Continuous polypyrrole nanotubes encapsulated Co_(3)O_(4)nanoparticles with oxygen vacancies and electron transport channels boosting peroxymonosulfate activation

Co_(3)O_(4)particles are promising heterogeneous catalysts for peroxymonosulfate(PMS)activation;whereas they still surfer from the extensive agglomeration,serious Co leaching,poor electronic conductivity,and difficult recovery.Herein,a novel hybrid nanoarchitectonic constructed by encapsulating Co_(3)O_(4)nanoparticles into continuous polypyrrole(PPy)nanotubes(Co_(3)O_(4)@PPy hybrids)was developed using electrospun fibers as the templates,which boosted the catalytic degradation toward tetracycline(TC).The continuous polypyrrole nanotubes could provide the confined spaces,offer effective electron transfer pathway,suppress cobalt ion loss,facilitate the oxygen vacancy(Ovac)formation,and accelerate the Co^(2+)/Co^(3+)cycles.Co_(3)O_(4)@PPy hybrids thereby exhibited a remarkably enhanced catalytic activity with the TC degradation efficiency of 97.2%(kobs=0.244 min^(−1))within 20 min and total organic carbon(TOC)removal rate of 66.8%.Furthermore,the recycle test,real natural water treatment,and fluidized-column catalytic experiments indicated the potential of Co_(3)O_(4)@PPy hybrids in the practical large-scale applications.

Freestanding polypyrrole nanotube/reduced graphene oxide hybrid film as flexible scaffold for dendrite-free lithium metal anodes

Lithium metal anode is the most potential anode material for the next generation high-energy rechargeable batteries owing to its highest specific capacity and lowest redox potential.Unfortunately,the uneven deposition of Li during plating/stripping and the formation of uncontrolled Li dendrites,which might cause poor battery performance and serious safety problems,are demonstrating to be a huge challenge for its practical application.Here,we show that a flexible and free-standing film hybriding with polypyrrole(PPy) nanotubes and reduced graphene oxide(rGO) can significantly regulate the Li nucleation and deposition,and further prohibit the formation of Li dendrites,owing to the large specific surface area,rich of nitrogen functional groups and porous structures.Finally,the high Coulombic efficiency and stable Li plating/stripping cycling performance with 98% for 230 cycles at 0.5 mA cm^(-2) and more than 900 hours stable lifespan are achieved.No Li dendrites form even at a Li deposition capacity as high as4.0 mA h cm^(-2).Besides,the designed PPy/rGO hybrid anode scaffold can also drive a superior battery performance in the lithium-metal full cell applications.