Latest development of double perovskite electrode materials for solid oxide fuel cells:a review

Recently,the development and fabrication of electrode component of the solid oxide fuel cell(SOFC)have gained a significant importance,especially after the advent of electrode supported SOFCs.The function of the electrode involves the facilitation of fuel gas diffusion,oxidation of the fuel,transport of electrons,and transport of the byproduct of the electrochemical reaction.Impressive progress has been made in the development of alternative electrode materials with mixed conducting properties and a few of the other composite cermets.During the operation of a SOFC,it is necessary to avoid carburization and sulfidation problems.The present review focuses on the various aspects pertaining to a potential electrode material,the double perovskite,as an anode and cathode in the SOFC.More than 150 SOFCs electrode compositions which had been investigated in the literature have been analyzed.An evaluation has been performed in terms of phase,structure,diffraction pattern,electrical conductivity,and power density.Various methods adopted to determine the quality of electrode component have been provided in detail.This review comprises the literature values to suggest possible direction for future research.

Biochar characterization of invasive Pennisetum purpureum grass:effect of pyrolysis temperature

Pennisetum purpureum is one of the most invasive perennial grasses of the Poaceae family,which are abundant in south-east Asia including Brunei Darussalam.The pyrolysis process at a slow heating rate proved to be highly promising for biochar production.The production and characterization of different Pennisetum purpureum biochars have been investigated at the pyrolysis temperatures of 400℃,500℃and 600℃with a heating and nitrogen flow rate of 5℃/min and 0.5 L/min,respec-tively.The observed higher heating values were 22.18 MJ/kg,23.02 MJ/kg,23.75 MJ/kg,and the alkaline pH were 9.10,9.86,10.17 for the biochar at 400℃,500℃,600℃temperatures,respectively.The water holding capacity was one hundred percent for all biochars and continued to increase for higher pyrolysis temperature.SEM images show that the porosity of the biochars has been enhanced with increased temperatures due to the rearrangement of crystallinity and aromaticity.On the other hand,the yields of biochar have been decreased from 35.13%to 23.02%for the increase of pyrolysis temperature from 400℃to 600℃.Energy dispersive X-ray analysis shows that the O/C atomic ratios were 0.15,0.08 and 0.06 for the biochar of 400,500 and 600℃which validates the improvement in heating values.FT-IR analysis revealed that the available functional groups in the biochars were C-O,C=C,and C-H.Thermogravimetric analysis(TGA)under pyrolysis condi-tion showed residue of 46.56%,51.13%and 55.67%from the biochar at 400,500,and 600℃,respectively.The derivative thermogravimetry(DTG)graph indicates that the degradation rate is higher for 400℃biochar than the 600℃biochar.