Membrane-encapsulated devices are attractive for solar-driven hydrogen production, as their design mitigates problems with concentration overpotentials, gas bubbles, and safety inherent in liquid electrolyte water-splitting devices. However, the competing processes such as heat, water, gas, and ion transport make it nontrivial to design such devices. Here, we show analytical expressions and associated design spaces for critical membrane dimensions and material properties required for stable and efficient gas, heat, proton, and water transport. The best condition for stable gas transport in thin film or gas channels is given by the critical Damköhler number. The maximum heating of the device is governed by the Heating and Nusselt numbers, which can be tuned to the desired level. The optimal dimensions of the device, to operate under tolerable ohmic losses, correspond to the maximum value of scaled Power-loss factor. An optimal device architecture is proposed for stable and efficient operation.
BT - Journal of the Electrochemical Society DA - 01/2014 DO - 10.1149/2.033408jes IS - 8 N2 -Membrane-encapsulated devices are attractive for solar-driven hydrogen production, as their design mitigates problems with concentration overpotentials, gas bubbles, and safety inherent in liquid electrolyte water-splitting devices. However, the competing processes such as heat, water, gas, and ion transport make it nontrivial to design such devices. Here, we show analytical expressions and associated design spaces for critical membrane dimensions and material properties required for stable and efficient gas, heat, proton, and water transport. The best condition for stable gas transport in thin film or gas channels is given by the critical Damköhler number. The maximum heating of the device is governed by the Heating and Nusselt numbers, which can be tuned to the desired level. The optimal dimensions of the device, to operate under tolerable ohmic losses, correspond to the maximum value of scaled Power-loss factor. An optimal device architecture is proposed for stable and efficient operation.
PY - 2014 SP - E3283 EP - E3296 ST - Journal of the Electrochemical Society T2 - Journal of the Electrochemical Society TI - Design of Membrane-Encapsulated Wireless Photoelectrochemical Cells for Hydrogen Production VL - 161 SN - 0013-4651 ER -