Investigation of Various Factors on Iodide Depletion Efficiency in Photocatalytic Water Splitting in Optofluidic Microreactors

Water splitting is a promising method to produce hydrogen as fuel. But it has low production rate in comparison with the common methods. There are some developments in microreactors and photocatalysts that combine these two methods to increase the production rate. Design of reaction chamber and also the loading of photocatalysts affect the outcome of the reaction. In this study, three optofluidic microreactors with different reaction chambers were fabricated. To monitor the performance of the fabricated microreactors, a water splitting reaction was performed in the presence of iodide/iodate as a redox mediator. Various factors such as iodide concentration, flow rate, and the amount of Pt deposited on Pt/TiO 2 were investigated. The durability of used photocatalyst in micro-spiraled and micro-pillared microreactors was also studied. The optofluidic microreactor with pillared structure showed higher hydrogen production compared to the spiral and grooved structure. The optimal value of Pt loading is 1% w/w so that the iodide depletion efficiency changes over time from 5.7 to 3.8% while that for 1.5% w/w varies from 3.2 to 0.67%.