Photocurrent and hydrogen production by overall water splitting based on polymeric composite Calix[n]arene/Cyanin Dye/IrO2 nanoparticle

Abstract In this study, a new photoelectrochemical cell based on overall splitting of water into oxygen and hydrogen is constructed to obtain an improved photocurrent under a visible range of light. The photoanode was obtained by a gold electrode (GE) modified with carboxylic acid functionalized SH-Calix-4-arene-COOH and IrO2 nanoparticles attached light absorbing cyanine dye via polymeric oligoaniline linkages. The conductive polymer, 4- (4H-Dithieno [3,2-b: 2 ′, 3′-d] pyrrol-4-yl)aniline, was coated on GE using electropolymerization and used as a photocathode after platinum nanoparticles (Pt) were attached on the surface. The system was illuminated under the visible light, and the water was oxidized via IrO2 catalyst to produce hydrogen on the photocathode side while oxygen on the photoanode. A photocurrent density of 182.03 μA cm−2 was obtained by direct transfer of electrons without using a mediator. The bilirubin oxidase (BOx) enzyme was successfully used to remove excess oxygen from the reaction chamber and a further increase in photocurrent was reached up to 272.44 μA cm−2. Hydrogen production in the reaction chamber was measured by gas chromatography at different time intervals and a maximum of 1.25 × 10−8 mol cm−2 was obtained.