Highly efficient K-doped Mn-Ce catalysts with strong K-Mn-Ce interaction for toluene oxidation

In this study,K_(x)-Mn-Ce catalysts prepared by sol-gel method were investigated for toluene oxidation.Compared with Mn-Ce,the catalytic performance of K_(x)-Mn-Ce was further improved.X-ray diffraction(XRD),high resolution transmission electron microscopy(HRTEM)and Raman analyses demonstrate that K ions enter the lattice of CeO_(2) and disperse uniformly.The results of X-ray photoelectron spectroscopy(XPS),H_(2)-temperature programmed reduction(H_(2)-TPR).and O_(2)-temperature programmed desorption(O_(2)-TPD)analyses indicate that there is a strong interaction between K,Mn and Ce;the charge co mpensation effect would be induced when K ions enter the lattice of CeO_(2),which leads to more oxygen vacancies due to the generation of more Ce^(3+).Toluene-TPD shows that K-doping enhances the activation ability of toluene.Among all catalysts,K0.1-Mn-Ce shows the highest concentration of Mn^(4+),Ce^(3+),Osur,and redox ability,resulting in higher low-temperature catalytic activity.Additionally,the results of stability and water resistance also prove that K0.1-Mn-Ce catalyst possesses excellent stability and water resistance.

The influences of silane coupling agents on the heat and moisture resistance of basalt fibre-reinforced composites

Basalt fibre composite materials have shown good application prospects in electrical equipment,but their reliability can be affected by damp-heat ageing.In this work,the interface,mechanical,and electrical properties of basalt fibre composites treated with three coupling agents via damp-heat ageing were compared.Molecular simulations were conducted to reveal the damp-heat ageing mechanism of the composites.The results show thatγ-aminopropyl triethoxy silane(KH-550)andγ-glycidoxy propyl trimethoxy silane(KH-560)perform better as coupling agents as they form bonds with the matrix resin,compared withγ-methacryloxy propyl trimethoxy silane(KH-570).After the dampheat ageing treatment,the hydrolysis of the defects of the amino groups in the interface of the KH-550-treated sample can weaken its mechanical properties and insulation properties greatly.The interface layer of the KH-560-treated sample is mostly composed of carbon–oxygen single bonds and methylene groups with its interface structure more stable,which endows the sample with better stability of its mechanical and insulating properties.Therefore,KH-560 is a more suitable coupling agent for processing basalt fibres to be used in electrical equipment.

The feasibility of continuous basalt fibre-reinforced polymer application to composite cross-arms

Composite cross-arms have the advantages of high lightning resistance but impose onerous requirements on mechanical and insulation reliability.Traditional glass fibre composites fail to meet the needs of practical applications.Basalt fibre exhibits better mechanical properties and stability than glass fibre and has potential application value.This study aims to evaluate the feasibility of its application to composite cross-arms.The mechanical,electrical,and physical properties of basalt fibre-reinforced polymer(BFRP)were investigated and compared with glass fibre-reinforced polymer(GFRP).The results indicate that BFRP has better thermal stability and mechanical properties than GFRP.Among them,the temperature at the maximum weight loss rate of BFRP is 14℃ higher than that of GFRP,and the tensile and flexural modulus of BFRP is 43%and 29%higher than those of GFRP.Furthermore,the dielectric losses of BFRP and GFRP at 50 Hz are 2%,and the breakdown field strength is 22 kV/mm,both of which have the same insulation properties.BFRP meets the requirements of composite cross-arm for quality and reliability to ensure the safety and stability of transmission lines.However,the interlaminar shear test and SEM show weak interfacial bonding strength between basalt fibre and resin.Furthermore,micro-computed tomography scanning of BFRP and GFRP and 3D construction of their internal microstructures indicate that the pore defect content of BFRP reaches 0.034%,which far exceeds that of GFRP.These findings show that the wettability and adhesion between basalt fibre and resin must be improved.Developing special sizing agents for basalt fibre is necessary further to improve the mechanical and electrical properties of BFRP.