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A new type of carbon dots (CD-Asp) with targeting function toward brain cancer glioma was synthesized via a straightforward pyrolysis route by using D-glucose and L-aspartic acid as starting materials. The as-prepared CD-Asp exhibits not only excellent biocompatibility and tunable full-color emission, but also significant capability of targeting C6 glioma cells without the aid of any extra targeting molecules. In vivo fluorescence images showed high-contrast biodistribution of CD-Asp 15 min after tail vein injection. A much stronger fluorescent signal was detected in the glioma site than that in normal brain, indicating their ability to freely penetrate the blood-brain barrier and precisely targeting glioma tissue. However, its counterparts, the CDs synthesized from D-glucose (CD-G), L-asparic acid (CD-A), or D-glucose and L-glutamic acid (CD-Glu) have no or low selectivity for glioma. Therefore, CD-Asp could act as a fluorescence imaging and targeting agent for noninvasive glioma diagnosis. This work highlights the potential application of CDs for constructing an intelligent nanomedicine with integration of diagnostic, targeting, and therapeutic functions.

Hydrogen peroxide (H2O2) is extensively used in production and life, functioning as an ecofriendly oxidant. However, the dominant method currently employed, the anthraquinone method, is not conducive to sustainable development. Recently, photocatalytic H2O2 synthesis has garnered significant attention as an environment‐friendly approach. Graphitic carbon nitride (g‐C3N4), a new type of photocatalyst, shows great potential for generating H2O2 due to its excellent stability, high photocatalytic activity, selectivity, easy adjustability, and low cost. However, the research on the mechanism of H2O2 photoproduction has not been fully understood, which limits its development and practical application. Herein, the recent progress on modified g‐C3N4 is summarized and the effect of modification methods on the photocatalytic activity and H2O2 generation process is discussed. The challenges and perspectives of g‐C3N4 toward H2O2 photoproduction are proposed. [ABSTRACT FROM AUTHOR]

Due to the COVID‐19 pandemic, many rapid antimicrobial agents have developed intensively. Carbon dots (CDs), a new type of carbon‐based nanomaterials, shows great potential against emerging infectious diseases and antimicrobial‐resistant infections due to their unique optical properties, excellent biocompatibility, and easy surface modification. With the definition of the CDs structure and properties, synthesis, and characteristic technology improvement, the research on the CDs as antimicrobial agents has made significant progress. However, the lack of high repeatable and exact preparation methods, and the regular antimicrobial activity make it far from practical application. In this review, we summarize the most recent progress and challenges of CDs antimicrobial. First, an overview of the characteristics and properties is given, and the advantage of CDs applied to antimicrobial is further discussed. Then, it focuses on research progress on antimicrobial mechanisms under different conditions, the critical factors affecting their antimicrobial activity, and the practical antimicrobial applications. Finally, the main challenges and future research perspectives of antimicrobial CDs are proposed. [ABSTRACT FROM AUTHOR]

A photocatalyst system is generally comprises a catalyst and cocatalyst to achieve light absorption, electron‐hole separation, and surface reaction. It is a challenge to develop a single photocatalyst having all functions so as to lower the efficiency loss. Herein, the active GaN4 site is integrated into a polymeric carbon nitride (CN) photocatalyst (GCN), which displays an excellent H2 production rate of 9904 μmol h−1 g−1. It is 162 and 3.3 times higher than that of CN with the absence (61 μmol h−1 g−1) and presence (2981 μmol h−1 g−1), respectively, of 1.0 wt % Pt. Under light irradiation the electron is injected and stored at the GaN4 site, where the LUMO locates. The HOMO distributes on the aromatic ring resulting in spatial charge separation. Transient photovoltage discloses the electron‐storage capability of GCN. The negative GaN4 promotes proton adsorption in the excited state. The positive adsorption energy drives H2 desorption from GaN4 after passing the electron to the proton. This work opens up opportunities for exploring a novel catalyst for H2 production. [ABSTRACT FROM AUTHOR]

Carbon nanodots (CDs) have generated enormous excitement because of their superiority in water solubility, chemical inertness, low toxicity, ease of functionalization and resistance to photobleaching. Here we report a facile thermal pyrolysis route to prepare CDs with high quantum yield (QY) using citric acid as the carbon source and ethylene diamine derivatives (EDAs) including triethylenetetramine (TETA), tetraethylenepentamine (TEPA) and polyene polyamine (PEPA) as the passivation agents. We find that the CDs prepared from EDAs, such as TETA, TEPA and PEPA, show relatively high photoluminescence (PL) QY (11.4, 10.6, and 9.8%, respectively) at λex of 465 nm. The cytotoxicity of the CDs has been investigated through in vitro and in vivo bio-imaging studies. The results indicate that these CDs possess low toxicity and good biocompatibility. The unique properties such as the high PL QY at large excitation wave length and the low toxicity of the resulting CDs make them promising fluorescent nanoprobes for applications in optical bio-imaging and biosensing. [ABSTRACT FROM PUBLISHER]

The g-C 3 N 4 -C 0.05 /FeTCPP hybrid photocatalysts exhibit high activity for the solar-fuels production under visible-light irradiation by virtue of the enhanced charge separation and electron transfer due to the incorporation of carbon dots into g-C 3 N 4. • g-C 3 N 4 -C x has been synthesized through thermal pyrolysis of citric acid and urea. • Appropriate carbon dots incorporation can improve charge separation of g-C 3 N 4. • Carbon dots can promote interfacial electron transfer from g-C 3 N 4 to FeTCPP. • Carbon dots can improve photocatalytic performance of g-C 3 N 4 -C x /FeTCPP. • g-C 3 N 4 -C 0.05 /FeTCPP hybrid photocatalyst exhibits the highest CO and H 2 evolution. Developing highly efficient photocatalysts for solar-fuels production under visible-light irradiation is of great promise, but still remains a big challenge. In this work, we use g-C 3 N 4 incorporated with carbon dots as the photosensitizer to couple with tetra(4-carboxyphenyl)porphyrin iron(III) chloride (FeTCPP) molecular catalyst. The obtained g-C 3 N 4 -C 0.05 /FeTCPP hybrid photocatalyst exhibits high activity for the solar-fuels production of CO and H 2 under visible-light irradiation, with CO yield of 23.1 mmol/g and H 2 yield of 71.1 mmol/g in 6 h. The enhanced mechanism has been studied by various techniques like photocurrent response, photoluminescence and mid-infrared femtosecond transient absorption. The presence of trace amount of carbon dots in the system can provide an alternative channel for the electron transfer, i.e., from g-C 3 N 4 to FeTCPP via the CDs. Accordingly, the interfacial charge separation and electron transfer can be promoted, leading to enhanced photocatalytic performance of the g-C 3 N 4 -C x /FeTCPP hybrid photocatalysts. [ABSTRACT FROM AUTHOR]

The XC-72R supported Pd catalysts exhibit low-temperature catalytic activity for CO oxidation under light irradiation. The CO conversion can reach 100% with the light irradiation of 900 mW·cm-2 at a catalyst temperature of 100 °C. Pd/C catalysts with different Pd loading have similar performance enhancement under light irradiation. The activation energy of 1% Pd/C catalyst remains unchanged implying that CO oxidation belongs to photothermal catalytic oxidation. The enhanced performance could be ascribed to ultrahigh surface temperature (275 °C) induced by the light irradiation of 800 mW·cm-2 and detected by an IR camera. That is higher than the catalyst temperature (187 °C) measured by the thermocouple. Carbon generates a higher temperature than Pd NP, causing heat transfers from carbon to Pd NP. In contrast, Pd NP produces a higher temperature than Al 2 O 3 for Pd/Al 2 O 3 catalyst, and heat is transferred from Pd to Al 2 O 3. These demonstrate that the enhanced performance contributes to the photothermal effect of carbon. [Display omitted] • Pd/C catalysts demonstrate high photothermal catalytic activity for CO oxidation. • The enhanced photothermal catalytic performance is attributed to the high local temperature. • The IR light plays a major role in raising the local temperature of the catalyst. • The carbon support could be regarded as microheater to achieve in-situ heating of Pd. [ABSTRACT FROM AUTHOR]