Recent Advancements in Ascribing Several Platinum Free Electrocatalysts Pertinent to Hydrogen Evolution from Water Reduction

The advancement of a sustainable and scalable catalyst for hydrogen production is crucial for the future of the hydrogen economy. Electrochemical water splitting stands out as a promising pathway for sustainable hydrogen production. However, the development of Pt-free electrocatalysts that match the energy efficiency of Pt while remaining economical poses a significant challenge. This review addresses this challenge by highlighting latest breakthroughs in Pt-free catalysts for the hydrogen evolution reaction (HER). Specifically, we delve into the catalytic performance of various transition metal phosphides, metal carbides, metal sulphides, and metal nitrides toward HER. Our discussion emphasizes strategies for enhancing catalytic performance and explores the relationship between structural composition and the performance of different electrocatalysts. Through this comprehensive review, we aim to provide insights into the ongoing efforts to overcome barriers to scalable hydrogen production and pave the way for a sustainable hydrogen economy.

Electrocatalytic barium-oxide decorated MWCNT amperometric sensor for the quantification of anesthetic drug Procaine

Procaine hydrochloride (P.HCl) is one of the earliest and most well-established local anesthetic drugs used in medicine. Though it is employed frequently for effective clinical nerve blocks during surgeries, its immoderate administration has often shown reports of systemic toxicity. To prevent such repercussions, developing a sensor for the drug is crucial to enable real-time monitoring of the drug and assist in quality control procedures during its industrial preparations. Thus, in this work, we have fabricated a simple yet highly selective and sensitive amperometric sensor for P.HCl detection based on a Barium-oxide multi-wall carbon nanotube-modified carbon paste electrode (BaO-MWCNT/CPE). Herein, we have adopted a novel approach devoid of sophisticated procedures and pretreatments for rapidly determining P.HCl. Furthermore, experimental conditions, including supporting electrolytes, pH, and scan rate, were optimized to achieve a well-defined P.HCl anodic peak current at 631 mV, which is lower than the previously reported peak potentials, indicating an advantage of reduced overpotential. Besides, a striking 66-fold rise in current responsiveness to P.HCl was achieved upon modification with BaO-MWCNT. Such an intense signal enhancement upon electrode modification compared to bare CPE was due to the strong electrocatalytic feature of BaO-MWCNT, which was verified using surface morphology studies with scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Additionally, the charge transfer kinetics analyzed via electrochemical impedance spectroscopy (EIS) justified the enhancement of electrocatalytic activity upon electrode modification. The developed sensor exhibited a remarkable analytical performance over a wide linear dynamic range of 2.0-100.0 µM with a detection limit of 0.14 µM. Moreover, a significant merit of this sensor is its excellent selectivity towards P.HCl even in the presence of various common interferants. Finally, the versatility of the sensor was further validated by implementing it for the trace analysis of urine and blood serum real samples.

Halloysite clay nanotubes with Fe–Al deposits for the oxidation of benzyl alcohol

Fe–Al/HNT catalysts are prepared and their application in the oxidation of benzyl alcohol to benzaldehyde at a temperature of 80 °C is investigated.

In-situ development of metal organic frameworks assisted ZnMgAl layered triple hydroxide 2D/2D hybrid as an efficient photocatalyst for organic dye degradation

Metal organic framework (MOF) supported layered triple hydroxide (LTH) 2D/2D hybrid material was prepared by a simple hydrothermal method. The photophysical properties of the prepared samples were investigated through a set of analytical methods such as X-ray diffraction, Fourier-transform infrared spectroscopy, field emission scanning electron microscope, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy and mapping. The photocatalytic degradation activity of as prepared 2D/2D MOF-5/LTH hybrid sample was investigated against methylene blue (MB) dye under the UV-visible light irradiation. The degradation efficiency of the MOF-5/LTH hybrid sample was twice a time greater than that of pristine MOF-5, particularly degradation efficiency of the MOF-5, LTH and MOF-5/LTH hybrid samples are 43.3, 57.7 and 98.1% respectively. The Pseudo first order rate and the reusing investigation was further used to study the catalytic activity and stability of the as-synthesized 2D/2D photocatalyst. The observed improvement in the photocatalytic activity of the hybrid samples were owed to enhance visible light absorption, efficient separation and transportation of photoinduced electrons and holes.

Enhanced oxygen reduction activity of bimetallic Pd–Ag alloy-supported on mesoporous cerium oxide electrocatalysts in alkaline media

Currently, the rational design and fabrication of Pt-free electrocatalysts towards the oxygen reduction reaction for extensive applications in fuel cells is a challenging task.

Unique Host Matrix to Disperse Pd Nanoparticles for Electrochemical Sensing of Morin: Sustainable Engineering Approach

Biomass-based carbon nanospheres derived from Mimosa pudica (commonly called "Touch-me-not") smeared on carbon fiber paper have been used as a host matrix for electrochemical deposition of palladium nanoparticles. The physicochemical characterization of modified electrodes was performed by field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy techniques. Cyclic voltammetry and electrochemical impedance spectroscopy were used to study the electroanalytical properties of the electrodes. The modified electrode demostrated an excellent electrocatalytic activity for the oxidation of a flavonoid, morin, which gave a sensitive anodic peak at -0.30 V (vs SCE). An ultralow-level detection limit of 572 fM with a linear dynamic range of 37.50-130 pM was achieved. The proposed electrochemical sensor was successfully employed for the analysis of morin in mulberry and guava leaves. This is a sustainable engineering approach where a perfect unique host matrix is created using carbon nanospheres from biomass.

Effect of cobalt doping on the electrochemical performance of trimanganese tetraoxide

Nanostructured transition metal oxides (TMO) are potential materials widely explored by researchers for energy storage applications. In this study, spinel trimanganese tetraoxide (Mn₃O₄) and cobalt doped trimanganese tetraoxide (Co-Mn₃O₄) was synthesized by using a simple solvent assisted hydrothermal route. Pure Mn₃O₄ and Co-Mn₃O₄ nanomaterials were characterized by an x-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), UV-diffuse reflectance spectroscopy (UV-DRS), field emission scanning electron microscope (FESEM), and high resolution transmission electron microscope (HRTEM). XRD analysis revealed the body centered tetragonal spinel structure of Mn₃O₄ and Co-Mn₃O₄ with a space group as l4₁/amd (141) and an approximate crystallite size of 45-33 nm. The presence of an Mn-O bond vibration was confirmed using FTIR and the band gap properties were analyzed through UV-DRS. Surface morphology and average grain size were examined using FESEM and HRTEM micrographs as nanosquares and nanospheres with diameter 126 nm and 118 nm, respectively. Electrochemical properties of Mn₃O₄ and Co-Mn₃O₄ were evaluated using cyclic voltammograms, charge-discharge curves, and electrochemical impedance spectra (EIS). Pure Mn₃O₄ showed a specific capacitance of 971 F g^-1 at 0.1 A g^-1 current density while Co-Mn₃O₄ achieved relatively higher specific capacitance of 1852 F g^-1 at the same current density. It is observed that the increased specific capacitance of Co-Mn₃O₄ mainly arises from the doping effect. Electrochemical analysis shows that the Co doped Mn₃O₄ nanomaterials can be a promising electrode material for supercapacitor.

Novel sonochemical synthesis of Fe3O4 nanospheres decorated on highly active reduced graphene oxide nanosheets for sensitive detection of uric acid in biological samples

In this study, a super-active Iron (II, III) oxide nanospheres (Fe₃O₄ NPs) decorated reduced graphene oxide (rGOS) nanocomposite was developed. Fe₃O₄ NPs were stabilized on rGOS through electrostatic interactions in the aqueous medium. This process involves an ultrasound assisted reduction reaction of the GOS. The as-synthesized Fe₃O₄ NPs@rGOS was characterized through the HRTEM, SEM, XRD, Raman, elemental mapping and EDX analysis. The Fe₃O₄ NPs@rGOS modified GCE was developed for the determination of biomarker. Uric acid is important biomarker based on gout and kidney stone with high adverse effect in human body. The results obtained showed that the modified electrode Fe₃O₄ NPs@rGOS shows good electrochemical reduction peak compared to bare electrode and control electrodes. The Fe₃O₄ NPs@rGOS modified sensor linear range 0.02-783.6 µM was observed with nanomolar LOD 0.12 nM. In addition, the modified Fe₃O₄ NPs@rGOS/GCE sensor has been applied to determination of uric acid concentration in urine and blood serum samples. Furthermore, advantages of the modified sensor are high stability, repeatability and reproducibility.

A review on ZnO nanostructured materials: energy, environmental and biological applications

Zinc oxide (ZnO) is an adaptable material that has distinctive properties, such as high-sensitivity, large specific area, non-toxicity, good compatibility and a high isoelectric point, which favours it to be considered with a few exceptions. It is the most desirable group of nanostructure as far as both structure and properties. The unique and tuneable properties of nanostructured ZnO shows excellent stability in chemically as well as thermally stable n-type semiconducting material with wide applications such as in luminescent material, supercapacitors, battery, solar cells, photocatalysis, biosensors, biomedical and biological applications in the form of bulk crystal, thin film and pellets. The nanosized materials exhibit higher dissolution rates as well as higher solubility when compared to the bulk materials. This review significantly focused on the current improvement in ZnO-based nanomaterials/composites/doped materials for the application in the field of energy storage and conversion devices and biological applications. Special deliberation has been paid on supercapacitors, Li-ion batteries, dye-sensitized solar cells, photocatalysis, biosensors, biomedical and biological applications. Finally, the benefits of ZnO-based materials for the utilizations in the field of energy and biological sciences are moreover consistently analysed.

Electrochemical Energy Storage Properties of Ni-Mn-Oxide Electrodes for Advance Asymmetric Supercapacitor Application

In this work, we report a facile one-spot synthesis process and the influence of compositional variation on the electrochemical performance of Ni-Mn-oxides (Ni:Mn = 1:1, 1:2, 1:3, and 1:4) for high-performance advanced energy storage applications. The crystalline structure and the morphology of these synthesized nanocomposites have been demonstrated using X-ray diffraction, field emission scanning electron microscopy, and transmission electron Microscopy. Among these materials, Ni-Mn-oxide with Ni:Mn = 1:3 possesses a large Brunauer?Emmett?Teller specific surface area (127 m² g^?1) with pore size 8.2 nm and exhibits the highest specific capacitance of 1215.5 F g^?1 at a scan rate 2 mV s^?1 with an excellent long-term cycling stability (?87.2% capacitance retention at 10 A g^?1 over 5000 cycles). This work also gives a comparison and explains the influence of different compositional ratios on the electrochemical properties of Ni-Mn-oxides. To demonstrate the possibility of commercial application, an asymmetric supercapacitor device has been constructed by using Ni-Mn-oxide (Ni:Mn = 1:3) as a positive electrode and activated carbon (AC) as a negative electrode. This battery-like device achieves a maximum energy density of 132.3 W h kg^?1 at a power density of 1651 W kg^?1 and excellent coulombic efficiency of 97% over 3000 cycles at 10 A g^?1.

Precise control of morphology of ultrafine LiMn2O4 nanorods as a supercapacitor electrode via a two-step hydrothermal method

Ultrafine 1D LiMn₂O₄ and its promising galvanostatic charge/discharge profiles in KOH/K₃Fe(CN)₆ electrolyte.

Morphology and phase tuning of α- and β-MnO2 nanocacti evolved at varying modes of acid count for their well-coordinated energy storage and visible-light-driven photocatalytic behaviour

α and β of MnO₂ nanocacti (comprising nanowires with 1–10 nm diameter self assembled by ultrathin sheets) as well as MnO₂ nanorods (10–40 nm diameter) are synthesized without any seed or template.

3-Acetyl-6-chloro-1-ethyl-4-phenyl-quinolin-2(1H)-one

In the title compound, C₁₉H₁₆ClNO₂, the dihedral angle between the plane of the phenyl substituent and 3-acetyl­quinoline unit is 75.44 (5)°. The crystal structure is stabilized by inter­molecular C—H⋯O hydrogen bonds

1-(3,5-Dimethyl-1H-pyrazol-1-yl)-3-phenyl-isoquinoline

The mol­ecular conformation of the title compound, C₂₀H₁₇N₃, is stabilized by an intramolecular C—H⋯N inter­action. The crystal structure shows inter­molecular C—H⋯π inter­actions. The dihedral angle between the isoquinoline unit and the phenyl ring is 11.42 (1)° whereas the isoquinoline unit and the pendent dimethyl pryrazole unit form a dihedral angle of 50.1 (4)°. Furthermore, the angle between the mean plane of the phenyl ring and the dimethyl pyrazole unit is 47.3 (6)°.

Methyl 2-methyl-2H-1,2,3-triazole-4-carboxyl-ate

In the title compound, C(5)H(7)N(3)O(2), all non-H atoms lie in a common plane, with a maximum deviation of 0.061 (2)° for the ester methyl C atom. The structure is stabilized by inter-molecular C-H⋯O hydrogen bonds.

1-(4-Chloro-3-fluorophenyl)-2-[(3-phenylisoquinolin-1-yl)sulfanyl]ethanone

In the title compound, C₂₃H₁₅ClFNOS, the isoquinoline system and the 4-chloro-3-fluoro­phenyl ring are aligned at 80.4 (1)°. The dihedral angle between the isoquinoline system and the pendant (unsubstituted) phenyl ring is 19.91 (1)°.

Methyl 1H-1,2,3-triazole-4-carboxylate

The title compound, C₄H₅N₃O₂, features an essentially planar mol­ecule (r.m.s. deviation for all non-H atoms = 0.013 Å). The crystal structure is stabilized by inter­molecular N—H⋯O hydrogen bonds and π–π stacking inter­actions (centroid–centroid distance 3.882 Å).

1,3-Dimethyl-2,6-diphenyl-piperidin-4-one

In the title moleclue, C₁₉H₂₁NO, the 4-piperidone ring adopts a chair conformation in which the two benzene rings and the methyl group attached to C atoms all have equatorial orientations. In the crystal structure, centrosymmetric dimers are formed through weak inter­molecular C—H⋯O hydrogen bonds [the dihedral angle between the aromatic rings is 58.51 (5)°].

3-(4-Methoxy-phen-yl)-1H-isochromen-1-one

The asymmetric unit of the title compound, C(16)H(12)O(3), contains two crystallographically independent mol-ecules. The isochromene ring system is planar (maximum deviation 0.024 Å) and is oriented at dihedral angles of 2.63 (3) and 0.79 (3)° with respect to the methoxy-benzene rings in the two independent mol-ecules.

Solvent-free syntheses of some quinazolin-4(3H)-ones derivatives

Solvent-free syntheses of quinazolin-4(3H)-ones were performed by reaction of anthranillic acid with different amides, such as nicotinamide, benzamide, formamide, etc., on montmorillonite K-10. Products were confirmed by FTIR, 1HNMR, and 13CNMR spectroscopic techniques. All synthesized compounds exhibited antioxidant properties and have been compared with standard antioxidant BHT.Key words: quinazolinone, montmorillonite K-10, solvent-free conditions, antioxidant properties.

Electro-oxidation of methanol on TiO2 nanotube supported platinum electrodes

TiO2 nanotubes have been synthesized using anodic alumina membrane as template. Highly dispersed platinum nanoparticles have been supported on the TiO2 nanotube. The supported system has been characterized by electron microscopy and electrochemical analysis. SEM image shows that the nanotubes are well aligned and the TEM image shows that the Pt particles are uniformly distributed over the TiO2 nanotube support. A homogeneous structure in the composite nanomaterials is indicated by XRD analysis. The electrocatalytic activity of the platinum catalyst supported on TiO2 nanotubes for methanol oxidation is found to be better than that of the standard commercial E-TEK catalyst.