Effects of TiO₂ nanoparticles and ZnO nanowires photoanodes on photoelectrochemical biofuel cell performances

Zinc oxide (ZnO) nanowire has been synthesized by electrodeposition technology and fully characterized by X-ray diffraction analysis, UV-Vis absorption spectra and Fourier transform infrared spectra measurements. The synthetic ZnO nanowire has been applied as a semiconductor photoanode of a photoelectrochemical biofuel cell (PEBFC) to evaluate its impact on solar-to-electric conversion efficiency. The ZnO-based PEBFCs show a short-circuit current (Isc) of 104.70 μA, an open-circuit potential (Voc) of 947 mV, a maximum power density (Pmax) of 37.80 μW/cm² and an overall energy conversion efficiency (η) of 2.31%, respectively. The PEBFCs comprising of ZnO nanoparticles semiconductor photoanode show improved electrochemical performances comparing the reported TiO₂-based PEBFC. The ZnO-based PEBFCs also indicate a higher incident photon-to-collected electron conversion efficiency, which is probably due to the large electron mobility and high electrical conductivity for ZnO. The relevant studies on the semiconductor photoanodes provide meaningful value for the development of high-performance PEBFCs. (author)