Liquid Metal Encased in Biomimic Polydopamine Armor to Reinforce Photothermal Conversion and Photothermal Stability.

Liquid metal (LM) faces numerous obstacles like spontaneous coalescence, prone oxidizability, and deterioration in photothermal conversion, impeding the potential application as photothermal agent. To tackle these issues, several studies have focused on surface engineering strategy. Developing a feasible and efficient surface engineering strategy is crucial to prevent the aggregation and coalescence of LM, while also ensuring exceptional photothermal conversion and biosecurity. In order to achieve these goals in this work, the biomimetic polydopamine (PDA) armor was chosen to encase a typical LM (eutectic gallium-indium-tin alloy) via self-polymerization. Characterization results showed that the PDA encased LM nanoparticle exhibited enhanced photothermal stability, photothermal conversion, and biosecurity, which could be derived from the following factors: (1) The PDA protective shell acted as an "armor", isolating LM from dissolved oxygen and water, inhibiting heating-accelerated oxidation and shape morphing. (2) The exceptional near-infrared absorption of PDA was conducive to the photothermal conversion. (3) The biomimetic characteristic of polydopamine (PDA) was advantageous for improving the biosecurity. Hence, this work presented a new surface engineering strategy to reinforce LM for photothermal conversion application.

A pyridine-based conjugated imprinted polymer as an adsorptive photocatalyst for efficient removal of aqueous Cr(VI).

Herein, a designed pyridine-based conjugated imprinted polymer (CIP) was constructed by introducing 4-vinylpyridine (4-VP) via an in situ copolymerization reaction. In addition to the good adsorption performance of Cr(VI), this polymer also showed high efficiency in reducing Cr(VI) in water by photocatalysis. The ingenious design of the polymer not only furnished insight into the enhanced photocatalytic reaction kinetics but also provided a new route for the modification of the molecular skeleton of the conjugated polymer photocatalyst.

Dual molecules engineered carbon nitride for achieving outstanding photocatalytic H2O2 production.

Molecular engineering of carbon nitride (CN) was considered as a suitable and compelling strategy to overcome the intrinsic imperfections and enhance photocatalytic H2O2 production. However, the photocatalytic H2O2 production of conventional single molecular engineering is still unsatisfactory, and the comprehension of photogenerated carrier migration and separation is still indistinct. Herein, dual molecules were engineered on CN molecular skeleton for achieving an outstanding photocatalytic rate of H2O2 production. The photocatalytic H2O2 production rate of the dual molecules engineered CN was up to 3320 µmol g-1 h-1, which was approximately 25 times than that of the pristine CN. After the dual-molecular engineering, pyrimidine and cyano group were co-grafted. Synchronously, K ion and Na ion were co-embedded near the interlamination of CN layers. The synergistic effect of the dual molecules in CN not only restrained photogenerated carrier recombination and broadened visible light response by modulating the intrinsic energy band structure, but also enhanced the capture of the photogenerated electrons and accelerated the migration of proton. Hence, the photocatalytic 2e- oxygen reduction reaction, the rate-determining step, was significantly strengthened. Additionally, caused by the positive valence band potential, the H2O oxidation reaction became an indispensable role in photocatalytic H2O2 production. This work provided a viable route to modulate the molecular skeleton of organic semiconductors and presented a promising strategy to obtain high-efficient photocatalytic H2O2 production.

ß-Cyclodextrin-Derivative-Functionalized Graphene Oxide/Graphitic Carbon Nitride Composites with a Synergistic Effect for Rapid and Efficient Sterilization.

The nonselectivity of phototherapy and the hydrophobicity of phototherapy agents limit their application in the treatment of antibiotic-resistant bacteria. In this work, ß-cyclodextrin-derivative-functionalized graphene oxide (GO)/graphitic carbon nitride (g-C3N4) antibacterial materials (CDM/GO/CN) were designed and synthesized. CN is used as a photosensitizer for photodynamic therapy (PDT) and GO as a photothermal agent for photothermal therapy (PTT). In addition, the supramolecular host-guest complex on the substrate can not only increase the inherent water solubility of the substrate and reduce the aggregation of the photosensitizer/photothermal agent but also manipulate the interaction between the photosensitizer/photothermal agent and bacteria to capture specific bacteria. The hyperthermia caused by PTT denatures proteins on the cell membrane, allowing reactive oxygen species (ROS) to enter the cell better and kill bacteria. The specific capture of Escherichia coli CICC 20091 by mannose significantly improves the sterilization efficiency and reduces side effects. The synergistic antibacterial agent shows excellent antibacterial efficacy of over 99.25% against E. coli CICC 20091 after 10 min of 635 + 808 nm dual-light irradiation. Moreover, cell proliferation experiments show that the composite material has good biocompatibility, expected to have applications in bacterial infections.

Cr(VI)-imprinted polymer wrapped on urchin-like Bi2S3 for reduced photocorrosion and improved photoreduction of aqueous Cr(VI).

Just like other metal sulfides, the misfortune of photocorrosion and undesired photogenerated electron-hole recombination for Bi2S3 was inevitable. In this work, a viable route to reduce photocorrosion of Bi2S3 and improve photoreduction of aqueous Cr(VI) was developed via "dressed" a Cr(VI) imprinting polymer (Cr(VI)-IP) on urchin-like Bi2S3 (U-Bi2S3). Cr(VI)-IP wrapped on the three dimensional U-Bi2S3 was implemented by a bulk polymerization. The wrapped Cr(VI)-IP enabled to fast enrich and adsorb Cr(VI) on U-Bi2S3 leading to improve the photoreduced efficiency of photogenerated carriers and restrain the photogenerated electron-hole recombination. What's more, Cr(VI)-IP wrapped on U-Bi2S3 was just like an "armor" which could support the three dimensional construction of U-Bi2S3 from the structural collapse of photocorrosion and retard the direct contact of oxygen and H2O from the surrounding media. As expected, the obtained U-Bi2S3@Cr(VI)-IP exhibited higher photostability, adsorption, photoreduction capacities towards the target Cr(VI) than the bare U-Bi2S3. The photocatalytic kinetic constant of U-Bi2S3@Cr(VI)-IP was 6 times higher than U-Bi2S3. After 3 times recycling uses, the morphology, crystal structure and chemical constitution of U-Bi2S3@Cr(VI)-IP were maintained. In addition, the removal efficiency of Cr(VI) by U-Bi2S3@Cr(VI)-IP was kept at 58% whereas U-Bi2S3 was almost lost to zero.