High surface area optofluidic microreactor for redox mediated photocatalytic water splitting

Photocatalytic water splitting is a promising approach for hydrogen generation, but the low efficiency of current photoreactors limits its widespread exploitation and commercialization. Recent developments in optofluidic microreactors open a window for advancing photocatalytic water splitting technology. Nevertheless, existing optofluidic microreactors with the planar design show the low active surface area and rate of mass transport, thereby restricting the hydrogen production performance. In this work, we proposed an optofluidic microreactor with staggered micro-pillars in the reaction micro-chamber. Such design not only enlarges the surface area to load catalyst but also induces perturbation to the liquid flow and shortens the transport length, which increases the active surface area and enhances the mass transfer and eventually boosts the hydrogen production rate. To evaluate the performance of this new optofluidic microreactor, a redox mediated water splitting reaction was implemented. Results showed that the developed microreactor with micro-pillar structure exhibited a higher reaction rate. As compared to the conventional planar optofluidic microreactor, the maximal increment of the reaction rate could reach 56%.