Latest ArticlesPhotoreduction of CO2 to solar fuels has caused great interest, but suffers from low catalytic efficiency and poor selectivity. Herein, we designed a S-scheme heterojunction (Cu-TiO2/WO3) with Cu single atom to significantly boost the photoreduction of CO2. Notably, the developed Cu-TiO2/WO3 achieved the solar-driven conversion of CO2 to CH4 with an evolution rate of 98.69 µmol g−1 h−1, and the electron selectivity of CH4 reached 88.5%. The yield was much higher than those of pristine WO3, TiO2/WO3 and Cu-TiO2 samples. Experimental and theoretical analysis suggested that the S-scheme heterojunction accelerated charge migration and inhibited the recombination of electron-hole pairs. Importantly, the charge separation effect of the heterojunction meliorated the position of the d-band. The uplifted d-band centers of Cu and Ti on Cu-TiO2/WO3 not only improved the electron interaction between Cu single atoms and substrate-TiO2, accelerated the adsorption and activation of CO2 on the active sites of Cu single atom, but also optimized the Gibbs free energies of CH4 formation pathway, leading to excellent selectivity toward CH4. This work provides new insights into the design of photocatalyst systems with high photocatalytic performance.
Stepwise energy transfer is ubiquitous in natural photosynthesis, which greatly promotes the widespread use of solar energy. Herein, we constructed a supramolecular light harvesting system based on sequential energy transfer through the hierarchical self-assembly of M, which contains a cyanostilbene core flanked by two ureidopyrimidinone motifs, endowing itself with both aggregation-induced emission behavior and quadruple hydrogen bonding ability. The monomer M can self-assemble into hydrogen bonded polymers and then form supramolecular polymeric nanoparticles in water through a mini-emulsion process. The nanoparticles were further utilized to encapsulate the relay acceptor ESY and the final acceptor NDI to form a two-step FRET system. Tunable fluorescence including a white-light emission was successfully achieved. Our work not only shows a desirable way for the fabrication of efficient two-step light harvesting systems, but also shows great potential in tunable photoluminescent nanomaterials.
The presence of alkali metals in exhaust gas from stationary resources causes a grand challenge for the practical application of selective catalytic reduction (SCR) of NOx with NH3. Here, alkali-resistant NOx reduction has been successfully implemented via tailoring the electron transfer over Fe and V species on FeVO4/TiO2 catalysts. The strong interaction between Fe and V induced electron transfer from V to Fe and strengthened the adsorption and activation of NH3 and NO over active VOx sites. In the presence of K2O, the strong electron withdrawing effect of Fe offset the electron donating effect of K on the VOx species, thus protecting the active species VOx to maintain the NOx reduction ability. The enhanced adsorption and activation of NH3 allowed SCR reaction to proceed via E-R mechanism even after K2O poisoning. This work elucidated the electronic effects on the alkali metals resistance of traditional ferric vanadate SCR catalysts and provided a promising strategy to design SCR catalysts with superior alkali resistance.
The construction of hydrogels with good mechanical properties and phosphorescent properties is full of challenges. Herein, we report a supramolecular phosphorescent hydrogel with long lifetime, high tensile strength and self-healing property, which can be easily constructed through in-situ thermal-initiated polymerization of isocyanatoethyl acrylate-modified β-cyclodextrin (β-CD-DA) and acrylate-modified adamantane (Ad-DA), acrylic acid (AA), followed by the non-covalent association with carbon dots (CNDs). The lifetime of phosphorescent hydrogel can reach 1261 ms at room temperature, and the quantum yield is 11%. Importantly, through the efficient triplet to singlet Förster resonance energy transfer (TS-FRET), the phosphorescent hydrogel shows the good phosphorescence energy transfer property for organic dyes Rhodamine B and Eosin Y with the delayed fluorescence lifetime up to 730 ms and 585 ms as well as the energy transfer efficiency (ΦET) up to 99.9% and 99.3%, respectively. Moreover, owing to the host-guest interactions between β-CD-DA and Ad-DA, the three-dimensional cross-linked network phosphorescent hydrogel can be easily stretched to 18 times of its original length, and can achieve self-healing of the cut surfaces within 30 min. These results will expand the scope of phosphorescent materials and provide new ideas and opportunities for materials science.
Due to its simplicity, high efficiency, and chemo-selectivity, bioorthogonal chemistry has shown a great application potential in pre-targeting. Currently, four bioorthogonal pairs as targeting tools, including (strept)avidin/biotin, antibody/antigen, oligonucleotide hybridization and IEDDA tools, have been developed and applied in targeted delivery. Nevertheless, all of these tools still suffer from some limitations, such as difficult modification, biochemical fragility and larger molecular weight for biological association tools, as well as chemical instability for IEDDA tools. Synthetic host-guest pairs with relatively small molecular sizes not only possess strong chemical stability, but also have the features of fast conjugation rate, tunable binding affinity, easy modification, and high chemo-selectivity. Consequently, they can be used as a novel non-covalent bioorthogonal tool for pre-targeting. In order to further promote the development of host-guest pairs as novel bioorthogonal tools for pre-targeted delivery, we firstly calculate their conversion rate to make researcher aware of their unique advantages; next, we summarize the recent research progress in this area. The future perspectives and limitations of these unique tools will be discussed. This review will provide a systemic overview of the development of synthetic host-guest pairs as novel bioorthogonal tools for pre-targeting, and may serve as a "go for" resort for researchers who are interested in searching for new synthetic tools to improve pre-targeting.
Microfluidic combined with magnetic field have been demonstrated to be the promising solutions for fast and low-damage particles separation. However, the difficulties in the precise layout of magnets and accurate prediction of particle trajectories lead to under and over separation of target particles. A novel particle separation lab-on-chip (LOC) prototype integrated with microstructures and micropolar arrays is designed and characterized. Meanwhile, a numerical model for the separation of magnetic particles by the synergistic effect of geometry-induced hydrodynamics and magnetic field is constructed. The effect of geometry and magnetic field layout on particle deflection is systematically analyzed to implement accurate prediction of particle trajectories. It is found that the separation efficiency of magnetic particles increased from 50.2% to 91.7% and decreased from 88.6% to 85.7% in the range of depth factors from 15 µm to 27 µm and width factors from 30 µm to 60 µm, respectively. In particular, the combined effect of the offset distance of permanent magnets and the distance from the main flow channel exhibits a significant difference from the conventional perception. Finally, the developed LOC prototype was generalized for extension to arbitrary systems. This work provides a new insight and robust method for the microfluidic separation of magnetic particles.
Exosomes are membrane-bound nanoscale extracellular vesicles, which produced by almost all organisms. Due to the excellent biocompatibility, long circulation time as well as low immunogenicity, exosomes as naturally-derived drug delivery carriers have experienced explosive growth over the past decades. However, issues such as insufficient loading efficiency, heterogeneous delivery efficiency, uncontrollable targeting ability, and low production limit their wide application. Recently, the emerging exosome–liposome fusion strategy has become a potential approach to solve such issues. Thus, this review mainly focuses on the currently developed exosome–liposome fusion strategy and their application in drug delivery as well as disease treatment. This review aims to shed light on the advantages of fusion strategy in drug delivery and provides a better understanding for more rational design. The current challenge and future perspective regarding their clinical translation and application will also be discussed.
Antimicrobial photodynamic therapy (aPDT) has been considered a noninvasive and effective modality against the bacterial infection of peri–implantitis, especially the aPDT triggered by near-infrared (NIR) light due to the large penetration depth in tissue. However, the complexity of hypoxia microenvironments and the distance of aPDT sterilization still pose challenges before realizing the aPDT clinical application. Due to the long lifespan and transmission distance of therapeutic gas molecules, we design a multi-functional gas generator that combines aPDT as well as O2 and CO gas release function, which can solve the problem of hypoxia (O2) in PDT and the problem of inflammation regulation (CO) in the distal part of peri–implant inflammation under near-infrared (NIR) irradiation. In the composite nanoplatform that spin-coated on the surface of titanium implants, up-conversion nanoparticles (UCNPs) were involved in converting the NIR to visible, which further excites the partially oxidized stannic sulfide (SnS2), realizing the therapeutic gas release. Indocyanine green (ICG) was further integrated to enhance the aPDT performance (Ti-U@SnS2/I). Therefore, reactive oxygen species (ROS), CO, and O2 can be controllably administered via a composite nano-platform mediated by a single NIR light (808 nm). This implant surface modification strategy could achieve great self-enhancement antibacterial effectiveness and regulate the lingering questions, such as relieving the anoxic microenvironment and reaching deep infection sites, providing a viable antibiotic-free technique to combat peri–implantitis.
Boosting the interfacial stability between electrolyte and Li-rich cathode material at high operating voltage is vital important to enhance the cycling stability of Li-rich cathode materials for high-performance Li-ion batteries. In this work, vinyltrimethylsilane as a new type of organic silicon electrolyte additive is studied to address the interfacial instability of Li-rich cathode material at high operating voltage. The cells using vinyltrimethylsilane additive shows the high capacity retention of 73.9% after 300 cycles at 1 C, whereas the cells without this kind of additive only have the capacity retention of 58.9%. The improvement of stability is mainly attributed to the additive helping to form a more stable surface film for Li-rich cathode material, thus avoiding direct contact between the electrolyte and the cathode material, slowing down the dissolution of metal ions and the decomposition of the electrolyte under high operating voltage. Our findings in this work shed some light on the design of stable cycling performance of Li-rich cathode toward advanced Li-ion batteries.
The efficiency of photocatalytic CO2 reduction reaction (PCRR) is restricted by the low solubility and mobility of CO2 in water, poor CO2 adsorption capacity of catalyst, and competition with hydrogen evolution reaction (HER). Recently, hydrophobic modification of the catalyst surface has been proposed as a potential solution to induce the formation of triple-phase contact points (TPCPs) of CO2 (gas phase), H2O (liquid phase), and catalysts (solid phase) near the surface of the catalyst, enabling direct delivery of highly concentrated CO2 molecules to the active reaction sites, resulting in higher CO2 and lower H+ surface concentrations. The TPCPs thus act as the ideal reaction points with enhanced PCRR and suppressed HER. However, the initial synthesis of triple-phase photocatalysts tends to possess a lower bulk density of TPCPs due to the simple structure leading to limited active points and CO2 adsorption sites. Here, based on constructing a hydrophobic hierarchical porous TiO2 (o-HPT) with interconnected macropores and mesopores structure, we have significantly increased the density of TPCPs in a unit volume of the photocatalyst. Compared with hydrophobic macroporous TiO2 (o-MacPT) or mesoporous TiO2 (o-MesPT), the o-HPT with increased TPCP density leads to enhanced photoactivity, enabling a high methanol production rate with 1111.5 µmol g−1 h−1 from PCRR. These results emphasize the significance of high-density TPCPs design and propose a potential path for developing efficient PCRR systems.