3D-Printed Photoelectrochemical Cell and its Application in Evaluation of Bismuth Vanadate Photoanodes: Synthesis, cell design and testing

Bismuth vanadate (BiVO₄) is proven to be a promising photocatalyst for water splitting. However,theeffectofmaterialssyntheses,electrode preparation and size of photoelectrode on the photocurrent output of BiVO₄ photoanodes needs further investigations. In this study, three different BiVO₄ nanoparticle synthesis were employed, namely hydrothermal (HT), HT in the presence of ethylene glycol (EG) and HT with the addition of hydrazine hydrate (HH). In addition, two molecular inks (Triton-X and ethyl-methyl-imidazole, EMI), were compared for the preparation of BiVO₄ photoanodes using a simple doctor-blade technique followed by calcination at 450°C. The photoanodes (9 cm² active surface) were then compared for their photocurrent density at AM1.5G illumination and 1.2 V (vs. standard hydrogen electrode (SHE)) bias in a specifically designed, three-dimensional (3D)-printed electrochemical cell. The highest photocurrent 0.13 ± 0.1 mA cm^–2 was obtained with the EMI ink, whereas tenfold lower photocurrent was obtained with Triton-X due to the higher charge transfer resistance, measured by electric impedance spectroscopy (EIS). The photoresponse was reproducible and relatively stable, with only 8% decrease in five consecutive illumination periods of 1 min.