“…Photocatalysis represents a promising and sustainable emerging water treatment technology that converts energy from light into electron–hole pairs that drive both oxidation and reduction reactions. 13,14 Photocatalysis can be applied towards many different applications, such as the treatment of organic pollutants 15–18 and green chemical/fuel synthesis, 19,20 and is enabled by a wide variety of semiconductor photocatalysts, with titanium dioxide (TiO 2 ) being the most widely and successfully used photocatalyst to-date. The photocatalytic reduction of Se( vi ) and Se( iv ) has been studied in some depth by various groups since its proof-of-concept in 1999, 21–27 and has been expanded to treat other recalcitrant Se compounds, such as SeCN.…”