Tailored Design of Mesoporous PdCu Nanospheres with Different Compositions Using Polymeric Micelles

Tannic acid modified PdAu alloy nanowires as efficient oxygen reduction electrocatalysts

Design of the structure, composition and interface of the catalysts is very important to improve oxygen reduction reaction (ORR) catalytic activity under alkaline environment. Herein, we propose a direct method to rapid synthesis of tannic acid (TA) modified PdAu alloy nanowires (PdAu@TA NWs). Compared with pure PdAu NWs and commercial Pt/C, the PdAu@TA NWs exhibit superior ORR electrocatalytic activity (mass activity: 0.73 A mg^-1_metaland specific activity: 3.50 mA cm^-2), stability, and methanol tolerance in an alkaline medium because PdAu@TA NWs possess sufficient active sites and synergistic effect that can effectively promote the oxygen reduction, inhibit the oxidation of the catalyst and improve the methanol tolerance of the catalyst. This synthetic method is a promising strategy to prepare metallic catalyst with surface functionalization.

Mesoporous TiO2 Microparticles with Tailored Surfaces, Pores, Walls, and Particle Dimensions Using Persistent Micelle Templates

Mesoporous microparticles are an attractive platform to deploy high-surface-area nanomaterials in a convenient particulate form that is broadly compatible with diverse device manufacturing methods. The applications for mesoporous microparticles are numerous, spanning the gamut from drug delivery to catalysis and energy storage. For most applications, the performance of the resulting materials depends upon the architectural dimensions including the mesopore size, wall thickness, and microparticle size, yet a synthetic method to control all these parameters has remained elusive. Furthermore, some mesoporous microparticle reports noted a surface skin layer which has not been tuned before despite the important effect of such a skin layer upon transport/encapsulation. In the present study, material precursors and block polymer micelles are combined to yield mesoporous materials in a microparticle format due to phase separation from a homopolymer matrix. The skin layer thickness was kinetically controlled where a layer integration via diffusion (LID) model explains its production and dissipation. Furthermore, the independent tuning of pore size and wall thickness for mesoporous microparticles is shown for the first time using persistent micelle templates (PMT). Last, the kinetic effects of numerous processing parameters upon the microparticle size are shown.

Recent advances in phosphorus containing noble metal electrocatalysts for direct liquid fuel cells

Direct liquid fuel cells (DLFCs) are considered as satisfactory alternatives to traditional fossil fuels owing to their unique advantages, e.g. environmental friendliness and easy storage. Noble metal catalysts are widely used to improve the efficiency of DLFCs. However, the high cost, low utilization and poor stability of noble metals restricted their practical applications. Therefore, it is of great significance to explore cost-effective electrocatalysts and further improve their electrocatalytic performance. Reducing the content of noble metals by adding low-priced phosphorus (P) has been considered as an effective strategy, which is able to enhance their electrocatalytic activity and anti-poisoning ability through effectively changing the electronic density of active sites. In the past few years, tremendous P containing catalysts have been synthesized and utilized in DLFCs. In this review, we summarize the fundamentals of electrochemical reactions and present recent progress in P containing noble metal catalysts for DLFCs, including the discussion of their shape, composition and the relationship between P and active sites. Finally, the challenges and some potential directions in this field are pointed out.

PdNi/Ni Nanotubes Assembled by Mesoporous Nanoparticles for Efficient Alkaline Ethanol Oxidation Reaction

The optimization of structure and composition is essential to improve the performance of catalysts. Herein, mesoporous nanoparticles assembled PdNi/Ni nanotubes (mPdNi/Ni NTs) are successfully fabricated using nickel nanowires as sacrificial template. The combination of nanotubular structure with mesoporous nanoparticle morphology can provide facilitated transfer channels and sufficient active sites, allowing the full contact and reaction between catalysts and reactants. Therefore, the synthesized mPdNi/Ni NTs exhibited superior ethanol oxidation performance to mesoporous Pd nanotubes and commercial Pd black. This study proposes a rational strategy for the development of nanoparticle assembled nanotubes with surface mesoporous morphology, which can greatly improve catalytic performance in various electrocatalytic fields.

Recent advances in porous nanostructures for cancer theranostics

Porous nanomaterials with high surface area, tunable porosity, and large mesopores have recently received particular attention in cancer therapy and imaging. Introduction of additional pores to nanostructures not only endows the tunability of optoelectronic and optical features optimal for tumor treatment, but also modulates the loading capacity and controlled release of therapeutic agents. In recognition, increasing efforts have been made to fabricate various porous nanomaterials and explore their potentials in oncology applications. Thus, a systematic and comprehensive summary is necessary to overview the recent progress, especially in last ten years, on the development of various mesoporous nanomaterials for cancer treatment as theranostic agents. While outlining their individual synthetic mechanisms after a brief introduction of the structures and properties of porous nanomaterials, the current review highlighted the representative applications of three main categories of porous nanostructures (organic, inorganic, and organic-inorganic nanomaterials). In each category, the synthesis, representative examples, and interactions with tumors were further detailed. The review was concluded with deliberations on the key challenges and future outlooks of porous nanostructures in cancer theranostics.

Porous Noble Metal Electrocatalysts: Synthesis, Performance, and Development

Active sites (intrinsic activity, quantity, and distribution), electron transfer, and mass diffusion are three important factors affecting the performance of electrocatalysts. Composed of highly active components which are built into various network structures, porous noble metal is an inherently promising electrocatalysts. In recent years, great efforts have been made to explore new efficient synthesis methods and establish structural-performance relationships in the field of porous noble metal electrocatalysis. In this review, the very recent progress in strategies for preparing porous noble metal, including innovation and deeper understanding of traditional methods is summarized. A discussion of relationship between porous noble metal structure and electrocatalytic performance, such as accessibility of active sites, connectivity of skeleton structures, channels dimensions, and hierarchical structures, is provided.

An electrochemical biosensor based on hemin/G-quadruplex DNAzyme and PdRu/Pt heterostructures as signal amplifier for circulating tumor cells detection

Metastasis due to circulating tumor cells (CTCs) shed from the original tumor accounts for the majority of cancer-related death. Efficient CTCs detection is pivotal to the diagnosis of early cancer metastasis. In this work, Platinum nanoparticles (PtNPs) decorated hyperbranched PdRu nanospines (PdRu/Pt) hierarchical structures were firstly synthesized to detect CTCs with the assistance of DNAzyme. Meanwhile, Super P and gold nanoparticles (AuNPs) acted as sensing medium to improve electrical conductivity and immobilization of anti-EpCAM antibody to specifically capture model CTCs. After immune-conjugation of anti-EpCAM-MCF-7-signal probes on the gold electrode, PtNPs, PdRu nanospines (PdRuNSs) and hemin/G-quadruplex co-catalyzed substrate H₂O₂ to realize multiplexed signal amplification, which significantly improves the analytical performance of the electrochemical biosensor. As-proposed biosensor reached a limit of detection (LOD) down to 2 cells mL^-1 and showed a wide detection range of 2 to 10⁶ cells mL^-1. Application of the biosensor to detect MCF-7 cells spiked human blood samples further demonstrated the feasibility for early cancer evaluation in clinic.

Electrochemical Synthesis of Mesoporous Architectured Ru Films Using Supramolecular Templates

The electrochemical synthesis of mesoporous ruthenium (Ru) films using sacrificial self-assembled block polymer micelles templates, and its electrochemical surface oxidation to RuO_x is described. Unlike standard methods such as thermal oxidation, the electrochemical oxidation method described here retains the mesoporous structure. Ru oxide materials serve as high-performance supercapacitor electrodes due to their excellent pseudocapacitive behavior. The mesoporous architectured film shows superior specific capacitance (467 F g^-1_Ru ) versus a nonporous Ru/RuO_x electrode (28 F g^-1_Ru ) that is prepared via the same method but omitting the pore-directing polymer. Ultrahigh surface area materials will play an essential role in increasing the capacitance of this class of energy storage devices because the pseudocapacitive redox reaction occurs on the surface of electrodes.