Controlled Growth of BiOCl with Large {010} Facets for Dye Self-Photosensitization Photocatalytic Fuel Cells Application

BiOCl with {010} facets could be a promising material for photodegradation and energy conversion devices such as dye self-photosensitization photocatalytic fuel cells (DSPFCs). However, the {010} facets usually diminish rapidly during the growth process as the result of its high surface energies. In this work, we reported a simple and efficient method to prepare BiOCl with tunable exposed {010} facets. It was found that the solvent used in the synthesis process had important roles in the formation of ultrathin construction and the growth of {010} facets by controlling the [H⁺]. For decreasing the surface energy and promoting the growth of high-active {010} facets, the thickness of BiOCl and the areas of {001} were reduced in its forming process. We had demonstrated that the enhancement of visible light-harvesting and photosensitization activity of BiOCl was primarily attributed to the decrease of thickness and the growth of {010} facets which could provide large surface areas and more active sites for dye absorption and photoelectron transfer. The BiOCl samples with tunable exposed {010} areas were evaluated as photoanode materials in DSPFCs. As expected, owing to its strong dye absorption capability and high transfer efficiency of charge carriers, the DSPFC with optimal performance was obtained by employing RhB as fuel when BiOCl possessed the larger areas of {010} facets and became a thinner nanosheet structure. Also, the J_sc and V_oc of DSPFC were measured to be 0.0058 mA/cm² and 0.689 V, respectively. Meanwhile, approximately 67% color removal was achieved on BiOCl{010}-Pt cell by treating 40 mL of 5 mg/L RhB under visible light for 240 min, which was much higher than that of P25-Pt (4%).