RESUMEN

In this work, a novel oxide combined with bismuth (Bi) and silver (Ag) was prepared via simple ball milling. This substance was optimized by adjusting the amount of pre-source. Preliminary characterization results confirmed the successful synthesis of Ag4Bi2O5. Subsequently, gaseous toluene was selected as model compound to evaluate the photocatalytic activity of Ag4Bi2O5 photocatalyst. According to the degradation results, Ag4Bi2O5 performed excellent visible light-driven photocatalytic activity with high stability. For the oxidation process of gaseous compound, reactive oxygen species (ROS) were responsible for the achievement, and the formation of oxygen vacancies on Ag4Bi2O5 were involved in the generation of ROS to promote the transfer of photogenerated electrons, and improving photocatalytic activity. DFT calculations revealed the theoretical band gap of Ag4Bi2O5 bulk is 1.758 eV. And the work function of Ag4Bi2O5 (112)ov was ca. at 4.447 eV. The material was easily fabricated and a reliable path was provided for the synthesis of new and efficient photocatalyst for the remediation of polluted indoor air.

Asunto(s)

Bismuto , Plata , Catálisis , Gases , Luz , Tolueno

RESUMEN

A novel Pt assisted self-modified Bi2WO6 composites (Pt/Bi-BWO) with high oxygen vacancies concentration was successfully fabricated via a simple in-situ NaBH4 reduction method in presence of H2PtCl6•6H2O. The Pt/Bi-BWO performed excellent photocatalytic activity on the degradation of gaseous toluene under visible light illumination. The photocatalytic reaction rate of 0.15% Pt/Bi-BWO was 2.88 times higher than that of Bi2WO6. Over 90% gas phase toluene was removed by 0.15% Pt/Bi-BWO in one hour and over 80% of which was degraded into CO2 and H2O. The Pt/Bi-BWO also performed great stability confirmed by circulating runs test. The mechanism of the promotion was explored by electron paramagnetic resonance (EPR) and DFT calculations. The produced oxygen vacancies were below conduction band (CB) of Bi2WO6, leading to a narrowed band gap. Meantime, the generated oxygen vacancies could activate O2 to enhance the production of reactive oxygen species (ROS), such as O2- and OH. In addition, the added Pt could act as electron trap to suppress the recombination of electrons-holes pairs. In a word, this work produced a novel simply made photocatalyst to remove volatile organic compounds.