Research On Preparation Of Modified Carbon Composite Materials And Their Ultrasonic Catalytic Performance

A series of piezoelectronic materials designed and prepared based on the nanopiezotronics effect have been widely used in pollutant degradation.Especially by combining with many advanced catalytic oxidation processes,such as photocatalysis,photoelectrocatalysis and ultrasoniccatalysis,to degrade pollutants,an enhanced catalytic effect is achieved.However,its current efficiency is still far from satisfying,suffering from severe charge recombination.In addition some Pb-containing piezoelectronic materials have environmental problems and are not suitable for large-scale use in the future.Therefore,the development of a new type of piezoelectronic catalyst that is environmentally friendly,non-toxic,low in preparation cost,and has good catalytic effect has become an urgent problem to be solved.We use cheap activated carbon foam as the flexible substrates,and successfully assemble core-shell heterostructure on activated carbon foam.Here,based on the nanopiezotronics effect,we propose three CuO-BTO,CuO-B_0.77S_0.23TO and CuO-STO core-shell heterostructure composites.And the high durability heterostructures with single crystals are prepared by a facile method combining a solvothermal reaction and impregnation sintering.We studied the preparation process of the composite materials and the degradation effect on the target pollutants and analyzed the degradation mechanism.The main contents and research results are as follows:(1)Using melamine foam as the carbon source,we study the preparation process of activated carbon foam materials,and successfully assemble core-shell heterostructure on activated carbon foam.The heterostructure's photocatalytic performance can be largely enhanced by a four-way coupling effect among piezoelectricity,semiconductor,photoexcitation and ultrasonic.The built-in electric field by mechanical stimulation induced polarization can serve as a flexible autovalve to modulate the charge-transfer pathway and facilitate carrier separation both in the bulk phase and at the surfaces of semiconductors.The composite materials based on activated carbon foam have more convenient recyclability than powdered materials.Under excitations of concurrent ultrasound at ultrasonic power of 250W,ultrasonic frequency of 40KHz,the degradation ratios of CuO-BTO/AFC composites for Methyl orange(MO),Methylene blue(MB)and Phenol reached 93.91%,97.61% and 87.53%in 25 min,respectively.(2)In order to solve the insufficient piezoelectronic performance of BTO and further improve the performance of composite piezoelectric-effect-enhanced ultrasonic catalysis,two composite materials,CuO-B_0.77S_0.23TO/AFC and CuO-STO/AFC with a core-shell heterostructure were prepared.The degradation ratios of CuO-B_0.77S_0.23TO/AFC composites for MO,MB and Phenol reached 96.57%,98.92%and90.76%,respectively,within 25 minutes.The degradation ratios of CuO-STO/AFC composites for MO,MB and Phenol reached 95.02%,97.81%and 87.72%in 25 min,respectively,under the same reaction conditions.The catalysts present a similar contaminant removal ratio and degradation reaction rate across five runs,which is important for its practical application.