Nitrogen-doped reduced graphene oxide (NrGO), manganese dioxide (MnO2), and a composite (NrGO-MnO) were synthesized via hydrothermal treatment, where the confined hydrothermal conditions facilitate controlled nucleation and anisotropic two-dimensional growth. Structural and morphological analyses confirmed the formation of poorly crystalline MnO fragments uniformly dispersed on the NrGO framework, effectively preventing graphene restacking and enhancing surface accessibility. BET surface area analysis revealed that NrGO-MnO exhibited a significantly higher specific surface area (62.56 m2 g-1) and pore volume (0.39 cm3 g-1) compared to pristine materials. Electrochemical characterization under CO2 saturated electrolytes demonstrated that the NrGO-MnO composite outperformed both NrGO and MnO2. Linear sweep voltammetry revealed a higher current density of approximately 12.0 mA cm-2 and 16.0 mA cm-2, respectively at -1.7 V vs. Ag/AgCl for both NrGO and NrGO-MnO electrodes under CO2 saturated conditions, accompanied by a more positive onset potential around -0.90 to -1.0 V vs. Ag/AgCl In contrast, MnO2 exhibited a lower current density of about 5.0 mA cm-2 with a more negative onset potential. Electrochemical impedance spectroscopy revealed lower charge-transfer resistance for NrGO and NrGO-MnO composites compared to MnO2, indicating enhanced electron and ion transport. The developed NrGO-MnO catalyst demonstrates improved in CH4 synthesis with a maximum faradaic efficiency of about 27%, emphasising its unique selectivity for deeper CO2 reduction products. These findings highlight interfacial synergy in catalyst design and offer guidance for developing scalable, high-performance CO2 electroreduction systems.

2D NrGO–MnO composite, synthesized via hydrothermal treatment exhibits superior electrochemical reduction of CO 2 .

The unique characteristics of the aqueous interfacial and micellar aggregates of surface-active ionic liquids (SAILs) endow them with excellent electrocatalytic properties, selectivity and efficiency toward electrochemical transformations. However, the low electron-tunnelling probability on account of the significant spatial separation between the electrode and the bulky SAIL-bound electroactive analytes is expected to render the SAILs with an apparent electrocatalytic performance that is significantly lower than their true potential. The availability of appropriate redox-mediators in the vicinity of SAIL-bound electroactive analytes is a possible strategy to bridge this undesired mismatch between the apparent and the expected electrocatalytic performance from the aqueous micellar solutions of SAILs. In anticipation of this presumption, the current work was designed to explore the potential utility of a well-known redox mediator, K4[Fe(CN)6], to enhance the electrocatalytic performance of aqueous micellar solutions of SAILs. The impact of K4[Fe(CN)6] over the surface activity, self-aggregation characteristics and electrocatalytic performance of 1-Dodecyl-3-methylimidazolium chloride ([DDMIM]Cl) was investigated using conductometry, voltammetry and scanning electrochemical microscopy (SECM). The carriedout investigations suggest that the ion-pairing of the negatively charged redox mediator with the imidazolium head groups at the electrode/electrolyte and micelle/water interface-localized SAIL units significantly enhances the electrocatalytic performance of aqueous micellar solutions of [DDMIM]Cl toward electro-dehalogenation of halocarbons, oxygen reduction reaction (ORR) and electrochemical sensing of nitrite ion. We demonstrate that the redox couple mediation in SAIL micellar solutions ensures electrocatalytic reduction of water-insoluble toxic halocarbons, 4-electron ORR and electrocatalytic oxidation of toxic nitrite ions over non-catalytic electrode surfaces. Importantly, the K4[Fe(CN)6] mediation in aqueous micellar solutions of [DDMIM]Cl is demonstrated to ensure selective and sensitive electrochemical sensing of nitrite ions with a sensitivity as high as 0.52 mu A nM- 1 and limit of detection as low as 0.2 nM (the best to be reported till date). The presented work, the first of its kind we believe, presents an innovative strategy to improve the electrocatalytic performance of aqueous micellar solutions of SAILs that shall have far-reaching implications over their use as green sustainable electrocatalytic solvent systems for large-scale practical applications.

The electrochemical nitrogen reduction reaction (ENRR), when coupled with the oxygen evolution reaction (OER), presents a sustainable, safe, and energy‐efficient alternative to the traditional Haber–Bosch process for ammonia synthesis. In this work, the rational design, synthesis, and electrochemical evaluation of two cobalt (II)‐based metal–organic frameworks (MOFs) incorporating 2‐methylimidazole (2‐MeIm) and benzimidazole (BIm) as organic linkers is reported. Comprehensive voltammetric and in situ spectroelectrochemical studies confirm that Co(2‐MeIm) and Co(BIm) MOFs exhibit excellent electrochemical stability and catalytic activity toward ENRR and OER. Notably, Co(BIm) MOF achieves an impressive ammonia production rate of 260 µg h⁻¹ mg⁻¹ with a Faradaic efficiency of 35.42%, significantly outperforming Co(2‐MeIm) MOF (5.0 µg h⁻¹ mg⁻¹ and 15.0%, respectively). Furthermore, Co(BIm) MOF demonstrates outstanding OER performance, with a low Tafel slope of 50.1 mV dec⁻¹ and an overpotential of just 290 mV to reach a current density of 10 mA cm⁻ 2 . To the best of the authors knowledge, these ENRR and OER metrics represent among the highest reported for MOF‐based electrocatalysts, highlighting the potential of tailored ligand environments in enhancing dual‐function electrocatalytic performance.

Iron oxides, one of the most ancient and earth-abundant materials, have long been studied for their remarkable magnetic, optical, and redox properties—attributes that have intricately linked them to the history of life on Earth. The renewed interest in sustainable materials with reduced dimensions has once again put iron oxides into intensive exploration, particularly for their catalytic, redox, and photoelectrochemical applications. However, the origin of the shape anisotropy in iron oxide nanocrystals and its functional significance in geochemical and photocatalytic processes remains largely unexplored. In this work, we investigated the role of naturally relevant organic ligands from sugar press mud (PM) in inducing shape anisotropy in iron oxide nanocrystals within the framework of non-classical crystallization theory (NCCT). Using an electro-analytical approach, we further examine the dynamic behaviour of these nanocrystals during photocatalysis. Our results reveal that the transformation from spherical to sheet- and rod-like morphologies (~24–44 nm) is consistent with NCCT, even in the presence of PM ligands as additives. However, differences in photocatalytic efficiency (rate constants, k ~ 0.014–0.038 min⁻¹) are better explained by electrochemical work function (Φ_ad^0) and electrochemically active surface area (ECSA) rather than solely by band gap (Eg) and charge carrier (e⁻/h⁺) dynamics. These findings not only provide insight into the fundamental mineralization processes in nature but also contribute to the rational design of sustainable photocatalysts.

Transition metal sulfides are promising electrode materials for supercapacitor devices, but their practical applications are limited due to critical challenges, such as poor redox active sites, low specific surface area, particle agglomeration during charging-discharging cycles, and low conductivity. To address these limitations, an innovative strategy of sulfur vacancy (Svac)-enrichment that boosts the proton storage sites in high surface area, mesoporous cobalt sulfide-carbon nanofiber (Co3S4/CNF) composites is presented. Controlled calcination of electrospun PVP-CoS fibers induces the phase transformation of hexagonal CoS to spinel Co3S4, comprising abundant Svac to serve as proton storage sites, as evidenced from the potential of zero charge (Epzc) analysis. It augments ion transport channels and redox active sites for enhanced surface adsorption, leading to an excellent performance for supercapacitive charge-storage devices delivering a high specific capacitance of 1092 F g-1 at 10 A g-1 and excellent cycling stability. Asymmetric supercapacitor device utilizing Co3S4/CNF achieves an energy density of 104 Wh kg-1 at a power density of 1053 W kg-1, retaining 95.7% of its performance over 10,000 cycles.

A simple strategy for the conjugation of copper‐1,4‐benzene dicarboxylic (CuBDC) MOF with zinc oxide (ZnO) matrix for the fabrication of CuBDC/ZnO is presented—a tandem electrocatalyst with excellent electrochemical stability and electrocatalytic performance toward selective electroreduction of CO 2 (ERCO 2 ). The tandem action and easy mass transport in mesostructured CuBDC/ZnO are demonstrated to facilitate efficient, facile, and selective production of methane, ethylene, and ethane from ERCO 2 . Conjugation with ZnO results in a sevenfold increase in specific activity of CuBDC MOF for ethylene evolution, along with a twofold decrease in its H 2 evolution activity. The exceptional electronic, mass transfer, and positive synergism among the different components in CuBDC/ZnO composite are demonstrated to endow it with excellent electrocatalytic performance (overall Faradaic efficiency (FE) of 77.5% for hydrocarbons, with FEC 1 = 50.9% and FEC 2 = 26.6%), lower Tafel slopes, enhanced exchange current density, appreciably low resistance to charge transfer, and electrochemical stability towards ERCO 2 (>14 h). The presented investigations suggest that the enhanced electronic conductivity, the open metal centers, the mixed valence states (Cu 1+ and Cu 2+ ), and tandem catalytic sites (Cu and Zn) for asymmetric *CO adsorption, hydrogenation, and CO bond dissociation endow the CuBDC/ZnO with excellent activity toward ERCO 2 for production of hydrocarbons.

Altering the edge sites of 2D MXenes for electrochemical dinitrogen reduction reaction (ENRR) is widely reported, whereas activation of its relatively inert basal planes is neglected. Herein, the activation and the optimization of the basal planes of Ti2CTx (T-x = *F, *O, and *OH) MXenes toward enhanced ENRR to ammonia is reported. The balanced surface functionalization in Ti2CTx regulates the ENRR kinetics by regulating the potential of zero charge (E-PZC) and the electrochemical work function (phi(o)(ad) ). Specifically, the altered E-PZC and phi(o)(ad) enhances electric field localization and potential screening at the Ti2CTx/water interface stabilizing the transition state and reducing ENRR activation energy (Delta E). Hydrodynamic voltammetry, in situ Raman, and post-ENRR X-ray spectroscopy suggest faster ENRR kinetics, via an associative distal pathway, with *OH and *F terminated Ti3+ as the dominant active sites over Ti2CTx surface. Ti2CTx achieves an ammonia yield of 35.2 mu gmg(cat.)(-1)hr(-1) at Faradaic efficiency of 5.9% in 0.05 m H2SO4, which further improves to 49% in 0.5 m NaBF4. The strategy concurrently modulates the ENRR interface via, proton-repelling functional groups (*F) on the electrode surface and weak proton donor electrolytes (NaBF4). This suppresses HER kinetics, minimizes competition for active sites, and promotes selective nitrogen activation, thereby boosting ENRR efficiency.

The operational, sustainability, safety, energy, and power advantages of direct formic acid fuel cells (DFAFCs) have established them as promising direct liquid fuel cell (DLFC) setups suitable for powering portable electronic devices and electric vehicles. However, the unavailability of cost-effective, stable, and efficient anode materials continues to hamper the large-scale commercialization of DFAFCs. Herein, we report a simple, easily scalable, one-pot hydrothermal strategy for the synthesis of nanoscale palladium phosphide (PdP) loaded three-dimensional nitrogen-doped graphene (3D-NrGO/PdP) composites as a potential anode electrocatalyst for formic acid electro-oxidation (FAEO). The stability and electrocatalytic activity of 3D-NrGO/PdP are shown to be strongly composition sensitive, with 3D-NrGO/PdP(2:1) (Pd:P ratio of 2:1) composite exhibiting the highest activity, stability, and tolerance to higher concentrations of formic acid under DFAFCs relevant conditions. The exceptionally high electrochemically active surface area, high electronic conductivity, and positive synergism among the components of optimally composed 3D-NrGO/PdP(2:1) composite are demonstrated to endow it with excellent electrochemical stability, low resistance to charge transfer, and hence high electrocatalytic performance toward FAEO. The excellent stability and electrocatalytic performance (mass activity) as observed for the 3D-NrGO/PdP(2:1) composite in the present work is far better than those reported till date for FAEO.

Aqueous micellar solutions of imidazolium-based surface-active ionic liquids (SAILs) are considered as promising green-electrocatalytic solvent systems for a variety of electrochemical transformations especially the electroreduction of CO2 (ERCO2) and electro-carboxylation with CO2 (ECCO2). However, the limited solubility of CO2 in these solvent systems continues to hinder their use for bulk-scale ERCO2 and ECCO2 reactions. We theorize that the formation of mixed aggregates of cationic and anionic SAILs is the easiest and most reliable approach to tune the size, composition and zeta potential and, hence, the solubility and electrocatalytic performance of the SAIL micellar aggregates. In anticipation of this presumption, the current work was designed to explore the composition dependence of the structural and physicochemical aspects of self-assembled aggregates in micellar mixtures of imidazolium-based SAILs, viz., 1-butyl-3-methyl-imidazolium dodecyl sulfate ([BMIM]DS) and 1dodecyl-3-methylimidazolium chloride ([DDMIM]Cl). The conductometric, UV-Vis spectroscopic, rheological, dynamic light scattering (DLS) and cyclic voltammetric (CV) investigations suggest that besides variation in the structural and physicochemical aspects of mixed micellar aggregates, composition variation of the [DDMIM]Cl plus [BMIM]DS SAIL mixtures results in a spontaneous micelle to vesicle transition. Besides their various physicochemical characteristics, the potential utility of the variedly composed [DDMIM]Cl plus [BMIM]DS SAIL micellar mixtures as electrolyte systems for electrochemical investigations was also investigated. The investigations carried out in this regard suggest that the SAIL mixtures exhibit composition-dependent solubilization, transport and electrocatalytic performance. The mass transport ability of the mixed aggregates and the concentration of the redox probe solubilized within them, investigated via electrochemical studies using a gold ultramicroelectrode (UME), were found to be the highest for the mixture with equal mole fractions of [BMIM]DS and [DDMIM]Cl (chi[DDMIM]Cl = 0.5). The differently composed SAIL micelle mixtures were also tested for their potential use as electrolytes for ERCO2. The findings indicate that the ability of these mixed micellar solutions to solubilize and transport non-polar redox-active probes determines their solubilization potential and electrocatalytic performance towards ERCO2. The study suggests that [BMIM]DS plus [DDMIM]Cl SAIL mixture with chi[DDMIM]Cl = 0.5 exhibits the highest electrocatalytic performance towards ERCO2. Overall, this study provides a comprehensive understanding of the physicochemical properties of aqueous micellar mixtures of imidazoliumbased SAILs and highlights the composition-specific variations in their properties. These findings may have important implications for the development of new materials with enhanced solubilization potential and electrocatalytic performance toward ERCO2.

In the present work, bismuth tungstate nanoflowers were fabricated via hydrolysis method using curcuma longa extract (Bi2WO6-G) and without extract (Bi2WO6-C). The analytes were characterized using X-ray diffraction, BET, Transmission electron microscopy (TEM), Field emission scanning electron microscopy (FESEM), UV–vis. DRS Spectroscopy. The as-fabricated nanostructures have been tested for photocatalytic degradation of methyl orange (MO) dye and a recalcitrant pollutant ‘phenol’. The present study showcased the effect of curcuma longa extract, an efficient adsorbent “curcuma longa” which is a rhizome of yellow turmeric on Bismuth tungstate photocatalyst. The improved photocatalytic performance of Bi2WO6/curcuma longa (Bi2WO6-G) heterostructure was mainly ascribed to the unique hierarchical structure, harvesting extended absorption of visible light, higher surface area and inhibiting recombination of photogenerated charges. The current findings may provide new insights to the effect of green extracts for fabrication of nanomaterials for enhanced photocatalytic efficiency.

Earth‐abundant and low‐cost materials are desirable for large‐scale solar hydrogen generation. In this outlook, cuprous oxide (Cu 2 O) has significant potential for photoelectrochemical (PEC) water splitting. Thin film growth patterns and high substrate conductivity are a cooperative approach for durable PEC response of Cu 2 O. Herein, we report the improved PEC performance and stability of Cu 2 O thin films electrodeposited on Ti‐coated FTO substrates, with further enhancement achieved through an alternative growth pattern and a corrosion‐protective MXene layer. The alternative growth pattern suppresses Cu 2 O photocorrosion by introducing spatially segregated nanoparticle domains. Upon integration with MXene, the Ti/Cu 2 O/MXene photocathode architecture achieves a significantly enhanced photocurrent (−2.4 mA cm −2 ) at −0.9 V versus Ag/AgCl/Cl − and prolonged stability (6.5 h) owing to improved charge separation and interfacial conductivity. Electrochemical impedance spectroscopy (EIS) analyses confirm the favorable band bending, reduced charge transfer resistance, and faster interfacial kinetics for Ti/Cu 2 O/MXene. Together, these modifications address the longstanding challenges of photo‐corrosion and poor stability in Cu 2 O‐based systems, offering a scalable and cost‐effective route for efficient solar‐driven hydrogen production.

A simple strategy for the conjugation of copper-1,4-benzene dicarboxylic (CuBDC) MOF with zinc oxide (ZnO) matrix for the fabrication of CuBDC/ZnO is presented-a tandem electrocatalyst with excellent electrochemical stability and electrocatalytic performance toward selective electroreduction of CO2 (ERCO2). The tandem action and easy mass transport in mesostructured CuBDC/ZnO are demonstrated to facilitate efficient, facile, and selective production of methane, ethylene, and ethane from ERCO2. Conjugation with ZnO results in a sevenfold increase in specific activity of CuBDC MOF for ethylene evolution, along with a twofold decrease in its H-2 evolution activity. The exceptional electronic, mass transfer, and positive synergism among the different components in CuBDC/ZnO composite are demonstrated to endow it with excellent electrocatalytic performance (overall Faradaic efficiency (FE) of 77.5% for hydrocarbons, with FEC1 = 50.9% and FEC2 = 26.6%), lower Tafel slopes, enhanced exchange current density, appreciably low resistance to charge transfer, and electrochemical stability towards ERCO2 (>14 h). The presented investigations suggest that the enhanced electronic conductivity, the open metal centers, the mixed valence states (Cu1+ and Cu2+), and tandem catalytic sites (Cu and Zn) for asymmetric *CO adsorption, hydrogenation, and C-O bond dissociation endow the CuBDC/ZnO with excellent activity toward ERCO2 for production of hydrocarbons.

The development of noble-metal-free, efficient, cost-effective, and stable pH-universal electrocatalysts for the oxygen reduction reaction (ORR) is essential for enabling the widespread adoption of ORR-based fuel cells and batteries in practical applications. Herein, we report the design and fabrication of a MnO2-supported Cu-Metal Organic Framework (Cu-MOF) as a cost-effective, efficient, stable, and above all a pH-universal ORR electrocatalyst. Specifically, a simple and scalable synthetic approach for the templated synthesis of CuBDC MOF networks over presynthesized MnO2 nanosheets for the fabrication of CuBDC/MnO2 composite is presented. The so-crafted CuBDC/MnO2 composite well-characterized for its chemical, morphological, and electrochemical characteristics is demonstrated to be a pH-universal ORR electrocatalyst exhibiting excellent stability and electrocatalytic performance that is at par with that reported recently for the state-of-the-art noble metal-based ORR catalysts. The CuBDC/MnO2 composite exhibits a mass transfer limited four-electron pathway ORR at a potential of just 0.74 V versus the reversible hydrogen electrode (RHE), with an overpotential (eta ORR) of 0.45 V under alkaline conditions. The as-fabricated electrocatalyst delivers a specific activity (current per unit area) of -4.58 +/- 0.01 mA/cm(2) and the mass activity (current per unit mass) of 8641.50 +/- 0.01 mA/mgcat. Our detailed physicochemical and electrochemical investigations clearly establish that the unique synergism among the metal-oxide and MOF components in the CuBDC/MnO2 composite endows it with unique features that result in the abundant availability and redox accessibility of Cu-redox sites and easy mass transportation of oxygen across an electronically and ionically good conducting [CuBDC/MnO2]/electrolyte interface. The work presented herein signifies a significant advancement toward the development of cost-effective and sustainable ORR electrocatalysts, potentially paving the way for their widespread adoption in clean and affordable electrochemical technologies for storage and conversion of energy.

Electrochemical sensing is a promising approach for the selective and highly sensitive sensing of oxidized and reduced states of Nicotinamide adenine dinucleotide (NAD+/NADH). However, the limited selectivity, large overpotential requirements and the electrode fouling concerns associated with the till date reported NADH-specific electrodes continue to impede their potential utility for the design and development of fast, inexpensive and highly reliable point of care devices for electrochemical sensing of NAD+ and NADH. Herein we present a simple covalent functionalization approach for the design and development of Cytochrome-c (Cyt-c) functionalized Cu-BDC MOF (Cyt-c/Cu-BDC) as a novel Cu-Fe based bio-mimic for electrochemical sensing of NADH. Our detailed physical, chemical and electrochemical investigations carried out over the so designed Cyt-c/Cu-BDC composite establish it as an electronically conducting, electrochemically stable redox-active electrode material with an exceptional activity towards the selective and ultrasensitive electrochemical sensing of NADH. We demonstrate the practical utility of Cyt-c/Cu-BDC composite for accurate and sensitive electrochemical sensing of NADH in the pico-molar concentration range. The herein demonstrated extremely low LOD (10.4 pM), high sensitivity (12.02 ± 0.119 μA nM−1 cm−2), good anti-interference ability and prolonged stability of the Cyt-c/Cu-BDC composite is far superior than the till date reported electrochemical sensors for NADH. These features qualify Cyt-c/Cu-BDC composite as a promising electrode material for the design of point-of-care NADH sensing devices for clinical diagnostics.

Herein we report construction of a dual heterojunction-based system consisting of simultaneous type-III and pn junction between Q/BiOBr/BiOI. The concentration of bismuth oxyhalides were varied from 0.2 to 0.8 viz. BiOBryI1-y-Q (y = 0.2, 0.4, 0.5,0.6, 0.8). The as-fabricated photocatalysts were used for photochemical-disintegration of Methyl Orange (MO) and Phenol (Ph) and the best activity was found for the BiOBr0.8I0.2-Q [MO (86.01 %, 90 min); Ph (69.9 %, 180 min)] heterostructures. The fabricated heterostructures were endowed with oxygen-vacancies within 15-minutes of fabrication time. During fabrication, Quercetin was able to grow on p-type-BiOBr and n-type-BiOI due to the presence of positively charged Bi(III)ions and negatively charged Oxygen ions of Q, respectively. The formation of the pn-junction was confirmed by the Mott-Schottky plot. Significantly, the Q was not only able to reduce BiOBr/ BiOI but was also able to create surface-oxygen-vacancies, which effectually improved visible-light absorption as well as charge separation efficiency. The photocatalytic efficiency has significantly convalesced from pristine BiOBr and BiOI. First-Principles Density Functional Theory (DFT) based calculations were performed on pristine BiOBr, BiOI as well as BiOBryI1-y-Q with and without oxygen vacancies, and an insightful understanding of the heterojunction formation, effect of oxygen vacancies, physical mechanism, and superior photocatalytic performance of BiOBr0.8I0.2-Q heterostructure over other samples have been provided.

Surface termination engineering in two-dimensional (2D) MXenes offers a transformative approach to tune electrocatalytic performance, particularly for the hydrogen evolution reaction (HER). While oxygen- and fluorine-terminated MXenes have dominated catalytic studies, the overlooked potential of other halogen terminations and non-metal surface doping offers a crucial frontier for designing next-generation electrocatalysts. Here, we combine first-principles simulation-guided experiments and data-driven structure-electronic property-reactivity correlations to systematically boost the catalytic performance of halogen-terminated Ti3C2 MXenes for the HER. Ti3C2Cl2 demonstrates optimal hydrogen adsorption energetics, as predicted computationally and confirmed experimentally through its superior catalytic current density (25.8 mA cm(-2) vs. 7.8 mA cm(-2) at -0.9 V vs. RHE) to F-terminated analogs. We explore non-metal substitution on Cl-terminated MXenes, revealing that ternary Ti3C2(Cl, O, T ')(2) (T ' = N, S, Se) surfaces achieve a near-thermoneutral Gibbs free energy change (Delta G(H) = -0.05 to -0.1 eV), with activity following T ' = N > S > Se. These computational predictions are further validated experimentally by synthesizing N- and S-doped Ti3C2(Cl, O, T ')(2) systems. The N-functionalized variant exhibits the most dramatically enhanced hydrogen evolution, in perfect agreement with in silico findings. The non-parametric structure-property-reactivity correlation mapping identifies that the catalytically active site-Ti bond length and localized charge at the active site are the key descriptors for designing efficient MXene-based catalysts for the HER. These findings emphasize the potential of termination engineering to precisely control the surface chemistry of MXenes, unlocking a new paradigm of high-efficiency, noble-metal-free electrocatalysts for sustainable hydrogen production.

A simple and scalable template-assisted strategy for synthesis of graphene oxide (GO)-supported HKUST-1 MOF composite (HKUST-1/GO) as an efficient, recyclable, heterogeneous catalyst for azide-alkyne "Click" reaction is presented. Field emission scanning electron microscopy, powder X-ray diffraction, and X-ray photoelectron spectroscopy analysis suggest that the use of GO as a synthetic template promotes the growth of Cu(I)-rich hierarchical MOF structures with elongated, regular cuboidal shapes. Catalytic investigations over room temperature reaction of alpha-naphthyl azide with phenylacetylene-as a model azide-alkyne cycloaddition (AAC) click reaction, reveal the outstanding catalytic performance and recyclability of the HKUST-1/GO composite. Besides the model AAC reaction, the HKUST-1/GO composite is demonstrated to exhibit exceptionally high catalytic performance toward cycloaddition reaction of various sterically challenging and biologically relevant azide-alkyne systems. Our investigations demonstrate that the templated growth of Cu-MOF over GO imparts it with mixed valence active Cu catalytic sites, improved electronic conductivity, and a unique morphology that enables rapid analyte transport. These GO-induced features confer excellent stability, recyclability, and activity to the HKUST-1/GO composite. The exceptional catalytic performance, ease of recovery, and excellent recyclability as demonstrated for HKUST-1/GO composite in the present work position it as a cost-effective, efficient, and reusable heterogeneous catalyst for AAC click reactions.

Supercapacitors are receiving considerable attention as energy storage devices for portable and wearable electronics. Their large-scale commercialization hinges on the design and development of cost-effective, stable electrode materials with high surface area and exceptional conductivity. This study reports the design and synthesis of an organic linker-based three-dimensional reduced graphene oxide (3D-rGO) as a potential electrode material for high-energy supercapacitors. Characterization shows that the crafted 3D-rGO is a robust microporous 3D network with a specific surface area as high as 930 m2/g. Electrochemical tests reveal that 3D-rGO possesses outstanding charge storage capabilities, achieving a specific capacitance of approximately 470 F/g at 10 A/g and an energy density of around 65.3 Wh/kg at a power density of 5000 W/kg. Additionally, it exhibits exceptional cyclic stability, retaining 120% of its capacitance after 5000 cycles. A prototype flexible symmetric device utilizing 3D-rGO as the electrode material and PVA-H2SO4 as the gel electrolyte exhibits a specific capacitance of 44 F/g, an energy density of 12.05 Wh/kg (at 2 A/g), and an impressive 98.4% capacitance retention after 10,000 cycles at 5 A/g. These findings underscore the potential of 3D-rGO as a cost-effective and highly efficient electrode material for high-energy charge storage applications.