Advanced Sensor and Energy Materials最新文献

In the face of environmental pollution and an energy shortage, how to reduce the cost of a noble metal catalyst in clean energy such as the fuel cell system and improve its electrocatalytic performance is one of the hot issues in this field. Here, a facile stepwise co-reduction route for synthesizing a series of PdFe/Cu catalysts with surface reconstruction is investigated and the ethanol oxidation reaction (EOR) performance is explored. The greater exposure of Pd active sites makes it excellent in EOR in alkaline media compared to the homemade and commercial Pd black catalyst. The mass activity of PdFe/Cu (794.97 mA mg⁻¹_Pd) is 2.52 times that of the Pd black catalyst (315.64 mA mg⁻¹_Pd). This kind of PdFe/Cu catalyst shows enhanced mass current density (255.66 mA mg⁻¹_Pd) after the 1800 s chronoamperometry test and only exhibits a decay of 1.4% after accelerated 500-cycle measurement. The enhanced EOR performance may be due to the change in the electronic structure of Pd caused by synergistic and strain effects among Pd, Fe, and Cu. This work provides an effective and kindly strategy to synthesize electrocatalysts with superior activity and durability in relation to EOR.

Direct methanol fuel cells (DMFCs) are highly sensitive to CO poisoning on the current Pt based anode at operating condition. In a paper recently published in Angewandte Chemie International Edition, Kong et al. and coworkers presented a precise position control of single atom via atomic layer deposition (ALD) to synthesis the selective deposition of Ru single atoms (SAs) on the concavities of corrugated PtNi nanoparticles (Ru-ca-PtNi), which exhibited high activity and stability for methanol oxidation reaction (MOR).

Fullerenes are widely applied in the field of ORR, OER, and HER due to their well-defined molecular structures, excellent electron affinity potential that can be used to regulate the electronic structures when composited with other materials, the π-π intermolecular self-assembly into super crystals, and the customizable chemical modifications including heteroatom doping, metal encapsulation, and functionalization. These advantages endow fullerene with a great number of derivates and composites. Many theoretical and experimental works are reported on electrocatalysts. To better understand the study progress, herein, we give a common review of the latest research. We first introduce the theoretical calculations of fullerenes and their derivates towards ORR, OER, and HER, aiming to give understandable reaction mechanisms and electrocatalytic active sites. Then, the experimental identification of the electrocatalytic performance was summarized. The experimental section is organized based on fullerene-based composites including fullerene/carbon composites, fullerene/sulfide composites, fullerene/LDH or metal composites, and fullerene molecular and its derivates including fullerene crystals, fullertubes, as well as endohedral fullerene. Finally, the challenges and opportunities for rational designing of electrocatalysts using fullerene as a precursor or additive are summarized and highlighted. The review not only points out the recent progress in fullerene application in electrocatalysts but also gives an in-depth insight into the materials design theoretically and experimentally that helps the future study directions.

Drug abuse has proliferated at an unprecedented rate worldwide, posing significant public health challenges that directly impact society, criminality, and the economy. This review presents the application of nanomaterials for qualitative and quantitative electrocatalytic analysis of drugs of abuse, mostly opioids (such as heroin (HER), morphine (MOR), codeine (COD), fentanyl (FEN), and tramadol (TR)), and addictive stimulants (such as cocaine (COC) and methamphetamine (MAM)) via direct oxidation. Electroanalytical techniques have attracted attention for generating point-of-use sensors because of their low cost, portability, ease of use, and the possibility of miniaturization. Electroanalytical-based devices can assist first responders with tools to identify unknown powders and to treat victims of drug abuse. Based on the drug therapeutic and usage purposes, research advances in drug electroanalysis can be classified and discussed with special emphasis on the electrochemical reaction mechanism of the drug. Therefore, this review discusses sensor enhancement based on the electrocatalytic properties introduced by various strategies, such as surface nanostructuring, the use of conducting polymers, and anodization of electrode surfaces Finally, a critical outlook is presented with recommendations and prospects for future development.

MicroRNAs (miRNAs) as a well-known kind of cancer marker are closely associated with the formation and metastasis of tumors. Here, a novel tetraphenylethylene (TPE)-doped covalent organic frameworks (TPE-COFs) with strong aggregation-induced electrochemiluminescence (AIECL) response was synthesized and introduced to construct an ultrasensitive biosensor for the detection of miRNA-21. The strong aggregation-induced emission (AIE) response was obtained because the molecular motion of TPE was restricted by COFs which had the porosity and highly ordered topological structure. Meanwhile, the porous structure of COFs allowed TPE to react with electrochemiluminescence (ECL) coreactants more effectively. Furthermore, COFs significantly improved the electron transport efficiency of the entire ECL system. All of these endowed the TPE-COFs with superior AIECL performance. Then, a TPE-COFs based ECL resonance energy transfer (ECL-RET) system was constructed for ultrasensitive miRNA-21 biosensing with differential signal readout. The proposed assays exhibited excellent sensitivity with a wide dynamic range from 10 aM to 1 pM and a low detection limit of 2.18 aM. Therefore, these indicated that doping TPE in COFs was a creative way to develop functional COFs and provided an effective way for enhancing AIECL. Furthermore, this work boarded the application of AIECL in analytical chemistry.

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.