Singlet oxygen species induced by colloidal crystalline carbon nitride induced for efficient H2O2 synthesis with in situ antibacterial effect.

Solar-driven hydrogen (H 2) and hydrogen peroxide (H 2 O 2) generation over visible-light responsive carbon nitride (CN) photocatalysts for in situ efficient sterilization is a promising and eco-friendly strategy. Herein, a colloidal potassium-ion (K+) intercalated crystalline CN nanosheets (KCCN) photocatalyst was constructed for boosting synergetic H 2 O 2 synthesis with isopropanol (IPA) oxidation and in situ antibacterial effect. The surface hydroxyl (−OH) and cyano (−C N) groups induced by molten salt (KCl)-assisted thermal treatments contributed to the colloidal nature of CN, facilitating for high wettability of KCCN in aqueous solution to gain active hydrogen (H+) from water sustainably. Meaningfully, the enhanced high-energy singlet oxygen species (1O 2) produced by KCNN-2 were verified by electron paramagnetic resonance (EPR) and 9,10-anthracenediyl-bis(methylene)-dimalonic acid (ABDA)-fluorescent probe, significantly contributing to H 2 O 2 production and antibacterial effect. Consequently, the optimal KCCN-2 exhibited a much enhanced H 2 generation of 4.11 mmol g−1 h−1, and H 2 O 2 production activity of 1.82 mmol L−1 h−1 with acetone yield rate of 47.3 mmol g−1 h−1 under visible-light (λ > 420 nm) irradiation in 10 vol% IPA solution. The in-situ generated H 2 O 2 can be activated to produce reactive oxygen species (ROS), especially 1O 2 , to effectively kill the Escherichia coli , reaching an improved an antibacterial rate of 89.7% under stimulated sunlight irradiation in 1 h. This work could offer a new insight into the photoinduced ROS for aqueous H 2 O 2 photosynthesis and antibacterial application. A colloidal K+ intercalated crystalline carbon nitride (KCCN) photocatalyst with abundant surface functional groups (including –OH, –C N groups) was fabricated for photocatalytic H 2 generation, H 2 O 2 production with isopropanol (IPA) oxidation to acetone (AC), and in situ sterilization. The obtained CN photocatalyst indicated accelerated charge separation and transfer in both in-plane and interlayer of carbon nitride, improved surface wettability and rich N-defects, leading to significantly enhanced photocatalytic H 2 O 2 generation with IPA oxidation activities, along with improved in situ antibacterial effect. [Display omitted] • The crystalline carbon nitride was altered by KCl-assisted thermal treatments. • A colloidal hydrophilic surface of carbon nitride nanosheets was achieved. • The generated 1O 2 species was participated in H 2 O 2 production and sterilization. [ABSTRACT FROM AUTHOR]