Performance Analysis of Plant Shells/PVC Composites under Corrosion and Aging Conditions

To make full use of plant shellfibers(rice husk,walnut shell,chestnut shell),three kinds of wood-plastic com-posites of plant shellfibers and polyvinyl chloride(PVC)were prepared.X-ray diffraction analysis was carried out on three kinds of plant shellfibers to test their crystallinity.The aging process of the composites was conducted under 2 different conditions.One was artificial seawater immersion and xenon lamp irradiation,and the other one was deionized water spray and xenon lamp irradiation.The mechanical properties(tensile strength,flexural strength,impact strength),changes in color,water absorption,Fourier transform infrared spectroscopy(FTIR),and microstructures of the composites before and after the two aging experiments were analyzed.The results showed that the chestnut shell had the highest crystallinity,which was 42%.The chestnut shell/PVC composites had the strongest interface bonding,the least internal defects,and the best general mechanical properties among the three composites.Its tensile strength,bending strength and impact strength were 23.81 MPa,34.12 MPa,and 4.32 KJ·m^(-2),respectively.Comparing the two aging conditions,artificial seawater immersion and xenon lamp irradiation destroyed the quality of the combination of plant shellfibers and PVC,making the internal defects of the composites increase.This made the water absorption ability and changes in the color of the composites more obvious and led to a great decrease in the mechanical properties.The general mechanical properties of the chestnut shell/PVC composites were the best,but their water absorption ability changed more obviously.

In-situ study for the elastic structure evolutions of threedimensional Ir-O framework during the oxygen evolution reaction in acid

Understanding the dynamic structural and chemical evolutions at the catalyst-electrolyte interfaces is crucial for the development of active and stable electrocatalysts.In this work,β-Li_(2)IrO_(3)is employed as a model catalyst for the oxygen evolution reaction(OER).Its elastic three-dimensional Ir-O framework enables us to investigate the Li^(+)cation dissolution-induced structure evolutions and the formation mechanism of amorphous IrO_(x)species.Electrochemical measurements by rotating ring disk electrode(RRDE)reveal that up to 60%of the measured OER current can be ascribed to catalyst degradation.A series of in-situ X-ray diffraction spectroscopy(XRD),X-ray absorption spectroscopy(XAS),and Raman spectroscopy are conducted.Structure vibration is observed with oxidation states of Ir being reduced abnormally during OER at high potentials.It’s hypothesized that the reversible proton intercalations are responsible for the Ir turn-over mechanism.Results of this work demonstrate a stable and elastic iridate structure and reveal the initial catalyst degradation behaviors during OER in acid media.