Unique BiFeO3/g-C3N4 mushroom heterojunction with photocatalytic antibacterial and wound therapeutic activity.

Bacterial infections have become a major problem threatening public health, and it is of great significance to treat wound infections in biological systems caused by bacteria. However, traditionally used bacteriostatic agents usually cause additional pollution. Herein a mushroom-shaped clean and Green BiFeO3/g-C3N4 composite is employed for the first time for photocatalytic antibacterial activity and for the further promotion of wound healing. The ratio between BiFeO3 and g-C3N4 was delicately regulated to control the generated amount of ˙OH and ˙O2- by catalyzing the decomposition of hydrogen peroxide (H2O2) under illumination. Results show that 10%BFO/CN demonstrates the best performance for ˙OH and ˙O2- production, resulting in the highest antibacterial ability against E. coli and S. aureus. In addition, the catalytic mechanism of BiFeO3/g-C3N4 towards antibacterial activity is disclosed by a combination of ESR monitoring and analysis of the Mott-Schottky diagram. Furthermore, in vivo experiments prove that 10%BFO/CN can effectively promote anti-infection and wound healing in nude mice. This work sheds deep scientific insight on the synergistic effect of photocatalysis and photo-Fenton degradation as well as their application in antibacterial and wound therapeutic activity.

Photoenzymatic Catalytic Cascade System of a Pyromellitic Diimide/g-C3N4 Heterojunction to Efficiently Regenerate NADH for Highly Selective CO2 Reduction toward Formic Acid.

Photocatalytic reduction of carbon dioxide (CO2) holds great promise for both clean energy and environment protection. However, the low activity and poor selectivity of photocatalysts are the main bottlenecks. Herein, inspired by artificial photosynthesis and taking advantages of high efficiency and specificity of bioenzymes, we marry photo with enzyme to synergistically solve the above problems. A metal-free heterojunction of pyromellitic diimide/g-C3N4 (PDI/CN) with an excellent visible light response (λ < 660 nm) is fabricated for achieving a photoenzymatic catalytic cascade system, which efficiently regenerates nicotinamide adenine dinucleotide (NADH) and selectively reduces CO2 to formic acid (HCOOH). The highest NADH yield of the PDI/CN hybrid achieved is 75%, and the HCOOH generation rate achieved is 1.269 mmol g-1 h-1 with nearly 100% selectivity, which is much higher than those of the reported materials. The excellent photocatalytic performance is attributed to the unique photoenzymatic catalytic cascade system, heterointerface effect, good conductivity, and a wide sunlight response range of the PDI/CN heterojunction. This work provides an efficient strategy and a corresponding photocatalyst for the directional conversion of CO2 to HCOOH.