Photoelectrochemical biofuel cell using porphyrin-sensitized nanocrystalline titanium dioxide mesoporous film as photoanode

Electrical energy generated directly from sunlight and biomass solution with a Photoelectrochemical Biofuel Cell (PEBFC) was investigated. The PEBFC consisted of a meso-tetrakis(4-carboxyphenyl)porphyrin (TCPP)-sensitized nanocrystalline titanium dioxide (TiO2) mesoporous film (NTDMF) as the photoanode and platinum black as the cathode. The interaction between TCPP sensitizer and NTDMF was evaluated by X-ray photoelectron spectra and FT-IR absorption spectra, indicating that the TCPP sensitizer was adsorbed on the NTDMF by bridging or bidentate coordinate bonds. The spectroscopic properties of pure TCPP ethanol solution and TCPP-sensitized NTDMF were obtained by UV–vis absorption spectra, demonstrating that the characteristic absorption peaks of TCPP on NTDMF displayed slight red shift compared with pure TCPP ethanol solution. The performances of the PEBFC were obtained by photocurrent–photovoltage characteristic curves. The open-circuit photovoltage (Voc), the short-circuit photocurrent (Isc) and the maximum power density (Pmax) was 0.74 V, 69.96 μA and 33.94 μW cm−2 at 0.45 V, respectively. The fill factor (FF) was 0.19 and the incident photo-to-current efficiency (IPCE) was 36.0% at 436 nm. The results demonstrated that the TCPP was an appropriate photosensitizer for PEBFC.

► We have constructed a novel photoelectrochemical biofuel cell (PEBFC).
► Meso-tetrakis (4-carboxyphenyl)porphyrin(TCPP) is anodic sensitizer of the PEBFC.
► TCPP has been immobilized on TiO2 by bridging or bidentate coordinate bonds.
► Open-circuit photovoltage of the PEBFC is 0.74 V.
► Maximum power density of the PEBFC is 33.94μW cm−2.