Porous Polyviologen-Polyoxometalate Based Photocatalysts And Their Applications In Degradation Of Methyl Orange And Formaldehyde

Photocatalytic degradation of dyes wastewater and indoor air pollutants as a safe and environmentally friendly technology has attracted worldwide attention.However,currently it is still lack of photocatalysts that can be efficiently regenerated with stable performance.In line with these,in this study,the polyviologen（PV）and polyoxometalates（POM）composite material（POM-PV）was designed and synthesized as the support of Ag@AgBr or Ag and g-C₃N₄ catalysts for promotion their photocatalytic performance including regeneration.For the degradation of dyes in wastewater,phosphomolybdic acid（HPMo）as the POM,the impregnation of Ag@AgBr photocatalyst in PMo-PV and its application in degradation of methyl orange were studied.Results showed that the Ag@AgBr@PMo-PV catalyst had abundant porous structure and showed its high photocatalytic activity,being better than the Ag@AgBr and commercial P25 catalysts.In the presence of H2O2,the Ag@AgBr@PMo-PV catalyst also showed much better reproducibility than that of the Ag@AgBr catalyst.When phosphotungstic acid（HPW）was used as the POM,the preparation of the Ag@PW-PV’（PV’ is modified polyviologen）catalyst was investigated through a series of modification and condition optimization.Results showed that the Ag@PW-PV’ catalyst not only had much higher photocatalytic activity,but also had much better reproducibility even under air condition.For the degradation of indoor air pollutant formaldehyde,the impregnation of g-C₃N₄ photocatalyst in PW-PV was studied.Results showed that the g-C₃N₄@PW-PV catalyst had abundant porous structure;compared with the performance of the pristine g-C₃N₄ photocatalyst,g-C₃N₄@PW-PV showed good dispersibility in water,which is advantageous for combination with waterborne coatings.In the degradation of methyl orange and formaldehyde,the g-C₃N₄@PW-PV catalyst showed higher photocatalytic performance than the pristine g-C₃N₄ catalyst,revealing its potential industrial application.