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Peripheral nerve injuries are common and can cause catastrophic consequences. Although peripheral nerves have notable regenerative capacity, full functional recovery is often challenging due to a number of factors, including age, the type of injury, and delayed healing, resulting in chronic disorders that cause lifelong miseries and significant financial burdens. Fluorescence imaging, among the various techniques, may be the key to overcome these restrictions and improve the prognosis because of its feasibility and dynamic real-time imaging. Intraoperative dynamic fluorescence imaging allows the visualization of the morphological structure of the nerve so that surgeons can reduce the incidence of medically induced injury. Axoplasmic transport-based neuroimaging allows the visualization of the internal transport function of the nerve, facilitating early, objective, and accurate assessment of the degree of regenerative repair, allowing early intervention in patients with poor recovery, thereby improving prognosis. This review briefly discusses peripheral nerve fluorescent dyes that have been reported or could potentially be employed, with a focus on their role in visualizing the nerve's function and anatomy. [ABSTRACT FROM AUTHOR]

Low-temperature processable p-type transparent conductors are essential for flexible transparent electronics. Current research focuses primarily on wide-band gap copper-based oxides for p-type transparent conductors. However, these oxides generally exhibit inferior performance compared to their n-type counterparts, and their high preparation temperature is unfavorable for flexible electronic applications. CuI serves as a p-type transparent conductor with the ability to be prepared at low temperatures while possessing properties comparable to n-type transparent conductors. The conventional method for CuI film fabrication involves iodination of Cu films. Nevertheless, films produced through this approach exhibit a frosted-glass-like appearance and challenging-to-regulate electrical properties, rendering them unsuitable for electronic devices. In this study, we successfully developed composite films of CuI–Cu2O, demonstrating improved surface morphology and electronic properties at room temperature. The inclusion of Cu2O suppresses the migration of CuI grain boundaries during the iodination process, leading to a reduction in CuI grain size and the formation of a polycrystalline structure with a smoother surface. The increased concentration of grain boundaries within the films, along with charge redistribution between Cu2O and CuI, results in a decrease in hole concentration. As the Cu2O content increases, the relative concentration of I vacancies in the films decreases, leading to an enhancement in hole mobility. The film conductivity initially rises and subsequently decreases with higher Cu2O content. For CuI–Cu2O films with optimized Cu2O composition, visible region transparency ranges from 70% to 80%, hole concentration measures 6.16 × 1018 cm−3, hole mobility reaches 25.40 cm2 V−1 s−1, and conductivity amounts to 18.57 S cm−1. Furthermore, after a period of six months, the electrical properties of CuI–Cu2O films exhibit greater stability compared to pure CuI films. These findings are expected to expedite the widespread application of CuI films within transparent electronics. [ABSTRACT FROM AUTHOR]

Triethylamine significantly harms the human body, so it is important to develop a triethylamine gas sensor with excellent performance for triethylamine detection. In this work, a Pd/PdO–In2O3 triethylamine gas sensor is developed by a simple, low-cost method, which exhibits improved comprehensive performance for triethylamine detection, including high sensitivity, fast response/recovery time, good selectivity, long-term stability, and certain moisture resistance. The unique method simultaneously realizes Pd loading and multiple PdO–In2O3 P–N heterojunctions, which accelerate the electron transport speed and increase electron transport channels, ultimately endowing Pd/PdO–In2O3 with excellent triethylamine sensing performance. This provides new methods and insights for preparing high-performance triethylamine sensors. [ABSTRACT FROM AUTHOR]

MIL-125, a titanium-based metal–organic framework (MOF) material with ultra-high specific surface area, large porosity, tunable structure, modifiable functionality, and multiple active sites, is commonly researched in the field of photocatalytic hydrogen evolution. However, MIL-125 still could not be directly used for practical application in photocatalytic hydrogen evolution because of its limited photoresponse. Therefore, it is necessary to systematically summarize the research on MIL-125 in the field of photocatalytic hydrogen evolution for its further development as well as that of other MOF materials. For MIL-125 photocatalysts, further modifications for promoting the photocatalytic activity of photocatalysts and improving the stability of photocatalysts are needed. Typical modification methods of MIL-125 include engineering functional groups and surface structure, doping metal ions, loading cocatalysts, and structuring composites. In this review, the research progress of MIL-125 in the field of photocatalytic hydrogen evolution is summarized, including its modification methods, photocatalytic hydrogen evolution activities, and micro-mechanisms. In view of the deficiencies and limitations of the current research, future developments of MIL-125 are prospected. [ABSTRACT FROM AUTHOR]

We propose a strategy to etch dopants to construct Mo2C with more unsaturated coordination of Mo atoms and lattice distortion for enhanced catalytic activity. It is more effective than doping and etching pure Mo2C and provides a novel strategy for the preparation of catalysts with high catalytic activity. [ABSTRACT FROM AUTHOR]

Artificially inducing abundant oxygen vacancies in perovskite-structured materials is an effective method to improve sensing activity. In this work, we prepared a highly sensitive and stable La0.9Fe0.75Sn0.25O3−δ hollow nanofiber by introducing A-site cation defects in LaFeO3 by electrostatic spinning technique, then combined with a water bath method to uniformly load the surface of La0.9Fe0.75Sn0.25O3−δ with well dispersed xPt (x = 0, 0.5%, 1%, and 1.5%, 2%) elements. Compared with La0.9Fe0.75Sn0.25O3−δ without Pt modification, the xPt–La0.9Fe0.75Sn0.25O3−δ sensing materials exhibited an excellent response to formaldehyde and greatly improved the overall performance of the sensing electrode, especially 1.5%Pt–La0.9Fe0.75Sn0.25O3−δ, achieving a response of 137 for 10 ppm formaldehyde at 160 °C, which is a significant improvement compared to the intrinsic LaFeO3. The improved gas-sensitive achievement is based on the abundant oxygen vacancies induced by the A-site cation defect, the large specific surface area, and the high catalytic activity of Pt(O) elements. This strategy of inducing abundant oxygen vacancies by artificially creating A-site cation defects and modifying noble metals can be used to develop more advanced and novel sensing electrodes. [ABSTRACT FROM AUTHOR]

Obtaining hydrogen energy from photocatalytic water splitting driven by solar energy is a promising strategy to solve the global energy crisis. Herein, by taking the photoinduced activation effects of TiO2, we obtained a Ti3+ self-doped TiO2 (Ti3+–TiO2). In situ characterization revealed that the presence of Ti3+ is attributed to the reduction reaction of Ti4+ on the TiO2 surface under UV light irradiation. The research results prove that the optical properties of TiO2 are modified by the active species Ti3+; the recombination rate of the photogenerated carriers is significantly decreased, and Ti3+–TiO2 exhibits a hydrogen production rate which is 1.7 times superior than that of pristine TiO2. To further enhance the self-activation effect of TiO2, we constructed a type II heterojunction TiO2/UiO-66-NH2 structure to transfer photoexcited electrons to TiO2, which gives a higher concentration and duration of the active species Ti3+. Ti3+–TiO2/UiO-66-NH2 shows improved photocatalytic hydrogen evolution activity with a rate 3.2 times better than that of pristine TiO2 due to the synergistic function of oxygen vacancies and Ti3+. A novel perspective was adopted in this work to observe the dynamic variation of active species and electron transfer pathways during TiO2 photocatalytic reactions. Since Ti3+ is generated on the TiO2in situ, this work could be extended to TiO2-based photocatalysts. [ABSTRACT FROM AUTHOR]

Electrochemical conversion of carbon dioxide and carbon monoxide into value-added multi-carbon products (C2+) offers a promising approach for artificial oxycarbide recycling. However, C2+ productivity is still limited by gas accessibility inside the catalyst layer. Here, a Cu-PMMA porous hybrid architecture with rich triple-phase boundaries was demonstrated to enhance both gas diffusion and electron transfer, and then, facilitate the kinetics of CO electrolysis. As a result, a high C2+ faradaic efficiency (FE) of 81.6% at a current density of 50 mA cm−2 and a maximum C2+ partial current density of 140 mA cm−2 were achieved, among the best performances for Cu/hybrid catalysts. This study provides a novel strategy for designing electrochemical CO reduction (ECORR) catalysts and paves the way for further developing gas-involving electrocatalysis. [ABSTRACT FROM AUTHOR]

Sodium ion batteries (SIBs) and potassium ion batteries (PIBs) are the most promising alternative candidates to lithium ion batteries (LIBS), owing to their natural abundance and low cost. Herein, a unique cubic/orthorhombic-CoSe2 phase-junction (c/o-CoSe2) anchored on SiC nanowires (NWs) (denoted as c/o-CoSe2@SiC) is developed. The electron coupling effect of phase-junction interface promotes the diffusion of Na+/K+. Meanwhile, SiC NWs play a pivotal role in stabilizing the active materials, improving the cycling stability and providing fast transport pathways for electrons. Thus, c/o-CoSe2@SiC exhibits a sodium storage performance of 413 mA h g−1 after 300 cycles at 0.2 A g−1 with an 86.66% capacity retention rate and 300 mA h g−1 after 1000 cycles at 1 A g−1, as well as a potassium storage performance of 190 mA h g−1 after 500 cycles at 1.0 A g−1. Moreover, the electrochemical reaction mechanism and the structural reversibility of c/o-CoSe2@SiC are also revealed by operando Raman, operando powder X-ray diffraction (PXRD) and ex situ high resolution transmission electron microscopy (HRTEM) characterization. And theoretical calculations revealed the redistribution of charge and the strongest adsorption of Na+ from the electrolyte at the phase-junction of c/o-CoSe2. Phase-junction engineering could provide a new strategy for developing high-performance SIBs and PIBs. [ABSTRACT FROM AUTHOR]

Immunotherapy is revolutionizing cancer treatment. Vaccination of antigenic peptides has been identified as a promising strategy for cancer immunotherapy while insufficient immune responses were stimulated due to low antigenicity. Moreover, immune checkpoint blockade therapy is still limited by a low objective response rate. In this work, cationic polymer–lipid hybrid nanovesicle (P/LNV)-based liposomes are designed to simultaneously deliver tumor vaccines composed of anionic antigen epitopes, toll-like receptor-9 agonist (TLR9), CpG (AE/CpG), and indoleamine-2,3-dioxygenase (IDO) inhibitor, 1-methyl-tryptophan (1-MT), to increase the immunogenicity of peptide antigens and meanwhile block the immune checkpoint. P/LNV liposomes efficiently enhanced the uptake of vaccines by dendritic cells (DCs) and improved the maturation of DCs indicated by the significantly increased percentage of CD86+MHCI+ DCs, resulting in a potent cytotoxic T-lymphocyte (CTL) response against B16-OVA tumor cells in vitro. Importantly, the combination immunotherapy showed significantly higher therapeutic efficiency towards melanoma tumors in mice, compared with an untreated or individual therapy modality. Mechanistically, the co-delivery system could elicit a strong cancer-specific T-cell response, as characterized by the remarkably increased infiltration of CD8+ T cells in the tumor and draining lymph nodes. Altogether, cationic liposomes delivered with tumor vaccines and IDO inhibitor provide a promising platform for cancer immunotherapy by provoking antitumor T-cell immunity and simultaneously reversing the immunosuppressive tumor microenvironment. [ABSTRACT FROM AUTHOR]

Recently, transition metal borides (MBenes, analogous to MXenes) have attracted interest due to their potential applications in energy conversion and storage. In this work, we performed density functional theory calculations to systematically explore the exfoliation properties of 14 MAlB phases and their water splitting and N2 reduction reaction (NRR) performances. Results showed a linear relationship between the binding energy and exfoliation energy with the coefficient (R2) of 0.95, indicating that the lower the binding energy of element Al in MAlB (M2AlB2), the higher the exfoliation energy required to synthesize monolayer MB from MAlB (M2AlB2). NiB (B site) was predicted to possess the best electrocatalytic activity for water splitting, hydrogen evolution reaction (HER), and oxygen evolution reaction (OER) among the studied MBenes, and overpotentials on the NiB surface were calculated to be 0.08 V (for HER) and 0.37 V (for OER), respectively. The electronic properties and dynamic simulations indicated that NiB is the best candidate catalyst for water splitting. Conversely, the Fe site on FeB (FeB-Fe) was predicated to have the highest nitrogen reduction reaction (NRR) activity among the studied MBenes, with the overpotential ηNRR of 0.11 V. Furthermore, the B site of TaB (TaB-B) was identified as the best NRR catalyst against HER among the studied MBenes considering the HER side reaction. [ABSTRACT FROM AUTHOR]

Bacterial infection is a serious clinical threat. The misuse of antibiotics has already resulted in the emergence of antibiotic-resistant strains of pathogenic bacteria. Efficient membrane-destructive antibacterial agents are considered as an alternative, promising solution against bacterial infection. Herein, we prepared a new type of comb-like cationic, polyethylene glycol (PEG) block polycarbonates with polyquaternium arms (G-CgQAs). The amphiphilic G-CgQAs could self-assemble into about 60 nm sized nanoparticles (NPs) with positive charges (20~30 mV). G-CgQA-3 NPs with an appropriate hydrophobic–hydrophilic balance in the polyquaternium arms showed antibacterial activity against Gram-negative, Gram-positive, and drug-resistant strains at low concentrations (MIC 64–128 μg mL−1) and low hemolysis (HC50 > 2000 μg mL−1). In vivo anti-infection tests indicated G-CgQA-3 NPs could highly inhibit the growth of vancomycin-resistant bacteria by spraying on wounds. Collectively, G-CgQA NPs hold great promise for the prevention of infection, serving as new antibacterial agents. This study also highlights the significance of a hydrophobic block in positive polyquaternium arms to facilitate the antibacterial activity of cationic, quaternized polymers. The design of comb-like amphiphilic cationic polycarbonates provides a new method for manufacturing antibacterial nano-agents. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitrides (CNs) are potential candidate materials for the electro-catalytic industry due to their unique physical and chemical properties. However, to date, a full understanding of the electro-catalytic properties of CNs is still lacking. Herein, by using density functional theory calculations, we systematically investigate the catalytic performances in the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), N2 reduction reaction (NRR), and CO2 reduction reaction (CO2RR) of monolayer graphitic carbon nitrides (C1−xNx), C3N (x = 1/4), C2N (x = 1/3), and g-C3N4 (x = 4/7). We also evaluated the NRR activity of B doped C1−xNx, and the CO2RR activity of Cu and Pd modified C1−xNx. The cohesive energy and ab initio molecular dynamics (AIMD) results show that C3N, C2N, and g-C3N4 are stable at room temperature. The C3N–C1 site is predicted to deliver the best HER catalytic performance with a reaction Gibbs free energy (ΔGH*) of −0.03 eV (close to the ideal value (0 eV)). Among the studied C1–xNx materials, the C3N–C2 site is predicted to possess a favorable ηOER of 0.82 V for OER. Pure C3N, C2N, and g-C3N4 are not suitable for NRR and CO2RR. Due to the strong hybridization between the N 2p orbital and the B 2p orbital, the NRR performances of B doped BN–C2N, BN–C3N, and BN–g-C3N4 are greatly enhanced, with corresponding overpotential ηNRR of 0.57 V, 0.70 V, and 0.72 V, respectively. The transition metals Cu and Pd can enhance the CO2RR activity of C3N, C2N, and g-C3N4. The limiting potentials UL of pure C3N, C2N, and g-C3N4 are 0.96 V, 0.86 V, and 2.37 V, respectively, while these values are 0.63 V, 0.68 V, and 0.77 V with Cu or Pd modification. This work provides deep understanding of the catalytic properties of monolayer C1−xNx and guidance for synthesizing higher activity catalysts in the future. [ABSTRACT FROM AUTHOR]

The synthesis of NH3 under ambient conditions using solar energy is the most attractive method of synthesis, and requires efficient and stable photo-catalysts with ultralow overpotentials, because a low overpotential ensures low energy consumption and a high yield of NH3. Here, by using density functional theory calculations, the catalytic activity enhancements from B decoration and the oxidation of black and blue phosphorene for N2 fixation photo-catalysis are predicted. The results show that the computed overpotentials (ηNRR) were 0.78 and 0.92 V through the end-on configuration of the B doped black phosphorene (B-BlP) and blue phosphorene (B-BeP), respectively. In addition, owing to the reduction of the band gap, decoration with B can greatly enhance the visible light and infrared light harvesting of BlP and BeP, guaranteeing them as ideal potential materials for the visible light reduction of N2. The formation energy of B decoration and the ab initio molecular dynamics simulation results indicate that B-BlP and B-BeP are highly stable under ambient conditions (300 K). The oxidation of the BlP and BeP surfaces can also enhance the N2 reduction reaction (NRR) performances using visible light driving, with the ηNRR values being 1.31 and 1.51 V through the end-on and side-on configurations, respectively. In summary, this work offers the opportunity for decorated phosphorene to act as a photo-catalyst for NH3 production. [ABSTRACT FROM AUTHOR]

Due to the unique properties of two-dimensional (2D) materials, van der Waals epitaxy or the remote epitaxy of nonplanar and planar materials on 2D materials plays an important role in various applications; however, it is often limited by low crystal quality due to misorientation in nonplanar materials or grain boundaries and high threading dislocation densities in planar materials. Selective area growth (SAG), in which orientations are concordant, grain boundaries can be avoided, and threading dislocations can be annihilated, is an effective way to overcome this limitation. It is believed that microscale materials are the predominant masks for SAG, and the nanoselective area growth (NSAG) technology is superior to SAG as it can allow the mechanical exfoliation of the epilayer from the substrate. Herein, we demonstrated the fabrication of architectural GaN nanostructures by the self-assembly NSAG (SNSAG) technology using multilayer graphene (MLG) as a nanomask. The microstructure and optical properties were characterized by scanning electron microscopy, transmission electron microscopy, cathodoluminescence, and micro-Raman and micro-photoluminescence spectroscopy techniques for evidencing the high-quality GaN nanostructures; moreover, high-quality, stress-relaxation GaN films were grown by SNSAG on MLG/SiC and mechanically exfoliated from the substrate for obtaining free-standing GaN. This technique enables the integration of any nonplanar and planar semiconductor material with graphene for extensible applications. [ABSTRACT FROM AUTHOR]

We have developed an efficient approach for preparation of ultrafine and well-dispersed crystalline Fe-doped TiO2 nanoparticles (Fe–TiO2) with a size distribution of 2.3 ± 0.9 nm under mild conditions by using covalent organic frameworks (COFs) as the interface engineering agent. The as-synthesized Fe–TiO2@COF shows an exceptional photocatalytic activity degrading methylene blue (MB) under ambient light. A trace amount (0.4 mg) of the optimal catalyst 5Fe–TiO2@COF can degrade MB (100 mg L−1, 4 mL) under ambient light. More importantly, the catalyst exhibits excellent stability and can be reused multiple times without any loss of catalytic activity. The use of a crystalline porous COF as a catalyst support has many unique advantages, including controlled-growth of nanoparticles with ultrafine size, stabilization of nanoparticles, efficient sorption of the organic pollutant thus increasing their local concentration around the catalysts, and facilitating the mass transfer through its porous channels. Our study provides an efficient and novel approach for preparation of well-dispersed ultrafine metal oxides with high stability and photosensitivity for energy and environmental applications. [ABSTRACT FROM AUTHOR]

The generation of hydrogen by water splitting through the electrocatalytic approach could become a sustainable way to replace traditional fossil energy. The search for alternatives to the precious metals (Pt, Pd, and Ir) for hydrogen production from water splitting is one of the central issues in the area of renewable energy. Two-dimensional metal carbide and nitride (MXenes) materials have shown some characteristics of promising catalysts for the hydrogen evolution reaction (HER). Herein, we performed density functional calculations to systematically explore the exfoliation properties of more than 50 MAX phases and the HER performances of 30 MXenes to search the universal descriptors for the HER performances of MXenes. The exfoliation properties of MAXs were studied and the results showed that for most MAXs, the lower the binding energy of A elements, the higher the exfoliation energy of 2D MXenes from MAXs. A critical value of exfoliation energy of 0.253 eV Å−2 was obtained, whereby MAXs with an exfoliation energy lower than this value favor exfoliation. For the predication of the HER performances of MXenes, two descriptors, namely Ne and Ef, have been proposed in the literature. The present calculations illustrated that these two parameters could not fully address the influence of hydrogen coverage on the Gibbs free energy of hydrogen adsorption (ΔGH*) on MXenes. Further studies indicated that both Ne and Ef relate to the surface-terminated O-p orbital center (εp), whereby the lower εp, the larger Ne and Ef, and the stronger interaction between O* with MXenes substrates. However, it is not favored for HER, if εp is either too large or too small. These results show that the surface-terminated O-p orbital center εp, could be used as a good descriptor for predicting the HER performances of MXenes. The best values of εp were in the range of −4.1 to −3.3 eV, with the corresponding values of Ne and Ef from 0.93 to 1.15 e and 3.15 to 3.78 eV, respectively, and ΔGH* from −0.3 to 0.3 eV. The result for the energy change in the HER process (Volmer–Heyrovsky and Volmer–Tafel mechanisms) of 10 M2CO2, and the minimum energy pathway of Mo2CO2 and Zr2CO2 confirmed that MXenes with a medium εp could deliver optimal HER performance. [ABSTRACT FROM AUTHOR]

Electrocatalysis has the potential to become a more sustainable approach to generate hydrogen as a clean energy source. Developing effective electrocatalysts for water splitting is central to the area of renewable energy. Herein, we performed density functional calculations to predict the electrocatalytic performance of a Ni2P surface and Ni2P/Cr2CO2 (MXene) interface as bifunctional electrocatalysts and clarified the mechanisms of the improvement of the electrocatalytic activity of the Ni2P/Cr2CO2 interface. The optimal overpotential of the Ni2P surface for the oxygen evolution reaction is 0.95 V, and the ideal overpotential of the Ni2P/Cr2CO2 interface for the oxygen evolution reaction is 0.80 V. The Gibbs free energy for the adsorption of atomic hydrogen (ΔGH*) on the Ni2P/Cr2CO2 interface can reach −0.09 eV at a suitable hydrogen coverage. The HER processes of both Cr2CO2 and the Ni2P/Cr2CO2 interface follow the Volmer–Heyrovsky mechanism with the activation energy barriers (Ea) of 0.76 eV and 0.68 eV, respectively. The Ni2P/Cr2CO2 interface promotes charge transfer from the Ni atom to O atom, which weakens the interaction between Ni and intermediates and therefore improves the catalytic effect of Ni2P for either the HER or OER. The present results indicate that the hierarchical Ni2P/Cr2CTx composite could be an effective medium for achieving a promising bifunctional electrocatalysis for water splitting. [ABSTRACT FROM AUTHOR]

Due to the lack of native GaN substrate, GaN-based devices are heteroepitaxially grown on foreign substrates. Heteroepitaxial GaN has high defect densities due to the lattice mismatch of GaN and substrate. Epitaxial lateral overgrowth (ELOG) technology is an effective way to reduce the defects. However, the reduction of threading dislocations (TDs) to ∼106 cm−2 remains a challenge. Herein, we have demonstrated the fabrication of TD-free GaN microrods on 4° off-axis SiC by ELOG technology, using graphene as a mask and revealed the evolution mechanism of defects. The microstructural properties were investigated by scanning electron microscopy (SEM), cathodeluminescence (CL), and transmission electron microscopy (TEM). I1-type basal plane stacking faults (BSFs) were the predominant defects in GaN. ELOG of GaN localized the defects at the interface by formation of “self-limited” SFs (SLSFs), which led to dramatic reduction of defects and TD-free at the surface of GaN microrods. This evolution mechanism of defects was different from that of traditional ELOG technology, and it opens up a guiding principle towards ultralow-threading-dislocation-density GaN films. [ABSTRACT FROM AUTHOR]

Carrier-transport is important in the field of metal oxide semiconductor gas sensors because it directly determines the sensor response and operating temperature. In this paper, gas sensors for monitoring of benzene are developed based on a boron-doped graphene quantum dot (BGQD)/Ag–LaFeO3 p–p heterojunction (B/APPH). The band gap of the BGQDs and Ag–LaFeO3 matched well, promoting separation of electron–hole pairs and enhancing the carrier transport ability. The introduced Ag catalytically oxidized benzene into CO2 and H2O in gas-sensing reactions. We optimized the selectivity of the B/APPH by benzene molecular imprinting. Our results show that B/APPH possesses a high response (17.5) and good selectivity, repeatability, and accuracy at a low operating temperature (65 °C) for detection of as little as 1 ppm of benzene. The heterojunction between the BGQDs and Ag–LaFeO3 improved the carrier-transport ability and reduced the operating temperature while maintaining the high sensing response and selectivity. The ability to modulate carrier-transport developed in this work will guide work on high performance gas sensors based on metal oxide semiconductors. [ABSTRACT FROM AUTHOR]

For developing highly sensitive, selective and stable gas sensing materials for the detection of volatile organic compounds, we report porous micro/nano-level structure Ag-LaFeO3 nanoparticles which have been successfully synthesized using a lotus leaf as a bio-template via a sol–gel process. Combined with the molecular imprinting technique, the selectivity of the gas sensor can be altered and enhanced gas-sensing properties are obtained due to the unique molecular recognition and large specific surface area. The Ag-LaFeO3 nanoparticles are found to exhibit an ultrahigh xylene response (Rg/Ra = 16.76 to 10 ppm), fast gas response and recovery (68 and 36 s) and superior selectivity against the other tested interfering gases at a relatively low operating temperature of 125 °C. They also exhibit excellent humidity stability and long-term stability with small deviations, and this result may deliver a new approach that enables the stable detection of xylene gas. [ABSTRACT FROM AUTHOR]

The cycloaddition of CO2 to epoxides to form cyclic carbonates is very promising and does not generate any side products. Metal-free, heterogeneous organocatalysts offer an environmentally friendly alternative to traditional metal-based catalysts. Herein two triazine-based covalent organic frameworks (COF-JLU6 and COF-JLU7) were successfully synthesized under solvothermal conditions. The structural and chemical properties of COFs were fully characterized by using powder X-ray diffraction analysis, structural simulation, Fourier transform infrared spectroscopy, 13C solid-state NMR spectroscopy, electron microscopy, thermogravimetric analysis and nitrogen adsorption. The two COF materials combine mesopores, high crystallinity and good stability, as well as a large number of hydroxy groups in the pore walls. They possess a high Brunauer–Emmett–Teller (BET) specific surface area up to 1390 m2 g−1 and a large pore volume of 1.78 cm3 g−1. The COF-JLU7 displays a high CO2 uptake of 151 mg g−1 at 273 K and 1 bar. Importantly, COF-JLU7 was found to be a highly effective catalyst to convert CO2 into cyclic carbonate through the cycloaddition reaction with epoxides under mild conditions. The effect of reaction parameters, such as reaction temperature, reaction time and CO2 pressure, on the catalytic performance was also investigated in detail. Moreover, the new framework-based catalyst can be recovered and reused five times without a significant loss of catalytic efficiency. [ABSTRACT FROM AUTHOR]

Two-dimensional covalent organic frameworks (2D-COFs) are excellent candidates for photocatalytic organic transformations due to their periodic columnar π-arrays and ordered nanochannels. Here, we present a novel 2D-COF that features permanent porosity with high surface area and large pore volume, and exhibits a high crystallinity and an excellent stability. Indeed, the new 2D-COF was found to be a highly efficient, metal-free, recyclable heterogeneous photocatalyst for oxidative C–H functionalizations under visible-light irradiation using O2 as a green oxygen source. [ABSTRACT FROM AUTHOR]

A novel mononuclear platinum(ii) complex, [PtL(DMSO)Cl]Cl (1, here L = danysl bis(2-benzothiazolylmethyl)amine), has been synthesized and characterized by ESI-MS, IR spectrum, 1H NMR, 13C NMR, molar conductivity, and elemental analysis. The results suggest that in the structure of complex 1, a platinum(ii) ion is coordinated by a tertiary amine nitrogen, a benzothiazole nitrogen, a DMSO sulfur, and an exogenous chlorine ion to form one square mononuclear structure. Complex 1 exhibits a cytotoxicity comparable to that of cisplatin against HeLa cell line and more potent activities against A-549 and MCF-7 cell lines. Compared to those of L, the potent cytotoxicity of 1 should result from the coordination of Pt(ii). DNA binding experiments demonstrate that 1 could strongly bind to calf thymus DNA (CT-DNA) by a groove binding mode accompanied with a moderate intercalation and induce a visible conformational variation of DNA. Investigation of the reaction of 1 with 5′-GMP by ESI-MS shows that complex 1 could first form a 1 : 1 adduct [PtL(DMSO)(GMP) − 2Na + H]+ with 5′-GMP and react further with a second equivalent of 5′-GMP to form a 1 : 2 adduct [PtL(DMSO)(GMP)2− 4Na + 3H]+, which is similar to those of [Pt(en)(DMSO)Cl]Cl and cisplatin. Therefore, the anticancer mechanism of these compounds might well be related to each other. The evalution of the protein binding ability shows that complex 1 could bind to human serum albumin (HSA) with a moderate binding affinity, quench the intrinsic fluorescence of HSA, and destroy the tertiary structure of HSA. [ABSTRACT FROM AUTHOR]

Cadmium telluride (CdTe) thin-film solar cells show great potential due to their high efficiency, thermal stability, and low manufacturing cost. However, the practical performance of CdTe solar cells is often severely restricted due to the deficiency or excess of Cu diffusion, leading to a non-ohmic contact and electrical shorts and thus performance degradation. Herein, we demonstrate an innovative strategy for the fabrication of a Cu-free back contact by depositing CdTe quantum dots (QDs) on a CdTe layer using the pulsed laser deposition (PLD) technique, and find that the average relative power conversion efficiency is significantly enhanced by ∼6.2%. More importantly, the as-prepared CdTe QDs are thermally stable and CdTe with CdTe QD/Au back contact devices show no sign of degradation during exposure to air even after nearly one year. This study provides new insight into the design and property modulation of CdTe-based photovoltaics. [ABSTRACT FROM AUTHOR]

Metal oxide semiconductors with special structures and morphologies have attracted considerable attention because of their promising applications in gas sensors. In this paper, Ag–LaFeO3 fibers, spheres and cages have been prepared. Based on X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), Brunauer–Emmett–Teller (BET) nitrogen adsorption and transmission electron microscopy (TEM) observations, the structure and morphology of the products were characterized. It has been revealed that the as-prepared materials have uniform morphologies and consist of numerous nanocrystals. Sensors based on the Ag–LaFeO3 fibers, spheres and cages all exhibited high responses and good selectivities to formaldehyde gas. Owing to their hollow and porous structure, large surface area and greater number of surface active sites, the Ag–LaFeO3 cages have the lowest operating temperature. The results suggest that the as-prepared Ag–LaFeO3 fibers, spheres and cages, especially the cages, are promising candidates for high performance formaldehyde sensors. [ABSTRACT FROM AUTHOR]

Herein we report on a charge-adaptive nanosystem for prolonged and enhanced in vivo antibiotic delivery. The nanocarrier achieves acid-dependent charge conversion, thus prolonging the circulation time and enhancing antibiotic accumulation in subcutaneous inflammation models. [ABSTRACT FROM AUTHOR]

Based on the protonation/deprotonation of poly(β-amino ester) (PAE), mixed-shell micelles (MSMs) with adaptive surfaces could rapidly and reversibly change surface properties to prolong circulation time in blood (pH 7.4) and enhance cellular uptake at tumor sites (pH 6.5). [ABSTRACT FROM AUTHOR]

A novel formaldehyde gas sensor has been developed for the first time using a molecular imprinting technique (MIT) in semiconductor oxides to recognize small organic molecules. For specific recognition, the as-prepared molecularly imprinted nanoparticles exhibit good selectivity for formaldehyde. The molecularly imprinted nanoparticles were mixed with Ag–LaFeO3 to form a compound. The compound with small dimensions and good dispersity possesses an extremely high surface-to-volume ratio. Therefore the compound exhibits even better formaldehyde-sensing properties. At 40 °C, the response to 0.5 ppm formaldehyde based on the compound is 24.5, and is lower than 3.0 to the other test gases. The response time and recovery time are 67 s and 104 s, respectively. [ABSTRACT FROM AUTHOR]

Correction for 'Co-delivery of anionic epitope/CpG vaccine and IDO inhibitor by self-assembled cationic liposomes for combination melanoma immunotherapy' by Qi Su et al., J. Mater. Chem. B, 2021, 9, 3892–3899, DOI: 10.1039/d1tb00256b. [ABSTRACT FROM AUTHOR]

The development of high-activity photocatalysts is crucial for the current large-scale development of photocatalytic hydrogen applications. Herein, we have developed a strategy to significantly enhance the hydrogen photocatalytic activity of Cu/Pr di-atom co-modified TiO 2 architectures by selectively anchoring Cu single atoms on the oxygen vacancies of the TiO 2 surface and replacing a trace of Ti atoms in the bulk with rare earth Pr atoms. Calculation results demonstrated that the synergistic effect between Cu single atoms and Pr atoms regulates the electronic structure of Cu/Pr-TiO 2 , thus promoting the separation of photogenerated carriers and their directional migration to Cu single atoms for the photocatalytic reaction. Furthermore, the d-band center of Cu/Pr-TiO 2 , which is located at -4.70 eV, optimizes the adsorption and desorption behavior of H*. Compared to TiO 2 , Pr-TiO 2 , and Cu/TiO 2 , Cu/Pr-TiO 2 displays the best H* adsorption Gibbs free energy (-0.047 eV). Furthermore, experimental results confirmed that the photogenerated carrier lifetime of Cu/Pr-TiO 2 is not only the longest (2.45 ns), but its hydrogen production rate (34.90 mmol g -1 h -1 ) also significantly surpasses those of Cu/TiO 2 (13.39 mmol g -1 h -1 ) and Pr-TiO 2 (0.89 mmol g -1 h -1 ). These findings open up a novel atomic perspective for the development of optimal hydrogen activity in dual-atom-modified TiO 2 photocatalysts.

CuI films present promising optoelectronic properties for transparent conductors. However, the high hole concentration in CuI films hinders the controllable modulation of hole mobility, limiting their application in low-dimensional thin-film transistors. In this study, CuI films were prepared through a Cu film iodination method at room temperature, and a systematic investigation was conducted on the modulation of hole concentration and mobility with varying film thickness. The films exhibited a zinc blende structure (γ-phase) with increasing grain size as the thickness increased. The transmittance and optical bandgap of the films decreased with increasing thickness. The correlation of vacancy concentration with changing film thickness was analyzed through photoluminescence spectroscopy, revealing the influence of grain boundary migration on vacancy formation. The reduction in film thickness diminishes the migration of CuI grain boundaries, consequently reducing the probability of Cu vacancy and I vacancy formation, resulting in diminished hole concentration and enhanced hole mobility and film conductivity. The film with a thickness of 20 nm demonstrated optimal performance, with a transmittance of 90%, hole concentration of 4.09 × 10 17 cm -3 , hole mobility of 506.50 cm 2 V -1 s -1 , and conductivity of 33.19 S cm -1 . This work deepens the understanding of hole transport such as hole concentration and mobility modulation in CuI films, highlighting the importance of controlling grain boundary migration during the film growth process., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

One of the most promising strategies for producing hydrogen is photocatalytic water splitting, in which the photocatalyst is a key component. Among many semiconductor photocatalysts, g-C 3 N 4 has attracted great attention due to its narrow band gap, excellent stability and low cost. However, practical application is limited by its poor intrinsic activity. In this work, a high-performance porous g-C 3 N 4 (PCN) photocatalyst with anchored Cu single atoms (CuSAs) was synthesized by a one-step co-heating approach. The obtained Cu1.5-PCN displays an excellent hydrogen evolution rate (HER) of 2142.4 μmol h -1 g -1 under visible light (=420 nm), which is around 15 and 109 times higher than those of PCN and bulk g-C 3 N 4 , respectively. In addition, it also shows good stability during H 2 evolution. The results of experimental research and DFT simulations indicate that the single Cu ions formed bonds with the N-ring and these remain stable. Meanwhile, the special electronic structure of the Cu-N charge bridge extends the light absorption band to the visible-light region (380-700 nm). This high-performance and low-cost photocatalyst has great potential in solar energy conversion., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

We propose a strategy to etch dopants to construct Mo 2 C with more unsaturated coordination of Mo atoms and lattice distortion for enhanced catalytic activity. It is more effective than doping and etching pure Mo 2 C and provides a novel strategy for the preparation of catalysts with high catalytic activity.