Z-scheme particle-suspension reactor designs consisting of freely suspended semiconductor particles in an electrolyte to drive solar water splitting could be cost-effective alternatives to produce renewable hydrogen. In this work, we develop a device-scale model to evaluate the effects of coupled light absorption, electrolyte species transport, and reaction kinetics on overall reactor performance and ability to sustain rector operation via diffusion. We also extend this work by numerically investigating particle-scale and -size effects on colloidal stability, light absorption and scattering, and charge-carrier transport across the semiconductor/cocatalyst/electrolyte interface.
Within the Joint Center for Artificial Photosynthesis (JCAP), we utilize continuum-scale modeling of the various components in order to determine design tradeoffs of vapor-feed or gas-diffusion electrode systems. Such systems can provide routes towards optimizing local reaction conditions and overcoming inherent liquid-phase transport limitations for carbon-dioxide reduction as well as solar water splitting to produce hydrogen. For the latter, integrated architectures can be used that are more stable than those in liquid environments. Overall, the functioning of both vapor feed and particle systems will be explored.