chlorine can be realized. Tremendous economic, environmental and social bene- fits can be expected. A wide adoption of this technology will significantly advance the sustainable development of polyurethane industry.

Improving CNT-Si solar cells by metal chloride-to-oxide transformation

Transitional metal oxides(TMOs)are important functional materials in silicon-based and thin-film optoelectronics.Here,TMOs areapplied in carbon nanotube(CNT)-Si solar cells by spin-coating solutions of metal chlorides that undergo favorable transformation in ambient conditions.An unconventional change in solar cell behavior is observed after coating two particular chlorides(MoCl,and WCls,respectively),characterized by an initial severe degradation followed by gradual recovery and then well surpassing the original performance.Detailed analysis reveals that the formation of correspondina oxides(MoOa and WO.)enables two primary functions on both CNTs(p-type doping)and Si(inducing inversion layer),leading to significant improvement in open-circuit voltage and fill factor,with power conversion efficiencies up to 13.0%(MoOg)and 13.4%(WOg).Further combining with other chlorides to increase the short-circuit current,ultimate cells efficiencies achieve>16%with over 90%retention after 24 h,which are among the highes stable efficiencies reported for CNT-Si solar cells.The transformation of functional layers as demonstrated here has profoundinfluence on the device characteristics,and represents a potential strategy in low-cost manufacturing of next-generation high efficiency photovoltaics.

Mechanism of Hg^0 oxidation in the presence of HCl over a commercial V_2O_5–WO_3/TiO_2 SCR catalyst

Experiments were conducted in a fixed-bed reactor containing a commercial V2O5/WO3/TiO2 catalyst to investigate mercury oxidation in the presence of HCl and O2. Mercury oxidation was improved significantly in the presence of HCl and O2, and the Hg^0 oxidation efficiencies decreased slowly as the temperature increased from 200 to 400℃. Upon pretreatment with HCl and O2 at 350℃, the catalyst demonstrated higher catalytic activity for Hg^0 oxidation. Notably,the effect of pretreatment with HCl alone was not obvious. For the catalyst treated with HCl and O2, better performance was observed with lower reaction temperatures. The results showed that both HCl and Hg^0 were first adsorbed onto the catalyst and then reacted with O2 following its adsorption, which indicates that the oxidation of Hg^0 over the commercial catalyst followed the Langmuir–Hinshelwood mechanism. Several characterization techniques, including Hg^0temperature-programmed desorption（Hg-TPD） and X-ray photoelectron spectroscopy（XPS）, were employed in this work. Hg-TPD profiles showed that weakly adsorbed mercury species were converted to strongly bound species in the presence of HCl and O2. XPS patterns indicated that new chemisorbed oxygen species were formed by the adsorption of HCl, which consequently facilitated the oxidation of mercury.

Strong in-plane optical anisotropy in 2D van der Waals antiferromagnet VOCl

Two-dimensional(2D)van der Waals(vdW)magnetic materials with strong in-plane anisotropy can make possible novel applications such as optospintronics and strain sensors.In this work,the strong in-plane optical anisotropy in 2D vdW antiferromagnet VOCl has been systematically investigated.The optical brightness and absorption coefficient exhibit evident periodic variation with the change of incident polarization,unveiling the strong in-plane anisotropic optical absorption.The Raman intensity in this material shows obvious dependence on the polarization angle of incident laser,demonstrating that the phonon properties possess strong in-plane anisotropy.Besides,we have also realized in-situ visualization of in-plane optical reflection anisotropy in this material.Moreover,the strong second harmonic generation(SHG)signal can only be detected when the incident polarization is along specific in-plane crystal orientations,illustrating the presence of strong in-plane nonlinear optical anisotropy.These findings will benefit the applications of VOCl in the field of polarization-dependent electronics and spintronics.

Amorphous high-entropy phosphoxides for efficient overall alkaline water/seawater splitting

Designing and synthesizing cost-effective bifunctional catalysts for overall alkaline water/seawater splitting is still a huge challenge for hydrogen production.Herein,Co/Ni/Fe/Mn based-amorphous high-entropy phosphoxide self-standing electrode(CNFMPO)is synthesized by the facile and fast electrodeposition method.CNFMPO exhibits excellent bifunctional electrocatalytic performances on alkaline water/seawater electrolysis.The hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)overpotentials of CNFMPO in alkaline water/seawater are as low as 43/73 and 252/282 mV to reach a current density of 10 mA cm^(-2),respectively.Additionally,two-electrode electrolyzers with CNFMPO||CNFMPO successfully achieve the current density of 10 mA cm^(-2) at low voltages of 1.54 and 1.56 V for overall alkaline water/seawater splitting,respectively.CNFMPO exhibits satisfactory long-term stability on overall alkaline water/seawater splitting for the surface reconstruction into active metal hydroxide/(oxy)hydroxide,phosphite,and phosphate.Moreover,no hypochlorite is detected during seawater electrolysis for the beneficial chlorite oxidation inhibition of the reconstructed phosphite and phosphate.The excellent catalytic performances of CNFMPO are due to the unique amorphous structure,multi-component synergistic effect,beneficial electronic structure modulation,and surface reconstruction during the catalytic reaction process.Therefore,CNFMPO has shown potential promotion to the development of the water/seawater splitting industry as a promising substituent for noble-metal electrocatalysts.This work provides new insights into the design of efficient bifunctional catalysts for overall water/seawater splitting.