Harvesting Energy from an Organic Pollutant Model Using a New 3D-Printed Microfluidic Photo Fuel Cell

The combination of a fuel cell and photocatalysis in the same device, called a photo fuel cell, is the next generation of energy converters. These systems aim to convert organic pollutants and oxidants into energy using solar energy as the driving force. However, they are mostly designed in conventional stationary batch systems, generating low power besides being barely applicable. In this context, membraneless microfluidics allows the use of flow, porous electrodes, and mixed media, improving reactant utilization and output power accordingly. Here, we report an unprecedented reusable three-dimensional (3D) printed microfluidic photo fuel cell (μpFC) assembled with low-content PtO/Pt dispersed on a BiVO₄ photoanode and a Pt/C dark cathode, both immobilized on carbon paper. We use fused deposition modeling for additive manufacturing a US$ 2.5 μpFC with a polylactic acid filament. The system shows stable colaminar flow and a short time light distance. As a proof-of-concept, we used the pollutant-model rhodamine B as fuel, and O₂ in an acidic medium at the cathode side. The mixed-media 3D printed μpFC with porous electrodes produces remarkable 0.48 mW cm^-2 and 4.09 mA cm^-2 as maximum power and current densities, respectively. The system operates continuously for more than 5 h and converts 73.6% rhodamine by photoelectrochemical processes. The 3D printed μpFC developed here shows promising potential for pollutant mitigation concomitantly to power generation, besides being a potential platform of tests for new (photo)electrocatalysts.