Enhanced electrophoretic deposition of hydrophobic BiVO4 photocatalytic coatings using Cu2+ ions as stabilizing agent

In this work, we report the preparation of monoclinic bismuth vanadate (BiVO4) coatings through an electrophoretic deposition process (EPD) using Cu2+ ions as a charge-stabilizing agent. BiVO4 was prepared through a rapid coprecipitation route, yielding rounded nanoparticles with sizes smaller than 100 nm. The bismuth vanadate nanoparticles were dispersed in isopropyl alcohol for electrophoretic deposition onto aluminum plates using a constant applied voltage of 12 V for 30 min. The results have shown that the deposited amount of BiVO4 nanoparticles increases with the initial concentration of the Cu(NO3)2⋅5H2O additive. According to XPS analysis, EPD coatings exhibit the presence of metallic copper due to the reduction of Cu2+ ions on the BiVO4 during the electrophoretic deposition process. The photocatalytic properties of BiVO4 coatings were assessed in the degradation of the antibiotic tetracycline under simulated solar irradiation. The BiVO4 coating prepared with an initial concentration of 0.5 mM of Cu(NO3)2⋅5H2O exhibited the highest photocatalytic performance, achieving a degradation efficiency of approximately 92 % after 240 min of irradiation. Furthermore, the BiVO4 coatings displayed superhydrophobic properties, as determined by measuring static water contact angles.