A ZnO-CuO heterojunction was synthesized by a coprecipitation method using a mixture of different volumes of equimolar (0.5 M) aqueous solutions of zinc nitrate hexahydrate (Zn(NO3)2•6H2O) and copper sulfate pentahydrate (CuSO2•5H2O) heated to 100 °C. Bismuth vanadate (BiVO4) was synthesized by mixing stoichiometric amounts of partially dissolved solutions of Bi(NO3)3•5H2O and NH4VO3. The resulting solution was then sonicated in an ultrasonic bath for 2 h at 45 °C. The synthesized photocatalysts have degraded methyl orange or methylene blue under solar irradiation.