Electrochemical Analysis Research Articles

Targeted Electrocatalysis for High‐Performance Lithium–Sulfur Batteries

The intricate sulfur redox chemistry involves multiple electron transfers and complicated phase changes. Catalysts have been previously explored to overcome the kinetic barrier in lithium–sulfur batteries (LSBs). This work contributes to closing the knowledge gap and examines electrocatalysis for enhancing LSB kinetics. With a strong chemical affinity for polysulfides, the electrocatalyst enables efficient adsorption and accelerated electron transfer reactions. Resulting cells with catalyzed cathodes exhibit improved rate capability and excellent stability over 500 cycles with 91.9% capacity retention at C/3. In addition, cells were shown to perform at high rates up to 2C and at high sulfur loadings up to 6 mg cm−2. Various electrochemical, spectroscopic, and microscopic analyses provide insights into the mechanism for retaining high activity, coulombic efficiency, and capacity. This work delves into crucial processes identifying pivotal reaction steps during the cycling process at commercially relevant areal capacities and rates.

Electrochemically Mediated Amine Regeneration-CO2 mineralization: Mechanism and influencing factors

High energy consumption due to the thermal amine regeneration is one of the key issues hindering its large-scale applications. Amine regeneration by electrochemical is a promising technology, which can reduce energy consumption by up to 40% for amine regeneration. However, there are still some problems during the utilization and storage of captured CO2. In response to the current problems, this study introduces an innovative approach termed Electrochemically Mediated Amine Regeneration-CO2 Mineralization (EMAR-M), which innovatively synergizes in-situ regeneration of CO2-rich amine with CO2 mineralization through an electrochemical method. Electrochemical analysis was utilized to examine the anodic and cathodic reactions of EMAR-M, incorporating findings from XRD and CO32- concentration analysis, the reaction pathways and mechanisms of EMAR-M were elucidated. The results suggested that the reaction of EMAR-M followed the order of electrochemically mediated metal ion release, in-situ metal-amine coordination desorption, directed migration of CO32- and mineralization of CO2. The analysis of influence factors identified that the types of amines, electrolytes and metal electrodes significantly influence the EMAR-M. Compared with DEA and TEA, MEA has good CO2 absorption and electrochemical regeneration properties, which is advantageous for EMAR-M. Although electrolytes such as NaCl, Na2SO4, and KCl did not significantly affect the CO2 absorption of the amine absorbent, NaCl can promote the redox reaction at the metal electrode, which also favors EMAR-M. Cu electrodes also favor EMAR-M due to its swift cathodic/anodic reaction rates. Compared to other technologies, EMAR-M can reduce energy consumption by up to 58% for CCUS. The utilization of calcium-based solid wastes such as calcium carbide slag for synergistic CO2 mineralization can further reduce the operating costs of the technology as well as enable green applications of solid wastes.

Signal amplification platform based on 2D MOF-on-MOF architectures-derived Co-decorated carbon@nitrogen-doped porous carbon for enhanced electrochemical acetaminophen sensing

Two-dimensional (2D) carbon-carbon hybrids derived from metal-organic frameworks (MOFs) are regarded as an intriguing type of electrode material in electrochemical sensing. In this work, a Co-decorated carbon@nitrogen-doped porous carbon heterostructure (Co/C@NC) was prepared via the simple calcination of 2D ZIF-L(Co)@ZIF-8. In this MOF-on-MOF precursor, the outer ZIF-8 layer not only prevents the collapse of ZIF-L(Co) during calcination but also endows the outer carbon an extended surface area and porous structure for more accessible active sites and a fast mass transfer process. Meanwhile, the formed CoNPs could facilitate the generation of graphitic carbon layers, which enhances electrocatalytic activity and boosted conductivity. Owing to these merits, the Co/C@NC-based sensor displays high electrochemical activity for acetaminophen (APAP) detection with a wide linear range (4 × 10-7 - 2 × 10-4 M) and a lower detection limit (8.2 × 10-8 M). The constructed sensor has been utilized for the analysis of APAP in real samples, yielding acceptable recovery between 96.6% and 104.0%. This work presents an efficient and convenient method for designing MOF-on-MOF-derived 2D carbon-carbon hybrids, which hold a promising prospect in electrochemical analysis.

Amorphous Cu/Fe nanoparticles with tandem intracellular and extracellular electron capacity for enhancing denitrification performance and recovery of co-contaminant suppressed denitrification

In this study, a functionally stable insoluble Cu/Fe nanoparticles (Cu/Fe NPs) were synthesized and applied denitrification with different contaminants. The results showed that 50 mg/L Cu/Fe NPs increased NO3–-N reduction rate up to 14.3 mg/(L·h) about 3 folds compared with the control system (4.7 mg/(L·h)), and Cu/Fe NPs exhibited excellent restorative effects on NO3–-N reduction under the stress of Cd2+, Nitrovin and Methyl Orange. Meanwhile, electrochemical analyses, enzyme activities, and related genes abundance together showed that pilus, cytochrome c and flavin mononucleotide were electron carriers to tandem extracellular and intracellular, increasing electron flux acting on NO3–-N in the respiratory chain. Metagenomic sequencing showed that microbial metabolic activity, electroactive bacteria (EAB) abundance with bi-directional electron transfer and Cu/Fe-compatible bacterial abundance were increased. Furthermore, denitrification performance was maintained by establishing C-EAB-Cu/Fe NPs cycling network. This study provided insights and applications for expanding the use of insoluble mediators in denitrification systems.

Engineering multiple nano-twinned high entropy alloy electrocatalysts toward efficient water electrolysis

Inducing defects in high entropy alloys (HEAs) has been recognized as a promising approach for tuning surface energetics and catalytic activities. However, the comprehensive understanding and facile synthetic methods for defect-rich HEAs remain challenging. Herein, we present an interstitial-atom engineering strategy that involves interstitial atom doping to synthesize B-doped FeCoNiCuMoB HEA films containing abundant multiple nano-twin boundaries. The resulting fivefold-twinned FeCoNiCuMoB catalyst exhibits exceptional performance in alkaline hydrogen evolution reaction (HER, 26mV at -10 mA cm-2) and oxygen evolution reaction (OER, 201mV at 10mAcm-2). Notably, the two-electrode electrolyzer composed of the FeCoNiCuMoB film electrodes achieved the 10mAcm-2 at an ultralow cell voltage (1.48V) for water electrolysis, simultaneously maintaining long-term durability. Through in-situ Raman spectroscopy, X-ray absorption spectroscopy (XAS), electrochemical analyses, and density functional theory (DFT) calculations, we elucidate that the unique twin boundaries play a crucial role in tailoring surficial electronic structures. Moreover, election-rich B atoms display optimized atomic configurations, synergistically contributing to a thermodynamically favourable HER/OER pathway. This work provides a platform via interstitial-atom engineering for designing exceptional HEA catalysts, integrating planar defects and electronic effects, to enhance the efficiencies in water electrolysis applications.

Fabrication and electrochemical investigations of nanostructured PtSn-NiTiO3 heterostructured electrocatalysts for direct methanol oxidation

The methanol oxidation reaction of a PtSn nanoparticle decorated NiTiO3 nanostructured material system is reported in this paper. NiTiO3 and PtSn nanoparticles were formed in rhombohedral and cubic phases, respectively. The crystallite size of the PtSn nanoparticles was calculated to be 2.8 nm from the XRD peak parameters and TEM studies. The surface plasmon resonance peak observed at 308 nm indicates the decoration of PtSn-NiTiO3 nanostructures with Pt nanoparticles on the surface. The chemical oxidation states investigated by XPS showed a metallic state of Pt and Sn with a small amount of surface oxidization. From the electrochemical analysis, the Pt0.5Sn0.5-NiTiO3 nanostructures showed superior electrocatalytic performance with higher electrochemical surface area (252 m2/g), high current density (196 mA/cm2), lower Tafel value (161.31 mV/dec) and small charge transfer resistance. This work demonstrated that the Pt0.5Sn0.5 −NiTiO3 nanostructure would be a suitable electrocatalyst for oxidation for methanol in DMFC.

High-specific capacitance, binder-free composite electrodes prepared from carbon dots embedded in copper oxide-nickel oxide nanowires grown on nickel foam for asymmetric supercapacitors

The binder-free electrodes based on CuO-NiO and sodium polyacrylate-derived carbon dots (CDs) composites were simply prepared on nickel foam in two steps: hydrothermal synthesis and thermal annealing. A specific capacitance as high as 635F g−1 (at 5 mV s−1) was achieved with the electrodes containing CDs embedded in the CuO-NiO nanowires, compared to only 468F g−1 for the CuO-NiO nanowire electrode without CDs, representing a 136 % improvement. To provide mechanistic insights on the supercapacitor performance, electrochemical analysis was carried out, and it was found that synergistic effects from CuO-NiO and CDs gave an optimum contribution of surface/diffusion processes of charge transfer. Asymmetric supercapacitor was also fabricated using activated carbon as a negative electrode and CDs/CuO-NiO@Ni-foam as a positive electrode, giving a 1.5 V, highest energy density of 20.3 Wh kg−1 at power density of 151.1 W kg−1. Due to simplicity and extraordinary performance, the binder-free CDs/CuO-NiO composite electrodes are potential candidates for the mainstream supercapacitors, and the strategy detailed in this work also provides an innovative, practical way for an electrode design for energy storage devices.

Z-scheme heterojunction photocatalyst of LaFeO3@CoS for tetracycline hydrochloride degradation by persulfate activation using visible light

An efficient and stable LaFeO3@CoS Z-scheme heterojunction photocatalyst was prepared through the hydrothermal method (HT). Photocatalytic activity of the LaFeO3@CoS was assessed by activating persulfate under visible light for the degradation of tetracycline (0.1 g/L). Under the condition of 0.06 g/L of KHSO5 (Peroxymonosulfate, PMS), the degradation efficiency of 88.7 % was achieved in 40 min using the 0.02 g/L of developed photocatalyst. The degradation kinetic constants of LaFeO3@CoS were 2.79 and 2.23 times higher than those of LaFeO3 and CoS, respectively. Furthermore, the catalyst exhibited excellent stability over five consecutive degradation cycles. Possible degradation mechanisms and the electron transfer mechanism of the heterojunction formed by the LaFeO3@CoS were investigated by quenching experiments, nitrogen N₂ purging experiments, electron spin resonance (ESR) measurements and corresponding electrochemical analyses. In the LaFeO3@CoS/Vis/PMS system, the Z-scheme charge transfer pathway not only accelerated charge transport efficiency but also effectively spatially separated electrons and holes, enhancing the photocatalytic performance of the photocatalyst. Additionally, the generation of reactive species such as 1O2, O2•−, and SO4• − significantly contributed to the improved degradation efficiency of the present catalyst during the degradation process.

Electrocatalytic degradation of naphthenic acids using reduced graphene oxide modified nickel foam cathode: Role of surface structure and superoxide radical

In this work, the reduced graphene oxide (RGO) modified nickel foam (Ni-foam) was prepared via the hydrothermal reduction self-assembly method and was applied as the cathode for the effective electrocatalytic (EC) degradation of recalcitrant naphthenic acids (NAs) that are abundantly present in the petroleum industrial wastewater. The Ni@RGO cathode has greatly enhanced the production of H2O2 in the system to boost the degradation of 1-adamantanecarboxylic acid (ACA) that was a model NA compound. Results showed that the EC/Fe(III)/Ni@RGO system achieved complete ACA degradation within 15 min due to its elevated H2O2 generation and Fe(III)/Fe(II) circulation, compared to EC/Fe(III)/Ni-foam and EC/Fe(III)/Graphite systems. Interestingly, abundant ·O2– radicals, which were produced in EC/Fe(III)/Ni@RGO system as a key intermediate for 2e- oxygen reduction reaction (ORR), could effectively accelerate the circulation of Fe(III)/Fe(II) to activate H2O2 to generate ·OH for ACA degradation. Results of material characterization, electrochemical analysis and density functional theory (DFT) calculations showed that Ni@RGO cathode has obtained elevated electron transfer efficiency compared to that of Ni-foam cathode. Surface structure of RGO, such as carbon edge and vacancy with specific configuration, residual –COOH oxygenation groups on RGO surface are main catalytic sites to enhance the capacity of 2e- ORR and electron capture processes in the system. This study provides new insights regarding the synthesis process of catalytic electrodes, the influence of carbon-based material structure on catalytic activity, and the critical role of free radicals in the electro-Fenton system with Ni@RGO cathode

Novel Mo: CoFe2O4 nanoparticles combustion synthesis for opto-magneto-electrochemical applications: A systematic analysis

In current work, various concentrations (0.0 wt%, 0.10 wt%, 0.25 wt%, 0.50 %,0.75 wt%, and 1 wt%) of Molybdenum (Mo) - doped cobalt ferrite (CFO) nanoparticles (Mo:CFO NPs) were synthesized using the flash combustion approach. The structural analysis of the prepared Mo:CFO was examined by the XRD patterns, and the obtained crystallite size 48.64, 46.72, 22.81, 21.05, 18.03, and 19.31 nm for 0.0 wt%, 0.10 wt%, 0.25 wt%, 0.50 wt%, 0.75 wt%, and 1 wt% Mo:CFO NPs, respectively. The presence of stoichiometry and homogeneity of the prepared Mo:CFO NPs was confirmed by the EDX analysis. The five phonon modes of the prepared Mo:CFO NPs were recorded by FT-Raman spectra, and the phonon modes were observed around 220, 312, 479, 624, and 685 cm−1 that corresponded o T2g(2), Eg, T2g(1), A1g(2), and A1g(1) symmetries, respectively. The grain sizes of the pure CFO and Mo:CFO NPs were evaluated using the images of scanning electron microscopy (SEM) and obtained in the range of 39–61 nm, respectively. The presence of valence states Co (2p), Fe (2p), O (1 s), and Mo (3d) in the prepared 1 wt% Mo:CFO NPs were examined XPS spectra. The particle sizes ~26.4 nm and ~ 16.7 nm were obtained for pure CFO and 1 wt% Mo:CFO NPs using lognormal function fitting. The emission peaks at 445 ± 3, 521 ± 3, and 620 ± 2 nm in the PL spectra were observed by PL spectroscopy. The decrease in saturation magnetization Ms. (70.80–66.54 emu/g) and reduced remanent magnetization Mr. (24.22–18.64 emu/g) of prepared Mo: CFO NPs was observed in the MH analysis by SQUID analysis. The electrochemical study of Mo: CFO NPs (0.0 %, 0.25 %, 0.50 %, and 1.0 %) was done in a three-electrode assembly cell. The capacitance of values 650.0 Fg−1, 800.0 Fg-1, and 810.0 Fg−1 for pure CFO, 0.25 % Mo: CFO, and 0.50 % Mo: CFO were recorded in electrochemical analysis. The highest capacitance of 840.0 Fg−1 was observed for the electrode with 1.0 % Mo: CFO NPs. It was analyzed that the increase in CFO electrodes enhances their performance, and therefore, it can be utilized for multifunctional devices.

Phenyl-C61-butyric acid methyl ester (PCBM) Nanoparticle Mediated Boasting of Photoelectrochemical and Photocatalytic Properties of Bismuth Vanadate/lead sulphide (BiVO4/PbS) Composite Thin-Film

This work delineates the fabrication and characterization of BiVO4/PbS and BiVO4/PCBM/PbS-based composite heterostructure for visible-light-driven applications, such as pollution remediation, photoelectrochemistry (PEC), and applied bias to photoelectrochemical hydrogen generation efficiency (ABPE). The heterostructured composite was synthesized by a combination of Spin coating (for bismuth vanadate - BiVO4 thin film fabrication and PCBM deposition), and Successive Ionic Layer Absorption and Reaction -SILAR (for lead sulphide - PbS deposition) method and characterized using UV-visible Spectroscopy, time-resolved photoluminescence spectroscopy (TRPL), field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and photoelectrochemistry (PEC) analysis (PEC). The key benefit of incorporation of PCBM nanoparticles in BiVO4/PCBM/PbS was realized through 1) ∼ 70% improvement in the photocurrent density during electrochemistry analysis, 2) ∼ 2.3 times enhancement in ABPE, and 3) ∼ 43% enhancements in ‘rate constant’ towards photocatalytic (methylene blue) degradation compared to BiVO4/PbS. The work shows the benefits of the PCBM-conductive carbon-based electron transport layer as a bridge between two inorganic semiconductors (BiVO4 and PbS) towards enhancing fast electron separation and transport at the interface during visible light irradiation.

Origin of giant dielectric constant in Ta+Gd co-doped TiO2 single crystals by optical traveling floating zone method

The co-doped TiO2 polycrystalline ceramics have dramatic dielectric behavior (>104), but its source is still not completely clarified. Compared to ceramic materials, single crystals can maintain most of the original properties of the material and eliminate the grain boundary and pore interferences, thus facilitating the exploration of the source of the dielectric properties. Here, we chose Gd3+ with a moderate ionic radius as the acceptor ion and Ta5+ as the donor, preparing (Gd0.5Ta0.5)0.01Ti0.99O2 single crystals by the optical traveling floating zone method to investigate giant dielectric properties. It was found that a dielectric constant (ε′ ∼1.5 × 104), and a dielectric loss (tanδ ∼ 0.07) were achieved simultaneously in (Gd0.5Ta0.5)0.01Ti0.99O2 single crystals at 105Hz. Electrochemical impedance spectroscopy and XPS analyses indicate that the high dielectric properties are mainly attributed to electrons pinning defective dipoles clusters. In addition, dielectric relaxation behavior under DC bias suggests that electrode effects also affect the dielectric constant. This study provides insights for the origin of the large dielectric constant and the growth of single crystals in TiO2-based materials.

DNA Sensing With Printed Circuit Board Electrode: Non-Faradaic Electrochemical Impedance Spectroscopy Analysis

DNA Sensing With Printed Circuit Board Electrode: Non-Faradaic Electrochemical Impedance Spectroscopy Analysis

Electro-chemo-physical analysis for long-term reinforcement corrosion within the reactive system of concrete

This paper presents an electro-chemo-physical model for analyzing long-term chloride-induced reinforcement corrosion in concrete structures. The integration of electrochemical and thermodynamic analyses enables the proposed model to capture the influence of simultaneous reactions within concrete on the corrosion process. The model is validated against experiments, where the necessity of considering the complicated reactions within concrete in long-term corrosion modeling is underscored. Building upon experimental observations and numerical explorations, a potential corrosion acceleration effect resulting from Friedel's salt dissolution in a longer term of corrosion propagation is discovered. Thereafter, a new qualitative model for describing the reinforcement depassivation process in concrete is proposed, along with discussions on governing mechanisms. From a computational perspective, the study also identifies hematite and magnetite as thermodynamically stable rusts under different concentrations of Fe2+ and O2. The proposed model and discoveries are poised to contribute significantly to scientifically robust predictions of deterioration and remaining service life for aging reinforced concrete structures.

Outside-in enhancement of phosphate solubilizing bacteria by sludge biochar for phenol remediation in soil: Pollution stress reduction, electron transfer gain and secretion regulation

The high toxicity of phenol poses a significant barrier to bacterial bio-removal capacity. This study innovatively proposes the utilization of sludge biochar (SB) to embed phosphate-solubilizing bacteria (CZB1), creating a composite system (SB-CZB1) that enhances the bio-removal efficiency of phenol. The research findings indicate that after being embedded with biochar, Phosphorus solubilizing bacteria (PSB) achieved a significant enhancement (49.7 %-67.0 %) in phenol removal efficiency across different concentration gradients (1500, 2000, 2500 mg/L). SB component in the SB-CZB1 composite system provides a stable and favorable growth environment for CZB1, significantly enhancing microbial metabolic activity. Notably, it stimulates CZB1 to secrete succinic acid and malic acid (with increases of 3.8 % and 23.9 %, respectively), effectively mitigating the detrimental effects of phenol toxicity on microorganisms. Three-dimensional fluorescence and electrochemical analysis demonstrate that SB not only exhibits exceptional electrochemical performance but also stimulates CZB1 to generate redox-active substances (quinone components in humic acid). The electron transfer rates between microorganisms and phenol in the SB-CZB1 system are 9.75–21.71 times and 23.94–63.95 times higher than those in SB and CZB1 alone, respectively. Meanwhile, the abundant oxygen-containing functional groups (COH/COC, COOH, CO) on the surface of SB-CZB1 play a pivotal role in the adsorption and removal of phenol. Furthermore, pot experiments further reveal that the SB-CZB1 composite system significantly enhances the removal efficiency of phenol in soil (98.1 %). Additionally, the application of SB-CZB1 effectively modulated soil properties, notably increasing available potassium and available phosphorus content by 40.86 % and 136.69 %. This application not only enriched soil microbial diversity but also promoted the proliferation of native organic pollutant remediation bacteria in the soil. Notably, the proliferation of Bacillus species affiliated with CZB1 was the most significant, increasing by 82.1 %. This result confirms that biochar embedding technology effectively enhanced the colonization of CZB1 in the soil, thereby significantly accelerating the bio-removal process of phenol.

Electrochemically Switchable Sulfurized Polyacrylonitrile for Controllable Recovery of Copper in Wastewater Based on Reversible Adsorption/Desorption Regulation.

Within the context of circular economy and industrial ecology, adsorption offers an effective manner for recycling resources from wastewater, but controllable desorption remains a challenge. Inspired by metal-thiol binding and reversible thiol-disulfide redox transformation in biological systems, this study reports the development of a reversible adsorption/desorption (RAD) system for controllable recovery of copper based on electrochemically switchable sulfurized polyacrylonitrile (SPAN). Density functional theory calculations offered theoretical prediction for the formation of S-Cu bonds and reversible weak interaction between S-S bonds and Cu2+. The SPAN anchored onto titanium suboxide ceramic foam (SPAN@TiSO) could regulate Cu2+ adsorption/desorption stimulated by the electrode potential, indicated by the adsorption capacity of 243.3 mg g-1 (30 min) at 0.2 V vs SHE and a desorption efficiency of 98.4% (5 min) at 0.8 V vs SHE. Electrochemical analysis revealed that the reversible redox transformation of S-S/-S- groups in SPAN was responsible for selective adsorption and rapid desorption in response to the electrode potential. This study provides a proof-of-concept demonstration of an electrochemically switchable polymer to build up a reversible RAD system for controllable recovery of heavy metals in wastewater, making value-added resource recovery more efficient, more intelligent, and more sustainable.

Systematic electrochemical analysis of high-capacity NMC-88 and NMC-83 cathodes for lithium-ion batteries

Systematic electrochemical analysis of high-capacity NMC-88 and NMC-83 cathodes for lithium-ion batteries

A Novel Co-MoS2/RGO-Based Highly Sensitive Sensor for Simultaneous Detection of Ascorbic Acid and Uric Acid

This study presents the synthesis of cobalt-doped MoS₂/reduced graphene oxide (Co-MoS₂/RGO) nanocomposites via a microwave-assisted technique. These nanocomposites were meticulously characterized, revealing intricate details of their nanostructure and surface morphology. Electrochemical analyses demonstrated distinct sensing mechanisms for the electrochemical oxidation of ascorbic acid (AA) and uric acid (UA) at the Co-MoS₂/RGO interface. The sensor exhibited a diffusion-controlled behavior, achieving remarkable detection limits of 0.013 μM for AA, 0.06 μM for UA, 0.248 μM for AA in the presence of UA, and 0.36 μM for UA in the presence of AA. Additionally, the Co-MoS₂/RGO composite demonstrated impressive individual and selective sensitivities for AA, measuring 8.42 μA μM−1 cm−2 and 2.786 μA μM−1 cm−2, respectively, and for UA, measuring 10.628 μA μM−1 cm−2 and 7.25 μA μM−1 cm−2, respectively. These results highlight the exceptional capability of the Co-MoS₂/RGO nanocomposite to distinguish and accurately quantify concentrations of AA and UA, both individually and simultaneously. Furthermore, the Co-MoS₂/RGO sensor demonstrated outstanding repeatability and reproducibility, consistently delivering high performance even after 15 days. These findings underscore the potential of the Co-MoS₂/RGO-based electrochemical sensor as an ultra-sensitive, highly selective, and dependable tool for real-time sample analysis in practical applications.

Aluminium oxide/aluminium cobalt oxide as an efficient electrocatalyst for the electrochemical detection of 4-nitroaniline in environmental samples

The rise of pollutants in our ecosystem has become a major threat to be resolved. 4-nitroaniline (4-NAE) is among the carcinogenic and toxic components present in the environment with harmful effects. Thus, we designed an electrochemical sensor to detect 4-NAE with the as-synthesized aluminium oxide/aluminium cobalt oxide (AO/ACO) via the hydrothermal preparation approach. Ensured with the physicochemical characterization of the sample (AO/ACO) with XRD, FTIR, Raman, and FESEM, the presence of AO/ACO was confirmed with no impurities. The electrochemical analysis of 4-NAE was analyzed after the optimization of the sample loading. The CV and DPV results signify that the developed sensor has excellent repeatability and reproducibility nature for 4-NAE detection with a low detection limit of 0.007µM and a sensitivity of about 17.96 µAµM-1cm-2. The selectivity test studied with the presence of various interfering compounds showed satisfactory results with no interference other than 4-NAE. The environmental samples applied for the spiked 4-NAE showed good results proving the sensor's ability to detect 4-NAE in real samples. Thus, the sensor will be a reliable technique for the implementation in environmental applications for the detection of 4-NAE and even other compounds with modifications.

Construction of Co-Ni3B/GDY heterostructured electrocatalyst for boosting oxygen evolution in alkaline media

Water splitting as the clean technology for hydrogen production garnered the widespread attention. The high overpotential required for oxygen evolution reaction (OER) is the central dilemma. Herein, Co-Ni3B/graphdiyne heterostructure on copper foam (Co-Ni3B/GDY/CF) was constructed for boosting alkaline OER. Detailed electrochemical analysis showed that Co-Ni3B/GDY/CF was an exceptional OER electrocatalyst with the low overpotentials of 270 and 335mV at 20 and 100mAcm−2 in 1.0M KOH solution, respectively, as well as high turnover frequency of 0.80s−1 at 400mV. Moreover, its catalytic performance outperformed the benchmarked RuO2/CF when the current density exceeded 200mAcm−2. Importantly, the equipped electrolyser Pt/C/CF||Co-Ni3B/GDY/CF showed low cell voltage (1.53V@10mAcm−2) and long-term durability. These results demonstrated that a synergistic effect at the heterointerface between GDY and Co-Ni3B was achieved, which regulated the electronic configuration, accelerated the charge transfer and increased the active surface areas. Furthermore, the density functional theory calculations revealed that Co-Ni3B/GDY with incomplete charge transfer lowered the energy barrier of the rate-determining step and optimized adsorption/desorption behavior of the intermediates, thereby effectively promoting O2 evolution.