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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]

Flexible control of the micropore size of carbon was achieved in a cost-efficient way by predesigned quantitative correlation between the sizes of extendable (CN2)x nanosized modulators and the generated micropore sizes ranged from 0.2 to 2.3 nm, with effectiveness for boosting the electrochemical performance systematically. [ABSTRACT FROM AUTHOR]

Developing new synthetic methods for carbon supported catalysts with improved performance is of fundamental importance in advancing proton exchange membrane fuel cell (PEMFC) technology. Continuous-flow, microfluidic reactions in capillary tube reactors are described, which are capable of synthesizing surfactant-free, ultrafine PtSn alloyed nanoparticles (NPs) on various carbon supports (for example, commercial carbon black particles, carbon nanotubes, and graphene sheets). The PtSn NPs are highly crystalline with sizes smaller than 2 nm, and they are highly dispersed on the carbon supports with high loadings up to 33 wt %. These characteristics make the as-synthesized carbon-supported PtSn NPs more efficient than state of the art commercial Pt/C catalysts applied to the ethanol oxidation reaction (EOR). Significantly enhanced mass catalytic activity (two-times that of Pt/C) and improved stability are obtained. [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]

Carbon nanodots (CNDs) have been widely applied in variety of fields, while some evidences indicate their components may be complicated. In this work, capillary electrophoresis (CE) was used to evaluate the effect of synthetic conditions of fluorescent CNDs prepared through the hydrothermal method using citric acid (CA) and Triaminoguanidinium chloride (TG Cl) as the starting materials. The results indicated that the fluorescent components of the products were affected by the ratio of the starting materials, the reaction temperature and reaction time. Under selected conditions, a ratio of TG Cl to CA of 1:6, the reaction at 180 °C for 3 h, the product contains more than 4 fluorescent components with similar optical properties. CNDs were used for the determination of Cr(VI) in environmental samples with recoveries ranging in 95.3–107%, and the mechanism was also confirmed. [Display omitted] • Novel N-doped CNDs were synthesized with hydrothermal method. • The effect of synthetic conditions was evaluated with the capillary electrophoresis. • The reaction conditions affected both the composition and yield of CNDs. • The CNDs contained multiple fluorescent components with similar optical properties. • Sensitive detection of toxic Cr(VI) in environmental samples was achieved. [ABSTRACT FROM AUTHOR]