Visible-light-induced reduction of Cr(VI) by PDPB-ZnO nanohybrids and its photo-electrochemical response

Abstract Photochemical conversion of solar photons is one of the most promising solutions to produce usable forms of energy such as electricity, solar fuels and environmental remediation. We have developed an efficient visible light active poly(diphenylbutadiyne) (PDPB)-ZnO nanohybrids (NHs) by facile adsorption of ZnO nanoparticles on PDPB nanofibers. The as‐prepared PDPB-ZnO NHs demonstrated enhanced photocatalytic activity compared to bare PDPB for the photoreduction of hexavalent chromium Cr(VI). Among the hybrid photocatalysts, PDPB-ZnO with 10 wt% of PDPB exhibited highest catalytic activity for Cr(VI) reduction under visible light irradiation. X-ray photoelectron spectroscopy data revealed the presence of Cr(III) on the surface of nanohybrid during photo-reduction of Cr(VI). The enhanced photocatalytic activity of nanohybrids could be attributed from the co-sensitization of ZnO NPs by oligomeric and polymer chain unit of PDPB nanofibers and efficient separation of photogenerated charge carriers as followed by impedance analysis and photocurrent measurements. PDPB-ZnO NHs showed enhanced photoelectrochemical current density by a factor of ∼8.1 compared to bare PDPB nanofibers and long-term stability under longer visible light illumination. The Mott–Schottky plot revealed that photo generated charge carrier concentration has been increased for PDPB-ZnO NHs (8.5 × 1019  cm−3) compare to pure ZnO (2.5 × 1019  cm−3). The present study provide an effective approach for the development of organic-inorganic nanohybrids which are suitable for photocatalytic removal of heavy metal ions as well as photoelectrochemical response revealing water splitting that would be useful in designing future solar devices.