Author: Xiaobao Li (Xi'an Jiaotong University) - This study proposes a structural optimization strategy for suspended photocatalytic microreactors, with hydrogen production rate as the primary metric. Employing CuO-TiO₂ photocatalysts, methanol as a sacrificial agent, and a xenon lamp light source, we established an experimental platform and developed a kinetic model for photocatalytic water splitting. The model was embedded into simulation software via User-Defined Functions (UDFs), enabling multiphysics simulations coupling light propagation, fluid flow, and chemical reactions. Experimental validation confirmed a simulation error below 3%.
Subsequently, flow field regulation was achieved by introducing micro-obstacles within the reactor. Results indicated that channel width and obstacle geometry significantly influence hydrogen production. At a channel width of 500 μm, reducing obstacle size expanded the effective flow cross-section, enhancing reaction efficiency. Increasing obstacle count improved flow velocity and mass transfer. Among tested configurations, the hydrogen production rate of the reactor with cylindrical obstacle structure is significantly higher than that with straight-channel-type obstacle structure. Furthermore, to further enhance the light-harvesting capability of the reactor, this paper proposes adopting a conical cilia structure instead of cylindrical microstructures. Under 300 mW·cm⁻² illumination and 20% methanol concentration, this novel structure achieved a hydrogen production rate of 26.9 mmol·g⁻¹·h⁻¹—demonstrating a 2.8-fold increase over the conventional reactor without microstructures (9.5 mmol·g⁻¹·h⁻¹). This work provides actionable insights for the structural optimization of photocatalytic reactors toward efficient solar-to-hydrogen conversion.