Recent advances in carbon monoxide-releasing nanomaterials.

As an endogenous signaling molecule, carbon monoxide (CO) has emerged as an increasingly promising option regarding as gas therapy due to its positive pharmacological effects in various diseases. Owing to the gaseous nature and potential toxicity, it is particularly important to modulate the CO release dosages and targeted locations to elucidate the biological mechanisms of CO and facilitate its clinical applications. Based on these, diverse CO-releasing molecules (CORMs) have been developed for controlled release of CO in biological systems. However, practical applications of these CORMs are limited by several disadvantages including low stability, poor solubility, weak releasing controllability, random diffusion, and potential toxicity. In light of rapid developments and diverse advantages of nanomedicine, abundant nanomaterials releasing CO in controlled ways have been developed for therapeutic purposes across various diseases. Due to their nanoscale sizes, diversified compositions and modified surfaces, vast CO-releasing nanomaterials (CORNMs) have been constructed and exhibited controlled CO release in specific locations under various stimuli with better pharmacokinetics and pharmacodynamics. In this review, we present the recent progress in CORNMs according to their compositions. Following a concise introduction to CO therapy, CORMs and CORNMs, the representative research progress of CORNMs constructed from organic nanostructures, hybrid nanomaterials, inorganic nanomaterials, and nanocomposites is elaborated. The basic properties of these CORNMs, such as active components, CO releasing mechanisms, detection methods, and therapeutic applications, are discussed in detail and listed in a table. Finally, we explore and discuss the prospects and challenges associated with utilizing nanomaterials for biological CO release.

Detection of Cd2+ in Aqueous Solution by the Fluorescent Probe of CdSe/CdS QDs Based on OFF-ON Mode.

The detection of heavy metals in aqueous solutions has always attracted much attention from all over the world. A fluorescent probe of CdSe/CdS core-shell quantum dots (QDs) was designed to detect trace Cd2+ in aqueous solutions using the OFF-ON mode rapidly and efficiently, likely based on adsorption and desorption reactions between ethylenediaminetetraacetic acid disodium salt (EDTA) and CdSe/CdS QDs. In the OFF mode, the optical shielding function of EDTA results in fluorescence quenching owing to the strong adsorption ability of EDTA with Cd2+ on the sites of CdSe/CdS QDs surface. In the ON mode, the introduction of Cd2+ promotes the desorption of EDTA from the EDTA-CdSe/CdS QDs and restores the fluorescence intensity. There were two linear response ranges which were 0.1-20 µmol/L and 20-90 µmol/L for the EDTA-CdSe/CdS system to detect Cd2+. The detection limit was 6 nmol/L, and the standard deviation was below 4% for the detection of Cd2+ concentration in tap water.

In suit constructing S-scheme FeOOH/MgIn2S4 heterojunction with boosted interfacial charge separation and redox activity for efficiently eliminating antibiotic pollutant.

Photocatalytic elimination of antibiotic pollutant is an appealing avenue in response to the water contamination, but it still suffers from sluggish charge detachment, limited redox capacity as well as poor visible light utilization. Herein, a particular S-scheme FeOOH/MgIn2S4 heterojunction with wide visible light absorption was triumphantly constructed by in-situ growth of MgIn2S4 nanoparticles onto the surface of FeOOH nanorods, and employed as a high-efficiency visible light driven photocatalyst for removing tetracycline (TC). Conspicuously, the as-obtained FeOOH(15 wt%)/MgIn2S4 elucidated the optimal TC removal rate of 0.01258 min-1 after 100 min of visible light illumination, which was almost 33.1 and 6.6 times larger than those of neat FeOOH and MgIn2S4, separately. The exceptional degradation performance was principally put down to the establishment of S-scheme heterojunction between FeOOH and MgIn2S4, which could not merely accelerate the detachment of photogenerated carriers, but also retain the powerful reducing ability of photoinduced electrons for MgIn2S4 and high oxidizing capacity of photoexcited holes for FeOOH, strongly driving the generation of plentiful active species including holes, superoxide and hydroxyl radicals. Additionally, the possible degradation mechanism and pathways of TC were also speculated. This work offers a valuable perspective for constructing high-efficiency S-scheme heterojunction photocatalysts for eradicating antibiotics.

Construction of cerium oxide nanoparticles immobilized on the surface of zinc vanadate nanoflowers for accelerated photocatalytic degradation of tetracycline under visible light irradiation.

Construction of Z-scheme heterojunction has been deemed to be an effective and promising approach to boost the photocatalytic activity on account of accelerating the separation efficiency of the photogenerated carriers and maintaining the strong redox ability. Herein, an attractive CeO2/Zn3V2O8 Z-scheme heterojunction photocatalyst was rationally constructed by zero-dimensional (0D) CeO2 nanoparticles immobilized on the surface of three-dimensional (3D) Zn3V2O8 nanoflowers using a simple mixing method, and applied to the photocatalytic degradation of tetracycline (TC) under visible light irradiation. As expected, it was observed that the prepared CeO2/Zn3V2O8 hybrid illustrated significantly boosted the photocatalytic activity for the elimination of TC compared to pure Zn3V2O8. More importantly, the optimized CeO2(40 wt%)/Zn3V2O8 hybrid owned the largest elimination rate of TC with 1.13 × 10-2 min-1, which was around 8.1 and 3.8 times as high as single CeO2 (0.14 × 10-2 min-1) and Zn3V2O8 (0.30 × 10-2 min-1), respectively. The appreciable performance improvement was mainly ascribed to the formation of Z-scheme heterojunction between CeO2 and Zn3V2O8, facilitating the transfer rate of photogenerated carriers and remaining the high reducibility of photoexcited electrons in CeO2 and strong oxidizability of photoinduced holes in Zn3V2O8. Active species capture experiments and electron spin resonance spectra showed that superoxide radicals and holes were the main active species for TC degradation. Besides, the possible degradation pathways of TC were speculated by identifying degradation intermediates, and the reasonable degradation mechanism including migration and transport behaviors of charge carriers and generation processes of reactive species were revealed in depth. This investigation enriches Zn3V2O8-based Z-scheme heterojunction photocatalytic system and offers a new inspiration for the construction and fabrication of high-efficiency Z-scheme heterojunction photocatalysts to remove the antibiotics from wastewater.

Ion-assisted construction of Sb/N-doped graphene as an anode for Li/Na ion batteries.

Although secondary batteries are common in many fields, new electrode materials with a reasonable structure are desired for high battery performance. Herein, Sb/N-doped graphene nanosheets (NGNS-Q) were constructed with the help of 7,7,8,8-tetracyanoquinodimethane anions (TCNQ·-). TCNQ·- were used to anchor Sb3+ into the graphene layer by electrostatic interaction, which improves the distribution of Sb nanoparticles. Meanwhile, TCNQ·- act as a N source to form N-doped graphene, enhancing the electron conductivity of the composite. Benefiting from the stable structure and good conductivity, the Sb/NGNS-Q composite achieved good electrochemical battery performance for Li/Na ion batteries (LIBs/SIBs). At a current density of 0.1 A g-1, Sb/NGNS-Q exhibited a capacity of 615 mAh g-1 after cycling 200 times and 240 mAh g-1 after 100 cycles for LIBs and SIBs, respectively.

Electronic synergism of pyridinic- and graphitic-nitrogen on N-doped carbons for the oxygen reduction reaction.

Nitrogen-doped carbon materials (NCs) are extensively studied for the oxygen reduction reaction (ORR). However, the nature of active sites of pyridinic nitrogen (NP) or graphitic nitrogen (NG) on NCs is still under debate. Herein, we demonstrated that the ORR activity of NCs in alkaline media depended on the electronic synergism between NP and NG, rather than any single type of N. We measured the transferable electrons of NCs by absorption spectroscopy using 7'7'8'8-tetracyanoquinodimethane as an electron acceptor. The transferable electron amount of NCs is relevant to either NP or NG, leading to the [NP] : [NG] ratio as an electron transfer descriptor of NCs in a reverse volcano curve manner across nineteen NCs. The similar dependence of ORR activity on the [NP] : [NG] ratio of NCs was also discovered, demonstrating the synergistic effect of NP and NG. These results provide a new angle to understand the nature of ORR activity of NCs and optimize the ORR catalyst.