Benzyl alcohol (99%, Alfa Aesar), benzaldehyde (99%, Sigma Aldrich), 1,1,2,2,-Tetrachloroethane (99 %, Sigma Aldrich), CDCl3 (99 %, Sigma Aldrich), CD3CN (99 %, Sigma Aldrich). Hydrogen peroxide (30 wt%, Sigma Aldrich), titanium oxysulfate sulfuric acid hydrate (TiOSO4 • xH2O) (Synthesis grade, Sigma Aldrich). Potassium poly(heptazine imide) (KPHI) photocatalyst was prepared according to the procedure described by Lotsch et al. Melon polymer preparation was accomplished by self-condensation of dicyandiamide in a muffle furnace at 550 C for 4 h. The obtained yellow solid was ground, washed 4 times with deionized water by centrifugation and dried in an oven at 70 C for 24 h. For the KPHI synthesis 1.5 g of melon polymer and 3 g of KSCN were separately dried at 140 C for 24 h, then the powders were ground together in a mortar, put in a lid-covered ceramic crucible and heated in a muffle furnace at a rate of 30 C min -1 first to 400 C for 1 h and then to 500 C for 30 min. Thus, prepared KPHI samples were cooled down to room temperature and then thoroughly washed with deionized water by centrifugation for 5 times. The washed powders were dried at 70 C for 24 h.