Promoting infrared light driven photocatalytic activity of W18O49 nanorods by coupling polypyrrole

Multifunctional screen-printed films using polymer nanocomposite based on PPy/TiO2: conductive, photocatalytic, self-cleaning and antibacterial functionalities

In this work, two electrically conductive samples based on polypyrrole (PPy) and (PPy/TiO₂) were synthesized via mini-emulsion polymerization. Synthesized samples were used as functional fillers to formulate two different screen-printing pastes (pastes A and B) to obtain the multi-purpose printed films with excellent properties, including electrical conductivity, antibacterial, photocatalytic activity, and self-cleaning. The surface tension, pH, and conductivity measurements validated the acceptable features of the produced pastes. Because of the shear-thinning behavior and viscosity buildup properties of the produced pastes, rheological investigations confirmed their potential for screen-printing. According to I–V test results, the optimum sintering temperature was chosen as a function of electrical conductivity, and the properties of the printed patterns were investigated by varying the printing sequences as 3, 6, and 9 times and sintered at the optimum temperature (90 °C). The contact angle of water on the optimum sample printed by Paste B was ca. 127° and relatively higher than the counterpart printed by Paste A which verified the superiority of the self-cleaning properties of the printed films with latter paste over the former. The photocatalytic studies concerning the degradation of methylene blue showed that the removal percentage of ca. 63% was achieved within the first 90 min of performing the test under UV light. The photocatalytic printed film was addressed the issue of filtering the unused suspension of nanoparticles, which made it difficult to remove the particles from the treated wastewater, in terms of sustainability. The fabricated patterns using Paste B exhibited improved properties, including electrical conductivity, antibacterial and photocatalytic activity.

Space-Confined Synthesis of Thin Polypyrrole Nanosheets in Layered Bismuth Oxychloride for a Photoresponse Antibacterial within the Near-Infrared Window and Accelerated Wound Healing

Bacterial infection greatly affects the rate of wound healing. Both photothermal and photodynamic antibacterial therapies activated by near-infrared (NIR) light with semiconductor nanomedicine are two effective approaches to address bacterial infections, but they cannot coexist synergistically to kill bacteria more efficiently because of the limitation of the band structure. Here, inspired by the natural core-shell structure and photosynthesis simultaneously, polypyrrole (PPy) is synthesized in the two-dimensional restricted area of the layered bismuth oxychloride (BiOCl) nanosheets through the in situ ultrasonic recombination method. The atomic-level interface contact and bonding formed in the PPy-BiOCl intercalated nanosheets not only improve the light-to-heat conversion capabilities of PPy but also promote the transmission of PPy photogenerated charge carriers to the BiOCl semiconductor. The nanocomposites take advantage of the deeper tissue penetration under NIR light irradiation and exhibit excellent photothermal and photodynamic synergistic antibacterial activity. In addition, PPy-BiOCl intercalated nanosheets have good biocompatibility and accelerate wound healing through their antimicrobial activity and skin repair function. The space-confined synthesis of thin PPy nanosheets in layered structures offers an efficient NIR photoresponsive nanomedicine for the treatment of pathogen infection, with promising applications in infected wound healing.

Ultrasound-assisted method to improve the structure of CeO2@polyprrole core-shell nanosphere and its photocatalytic reduction of hazardous Cr6

In this work, the CeO₂@polypyrrole (CeO₂@PPy) core-shell nanosphere has been synthesized via an ultra-sonication method using bath type (WUC-D22H, Daihan Scientific, Korea) and they are utilized for the photo-reduction of hazardous Cr⁶⁺ to benign Cr³⁺. The ultrasonic frequency and power were 20 kHz and 100 W, respectively. The PPy shielded CeO₂ in aqueous solution could prevent the dissolution of CeO₂ and to improve the photocatalytic ability of CeO₂. X-ray diffraction was used to confirm the crystalline structure of as prepared CeO₂@PPy core-shell and FT-IR was used to identify the functional groups. The uniform sized core of PPy and shell of CeO₂ were observed by transition electron microscopy. The ultrasonic assisted synthesized CeO₂@PPy core-shell exhibits a narrow bandgap (UV-DRS) and good reduction efficiency with higher reusability and stability compared to pure CeO₂, PPy and mechanical mixing of CeO₂@PPy. Moreover, the synergistic effect of CeO₂ and PPy core-shell structure facilitate a higher electron transfer rate and prolong lifetime of photogenerated electron-hole pairs which can achieve good reduction rate of 98.6% within 30 min. In particular, the pH, catalyst, and Cr⁶⁺ concentration effects were optimized in photocatalytic reduction reactions. Meanwhile, this photocatalysis with fast and effective electron transfer mechanism for the Cr⁶⁺ reduction was elucidated. This method opens a new window for simple fabrication of conducting polymers-based metal oxide nanocomposite towards wastewater remediation and beyond.