The LiMn_0.6Fe_0.4PO₄@C@Al₂O₃ (LMFP64/CA) compound was synthesized through solvothermal and liquid-phase coating methodologies. The LMFP64/CA composite with the carbon layer and Al₂O₃ protective layer as cathode materials can obtain excellent cycle performance and rate performance.

Abstract

As an indispensable cathode material for lithium-ion batteries, LiMn _x Fe_1−x PO₄ (LMFP) has garnered significant attention among scholars due to its considerable energy density and remarkable safety characteristics. However, the further advancement of LMFP is hindered by its poor conductivity and limitations in terms of cycle stability. Herein, LiMn_0.6Fe_0.4PO₄@C@Al₂O₃ (LMFP64/CA) composite materials with core-shell structure were prepared through simple solvothermal and liquid phase coating methods. The carbon layer can further bolster the structural robustness of the active material, increase conductivity, and facilitate ion and electron transfer; while the Al₂O₃ layer can function as a protective interface, effectively mitigating the detrimental electrochemical side effects arising from hydrofluoric acid (HF) generated during electrolyte decomposition within a wide voltage range. Consequently, the LMFP64/CA electrode exhibits impressive electrochemical performance including notable reversible capacity (125.1 mAh g⁻¹ at 0.5 C), exceptional rate performance (111.2 mAh g⁻¹ at 1 C), and remarkable cycle stability at 5 C (0.021 % decay rate over 500 cycles).

Photo/electrocatalytic reduction of CO₂ to C2+ products is one of the most promising approaches for simultaneously mitigating the greenhouse gases CO₂ emission and producing value-added fuels. In this review, we present an overview of the latest advances of photo/electrocatalytic CO₂ reduction to C2+ products with focus on the catalytic performance depending on rational design of desired MOF-based catalysts.

Abstract

Efficient conversion of CO₂ to valuable fuels is a desired approach to reduce global warming effect and remit sustained fossil fuel demand. Metal–organic frameworks (MOFs), a class of crystalline porous materials with unique features, have been widely studied for potential applications in varied fields. Recently, photo/electrocatalytic reduction of CO₂ to two or more carbons (C2+) products has attracted extensive attention because of their higher market values than one carbon (C1). However, the major products of CO₂ reduction currently are carbon monoxide, formate, or methane, which are all typical C1 products. Generally, for photocatalytic reduction of CO₂ system, relatively low efficiency of electron transfer with inadequate capability results sluggish kinetics of C−C coupling. And for electrocatalysis, high current densities curtail the stability, which limits selectivity towards C2+ products. In this review, we provide very latest reports that have make some breakthroughs to overcome the above difficulties in photo/electrocatalytic reduction of CO₂ to C2+ products using MOF-based materials. Special emphases are given on design strategies of synthetic MOF-based catalysts and the mechanisms of catalytic CO₂ to C2+ products. The challenges and prospects of photo/electrocatalytic reduction of CO₂ to C2+ products associated with MOF-based materials are also discussed.

Colloidal, atomically dispersed Pd-doped Ni₂P nanoparticles were prepared. The Pd dopant regulates the electronic structure of Ni₂P NPs and provides an efficient active site for hydrogen production, which exhibits efficient water splitting.

Abstract

Hydrogen production through electrochemical water splitting has gained significant attention owing to its environmental benefits over traditional methods. However, designing an efficient electrocatalyst for the hydrogen evolution reaction (HER) in an alkaline electrolyte remains a significant challenge. In this study, colloidal Pd-doped Ni₂P nanoparticles were prepared via a thermal decomposition-based strategy and used as electrocatalysts for the hydrogen evolution reaction. The Pd dopant is atomically dispersed within the Ni₂P nanoparticles, regulating their electronic structure and providing an efficient active site for hydrogen production. The Pd-doped Ni₂P nanoparticles exhibited excellent electrocatalytic performance with an overpotential of 77 mV at 10 mA cm⁻² in an alkaline electrolyte and a small Tafel slope of 46 mV dec⁻¹.

Hydrogen evolution reaction (HER) is one of prospective methods to produce hydrogen energy, and the key technology of which lies in the preparation of electrocatalysts. Preparations of catalysts with high efficiency, low price and good stability are expected. In this work, a new polyoxometalate-based copper-organic framework, [{CuII(C10N6H7)4(H2O)2}H6(PMo12O40)2]·12H2O (1) [C10N6H7: 3-(1H-pyrazol-4-yl)-5-(pyridin-4-yl)-1,2,4triazole], was synthesized as an electrocatalyst precursor, and confirmed by infrared spectroscopy (IR), single-crystal X-ray diffraction (SXRD) and X-ray powder diffraction (PXRD). A newelectrocatalyst (Cu2S-MoS2@CC-1) was synthesized from 1, thiourea (TU) and carbon cloth (CC) by a one-pot hydrothermal method. Tue to the synergistic effects between Cu2S and MoS2, the Cu2S-MoS2@CC-1 catalyst exhibits high electrocatalytic HER activity and goodstability in 0.5 M H2SO4. Namely, Cu2S-MoS2@CC-1 shows low overpotential of 150 mV@10 mA·cm-2 vs reversible hydrogen electrode (RHE) and small Tafel slope of 61 mV dec-1, and remains good stability at least 94 h and over 1000 catalytic cycles. This method provides a promising strategy for development of non-noble metal catalysts.

Chemosensors are promising candidates to visualize molecular recognition information through colorimetric or fluorescence responses. In chemosensor designs, the following requirements should be considered; 1) molecular geometries with analytes, 2) mechanisms to cause optical changes upon analyte capture, and 3) solubility for sensing applications. On the other hand, the designs and realization of chemosensors covering the abovementioned requirements are still at the frontiers. In the conventional strategy,  molecular geometries between receptors and analytes have been mainly considered. However, this approach confronts issues of synthetic efforts to obtain elaborate designs of chemosensors, which leads to a decrease in the water solubility of chemosensors derived from the complicated and aromatic molecular structures. Herein, this Review summarizes methodologies for self-assembled chemosensors only using off-the-shelf reagents to easily obtain various chemosensors without organic synthesis. The concept of self-assembled chemosensors comprising off-the-shelf reagents with water-solubility realizes not only the easy tuning of optical sensing properties but also chemical sensing in real samples. Through the comprehensive sensing applications using the facile self-assembled chemosensors and their arrays, the usability of off-the-shelf reagents in analytical chemistry will be clarified.

Schematic representation of bright blue, fluorescent bovine serum albumin-stabilized carbon dots (BSA-CDs) as a fluorescent probe for the detection of heparin and protamine. Heparin, a polyanionic drug is introduced into (BSA-CDs), resulting in fluorescent “turn-off”. Furthermore, on addition of cationic protein protamine, the fluorescence is “turn-on”, facilitating electrostatic interactions on the surface. Thus, an effective “turn-off-on” fluorescent probe was developed for the sensitive detection of heparin and protamine in human serum and urine.

Abstract

Heparin and protamine are two therapeutically significant biomolecules utilized in surgeries and extracorporeal therapy. Hence, real time monitoring of their concentration levels in body fluids is quite requisite. Herein, we developed, Bovine Serum Albumin stabilized carbon dots by a microwave-assisted synthesis for the detection of heparin and protamine. Heparin has sulfate and carboxy groups that can interact with the positively charged surface amino groups of protamine through electrostatic interactions and hydrogen bonds. The blue fluorescence exhibited by BSA-Carbon dots shows decrease in fluorescence emission on addition of negatively charged heparin. When cationic protein protamine is introduced to this system, the fluorescence is recovered due to electrostatic interaction with heparin. The system shows a Limit of detection (LOD) of 0.014 mM and 0.053 mM on addition of heparin and protamine respectively. The probe exhibited positive results with good selectivity and sensitivity towards other coexisting biomolecules and ions that appear in body fluids. The study was extended in biological matrix such as human serum and urine and found good recovery percentage in between 90–120%. The practical applicability was analyzed using a paper strip assay. Hence, a sensitive “turn-off-on” probe was effectively developed for the detection of heparin and protamine on a clinical basis.

The research demonstrates a new method for preparing flexible microcircuits and conductive sheets from liquid metals. The microcircuit carved on the surface of a liquid metal deposit has good conductivity, which greatly reduces the possibility of an open circuit.

Abstract

Liquid metal (LM) is of great use in many fields (e. g., sensors, biology, electronic circuits). With special mobility, high surface tension and excellent electrical conductivity, it can play a role in the field of flexible electronics. Due to its surface tension, it easily shrinks into a spheroid shape. Especially under the same current condition, the shrinkage of the volume will lead to open circuit, so it is very difficult to produce stable liquid metal ultrathin, ultrafine wire, which has become a barrier limiting the use of liquid metal. In this work, LM is mixed with polydimethylsiloxane to form a micrometer-thick conductive layer by free deposition. The LM is located inside the polymer holes. Not only that, microcircuits are also mapped on the surface of LM deposits. It not only has excellent electrical conductivity, but also has good flexibility. This work explores a simple method to produce a ultrathin conductive film and reduce the size of electronic components, which has potential applications in integrated circuits.

Ultrafine and highly dispersible MnO₂ nanoparticles were synthesized by hydrothermally reducing KMnO₄ with (NH₄)₂HPO₄ as the reductant. The MnO₂ nanoparticles prepared via this method exhibited excellent dispersibility in water, as well as a high specific capacitance of ~135.7 F ⋅ g⁻¹ at 5 mV ⋅ s⁻¹. This method is an advance in the preparation of nanomaterials that can be adapted to ink-printing supercapacitors or other energy storage devices.

Abstract

Manganese dioxide (MnO₂) has been extensively investigated as an electrode material for supercapacitors because of its high theoretical capacitance, great abundance, and low toxicity. To obtain satisfactory capacitance performance, in recent years, many efforts have been dedicated to the fabrication of MnO₂ nanoparticles that offer a larger specific surface area and an escalated chemical activity. Beyond them, the ideal dispersibility of nanoparticles in a liquid medium is also of vital importance when processing those powdery materials into slurry ones for some particular uses, such as editable and ink-printing supercapacitor devices. In this study, the as-synthesized ultrafine MnO₂ nanoparticles having excellent dispersibility in water can be prepared via a facile one-step hydrothermal route, with a uniform size in diameter of 200 nm exhibiting a large specific surface area of ~389.7 m² g⁻¹, and a high specific capacitance of 135.7 F g⁻¹ at 5 mV s⁻¹.

The cover picture illustrates how the form of the copper species deposited on the surface of MCM-41 nanospheres influences the catalytic activity of the obtained catalysts. The original SEM image of silica spheres was used as the background. In the upper left part, a drawing of the MCM-41 channels containing an organic template is presented. On the right side of the figure, an enlargement of MCM-41 channel is shown and also illustrated the procedure of template ion-exchange (TIE). Deposition of various copper phases using TIE was possible. Cu²⁺ are more active in the NO_x conversion, while CuO effectively oxidizes NH₃ - bottom of the picture. More information can be found in the Research Article by Aleksandra Jankowska, and Lucjan Chmielarz et al.

Silver nanoparticle-loaded SERS glass substrates prepared through static thermal evaporation technique showed promise towards easy label-free SERS fingerprinting of lung cancer cells A549 and fibroblast WI-38 cells. Though acquired spectral information revealed minor differences in the Raman fingerprints of specific biomolecules, the supervised linear discriminant analysis could discriminate malignant from healthy cells to a better extent.

Abstract

Lung cancer ranks first for cancer-related mortalities primarily due to late diagnosis. Though Surface-Enhanced Raman spectroscopy (SERS) is a popular bioanalytical technique, its direct application to diagnosis is impeded by low data reproducibility. Colloidal nanoparticles suffer from SERS intensity fluctuations due to unavoidable aggregation, and Brownian and diffusion motions in biological samples. The processes for solid-state SERS substrates are either sophisticated or difficult to reproduce. Herein, we revisit the well-established thermal evaporation process for the easy and reproducible preparation of silver nanoparticles loaded SERS glass substrates. The static mode of thermal evaporation yielded closely packed and uniformly distributed silver nanoparticles. The properties of these nanoparticles are tuned for the best performance by controlling the thermal evaporation process. And SERS substrate exhibited a reasonably good enhancement factor of ~10⁵ with uniformity and reproducibility <6 % RSD over a large area. It was utilized for label-free SERS fingerprinting of lung adenocarcinoma cells A549 and normal lung fibroblast cells, WI-38. The obtained data shows a slight distinction of Raman fingerprints in terms of certain biomolecules like nucleic acids, proteins, and lipids. Further multivariate statistical tools have been utilized which ensures a clear divergence between the cancerous cells and normal cells.