Precursors Of Analogues Research Articles

Surface Engineering of Cobalt Nano Cube by Enhanced Nitrogen Content in Surface Carbon Shell for Efficient Hydrogen Evolution Reaction in Anion Exchange Membrane Water Electrolysis

To address the pressing concerns of fossil fuel depletion and environmental degradation, extensive research is underway on hydrogen production via water electrolysis. The formidable energy barrier inherent in electrochemical water decomposition significantly impedes efficient hydrogen generation, thus necessitating the development of highly effective electrocatalysts. Surface modifications of transition metals offer a promising avenue for reducing the energy barrier associated with the hydrogen evolution reaction (HER), as well as the hybrid structure with carbon materials can augment electrical conductivity and structural resilience. Furthermore, surface engineering through nitrogen doping on carbon shells can furnish electrochemically active catalytic sites. In this study, we present the synthesis of Cobalt-Iron nano cubes encapsulated within a nitrogen-doped carbon shell. The N-doped carbon shell was obtained through the calcination of a polymer layer coated on a Co-Fe Prussian blue analogue precursor. Additionally, the nano cubes were further encapsulated in a melamine layer to enhance the nitrogen dopant content, thus optimizing the electrocatalytic performance. The optimized CoFe@highly n-doped shell exhibits a low overpotential (98.2 mV) than CoFe@n-doped shell (133.2 mV) at 10 mA cm-2 on alkaline HER performance, and the exhibited performances were stable after 3,000 CV cycles. To commercialize electrocatalyst for hydrogen production, the CoFe@highly n-doped shell was applicated on anion exchange membrane (AEM) device. The CoFe@highly n-doped shell as cathode catalyst in AEM water electrolyzer shows low cell voltage of 1.808 V to achieve current density of 0.5 A cm-2.

Multi-heterogeneous interfaces boost dielectric polarization in PBA-derived Co/MnO@NC ternary composites for electromagnetic wave absorption

The elaborate construction of multi-component composites has been deemed as a promising strategy to enhance dielectric polarization response capability in the preparation of highly efficient microwave absorbers. However, the rational design and integration of homogeneous composites with diverse components continues to pose a great challenge. Herein, we propose a straightforward self-assembly-carbonization strategy for fabricating Co/MnO@NC ternary composites derived from CoMn-Prussian Blue Analogous precursors, featuring enriched heterogeneous interfaces and balanced magneto-electric coupling synergy. The ternary composites effectively introduce diverse dissipation mechanisms, including interfacial polarization behavior originated from the constructed heterogeneous interfaces, dipole polarization relaxation triggered by atomic defects, and optimized magnetic loss ability from well-dispersed metallic Co species. Benefiting from these advantages, the Co/MnO@NC composites demonstrate superior electromagnetic wave absorption performances, with a minimum reflection loss value of −61.37 dB at the thickness of 3.5 mm and effective frequency absorption bandwidth of 6.32 GHz, covering the full Ku-band. Furthermore, power loss density and radar cross-section simulations validate that the Co/MnO@NC ternary composites possess exceptional microwave signal attenuation abilities, with a maximum radar cross-section reduction value of up to 27.98 dBm2 at 0°. Such outstanding absorption properties exceed those of most currently reported ternary composites and exhibit significant potential to replace conventional ferromagnetic-based absorbers. This work offers a straightforward strategy to fabricate ternary composites with excellent electromagnetic wave attenuation properties and sheds novel insights into the dissipation mechanisms.

A Caged Neutral 17-Valence-Electron Iron(I) Radical [Fe(CO)2(Cl)(P((CH2)10)3P)]•: Synthetic, Structural, Spectroscopic, Redox, and Computational Studies.

UV irradiation of yellow CH2Cl2 solutions of trans-Fe(CO)3(P((CH2)10)3P) (2a) and PMe3 (10 equiv) gives, in addition to the previously reported dibridgehead diphosphine P((CH2)10)3P (46%), a green paramagnetic complex that crystallography shows to be the trigonal-bipyramidal iron(I) radical trans-[Fe(CO)2(Cl)(P((CH2)10)3P)]• (1a•; 31% after workup). This is a rare example of an isolable species of the formula [Fe(CO)4-n(L)n(X)]• (n = 0-3, L = two-electron-donor ligand; X = one-electron-donor ligand). Analogous precursors with longer P(CH2)nP segments (n = 12, 14, 16, 18) give only the demetalated diphosphines, and a rationale is proposed. The magnetic susceptibility of 1a•, assayed by Evans' method and SQUID measurements, indicates a spin (S) of 1/2. Cyclic voltammetry shows that 1a• undergoes a partially reversible one-electron oxidation, but no facile reduction. The UV-visible, EPR, and 57Fe Mössbauer spectra are analyzed in detail. Complex 2a is similarly studied, and, despite the extra valence electron, exhibits a comparable oxidation potential (ΔE1/2 ≤ 0.04 V). The crystal structure shows a cage conformation, solvation level, disorder motif, and unit cell parameters essentially identical to those of 1a•. DFT calculations provide much insight regarding the structural, redox, and spectroscopic properties.

The influence of Nano-composite metal oxides on the thermal decomposition performance of RDX

Abstract In order to investigate the effect of nano-composite metal oxides on the thermal decomposition performance of hexogen (RDX), this study prepared nano nickel-iron (NFO), nickel-cobalt (NCO), and nickel-iron-cobalt (NFCO) composite oxides by liquid-phase co-precipitation method. The precursor of Prussian blue analogs was synthesized and then calcined in air at 600°C. The addition of nano nickel-iron (NFO), nickel-cobalt (NCO), and nickel-iron-cobalt (NFCO) composite oxides to RDX has a significant impact on its thermal decomposition process. The peak exothermic temperatures were delayed by 8.4°C, 8.5°C, and 8.3°C, respectively, after adding the nano-composite metal oxides, and the heat release also increased to a certain extent. Among them, the addition of NCO nano-composite metal oxides had the greatest impact on the exothermic peak temperature of RDX, while the addition of NFCO nano-composite metal oxides resulted in the largest increase in heat release. This indicates that the addition of NFO, NCO, and NFCO to RDX altered the thermal decomposition reaction process to some extent.

Highly selective regulation of non-radical and radical mechanisms by Co cubic assembly catalysts for peroxymonosulfate activation

Peroxymonosulfate (PMS) activation on efficient catalysts is a promising strategy to produce sulfate radical (SO4−) and singlet oxygen (1O2) for the degradation of refractory organic pollutants. It is a great challenge to selectively generate these two reactive oxygen species, and the regulation mechanism from non-radical to radical pathway and vice versa is not well established. Here, we report a strategy to regulate the activation mechanism of PMS for the selective generation of SO4− and 1O2 with 100 % efficiency by sulfur-doped cobalt cubic assembly catalysts that was derived from the Co-Co Prussian blue analog precursor. This catalyst showed superior catalytic performance in activating PMS with normalized reaction rate increased by 87 times that of the commercial Co3O4 nanoparticles and had much lower activation energy barrier for the degradation of organic pollutant (e.g., p-chlorophenol) (18.32 kJ⋅mol−1). Experimental and theoretical calculation results revealed that S doping can regulate the electronic structure of Co active centers, which alters the direction of electron transfer between catalyst and PMS. This catalyst showed a strong tolerance to common organic compounds and anions in water, wide environmental applicability, and performed well in different real-water systems. This study provides new opportunities for the development of metal catalyst with metal-organic frameworks structure and good self-regeneration ability geared specifically towards PMS-based advanced oxidation processes applied for water remediation.

Precise electronically modulated Mn doped nickel iron phosphate with P, N codoped carbon decorated P-doped carbonized bacterial cellulose for efficient electrocatalytic glucose conversion coupled with H2 generation

Biomass electrocatalytic-conversion coupled with hydrogen generation exhibits low energy consumption, efficient hydrogen production and green syntheses of value-added chemicals. However, constructing electrocatalysts with precise electronic modulation and structures for efficient biomass electrocatalytic conversion coupled hydrogen production remains challenging. Herein, a bacterial cellulose substrate was combined in situ with a Mn-doped NiFe Prussian blue analogue (PBA) precursor, and one-step carbonization-phosphorylation was developed for the preparation of Mn-doped nickel iron phosphate (MNFP) embedded in a P, N codoped carbon (PNC) substrate grown directly on P-doped carbonized bacterial cellulose (MNFP-PNC/PCBC). Benefiting from the three-dimensional network structure of P-doped carbonized bacterial cellulose (PCBC) and atomic doping, MNFP-PNC/PCBC exhibited an optimized electronic structure, abundant active sites and excellent electrical conductivity. Therefore, the voltages required with hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and glucose electrocatalytic-conversion (GCR) to drive a current density of 50 mA cm−2 were 0.214, 1.5, and 1.34 V, respectively. Moreover, the required cell voltage of the novel electrolyser containing MNFP-PNC/PCBC as electrodes can be further reduced to 1.55 V at 50 mA cm−2 compared to overall water splitting, resulting in more than 8-time improvement in hydrogen production efficiency and production of value-added formate. This work provides a unique approach for electrocatalytic-conversion of biomass coupled with electrocatalytic hydrogen generation.

Degradation of atrazine by N-doped graphitic carbon encapsulated Nickel-iron alloy via heterogeneous activation of peroxymonosulfate

Heterogeneous magnetic catalysts for peroxymonosulfate (PMS) activation that are used to degrade pollutants have attracted growing attention, and bimetallic alloy catalysts have excellent catalytic performance. In this study, nitrogen-doped graphite carbon encapsulated NiFe (NiFe@NC) alloy catalysts were synthesized using nickel-iron Prussian blue analog precursors to remove atrazine (ATZ) via the activation of PMS. The effects of various operating parameters (NiFe@NC dosage, PMS concentration, initial solution pH, and reaction temperature), and the effects of co-existing components were investigated. The synergistic catalysis of Ni and Fe gives NiFe@NC good catalytic properties. The NiFe@NC/PMS system achieved 100% removal of 10 mg L−1 ATZ was achieved in 30 min with an initial pH of 5.9; the TOF was 4.33 min−1, and the system exhibited resistance to interference from many co-existing substances. The graphite-carbon core-shell structure of NiFe@NC slowed down the leaching rate of metal ions and had good stability. Redox cycles in the system were achieved by facilitating the interaction between the transition metal and HSO5-, ensuring the continuous generation of reactive oxygen species. Ecotoxicity assessment showed that the toxicity level was significantly reduced after treatment. The total treatment cost of treating 1 m3 wastewater was lower than that of Fenton sludge catalyst. A continuous flow reactor was constructed to achieve continuous degradation of ATZ for long periods. This study expanded the application of PMS advanced oxidation technology by synthesizing an economical and recyclable magnetic catalyst and provided new insights for the removal of refractory organic matter.

Tungsten-doped cobalt-iron bimetallic phosphide nanoparticles for enhanced oxygen evolution reaction

BackgroundHydrogen obtained from electrochemical water splitting is an efficient method for hydrogen production, which is urgent to develop high efficiency electrocatalyst and commercialize the process. MethodsIn our work, we used coprecipitation, doping and phosphating strategies to report the trimetallic Prussian blue analogue precursors (W-CoFe PBA) were prepared by doping sodium tungstate into cobalt-iron-Prussian blue analogues (CoFe PBA), and then by a low temperature phosphating treatment to obtain tungsten doped cobalt-iron phosphide (W-CoP/FeP) heterostructures. This strategy of doping and then phosphating can allow the charge distribution is adjusted, the conductivity is increased, the electron transport to the surface is accelerated, and the synergistic effect between CoP and FeP is enhanced. Significant findingsThe experimental results show that the mass ratio of tungsten source to CoFe-PBA is 0.5 (0.5W-CoP/FeP), which shows outstanding activity with overpotentials of 282 mV for the oxygen evolution reaction (OER) in 1 M KOH at a current density of 10 mA cm−2 and Tafel slope of 29.14 mV dec−1. Simultaneously, it also exhibits excellent stability for 24 h in the chronopotentiometry test. This work provides a simple improvement for the application of Prussian blue analogues in the electrochemical water splitting.

Incorporating azaheterocycle functionality in intramolecular aerobic, copper-catalyzed aminooxygenation of alkenes.

Despite the maturity of alkene 1,2-difunctionalization reactions involving C-N bond formation, a key limitation across aminofunctionalization methods is incompatibility with substrates bearing medicinally relevant N-heterocycles. Using a cooperative ligand-substrate catalyst activation strategy, we have developed an aerobic, copper-catalyzed alkene aminooxygenation method that exhibits broad tolerance for β,γ-unsaturated carbamates bearing aromatic azaheterocycle substitution. The synthetic potential of this methodology was demonstrated by engaging a densely-functionalized vonoprazan analogue and elaborating an amino oxygenated product to synthesize a heteroarylated analogue precursor of the FDA-approved antibiotic chloramphenicol.

Synergistic enhancement of chemisorption and catalytic conversion in lithium-sulfur batteries via Co3Fe7/Co5.47N separator mediator

Lithium-sulfur batteries (LSBs) show considerable potential in next-generation high performance batteries, but the heavy shuttle effect and sluggish redox kinetics of polysulfide hinder their further applications. In this paper, to address these shortcomings of LSBs, Co3Fe7/Co5.47N heterostructure were prepared and constructed from their Fe-Co Prussian blue analogue precursors under the condition of high temperature pyrolysis. The obtained Co3Fe7/Co5.47N display excellent immobilization-diffusion-conversion performance for polysulfides by synergistic effect in successfully hindering the shuttle effect of polysulfides. When the Co3Fe7/Co5.47N heterostructure were applied to modify the commercial polypropylene (PP) separator, the batteries displayed fantastic rate capacity and cycling stability. Specifically, the Co3Fe7/Co5.47N-PP batteries exhibit an extremely satisfactory initial specific capacity of 1430 m Ah/g at 0.5C, wonderful rate capacity of around 780 m Ah/g at 3C and superior per cycle decaying rate of 0.08 % for 500 cycles at 0.5C. When the current density reaches to 2C, the batteries still exhibit 501 m Ah/g after 900 cycles with 0.015 % per cycle decay rate. Besides, even in the high loading of sulfur (3.0 mg cm−2) at 0.5C, the superior cycling stability (0.075 % per cycle decay rate after 200 cycles) and high specific capacity (741 mAh/g after 200 cycles) can still be performed. Thus, this work provides a facile method for high-powered and long-life Li-S batteries with eminent entrapping-conversion processes of polysulfides.

An amorphous manganese iron oxide hollow nanocube cathode for aqueous zinc ion batteries

Aqueous zinc ion batteries (ZIBs) are attracting considerable attentions for practical energy storage because of their low cost and high safety. Nevertheless, the traditional manganese oxide cathode materials suffer from the low intrinsic electronic conductivity, sluggish ions diffusion kinetics, and structural collapse, hindering their large-scale application. Herein, we successfully developed a latent amorphous Mn1.8Fe1.2O4 hollow nanocube (a-H-MnFeO) cathode material derived from Prussian blue analogue precursor. The amorphous nature endows the cathode with lower diffusion barrier and narrower band gap compared with crystalline counterpart, resulting in the superior Zn2+ ions and electrons transport kinetics. Hollow structure can furnish abundant surface sites and suppress the structural collapse during the repeated charge/discharge processes. By virtue of the multiple advantageous features, the a-H-MnFeO cathode exhibits exceptional electrochemical performance, in terms of high capacity, excellent rate capability, and prolonged cycle life. This strategy will pave the way for the structural design of emerging cathode materials.

Structural and Electrochemical Identification of CoFe Pnictide Catalysts Affecting the Performance of the Oxygen Evolution Reaction

The advance of efficient electrocatalysts for electrochemical water splitting is highly significant for the energy conversion system, but is hindered by the high overpotential of the oxygen evolution reaction (OER) by four-electron transfer. Herein, we report a variation of transition metal compound based on the Co–Fe Prussian blue analogue (PBA) precursor. CoP/FeP, Co2N/Fe3N, and CoFe catalysts are synthesized in N2 atmosphere by phosphorization, nitridation, and calcination, respectively. After phosphorization, the synthesized mesoporous CoP/FeP nanocubes contribute to the improvement of the electrocatalyst performance by maintaining the shape of the precursor. The mesoporous structure of the CoP/FeP catalyst enhanced the electrochemically active surface area (ECSA) than other Co2N/Fe3N and CoFe catalysts, resulting in better OER performance with an overpotential of 279 mV at a current density of 10 mA∙cm−2, a Tafel slope of 74 mV∙dec−1, and good stability for 24 h with only 5.64% degradation in alkaline solution (1.0 M KOH).

Prussian blue analog-derived nickel iron phosphide-reduced graphene oxide hybrid as an efficient catalyst for overall water electrolysis

Efficient and bifunctional nonprecious catalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are essential for the production of green hydrogen via water electrolysis. Transition metal (Ni, Co, Fe, etc.) phosphides are frequently documented HER catalysts, whereas their bimetallic oxides are efficient OER catalysts, thus enabling bifunctional catalysis for water electrolysis via proper operation. Herein, phosphide-reduced graphene oxide (rGO) hybrids were prepared from graphene oxide (GO)-incorporated bimetal Prussian blue analog (PBA) precursors. The hybrids could experience partial surface oxidation to create oxide layers with OER activities, and the hybrids also possessed considerable HER properties, therefore enabling bifunctional catalytic features for water electrolysis. The typical NiFeP-rGO hybrid demonstrated an overpotential of 250 mV at 10 mA cm−2 and good durability for OER, as well as moderate HER catalytic features (overpotential of 165 mV at −10 mA cm−2 and acceptable catalytic stability). Due to the bifunctional catalytic features, the NiFeP-rGO-based symmetric water electrolyzer demonstrated a moderate input voltage and high faradaic efficiency (FE) for O2 and H2 production. The current work provides a feasible way to prepare OER and HER bifunctional catalysts by facile phosphorization of PBA-associated precursors and spontaneous surface oxidation. Given the oxidation/reduction bifunctional catalytic behaviors, phosphide-rGO hybrid catalysts have great potential for widespread application in fields beyond water electrolysis, such as electrochemical pollution abatement, sensors, energy devices and organic syntheses.

CuCo Nanocube/N-Doped Carbon Nanotube Composites for Microwave Absorption

Metal–organic frameworks (MOFs) have come into the limelight in the field of microwave absorption since they can be developed into porous carbon-based MOF derivatives with a variety of features, such as controlled defects, tunable structures, and variable compositions. In this paper, Cu3[Co(CN)6]2 Prussian blue analogue (CuCo-PBA) precursors with a regular cubic morphology were synthesized by a simple co-precipitation method and converted into CuCo nanocube/N-doped carbon nanotube (CuCo/NCNT) derivatives by annealing them in argon. It was found that when the annealing temperature was 850 °C, the minimum reflection loss (RLmin) of CuCo/NCNT could reach −54.13 dB with an effective absorption bandwidth of 4.01 GHz. The excellent microwave absorption properties were attributed to the mutual synergy of conduction loss, interfacial polarization, magnetic resonance loss, and eddy current loss. Therefore, this work provides an effective preparation method for the design of lightweight carbon-based microwave-absorbing materials with heterogeneous interfaces using Prussian blue.

Precursor design in a self-templating strategy for carbon-encapsulated bimetallic CoFe catalysts: Boosting organic pollutant degradation via nonradical pathways

Designing high-performance heterostructure catalysts for peroxymonosulfate (PMS) activation is a promising research area. PMS-driven organic pollutant degradation via radical pathways usually suffers from the interference of other coexisting matters. In this study, we took a source design approach and employed a self-templating strategy using Prussian blue analog (PBA) precursors to fabricate CoFe/C heterostructure catalysts dominated by a nonradical pathway. Slow-speed coordination renders the CoFe PBA precursor with a highly ordered crystal structure and fewer coordinated water, resulting in an ideal carbon-encapsulated CoFe bimetallic catalyst (CoFe-S-T) with more high-valence metals and a graphitized carbon layer in its heterostructure; the obtained catalyst is proven to have superior catalytic performance for tetracycline (TC) degradation through a nonradical pathway in PMS-driven oxidation. The high CoIII/CoII ratio and surface oxygen content make CoFe-S-T an excellent catalyst by boosting the generation of 1O2, which is the predominant active species. In addition, CoFe-S-T has a high proportion of graphitized carbon layers, which significantly improves the direct electron transfer pathway. Thus, utilizing precursor design in a self-templating strategy is an effective method to synthesize high-performance heterostructures for PMS-driven organic pollutant degradation.

An attempt to prepare sulfonyl analogues of fotemustine: unexpected rearrangement to sulfamate during nitrosation step

A flexible strategy to access to dialkyl (((N-(2-chloroethyl)-N-sulfamoyl) amino) arylmethyl) phosphonates, as sulfonamidophosphonates precursors of Fotemustine analogues was developed. The last nitrosation step proceeded as a rearrangement to the non expected sulfonate analogues.

Effect of different substituents on the fluorescence properties of precursors of synthetic GFP analogues and a polarity-sensitive lipid droplet probe with AIE properties for imaging cells and zebrafish.

The green fluorescent protein (GFP) is a purely natural specialty protein that has been widely used to design synthetic fluorescent probes. In the present work we designed and synthesized a series of fluorescent compounds akin to GFP precursors by a one-step method, and investigated the luminescence properties of the fluorescent compounds by varying the substituents. We presented the first systematic summary of the photophysical data including extinction coefficients and fluorescence quantum yields for this class of fluorescent dyes. We also carried out density functional theory (DFT) calculations for these dyes to investigate the effect of electronic effects due to different substituents. These studied optical properties may provide a reference for later probe design. More interestingly, we have developed a polarity-sensitive lipid droplet probe T-LD with AIE properties on this basis. The probe exhibited not only favorable pH stability and kinetic stability in terms of optical properties, but also solvent discolouration and polarity-sensitive properties, and was able to label intracellular lipid droplets. We successfully applied the probe for intracellular lipid droplet level monitoring and zebrafish imaging.

The transition from soluble to insoluble organic matter in interstellar ice analogs and meteorites

Context. Carbonaceous chondrites are sources of information on the origin of the Solar System. Their organic content is conventionally classified as soluble (SOM) and insoluble organic matter (IOM), where the latter represents the majority. Aims. In this work, our objectives are to identify possible relations between soluble and insoluble organic matter generated in laboratory experiments and to extrapolate the laboratory analog findings to soluble and insoluble organic matter of meteorites to test their connection. Methods. Using laboratory experiments, processes possibly linking IOM analog (IOMA) to SOM analog (SOMA) precursors are investigated by assuming that dense molecular ices are one of the sources of organic matter in the Solar System. Each organic fraction is analyzed by laser desorption coupled to a Fourier transform ion cyclotron resonance mass spectrometer on a comprehensive basis. Results. SOMA and IOMA significantly differ in their chemical fingerprints, and particularly in their aromaticity, O/C, and N/C elemental ratios. Using an innovative molecular network, the SOMA–IOMA transition was tested, revealing connection between both classes. This new network suggests that IOMA is formed in two steps: a first generation IOMA based on precursors from SOMA, while a second IOMA generation is formed by altering the first IOMA generation. Finally, using the same analytical technique, the molecular content of IOMA and that of the Paris IOM are compared, showing their molecular similarities for the first time. The molecular network application to the Paris SOM and IOM demonstrates that a possible connection related to photochemical ice processing is present, but that the overall history of IOM formation in meteorites is much more complex and might have been affected by additional factors (e.g., aqueous alteration). Conclusions. Our approach provides a new way to analyze the organic fraction of extraterrestrial material, giving new insights into the evolution of organic matter in the Solar System.

Ni3Fe nanoparticles encapsulated by N-doped carbon derived from MOFs for oxygen evolution reaction

It has been a hot research topic to look for inexpensive alternative oxygen evolution reaction (OER) catalysts to replace noble metal-based materials due to their scarcity. Transition metals are ideal candidates because of their high abundance, impressive activities, and easy accessibility. However, a facile method leading to improved performance and stability is still needed. Herein, a highly efficient carbon-encapsulated bimetal catalyst derived from Ni-based metal-organic-frameworks (MOF) was successfully prepared through the low-temperature (350 ℃) pyrolysis of Prussian blue analogue (PBA) precursors under H 2 /Ar atmosphere. Cube-structured PBA as template and precursor，parameters during the pyrolysis process including temperature and calcination atmosphere can be tuned to control the structure and properties of the catalysts. Benefiting from the porous three-dimensional (3D) cubic structure and abundant defect-rich amorphous N-doped carbon shell, Ni 3 Fe@NC-350 exhibits excellent OER activity. The as-prepared catalysts exhibited excellent catalytic performance for OER in 1.0 M KOH with an overpotential of 237 mV to achieve 10 mA cm −2 . More importantly, the presented catalyst has an extremely good durability. • A simple low-temperature annealing method was developed to produce alloy encapsulated with N-doping carbon. • The NiFe PBA was employed as nitrogen and carbon source. • The increased activity of OER is due to the synergy of Ni 3 Fe alloy and N-doped carbon layer. • Theoretical calculations revealed that the synergistic effect of NiFe alloy nanoparticles and N-doped carbon layer.

Photochemical Release of Hydropersulfides.

Hydropersulfides (RSSH) have received significant interest in the field of redox biology because of their intriguing biochemical properties. However, because RSSH are inherently unstable, their study is challenging, and as a result, the details of their physiological roles remain ill-defined. Herein, we report strategies to release RSSH utilizing photoremovable protecting groups. RSSH protection with the well-established p-hydroxyphenacyl (pHP) photoprotecting group resulted in inefficient RSSH photorelease along with complex chemistry. Therefore, an alternative precursor was examined in which a self-immolative linker was inserted between the pHP group and RSSH, providing nearly quantitative RSSH release following photolysis at 365 nm. Inspired by these results, we also synthesized an analogous precursor derivatized with 7-diethylaminocoumarin (DEACM), a visible light-cleavable photoprotecting group. Photolysis of this precursor at 420 nm led to efficient RSSH release, and in vitro experiments demonstrated intracellular RSSH delivery in breast cancer MCF-7 cells.