“…Wet impregnation routes, on the other hand, are simple and costeffective: for example, by using metal salt impregnation followed by thermal decomposition. [26][27][28][29] Although some previous works have reported the synthesis and application of such cocatalyst-loaded TiO 2 powders in photocatalysis, 11,14,17,[30][31][32][33][34][35][36][37] many inconsistencies, originating from the wide variety of synthetic and calcination conditions, remain. Furthermore, the lack of comparative activity evaluations leave a gap in the fundamental understanding of their actual active state.…”