Nature-Derived Approach to Oxygen and Chlorine Dual-Vacancies for Efficient Photocatalysis and Photoelectrochemistry

Crystal defect engineering has sparked huge interests owing to their significance for tailoring surface properties, photoelectronic properties, etc. However, conventional methods, e.g., H-2 reduction, can only achieve a single type of vacancy and always suffer from the drawbacks of harsh synthetic condition, complex procedure, and energy consuming. Herein, we report a green, cost-effective, and scalable nature derived reduction protocol with extracting solution of green tea and spinach to in situ achieve oxygen and chlorine dual vacancies in BiOCl (BiO1-xCl1-y). The introduction of O and Cl vacancies gives rise to enormous amelioration on the crystal structure, electronic band structure, and surface state, thereby resulting in enhanced photoabsorption and a remarkably enhanced surface charge transfer efficiency (11-fold enhancement). Profiting from these merits, BiO1-xCl1-y exhibits highly promoted photocatalytic oxidation ability and an efficient activity for selective CO2 reduction into CO. Interestingly, continuously adjustable photoresponse and defect level for BiO1-xCl1-y was realized by simply regulating the extract concentration, which can well balance photoabsorption and photoredox driving force. The current synthetic route is demonstrated to be also applicable to BiOBr and BiOl. To verify the role of the current natural antioxidant, BiO1-xCl1-y is also successfully synthesized by the chemicals of extracting solution ingredients. This work exclusively sheds new light on engineering crystal defects via the eco-friendly bioinspired tactics and also provides a reference for promoting photo (electro) chemical property by dual-vacancies cooperation.