Advanced Sensor and Energy Materials最新文献

Metal-organic frameworks (MOFs) are porous materials, which possess a large specific surface area, various coordination types and modes, and versatile and adaptable morphologies and characteristics. MOFs have drawn much interest recently because of their appealing structure and potential for extensive use. With excellent characteristics, including high sensitivity, a low detection limit, and robust stability, nickel (Ni)-based MOFs have several benefits in electrochemical sensing. However, the weak conductivity of pure Ni-based MOFs limits their electrochemical applications. It is essential to further improve the characteristics and enhance the electrical conductivity of pure Ni-based MOFs aiming at enhancing their performance in electrochemical sensing. Herein, the three preparation methods of pure Ni-based MOFs are introduced, then the most recent advancements of pure Ni-based MOFs in electrochemical sensing applications are detailed in this work. In addition, it described how to adapt pure Ni-based MOFs to improve their electrochemical characteristics in three ways. In the introduction of these processes, the structures and morphologies of the prepared pure or modified Ni-based MOF are also described. It is envisaged that this work may give some extending techniques for future research of Ni-based MOFs materials in this burgeoning sector.

Proton exchange membrane fuel cells (PEMFCs), which can directly convert chemical energy into electrical energy with high efficiency and zero carbon emission, have attracted extensive attention. Unfortunately, the sluggish kinetics of oxygen reduction reaction (ORR) on the cathode leads to considerable overpotential and thus severely lowering its operational energy conversion efficiency. Although Pt-based catalysts have been developed as the most efficient catalyst towards ORR, however, their stability is far from the application requirements, which hinders the large-scale application of PEMFCs to a certain extent. Thus, improving the stability of Pt-based catalysts is urgently desirable to advance the widespread commercialization of fuel cells. This review focuses on the stability of Pt-based ORR catalysts in PEMFCs, from the perspectives of catalyst degradation mechanism and stability improvement strategies. It is aimed at providing research directions for the development of stable Pt-based catalysts. Firstly, degradation of metal nanoparticles (dissolution, migration, agglomeration, Ostwald ripening, etc.) and corrosion of carbon supports are introduced. To conquer the two attenuation mechanisms, stability improvement strategies such as constructing intermetallic compounds, enhancing metal-support interaction and the modification of carbon support, are summarized in detail. In addition, some typical stability characterization techniques are outlined. Finally, we discuss the challenges and possible research directions in the future. We hope this review can help readers gain insights into the stability issues of Pt-based ORR nanocatalysts and encourage research that will enable the commercialization of PEMFCs.

Although photocatalytic technology is applied in water treatment, the challenge still exists due to its low photocatalytic performance. Herein, a photocatalytic reactor coupled with nanobubbles (NBs) is developed to degrade organic pollutants in wastewater. The reactor contains Ti mesh coated with TiO₂ nanotube arrays as a photocatalyst. The introduction of NBs in the reactor increases the dissolved oxygen content to enhance photocatalytic performance. The photocatalytic reactor exhibits outstanding photocatalytic performance, and the degradation ability of Rhodamine B is 95.39% after 2 h of irradiation treatment. The reactor also shows excellent photodegradation performance for other organic pollutants, such as methylene blue (74.23%), tetracycline (68.68%), and oxytetracycline hydrochloride (64.10%). Radical trapping experiments further prove that ·O₂⁻, h⁺ and ·OH are the active species for the degradation of RhB in the photocatalytic system. Therefore, this work provides a feasible strategy to design a photocatalytic reactor coupling with nanobubbles technology for the photodegradation of organic pollutants in wastewater.

The open circuit potential (OCP) of a semiconductor electrode can be used to quantify the transient photopotential (E_p), which represents wavelength-dependent charge accumulation and relaxation kinetics of a photoelectrode. Here OCP responses of a plasmonic Au@TiO₂ nanorods (NRs) photoelectrode can be quantified without causing electrochemical corrosion of Au. The photogenerated charge accumulation kinetics data based on the wavelength-dependent growth rates of |E_p| can resolve the plasmonic effects on photoelectrochemistry (PEC) of Au@TiO₂ NRs. Data fitting with Kohlrausch-Williams-Watts (KWW) stretched exponential kinetics model illustrates the complex charge relaxations at the Au/TiO₂ Schottky contact, from which long relaxation lifetimes with broad lifetime distributions can be obtained. This is attributed to the abundant deep defects in the nanostructure TiO₂, which has been strongly confirmed by reducing the oxygen vacancies using a post-thermal annealing treatment. Single-particle dark-field scattering (DFS) spectrum is measured with a tunable wavelength light source to support visible light activities of PEC characteristics of Au@TiO₂ NRs. Light scattering spectra of >200 single Au@TiO₂ NRs particles are collected to compare directly with PEC responses of OCP of the ensemble Au@TiO₂ NRs.

Methanol as an important hydrogen-rich fuel has received increasing attention in energy storage and conversion techniques, and energy release can be realized in the methanol oxidation reaction (MOR) process. Note that highly efficient catalysts are still required to drive methanol oxidation, and the Ni-based catalysts have received intensive attention due to their facile active site generation based on the electrochemical-chemical oxidation mechanisms. In light of the significant advances made recently, herein, we reviewed the recent advances of Ni-based catalysts for methanol oxidation in the alkaline medium. The fundamental of methanol oxidation in the alkaline medium was first presented, and then the catalyst design principles including synergistic effect, electronic effect, defect construction, doping effect, as well as surface reconstruction were presented; and the advances of various Ni-based catalysts for MOR are summarized and discussed by combining with some typical examples. The problems and challenges were also concluded for the Ni-based catalyst fabrication, the performance evaluation, and their application. We believe that the summary of this review will be helpful in the design of nickel-based catalysts and understanding the catalysis mechanism of nickel-based materials in alcohol fuel electrochemical reactions.

Perovskite (PRV) luminescent solar concentrators (LSCs) use PRV materials to concentrate and convert sunlight into electricity. LSCs are made up of a flat plate or sheet of glass or plastic that contains a layer of luminescent PRV material. When sunlight enters the LSC, the PRV material absorbs the light and emits it at a longer wavelength. This emitted light is then trapped inside the LSC by total internal reflection, and it travels to the edges of the plate where it is collected by photovoltaic (PV) solar cells (SCs). The use of PRV materials in LSCs offers several advantages over other materials. PRV materials are highly efficient at converting light into electricity. They are also flexible, low-cost, and easy to manufacture, making them a promising candidate for large-scale solar energy applications. However, PRV materials have some challenges preventing their adoption. They are sensitive to moisture or heat and can degrade quickly over time. This significantly limits their lifespan and stability. Research on PRV is mostly focused on making them more stable and durable, but finding ways to improve the manufacturing process to reduce costs and increase efficiency is also relevant. While the opportunities offered by PRV materials for the specific application to LCSs are certainly interesting, the challenges make the prospect of a commercial product very unlikely in the short term.

Proton exchange membrane fuel cells (PEMFCs) represent a promising technology to overcome the current energy and environmental issues, where high-performance cathodic catalysts are badly needed due to the sluggish kinetics of oxygen reduction reaction (ORR). By far Pt stands for the best ORR catalyst, however, considering the scarcity and high cost, it is imperative to further improve its catalytic activity and atomic efficiency to reduce the loading amount. In view of the key issues, this review concentrates on recent advances on developing high-performance Pt-based nanocatalysts for ORR. The catalytic ORR mechanism was first described, followed by presenting the major principles to regulate ORR activity involving ligand effect and geometric effect. Guided by the principles, typical design strategies of Pt-based nanocatalysts were detailedly summarized, with emphasis on increasing intrinsic activity of single active site and electrochemical active surface area. We finally concluded by providing the remaining challenges and future directions in this field.

Metal/carbon nanocomposites have shown great potential as high-performance, low-cost electrocatalysts owing largely to their unique metal-support interactions. These nanocomposites are typically prepared by conventional pyrolysis that is tedious and energy-intensive. Herein, we report the ultrafast preparation of cobalt/carbon nanocomposites by magnetic induction heating (MIH) of metal organic frameworks within seconds under an inert atmosphere. The resulting samples consist of cobalt nanoparticles encapsulated within defective carbon shells, and effectively catalyze oxygen evolution reaction (OER) in alkaline media. Among the series, the sample prepared at 400 A for 10 s exhibits the best OER performance, needing a low overpotential of +308 mV to reach the current density of 10 mA cm⁻², along with excellent stability, and even outperforms commercial RuO₂ at high overpotentials. This is ascribed to the charge transfer between the carbon scaffold and metal nanoparticles. Operando X-ray absorption spectroscopy measurements show that the electrochemically produced CoOOH species is responsible for the high electrocatalytic performance. The results highlight the unique potential of MIH in the development of effective nanocomposite catalysts for electrochemical energy technologies.

The levels of dopamine (DA) in living organisms have strong effects on many biological processes and diseases, such as Parkinson's disease and Alzheimer's disease. Therefore, it has great significance for sensitive and selective detection of DA. Herein, the AuPd@Fe₂O₃ nanoparticles-based electrochemical (EC) sensor (AuPd@Fe₂O₃ NPs/GCE) is developed for chronoamperometric detection of DA with high sensitivity and good anti-interference ability through simple immobilization of AuPd@Fe₂O₃ nanoparticles on glassy carbon electrode (GCE) by Nafion. Under the application of oxidation potential, the AuPd@Fe₂O₃ NPs/GCE exhibits good electrocatalytic activity toward DA, which enables to linearly detect DA in the range of 10 nM–831.61 μM (R² = 0.9983). The AuPd@Fe₂O₃ NPs/GCE also shows good selectivity and reproducibility for the detection of DA. Furthermore, the practicability of AuPd@Fe₂O₃ NPs/GCE has been demonstrated by detection of DA in dopamine hydrochloride injection and human serum.

Plasmonic semiconductors with high free carrier concentration is a class of attractive materials that exhibit metal-like localized surface plasmon resonance (LSPR) for light extinction with tunable features. Their applications in artificial photosynthesis have witnessed considerable advances in terms of the determinants for solar-to-chemical energy conversion efficiency improvement, including light harvesting, charge dynamics as well as surface photochemistry. In this review, we begin with the fundamental introduction to physical principles and unique characters of LSPR excitation in plasmonic semiconductors. The doping strategies for activating LSPR response and the intrinsic merits in artificial photosynthesis are subsequently summarized in detail. In addition, the remaining challenging and future perspectives are briefly outlooked. We anticipate that this review can provide a tutorial guideline to broaden the horizons for plasmonic semiconductors in the exploration of sustainable plasmon-assisted photochemistry application.