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Nanotechnology in cancer therapy increases medication bioavailability and lowers systemic toxicity. Additionally, polyprodrug delivery systems provide higher drug-carrying capacity and biosafety than traditional nano-drug delivery techniques. Nevertheless, the majority of prodrug delivery systems have low drug delivery efficiency and lack drug carriers that are targeted to the tumor environment. To address these issues, we synthesized poly(ferulic acid) (PFA) by polycondensation of ferulic acid (FA) and combined it with hyaluronic acid (HA) via disulfide bonds to create an HA-SS-PFA amphiphilic polyprodrug nano platform with redox sensitivity and targeting, which has high drug loading and good biocompatibility. Through the specific binding of HA to the CD44 receptor overexpressed in tumor cells, this polyprodrug carrier achieves the ability to deliver drugs in a precisely targeted manner, enabling rapid and selective drug release at the target site while reducing the toxicity of the drug to non-target organs. Furthermore, it is able to react favorably with the glutathione (GSH) concentration in tumor cells by employing redox-sensitive chemical bridging based on "sulfur bonding". This causes the disulfide bond to break and the drug to be released from the carrier rapidly, ultimately leading to tumor cell apoptosis. In vivo and in vitro experiments showed that this polyprodrug nano-delivery platform could effectively inhibit hepatocellular carcinoma cells with a high tumor inhibition rate, boost the therapeutic effect of the antitumor drug and improve the therapeutic efficiency, and is a potentially efficient drug delivery strategy. [ABSTRACT FROM AUTHOR]

In this work, a series of high-performance graphite foams (GFs) were synthesized using a melamine foam (MF) template-assisted strategy, which employed AR mesophase pitch (AR MP) as the carbon precursor and airflow was applied to achieve orientation and solidification in the MF network combined with carbonization and graphitization. The results show that the thermal conductivity, compressive strength, and graphitization degree of GFs increase with an increase in AR MP slurry concentration. In contrast, the electromagnetic interference shielding effectiveness (EMI SE) and porosity exhibit an opposite trend. When the concentration was 70 wt%, GF-70 displays isotropic thermal conductivity reaching up to 74.29 W m−1 K−1 in-plane and 76.27 W m−1 K−1 through-plane. Meanwhile, it also shows an EMI SE of 35 dB in the X-band. However, when the concentration drops to 40 wt%, the EMI SE of GF-40 reaches 71 dB, and thermal conductivities of 32.13 W m−1 K−1 and 31.46 W m−1 K−1 in two planes have been achieved in GF-40. The isotropic performance of GFs is related to the structure of the template. At the same time, the superior thermal conductivity of GFs is attributed to the ligaments of a parallel arrangement. The outstanding electromagnetic shielding effectiveness (EMI SE) is ascribed to the porous structure's multiple reflections and repeated scattering. This strategy of the adjustable combination of thermal conductivity and EMI SE paves the way for dual-function thermal management materials. [ABSTRACT FROM AUTHOR]

Carbon materials with a three-dimensional (3D) conductive network have attracted considerable research and commercial interest due to their low density and high electrical conductivity toward electromagnetic interference (EMI) shielding. In the present work, an ensemble of reduced graphene oxide (rGO) layers full of bubbles made by the template-free method employed vitamin C (VC) as a reduction agent at low temperatures. The effect of the VC amount on the EMI shielding effect (SE), electrical conductivity, and compressive strength of rGO bubbles was investigated. The results showed that the EMI SE and electrical conductivity all increased with the increase in VC until the ratio reached 1. rGO bubbles prepared with a VC/GO ratio of 1 had a low density of 0.06 g cm−3, high porosity of 94%, but high compressive strength of 0.0033 MPa at a strain of 4%. Bubbles with a thickness of 1.346 mm exhibited a respectable EMI shielding effectiveness (SE) of 70 dB and SE/density (SET/ρ) of 1167 dB cm3 g−1 at the X-band and higher than 54 dB in the wideband region of 2–18 GHz. The excellent EMI SE was mainly ascribed to the conductive dissipation, and the multiple reflections and the repeated scattering of the bubble structure. This work provides some insight into preparing an ensemble of reduced graphene oxide layers with bubbles, which has potential applications in the EMI shielding field. [ABSTRACT FROM AUTHOR]

Atomically ordered intermetallic nanomaterials represent one class of the most attractive catalysts for direct alcohol fuel cells, whereas they remain arduous owing to both the complexity of conventional synthetic approaches and their susceptibility to intermediates (especially CO). Herein, a facile one-step surfactant-free strategy is reported for producing Cu-incorporated PtBi intermetallic nanofiber bundles (Cu–PtBi NFBs) served as robust electrocatalysts towards bifunctional methanol and ethanol oxidation reactions (MOR and EOR). The resultant Cu–PtBi NFBs not only achieve remarkable CO tolerance, and superior mass and specific activities (6.79 A mgPt−1 and 11.26 mA cm−2) with a maximum onset potential shift (77 mV) relative to commercial Pt/C for the MOR, but also show 4.3-fold improved EOR mass activity (4.00 A mgPt−1) compared to commercial Pt/C. X-ray absorption fine structure analysis and density functional theory simulation corroborate that the ordered PtBi-based hexagonal close-packed structure, as well as the Cu-induced bifunctional effect, is key to substantially weakening the bonding strength between CO* and Pt sites and strengthening the anchoring of OH* on adjacent Cu sites, thereby optimizing the CO-poisoning pathway. This work provides an effective design strategy for Pt-based intermetallic nano-electrocatalysts as high-efficiency anodic materials in fuel cell applications. [ABSTRACT FROM AUTHOR]

The water oxidation reaction involves a four electron–proton coupled process that is kinetically sluggish and has hindered the widespread application of water-splitting technology. Metal-MOF-coupled heterostructures serve as good OER electrocatalysts due to their endowed MOF frameworks and numerous transition metal active sites at the interface. In this study, a simple ultrasonic impregnation strategy was used to prepare CoOx/UiO-66-300 and NiO/UiO-66-300 heterostructures via the impregnation of Co and Ni ions into UiO-66 followed by roasting in air at 300 °C to obtain heterostructures with UiO-66-retained frameworks as revealed by SEM. The electrochemical results show that the respective impregnation successfully modulated the electronic charge at the interface of the heterostructures, leading to rapid electron transfer that enhanced the OER activity. CoOx/UiO-66-300 and NiO/UiO-66-300 heterostructures showed good oxygen evolution reaction activities of 283 mV and 291.6 mV, respectively, due to the retained UiO-66 framework, while CoOx/UiO-66-550 and NiO/UiO-66-550 heterostructures calcined at 550 °C showed a decrease in OER activities of 332.6 mV and 346.6 mV, respectively, due to the collapsed UiO-66 framework. This work gives insight into the development of heterostructures of MOF-retained frameworks for energy applications. [ABSTRACT FROM AUTHOR]

Owing to their high energy density and low cost, lithium–sulfur (Li–S) batteries are deemed as promising next-generation energy-storage systems. However, the practical applications of Li–S batteries are still intercepted by the notorious shuttle effect and sluggish reaction kinetics. Herein, a porous nitrogen-doped carbon nanorod embedded with ultrafine Bi nanoparticles (Bi-NC) is constructed to function as an advanced sulfur host. The existence of Bi nanoparticles induces the local charge rearrangement and hence optimizes the electronic structure of Bi-NC. As a result, Bi-NC significantly features the effective chemical adsorption and remarkable redox catalyzation for polysulfides, corroborated by both computational and experimental demonstrations. Profiting from these distinctive superiorities, the enhanced utilization of sulfur species and facilitated redox kinetics of polysulfides are achieved. Therefore, the Bi-NC/S electrode delivers a high initial capacity of 1157 mA h g−1 at 0.5C, a superb capacity retention of 811 mA h g−1 at 1C after 500 cycles, and an excellent areal capacity of 6.48 mA h cm−2 even under a high-sulfur loading of 7.0 mg cm−2. This work affords an innovational regulation of electronic structures via the local charge rearrangement for developing ideal hosts towards the practical high-performance Li–S batteries. [ABSTRACT FROM AUTHOR]

Cost-effective carbon-based materials are appealing candidates for the electrochemical nitrogen reduction reaction (NRR), while the large bandgap results in a low reactivity and selectivity of the NRR. Work function (W) regulation, altering the electron-transfer ability of carbon materials, is regarded as an encouraging descriptor to enhance the reaction kinetics of the electrochemical NRR, but it has been rarely investigated. To address this issue, Mott–Schottky heterostructural metal/nitrogen-doped carbon nanotubes (M@NCNTs) were designed. Work function theory predicts that systems with a lower W value require smaller extra energy to activate adsorbed N2 molecules. As expected, Ni@NCNTs with the lowest W value displayed the highest faradaic efficiency of 7.33% compared to the other samples. Theoretical simulations and orbital component analysis revealed that different encapsulated metals could tune the work function of M@NCNTs, especially by inducing an upshift of the Fermi level of the outer NCNTs and accelerating the transfer of electrons from the catalyst surface to the adsorbed N2 through the upshifted C–N (π) orbitals, thus guaranteeing the effective activation of N2 molecules. This work provides a guideline for the rational design of NRR catalysts by tuning the work function. [ABSTRACT FROM AUTHOR]

Defect engineering through heteroatom doping is one of the most important strategies towards the development of catalytic active materials for energy related applications. Herein, a novel trifunctional Br/Co/N Co-doped and defect-enriched porous carbon framework (BrHT@CoNC) is designed, which shows excellent electrocatalytic activity for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) as well as the hydrogen evolution reaction (HER). Introduction of extensive defects by heteroatom-doping is simply achieved by pyrolysis of the surfactant, dimethyldioctadecylammonium bromide (DODAB) modified ZIF-67. The BrHT@CoNC composite shows great potential as an economical catalyst/electrode for both rechargeable Zn–air batteries and overall water splitting devices. This work opens a new avenue toward the exploration of cost effective heteroatom doped catalysts for efficient integration of three or more functions into one freestanding electrode. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of N2 into NH3 (N2RR) under ambient conditions has emerged as a sustainable approach alternative to the Haber–Bosch process. However, the more favored H+ reduction in aqueous electrolytes can lead to low faradaic efficiency for NH3 production. Thus, designing electrocatalysts to suppress proton reduction is the key to improve the activities towards the N2RR. As an efficient strategy for modulating the associated electronic properties of surface catalysts, the support effect is drawing growing attention. Sparked by the support effect, Ni2P nanoparticles supported by N,P co-doped carbon nanosheets (Ni2P/N,P-C) were synthesized and found to have a higher affinity for N2 molecules than for H+ which makes it a good candidate for the N2RR. The prepared catalyst showed an NH3 yield rate of 34.4 μg h−1 mgNi2P−1 at −0.2 V vs. the reversible hydrogen electrode (RHE) with a faradaic efficiency of 17.21% in 0.1 M HCl (22.89% and 57.2 μg h−1 mgNi2P−1 in 0.2 M PBS; 19.82% and 90.1 μg h−1 mgNi2P−1 in 0.1 M KOH), which is higher than the best values ever reported for noble-metal free catalysts in aqueous solution under ambient conditions. Importantly, the N,P-C substrate in this work is regarded as an electronic storage medium that regulates the electronic distribution of Ni2P/N,P-C when N2 is chemically adsorbed at the Ni site, playing a vital role in inhibiting the adsorption of H and promoting the adsorption and activation of N2 molecules. This work not only gives a new insight into understanding the transformation of the HER to the N2RR, but also provides a guideline for the development of highly active non-noble-metal catalysts. [ABSTRACT FROM AUTHOR]

The oxygen evolution reaction (OER) is a half reaction of electrochemical water splitting that suffers from a kinetically sluggish four-electron process, and it is regarded as the efficiency-limiting step in water splitting. Herein, heterostructures of CoSe (cobalt selenide) nanoparticles and MoSe2 (molybdenum selenide) nanosheets (CoSe/MoSe2 hybrids) were fabricated through a non-metal-induced growth method. Due to the increase in the effective specific area and the electron transfer ability caused by the formation of the heterogeneous interface, the obtained CoSe/MoSe2 hybrids show superior OER performance (η = 262 mV at 10 mA cm−2) and long-term stability (20 h for continuous testing) as compared to pure CoSe, MoSe2 and physically mixed CoSe and MoSe2. Schematic energy band diagrams derived from ultraviolet photoelectron spectroscopy results further confirmed the electronic modulation between CoSe and MoSe2 and revealed that the d-band center of CoSe/MoSe2 hybrids moved closer to the Fermi level, giving rise to high charge carrier density and low intermediate adsorption energy as compared to CoSe and MoSe2. This work provides some insight into the design and synthesis of heterostructured nanomaterials from the MOF precursors. [ABSTRACT FROM AUTHOR]

Chopped carbon fibers (CFs) and TaC particles were dispersed uniformly and then sintered at temperatures of 1773, 2123, 2298, 2473 and 2823 K, respectively. The effect of sintering temperature on the microstructure of CFs was investigated. The results showed that the reaction between CFs and TaC particles was controlled by solid diffusion. When the temperature was lower than 1773 K, mainly carbon diffused into TaC. However, Ta diffused into the CFs while carbon diffused into TaC particles and then precipitated as graphite when the sintering temperature was above 2123 K. During the process, the structure of TaC was not influenced. The preferential crystalline orientation of the graphite precipitated from TaC particles increased with the increase of sintering temperature. The R value determined by Raman spectra decreased from 0.12 to 0 as the temperature increased from 2123 to 2823 K, meaning the formation of perfect graphite crystallites. [ABSTRACT FROM AUTHOR]