Advanced Sensor and Energy Materials最新文献

Porphyrins and their derivatives have been extensively applied in various fields owing to their photophysical and electrochemical properties. However, the drawbacks of self-aggregation and self-quenching in aqueous media limit their biological applications. Porphyrinic metal-organic frameworks (PMOFs) have attracted considerable attention because the introduction of porphyrins as organic linker into frameworks overcomes the limitations of free porphyrins. This review summarizes the strategies for the construction of PMOFs and their biological applications. The challenges and chances displayed by this class of emerging materials are also discussed.

The sluggish electron transfer process in the oxygen evolution reaction (OER) greatly restrict the large-scale application of water electrolysis for hydrogen generation. The modification of the electronic states around the Fermi level of the electrocatalysts is significant for accelerating the sluggish OER kinetics. So far, the OER kinetics solely involve either an adsorbate evolution mechanism (AEM), or a lattice oxygen oxidation mechanism (LOM). In a paper recently published in Nature, Xue and coworkers report an electron transfer mechanism that involves a switchable AEM and LOM in nickel-oxyhydroxide-based materials triggered by the light [1]. In contrast with previously reported electrocatalysts, the electrocatalyst proceeding through this mechanism shows a better OER activity. Hence, the reported light-triggered mechanism that couples AEM and LOM pioneers an innovative pathway towards the exploration of OER kinetics.

The development of advanced and efficient anode catalysts to accelerate the kinetic rate of methanol oxidation plays an important role in the large-scale commercial application of the direct methanol fuel cells (DMFCs). Herein, we report the design and construction of small-sized rhodium nanocrystals decorated on 3D hybrid aerogels built from graphene and metal-organic framework (Rh/G-ZIF) via a solvothermal co-assembly method. Benefiting from the 3D rigid crosslinked architecture, abundant porous channels, and highly dispersed ultrafine Rh nanoparticles, the optimized Rh/G-ZIF aerogel exhibits a large electrochemically active surface area, high mass and specific activities, and excellent long-term durability toward the methanol electrooxidation, all of which are significantly superior to those of Rh catalysts supported by traditional carbon materials (such as carbon black, carbon nanotube, and graphene).

We present a fluorescent microscopic method using an ultra-pH-sensitive polymeric probe to rapidly map within subsecond the pH distribution resulting from oxygen reduction reaction electrocatalysed by an array of platinum nanoparticles. Upon voltammetry of the surface-supported Pt catalysts, fluorescent quenching waves are observed to depend on the electrode potential. The spatiotemporal fluorescent evolution is then confirmed under a constant potential control to be due to the local pH change as a function of diffusing time by an estimation of the proton diffusion coefficient $\left(L\alpha t^{1/2}\right)$. On these bases, the fluorescent measurements at short reaction times can provide quantitative information regarding the one and two dimensional pH distributions, which are shown to exhibit the expected shape of a typical diffusion-driven concentration gradient. Such imaging of proton/pH profiles may find important applications such as efficient screening of different micro/nanoscale electrocatalysts.

Among various energy storage devices, lithium-sulfur batteries have attracted widespread attention due to their high theoretical energy density and specific capacity. To improve the performance and realize practical applications of lithium-sulfur batteries, it is crucial to unravel the dynamic evolution and reaction mechanism at the electrode/electrolyte interfaces during cycling. Nevertheless, the details are still not well known despite generous efforts, which need more in situ and non-destructive imaging characterizations. Herein, we have combined AFM with an electrochemical workstation to dynamically visualize the morphological evolution and structural changes of the interfacial process, which reveals the lithium iodide-mediated interfacial reactions in lithium-sulfur batteries. In situ measurements showed that the electrode surface was coated by a reticular layer consists of elemental iodine and polyether with lithium iodide additive during charging, which could effectively prevent insolube sulfides from gathering on the surface and improve the cycling performances of lithium-sulfur batteries. These findings shed new light on the interfacial mechanism and establish design ideas for the future development of better electrolytes for lithium-sulfur batteries.

The increased demand for energy due to industrialisation and a steadily growing population has placed greater strain on the development of eco-friendly energy storage devices in recent years. Current methods with high efficiency are limited by high costs and waste. As a result, greater importance has been placed on the development of low-cost, lightweight, flexible, and biodegradable energy storage systems developed from paper and paper-like substrates. This study reviews recent advances in paper-based battery and supercapacitor research, with a focus on materials used to improve their electrochemical performance. Special mention is made of energy-storage configurations ranging from metal-air and metal-ion batteries to supercapacitors. Furthermore, methods of fabrication, functional materials, and efficiency are reviewed to offer prospects for future research into the field of paper-based Na-ion batteries. The review provides an updated discussion of recent research conducted in the field of paper-based energy systems published over the last five years and highlights the challenges for their commercial integration prospects.

Pt-rare earth (RE) alloys are among the most efficient catalytic materials for the oxygen reduction reaction in acidic media, which, however, are very difficult to synthesize. Previous theoretical and experimental studies indicated that the optimum particle structure is the Pt₅RE intermetallic phases with the optimum sizes of around 6–9 nm. In this work, using a synthesis method recently developed by our group, we attempt to synthesize such alloy catalysts. Firstly, we explored the synthesis conditions to obtain pure-phase Pt₅Ce. Secondly, we attempted to control the size of the alloy particles, which turned out to be the main challenge of this study. To that end, we have investigated the growth pattern of the particles during the synthesis process and used two synthesis parameters, the metal loading and the surface area of the carbon support, to tailor the particle sizes. The sizes and oxygen reduction reaction (ORR) performance of the best Pt₅Ce/C sample obtained so far are discussed.

Urine glucose detection is an important diagnostic tool for screening and early diagnosis of diabetes mellitus. Detection of urine glucose has many advantages over blood glucose, such as non-invasive, easy-to-detect, simple sampling and being well accepted by patients. Therefore, it is commonly used to monitor diabetes progression, assist in therapeutic intervention as well as in point-of-care testing (POCT). In recent years, with the development of material science, electrochemistry and miniaturization technology, novel applications of natural enzymes, nanozymes as well as nanomaterials, such as metal (Au, Pt, Ni, Co, etc.), alloy, grapheme, in the analysis of urine glucose level have been increasing sharply. In particular, different types of nanozymes-based biosensors, inspired by natural enzymes, have been developed with improved characteristics of being low-cost, stable, and mass-produced. On the other hand, making use of portable devices, such as smartphones and microfluidic paper-based analytical devices, has facilitated on site accurate urine glucose monitoring in real time. All these rapid advancements in nanotechnologies and devices have contributed greatly to the development of cost effective, highly sensitive, user friendly urine glucose biosensors. This review summarizes the most recent improvements in two major types of urine glucose biosensors: the optical- and electrochemical-biosensors. We also discuss the limitations, challenges and perspectives of these biosensors. Finally, we propose future research directions, development trends and potential clinical applications of nanomaterial-based biosensors developed for urine glucose detection.

As one of most advanced transduction techniques, electrochemiluminescence (ECL), such as that generated by tris(2,2′-bipyridyl)ruthenium (Ru(bpy)₃²⁺), has been extensively used in chemical sensing and analysis, but the reaction mechanism has not been fully resolved. Aiming at gaining insightful mechanistic information on the coreactant system involving (Ru(bpy)₃²⁺) and tri-n-propylamine (TPrA), herein we investigate the variation of thickness of ECL layer (TEL) with the concentration ratio of (Ru(bpy)₃²⁺) to TPrA (c_Ru/c_TPrA) by ECL microscopy. Using carbon fiber as the working electrode, TEL was observed to grow with the increase of c_Ru/c_TPrA remarkably. In conjunction with finite element simulations, the extension of ECL layer was rationalized to be associated with the incremental contribution of so-called “catalytic route”. This route offers an additional channel of generating remote light emission in solution, apart from surface-confined emission produced by the “oxidative-reduction route”. Given the quantitative analysis of coreactant-type analytes is often based on the calibration curve, namely a graph generated by plotting the measured light intensity of a series of standard solutions against their concentrations, the contribution of “catalytic route” particularly at a low concentration of analyte (equivalent to a relatively large c_Ru/c_TPrA) is favorable to the analytical sensitivity. Moreover, the presence and absence of this route will result in a nonlinear and linear calibration curve, respectively, for example in the detection of TPrA and pyruvate. The results highlight the microwire-based imaging approach can provide insightful mechanistic information and help unveil the concentration dependence of measured ECL intensity for precise quantitative analysis.