Effects of constituents in photo/biocatalytic hydrogen production system using experimental design tool

This study photoelectrochemically and photocatalytically examined the effects of constituents in photo/biocatalytic hydrogen production system, being eventually composed of photoanode and cathode, just after that preliminary mixed slurry system had been investigated to see the insights of the hybrid system. Experiments with the mixed slurry system revealed the following four cases; direct interphase electron transfer from photocatalyst to enzyme in the absence of electron relay was a rate-determining step, enzyme was deactivated by irradiated light, physical properties of photocatalysts, obtained by a couple of preparation methods, seldom affected the production rate, and each material needs different reaction conditions such as pH and temperature. These results led the study to the system where the materials were separated into photoanode and cathode and each material has been studied individually and simultaneously to get the possible optimum condition: for the former photoanodic current and photovoltage were measured for each prepared photocatalysts and for the latter change in the amount of evolved hydrogen was checked according to external bias. Then both reaction parts were connected through Nafion membrane and salt bridge to perform light-induced hydrogen production for the hybrid system. No synergistic effect of the system happened with Nafion, but promising result was obtained with salt bridge. Detailed investigations are under way.