Mechano-catalysis And Pyro-catalysis Of Ferroelectric NaNbO₃ Nanomaterials

In recent years,organic dye wastewater of textile industry has resulted in severe environmental pollution and health problems.So far,many chemical,physical,and biological treatment technologies have been developed to deal with dye wastewater,but still suffer many problems.It's well-known that vibration energy and heat energy are prevalent energy sources in our ordinary living environment.New and environmentally-friendly methods,including mechano-catalysis and pyro-catalysis,is designed to deal with dye wastewater harvesting environmental vibration energy and heat energy.Thus,ferroelectric NaNbO3 nanomaterials are synthesized and their pyro-catalytic and mechano-catalytic properties are studied in this work.The main content are as follows:1.Pyro-catalysis of ferroelectric NaNbO3 nanomaterials for room-temperature dye decompositionPyro-catalytic effect is realized in hydrothermally-synthesized ferroelectric NaNbO3 nanoparticles for Rhodamine B solution(-5 mg/L)via the product of pyroelectric effect and electrochemical redox.The influence of particle shape on the catalytic performance is also discussed.Under the 23-50? heating-cooling cycle,the maximum pyro-catalytic decomposition ratio of NaNbO3 nanorods,nanosheets and nanocubes are 96%,76%and 33%,respectively.Larger surface-to-volume ratio may result in higher active site density,achieving a higher decomposition ratio.2.Ferroelectric BiFeO3 nanomaterials for mechano-catalytic dye decomposition A?80%mechano-catalytic decomposition ratio of NaNbO3 nanomaterial is achieved for a Rhodamine B solution(?5 mg/L)after vibrating for?120 min.Strong oxidation middle active species,such as OH·,were also observed,which suggested the importance of piezoelectric effect in mechano-catalysis.Finally,the recycling experiments of NaNbO3 nanomaterials' mechano-catalytic decomposition of Rhodamine B dye were carried out.After four runs for the mechano-catalytic experiments,the mechano-catalytic decomposition is up to 75%.3.Mechano-/pyro-bi-catalysis of piezoelectric/pyroelectric NaNbO3 nanofibers for dye decompositionA mechano-/pyro-bi-catalysis of piezoelectric/pyroelectric NaNbO3 nanofibers for dye decomposition were performed to characterize the influence of bi-catalysis in catalytic efficiency.The mechano-/pyro-bi-catalytic decomposition efficiency of Rhodamine B solution(?5 mg/L)can reach up to-87%,which was much higher than the mechano-catalytic decomposition efficiency of?75%or the pyro-catalytic decomposition efficiency of-63%.