Nd3+-doped TiO2 nanoparticles incorporated with heteropoly phosphotungstic acid: A novel solar photocatalyst for degradation of 4-chlorophenol in water

• A highly efficient, novel solar photocatalyst was synthesized by Nd3+ doping and heteropoly acid incorporation in nano TiO2.
• This catalyst showed higher rate of degradation of persistent organic pollutant, 4-chlorophenol under sunlight than the commercially available photocatalyst, Degussa P-25.
• Nd3+ doping and HPA addition were found to significantly increase the photocatalytic activity of TiO2 under sunlight.
• This study provides a versatile approach for the degradation of toxic compounds like 4-CP under sunlight.
• The new system, Nd3+-TiO2-HPA can be used for the development of an environmentally sustainable photocatalytic treatment process for the degradation of persistent organic pollutants using sunlight in place of an artificial UV light.

Different Nd3+-doped TiO2 nanoparticles incorporated with heteropoly phosphotungstic acid (HPA) (Nd3+-TiO2-HPA nanocomposites) were synthesized, and their structure and optical properties were characterized. UV–vis diffuse reflectance spectra of Nd3+-TiO2-HPA nanocomposites supported that the nanocomposites absorb visible light as well as ultra violet light. Consequently they exhibit efficient photocatalytic degradation of methylene blue (MB) upon illumination by the solar simulator, and the photocatalytic efficiency was found to depend on neodymium doping and heteropoly acid incorporation. These new photocatalysts were applied to the complete degradation of the organochlorine toxic chemical, 4-chlorophenol (4-CP) in water within 60 min upon sunlight illumination, indicating that Nd3+-TiO2-HPA nanocomposites would be very useful for cleaning polluted surface water by sunlight through the advanced oxidation process. Photocatalytic degradation pathway of 4-chlorophenol was examined using mass spectral analysis.

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