Investigation of adsorption-photocatalytic synergistic mechanism of globular TiO2–ZrO2–SiO2 composites by a synergy factor

Abstract

Synergy is essential to maximize the photocatalytic performance of the catalyst, which makes the preparation of photocatalytic materials with the synergistic effect of adsorption and catalysis become an attractive research direction. Therefore, we have prepared TiO 2 –ZrO 2 –SiO 2 nano-powders by simple Pechini sol-gel method, which can effectively improve the synergistic effect of adsorption and degradation of photocatalytic materials. The results demonstrate that TiO 2 –ZrO 2 –SiO 2 possesses excellent photocatalytic performance and adsorption ability. And it can be deduced that in the TiO 2 –ZrO 2 –SiO 2 system, SiO 2 is as for adsorbent, and TiO 2 and ZrO 2 act synergistically as a photocatalyst. The enhanced photocatalytic ability of TiO 2 –ZrO 2 –SiO 2 is attributed to the acceleration of mass transfer by adsorption process, narrowed bandgap (Eg = 2.9 eV) and effective charge separation rate resulting from the formation of Ti–O–Zr. This work also studied the synergy effect between adsorption and photocatalytic properties in TiO 2 –ZrO 2 –SiO 2 , and synergy factor β is used to evaluate the synergistic effect. Moreover β > 1 in first 30 min of visible light irradiation demonstrates that the remarkable synergistic effect exists in TiO 2 –ZrO 2 –SiO 2 compound system. • TiO 2 –ZrO 2 –SiO 2 photocatalyst with both adsorption and photocatalytic properties was successfully prepared. • β (synergy factor) which explains the adsorption-photocatalytic synergistic effect of TiO 2 –ZrO 2 –SiO 2 system is remarkable. • The adsorption-photocatalytic performance can be regenerated.