O2 activation and 1O2 generation over phosphate modified BiOCl for efficient photodegradation of organic pollutants

Phosphate modification over semiconductor photocatalyst was an effective route to promote photodegradation of organic pollutants. Studies on promoted O 2 adsorption, better charge separation, and free ∙OH radicals raised from phosphate modification are clear, whereas O 2 activation and the generated reactive oxygen species (·O 2 - , H 2 O 2 , and 1 O 2 ) have been ignored. Herein, the hydrogen bond network constructed between BiOCl surface and phosphate weaken the surface Bi-O bond thus benefit the formation of oxygen vacancy (OVs). OVs not only facilitate the adsorption of organic pollutants but also promote the O 2 activation to generate H 2 O 2 and 1 O 2 . Another route for 1 O 2 generation relies on the H 2 O 2 reacted with HClO from lattice chlorine oxidation was demonstrated. The directly attack of surface adsorbed 4-CP via h + , in addition with the selective oxidation via 1 O 2 , synergetically contribute excellent photodegradation performance. This study systematically reveals the O 2 activation and 1 O 2 generation for efficient photodegradation over phosphate modified BiOCl. Phosphate modification constructs the surface hydrogen bond network thus weaken the surface Bi-O bond accordingly benefit the formation and regeneration of oxygen vacancy (OVs). OVs not only facilitate the adsorption of organic pollutants but also promote the O 2 activation to generate H 2 O 2 and 1 O 2 . Another route for 1 O 2 generation relies on the H 2 O 2 reacted with HClO from lattice chlorine oxidation was demonstrated. The better charge separation resulted from the negative electronic field would drive more h + migrated to surface to directly oxidize the surface adsorbed 4-CP molecular, in addition with the selective attacking of electron-rich moiety via 1 O 2 , greatly contribute the efficient photodegradation over phosphate modified BiOCl. • Better O 2 activation is achieved over P-BOC with oxygen vacancy. • The major ROSs produced via O 2 activation are H 2 O 2 and 1 O 2 over P-BOC. • 1 O 2 generation from H 2 O 2 and HClO (H 2 O 2 + HClO→ 1 O 2 + Cl - + H 2 O + H + ) is demonstrated over P-BOC. • Both h + and 1 O 2 make great contribution on the efficient photodegradation over P-BOC.