Photoelectrochemical (PEC) Flow Cell with Gas-Diffusion Electrode (GDE) for Solar Fuel Generation, CSFGPECFCGDE

A Photoelectrochemical (PEC) Flow Cell with a Gas-Diffusion Electrode (GDE) is an advanced reactor design that overcomes the primary limitation of traditional solar fuel systems: the low solubility and slow diffusion of gases (like CO2 or N2) in liquid electrolytes. By integrating a GDE—a porous, hydrophobic electrode—directly into a PEC flow cell, gaseous reactants can reach the photoactive catalyst surface at much higher rates, enabling "solar-to-fuel" (STF) conversion at commercially relevant current densities.

The design typically consists of a "three-phase interface" where the solid catalyst, liquid electrolyte, and gaseous reactant meet. (1) Optical Window: Usually made of Quartz, allowing solar or simulated light to reach the photoelectrode without significant absorption losses. (2) Gas-Diffusion Photoelectrode: A porous substrate (like carbon paper or PTFE-treated carbon cloth) coated with a semiconductor (e.g., TiO2, Cu2O, or BiVO4). The gas is fed from the "dry" back-side, while the "wet" front-side is in contact with the electrolyte. (3) Flow Channels: Serpentine or parallel channels that circulate the liquid electrolyte to remove products and manage local pH levels.

References:

1. H. Jung, et al., Continuous Flow Photoelectrochemical Reactor with Gas Permeable Photocathode: Enhanced Photocurrent and Partial Current Density for CO2 Reduction, Adv. Sci., 2025, 12, 2411348. 

2. B. Liu, et al. Back-illuminated photoelectrochemical flow cell for efficient CO2 reduction, Nature Communications. 2022, 13, 7111.