Modular 3D-printed flow reactor for lab-scale PEC analysis benchmarked with BiVO4/NiO/FeOOH thin-film photoanodes

Abstract

This work describes a modular 3D-printed flow reactor designed for lab-scale photoelectrochemical (PEC) water splitting. The reactor's modular design is optimized for testing a range of photoelectrodes and supports single- and dual-electrode configurations. Moreover, the internal design enables gas-liquid separation, cycling and in-line analysis. Key advantages of this 3D-printed reactor design include gas and electrolyte cycling, accessibility for research facilities worldwide, and reduced environmental impact by eliminating platinum electrodes and long supply chains. Reactor versatility is demonstrated through PEC benchmarking, including linear sweep voltammetry, chronoamperometry coupled with in-line gas analysis and photoelectrochemical impedance spectroscopy. The BiVO4/NiO/FeOOH thin-film photoanode exhibits an onset potential of 0.276 V vs RHE and a photocurrent density of 3.02 mA/cm2 at 1.2 V vs. RHE. The reported performance was obtained under Xe-Hg illumination (150 mW cm−2) to demonstrate the capability of the proposed reactor under the employed experimental conditions. Furthermore, the photoelectrode demonstrates stable operation, retaining 97% photocurrent density with a maximum Faradaic efficiency of 81.4% (based on triplicate averaged measurements) toward hydrogen during 1 h operation at 0.8 V vs. RHE.