Nano Research最新文献

Zn is a frequently used and sometimes even an inevitably involved element (when zeolitic imidazolate framework-8 (ZIF-8) is adopted as the precursor) for preparing high-performance Fe-N-C oxygen reduction reaction (ORR) catalysts. However, how the Zn element affects the physicochemical architecture of the catalysts, how it enhances the catalytic activity and whether Zn atoms serve as the active centers remain unclear. Herein, we proposed a novel route that adopted pyrrole as the precursor and flexibly controlled the addition of exogenous Zn and Fe dopants before pyrrole polymerization. In this way, a series of nitrogen-carbon catalysts with or without Zn or Fe doping were synthesized. The detailed characterization revealed the role of Zn and Fe doping in the catalyst morphology, pore structure, active site configurations, ORR catalytic activity and fuel cell performance. Importantly, the findings revealed that Zn doping has little effect on the ORR mechanism and pathway. It enhances ORR activity primarily by increasing the number of active sites via introducing more micro- and meso-pores, rather than by creating new active sites. While Fe doping participated in forming both pores and active site centers. Moreover, the catalyst that co-doped with Zn and Fe atoms (Zn-FeNC), synthesized via this simple and template-free route we proposed, presented a unique hollow and hierarchical pore structure with highly boosted ORR activity. It exhibited a 40 mV higher E_1/2 value than Pt/C in alkaline media, along with a rapid current response in air-cathode of the direct formate fuel cell. These results are valuable in guiding the synthesis of high-performance Fe-N-C catalysts.

Cardiovascular diseases remain the leading cause of mortality worldwide, with percutaneous coronary interventions (PCI) using drug-eluting stents (DES) as the standard treatment for coronary artery disease. Despite advancements in DES technology, challenges such as restenosis and stent thrombosis still necessitate further interventions and carry considerable risks, highlighting an urgent need for a novel therapeutic approach with lower restenosis rates and reduced reintervention risks. Drug-eluting balloons (DEBs) coated with anti-proliferative agents offer a novel method of local drug delivery for reducing restenosis by directly administering drugs to the lesion site. However, efficient delivery of drugs within the brief procedural window while minimizing drug loss during maneuvering to the target site remains a challenge. Herein, we developed a pressure-responsive and pH-triggered, paclitaxel (PTX) coated DEB catheter for rapid and high-dose delivery of paclitaxel to the lesion sites, overcoming the limitations of drug dispersion and inefficiencies associated with conventional DEBs. Using the charge reversion of albumin around its isoelectric point, paclitaxel-loaded human serum albumin nanoparticles (PTX-HSA-NPs) and heparin were coated using a layer-by-layer deposition method at pH 4.0. Upon exposure to physiological pH (i.e., 7.4), the coating is rapidly released from the balloon surface. Combined with a protective shellac coating, the DEB achieved controlled release of high-dose paclitaxel to the arterial tissue in vivo (up to 400 µg per gram tissue), exceeding current DEBs in the clinic. These results suggest the pH-responsive, multi-layer coated DEB’s potential for superior procedural outcomes, addressing a critical unmet need in PCI.

Immunotherapy has markedly reinvented how we treat cancer, as shown by numerous Food and Drug Administration (FDA) drug approvals that have made significant clinical impact and ongoing clinical trials. However, undesirable side effects, such as autoimmunity and inflammation, and inconsistent clinical outcomes remain a major challenge. Improving response rates across various immunotherapeutic reagents is imperative to enhance overall effectiveness and reduce adverse side effects. To address this challenge, interdisciplinary approaches have been explored by incorporating immunotherapies into hydrogels, enabling fine-controlled delivery to target tissues. This review focuses on recent progress in the utilization of hydrogel-based delivery systems for cancer immunotherapy and their potential to further enhance treatment response rates. Specifically, recent preclinical advances in hydrogels implemented with immune checkpoint inhibitors, combination therapies, and vaccines, along with self-assembled peptide hydrogels, are reviewed. We also discuss technological advances and drawbacks in this area and provide insights to ultimately realize the clinical application of hydrogels in cancer immunotherapy.

The increasing need for sustainable energy and the transition from a linear to a circular economy pose great challenges to the materials science community. In this view, the chance of producing efficient nanocatalysts for water splitting using industrial waste as starting material is attractive. Here, we report low-cost processes to convert Mo-based industrial waste powder into efficient catalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). pH controlled hydrothermal processing of Mo-based industrial waste powder leads to pure orthorhombic MoO₃ nanobelts (50–200 nm wide, 10 µm long) with promising OER performances at 10 mA·cm⁻² with an overpotential of 324 mV and Tafel slope of 45 mV·dec⁻¹ in alkaline electrolyte. Indeed, MoS₂/MoO₃ nanostructures were obtained after sulfurization during hydrothermal processes of the MoO₃ nanobelts. HER tests in acidic environment show a promising overpotential of 208 mV at 10 mA·cm⁻² and a Tafel slope of 94 mV·dec⁻¹. OER and HER performances of nanocatalysts obtained from Mo industrial waste powder are comparable or better than Mo-based nanocatalysts obtained from pure commercial Mo reagent. This work shows the great potential of reusing industrial waste for energy applications, opening a promising road to join waste management and efficient and sustainable nanocatalysts for water splitting.

Carbon dioxide (CO₂) is a principal greenhouse gas with a substantial impact on global climate change. The photocatalytic reduction of CO₂ represents an economically viable and environmentally benign approach. This technique involves the catalysis of the reaction between CO₂ and epoxides under photocatalytic conditions to yield cyclic carbonates. Notably, this process has garnered significant attention due to its high atomic efficiency and alignment with green chemistry principles. Increasingly, photocatalysts are employed to facilitate the synthesis of cyclic carbonates, demonstrating outstanding performance even under natural light. This review evaluates the current state of research on the photocatalytic cycloaddition of CO₂ with epoxides, analyzes the reaction mechanism and key influencing factors, and provides a comparative summary of the photocatalysts developed in this domain. Additionally, this paper underscores the significance of the reaction devices. The paper explores reaction devices with potential applications for photocatalytic CO₂ and epoxides and envisions future integrations of CO₂ photocatalytic cycloaddition reactions with advanced reaction devices for practical applications in this area.

The overuse and ineffective management of plastics have led to significant environmental pollution. Catalytic upcycling into value-added chemicals has emerged as a promising solution. This review provides a comprehensive overview of recent advances in catalytic upcycling, focusing on the cleavage of chemical bonds such as carbon-carbon (C-C), carbon-oxygen (C-O), and carbon-hydrogen (C-H) in plastics. It systematically discusses plastics conversion via electrocatalysis, thermal catalysis, and photocatalysis. Additionally, it explores the conversion of plastics into value-added chemicals and functional polymers. The review also addresses the challenges in this field and aims to offer insights for developing sustainable and effective plastics upcycling technologies.

Size hierarchy is a distinct feature of nanogold-catalysts as it can strongly affect their performance in various reactions. We developed a simple method to generate Au_nS_m nanoclusters of different sizes by thermal treatment of an Au₁₄₄(PET)₆₀ (PET: phenylethanethiol) parent cluster. These clusters, deposited on activated carbon, exhibit excellent catalytic performance in the hydrochlorination of acetylene. _In-situ ultraviolet laser dissociation high-resolution mass spectrometry of the parent cluster in the presence of acetylene revealed a remarkable cluster size-dependence of acetylene adsorption, which is a crucial step in the hydrochlorination. Systematic density functional theory calculations of the reaction pathways on the differently-sized clusters provide deeper insight into the cluster size dependence of the adsorption energies of the reactants and afforded a scaling relationship between the adsorption energy of acetylene and the co-adsorption energies of the reactants (C₂H₂ and HCl), which could enable a qualitative prediction of the optimal Au_nS_m cluster for the hydrochlorination of acetylene.

Cu-based chalcogenide materials exhibit significant promise for the development of Zn-metal-free anode materials for aqueous Zn-ion batteries (AZIBs). Here, we present the establishment of an efficient and universal strategy that capitalizes on the pyrolysis of copper nanoclusters to fabricate conversion-type Cu₇S₄ anodes engineered for AZIBs, showcasing outstanding electrochemical performance. Furthermore, by exploiting ligand engineering, we enable the precise control of both the type of molecular fragments generated during nanocluster pyrolysis, thus enabling the manipulation of vacancy concentrations and ion/electron migration in the resultant pyrolysis products. In contrast to the direct pyrolysis of metal salts and ligands, the products derived from copper nanoclusters exhibit enhanced specific capacity, rate performance, and overall stability. This research offers valuable insights for the development of novel electrode materials through the pyrolysis of atomically precise nanoclusters.