Synthesis of an efficient, and recyclable mesoporous BiVO4/TiO2 direct Z-scheme heterojunction by sonochemical route for photocatalytic hydrogen production and photodegradation of rhodamine B dye in the visible region

Abstract

Sonicated mesoporous BiVO 4 /TiO 2 heterojunctions were recorded for highly efficient photodegradation of rhodamine B dye and production of hydrogen gas. The heterojunction structures were characterized by XRD, DRS, FTIR, BET, FESEM, HRTEM and PL. The efficiency of the radiation power of ultrasound waves [50–300 Watt/cm 2 ] on dye degradation and efficiency of hydrogen production was established. BiVO 4 shifts the photocatalytic response of titania toward visible region. The photocatalytic efficiency of RhB removal on the nanocomposites surface containing 10 wt% BiVO 4 is 0.021 min −1 tenfold higher than that of bare TiO 2 (0.0023 min −1 ). The optimum concentration of BiVO 4 was found to be 10 wt% that generate hydrogen gas with rate equal to 14.3 mmolg −1 h −1 . Ultrasound radiation is a prime key in reducing the population of particle aggregates and reflects a strong interaction between BiVO 4 and TiO 2 nanoparticles that results in lowering the electron-hole pairs recombination rate and increase the concentration of active sites and amount hydrogen evolved. The production of hydroxyl and superoxide radicals suggest a direct Z-scheme mechanism for explaining the high photocatalytic reactivity of sample. • Novel BiVO 4 /TiO 2 nanocomposites were synthesized by sonochemical route. • A strong chemical interaction between BiVO 4 and TiO 2 nanoparticles. • Z-electron transfer scheme is purposed. • A stable photocatalyst for five consecutive cycles.