Sulfur tuning oxygen vacancy of Ba2Bi1.4Ta0.6O6 for boosted photocatalytic tetracycline hydrochloride degradation and hydrogen evolution.

Photocatalysis, such as solar-driven photodegradation and energy conversion, has attracted great attention, given that it provides a promising solution for alleviating the energy shortage and environmental contamination issues. However, the insufficient light absorption and charge separation/transport efficiency restrict the solar conversion efficiency. It has been proved that oxygen vacancies (Ov) can improve the photocatalytic activity by enhancing the light absorption. But in this study, we show that oxygen vacancies hinder the charge separation/transfer in Ba2Bi1.4Ta0.6O6. The incorporation of S further pushes the light absorption edge up to 1170 nm. Therefore, the S/Ov-Ba2Bi1.4Ta0.6O6 sample can absorb not only the full range of visible light but also part of near-infrared light. More importantly, it mitigates the drawback of oxygen vacancies, improving the charge separation/transport by 1.65 times. As a result, The S/Ov-Ba2Bi1.4Ta0.6O6 nanowires manifest 4.41 times and over 100 times higher photocatalytic activity for tetracycline hydrochloride degradation and hydrogen production, respectively.