High Electrocatalytic Activity Research Articles

High-entropy alloy nanocages with highly ordered {100} facets and ultrathin features for water splitting in an acidic medium

PtIrRuRhPd HEA cubic nanocages with ordered {100} facets and ultrathin shells exhibit high electro-catalytic activities for hydrogen and oxygen evolution reactions in an acidic medium.

Nickel 2‐Methylimidazole Metal–Organic Framework Ultrathin Nanosheets/Titanium Carbide MXene Hybrid Nanostructure as a Bifunctional Electrocatalyst for Methanol and Urea Oxidation Reactions

In the development of direct methanol and direct urea fuel cells, efficient electrocatalytic methanol oxidation reaction (MOR) and urea oxidation reaction (UOR) are employed. These approaches are essential in fuel cell technology for addressing the rising global energy and environmental concerns. In this research, nickel 2‐methylimidazole metal–organic framework (Ni‐MOF) and Ni‐MOF‐integrated titanium carbide (Ti3C2) MXene hybrid nanostructures (Ni‐MOF/Ti3C2) were controllably synthesized via a facile solvothermal method. Ti3C2 MXene nanosheets are utilized as two‐dimensional support to enhance the catalytic activity of the Ni‐MOF/Ti3C2 hybrid nanostructure. Furthermore, the methanol and urea electro‐oxidation activity of the Ni‐MOF/Ti3C2 hybrid nanostructure is investigated. The synergistic effect between Ni‐MOF and Ti3C2 MXene resulted in excellent and durable electrochemical performance. Thus, the newly synthesized electrode material exhibited high electrocatalytic activity at 0.8 V vs. Hg/HgO for methanol (166 mA cm−2) and urea electro‐oxidations (161 mA cm−2). The methanol and urea oxidation rates of the Ni‐MOF/Ti3C2‐10 hybrid nanostructure are approximately five and three times higher than that of pure Ti3C2 MXene and pristine Ni‐MOF, respectively. This work provides the potential of the Ni‐MOF‐integrated Ti3C2 MXene hybrid nanostructure as a promising electrocatalyst for MOR and UOR.

Electrodeposition of nickel nanoparticles on graphene/iron (III) phthalocyanine-4,4’,4,”,4’”-tetrasulfonic acid coated electrode for glucose sensing

Glucose is vital to the body and a significant source of energy for both human activity and all bodily cells. In order to diagnose, monitor, and treat diabetes, we make use of the blood glucose index to measure the blood glucose concentration. Herein, we present the development of an electrochemical sensor for the detection of glucose levels utilizing graphene incorporated with an iron (III) phthalocyanine-4,4’,4,”,4”’-tetrasulfonic acid and nickel nanoparticles (Gr/FePc/Ni) nanocomposite material. For this purpose, the screen-printed carbon electrode (SPE) was coated with graphene/FePc film, which was later dipped into 10 mM nickel acetate solution. In this step, nickel ions were adsorbed on to graphene/FePc film modified SPE which was later reduced to Ni nanoparticles by electrochemical reduction process. Next, as-prepared Gr/FePc/Ni film was characterized by FE-SEM, FT-IR, EDS and cyclic voltammetry (CV). Gr/FePc/Ni composite-modified screen-printed electrode (Gr/FePc/Ni/SPE) had demonstrated remarkable electrocatalytic activity and sensitivity towards glucose in 0.1 M KOH by CV and amperometry methods. The observed high electrocatalytic activity of Gr/FePc/Ni/SPE was credited to the synergistic effect between the anchored nickel nanoparticles (NPs) and the Gr/FePc film. Moreover, Gr/FePc/Ni/SPE was used to detect glucose from 5 µM to 930 µM by amperometry (i-t) and the lowest limit of detection (LOD) was 0.227 μM. Finally, Gr/FePc/Ni modified sensor was applied to detect glucose in the human blood samples with the acceptable the recovery rate from ∼ 99.48 to 99.94 %.

Mild and scalable synthesis of a high performance CrFeCoNiRu0.05 high entropy nano-alloy/carbon electrocatalyst for efficient urea production with a chelate-based ionic liquid

We firstly reported synthesis of CrFeCoNiRu0.5 high-entropy alloy nanoparticles using an ionic liquid. The CrFeCoNiRu0.5 high-entropy alloy provides exceptionally high electrocatalytic activity for green urea synthesis.

Poly (3, 4-propylenedioxythiophene)/Hollow carbon sphere composites supported Pt NPs to facilitate methanol oxidation reactions

Direct methanol fuel cells (DMFCs) are thought of as portable, sustainable, and non-polluting energy devices. The exploration of efficient and affordable catalysts for the methanol oxidation reaction (MOR) is significant for the industrial application of DMFCs. In this study, nitrogen-doped hollow carbon spheres (HCS) derived from polydopamine were proposed for the catalyst support for platinum nanoparticles (Pt NPs) for serving as the anode catalyst for DMFCs, and a composite support material was fabricated by in-situ oxidation of 3,4-ethylenedioxythiophene (ProDOT) with HCS to get core-shell structured poly(3,4-propylenedioxythiophene) (PProDOT)-embellished hollow carbon spheres (HCS) (PProDOT/HCS) for further improving the catalytic activity for supported catalyst. The results indicated that the platinum (Pt) on the surface of HCS was well dispersed, and the Pt became smaller and more evenly distributed with the introduction of PProDOT. Simultaneously, the Schottky junction formed between PProDOT and Pt NPs contributes to enhanced charge transfer and catalytic activity of the catalyst. Notably, the core-shell structure of the ternary catalyst, its excellent charge transfer capability, and the interaction between platinum and the support contribute to its high electrocatalytic activity. Electrochemical tests demonstrated that the PProDOT/HCS/Pt catalyst exhibited a mass activity of 1169.6 mA mg−1Pt for methanol oxidation in acidic electrolytes, surpassing the activity of the HCS/Pt catalyst (472.4 mA mg−1Pt) and commercial Pt/C (281.0 mA mg−1Pt).

A Hierarchical Polyoxometalate/Pd/Mos2 Hybrid: Developing an Efficient Novel Bifunctional Catalyst for Water Splitting

AbstractCatalytic water splitting is a promising approach to produce clean hydrogen fuel from renewable energy sources. However, developing hybrid heterostructures capable of efficiently breaking down water into its constituent elements, hydrogen, and oxygen, presents a considerable challenge. In this study, a novel hierarchical POM/Pd/MoS2 hybrid heterostructure, composed of sheets of MoS2 modified with Pd nanoparticles and combined with a cobalt‐based polyoxometalate (POM), serving as bifunctional catalyst for water splitting is reported. Through a synergistic synthetic approach, MoS2, acting as a reducing agent, triggers the nucleation and growth of Pd nanoparticles, which, in turn, serve as anchoring sites for the polymerization of the cobalt‐based POM into fibers. POM/Pd/MoS2 hybrid exhibits an enhanced oxygen evolution reaction (OER) activity, comparable to the benchmark catalysts Ir/C and IrO2/C in alkaline media, being its hydrogen evolution reaction (HER) activity similar to the activated Pd/MoS2 hybrid. The intriguing electrocatalytic capability of the resulting material for producing hydrogen and oxygen through electrochemical means arises from the enhanced charge storage capacity and conductivity of MoS2, the multi‐electron transfer facilitated by the POM, and the high electrocatalytic activity of the metals.

Enhanced stability and conductivity of montmorillonite and sucrose loaded Fe-MOFs for degradation of chlortetracycline hydrochloride via electrochemically activated persulfate

Ferreous metal-organic frameworks (Fe-MOFs) have provided excellent platforms for the removal of refractory contaminants from water, whereas poor conductivity and intrinsically fragile limit applications in electrochemistry and heterogeneous catalyst, respectively. Hence, we synthesized a novel Fe-based MOFs(Mt@Fe-MOFs@C) obtained through introducing sucrose to improve conductivity and montmorillonite (Mt) to enhance cycling stability, and combined with persulfate (PS) and electrochemical (EC) method to remove chlortetracycline hydrochloride(CTC) from water environment. The electrochemical impedance spectroscopy (EIS) demonstrated Mt.@Fe-MOFs@C was more conductive than pure Fe-MOFs. Mt.@Fe-MOFs@C showed high electrocatalytic activity for degradation of CTC in EC/Mt.@Fe-MOFs@C/PS system. The mechanism study indicated that SO4•− and HO• played dominant role in the elimination of CTC. Mt.@Fe-MOFs@C also exhibited excellent reusability with 83% removal efficiency after 5 cycle degradation. This work demonstrated that Mt.@Fe-MOFs@C would have potential for electrochemical wastewater remediation.

(Invited) Mixed Conductors for Advanced Solid Oxide Fuel Cells

Developing innovative electrode materials with high electrocatalytic activity is essential to advance the commercial viability of solid oxide fuel cells (SOFCs). Perovskite-type metal oxides have shown great potential as electrocatalysts for the oxygen reduction reaction and fuel oxidation. Mixed ionic and electronic conducting (MIECs) perovskites are being explored as electrodes which have demonstrated excellent chemical stability and provide more electrochemically active surface area. Here, we discuss our strategies towards the rational design of compositions to develop cost-effective and high-performance electrode materials for intermediate-temperature solid oxide fuel cells. Particular attention is centred on cathode materials and the role of thermal compatibility, electrical conductivity, and chemical stability towards improving the electrochemical performance of the cathode materials has been discussed.

The Durability of the Platinum/Polypyrrole Nanotubes' Catalysts in Oxygen Reduction Reaction

Platinum (Pt) catalysts supported on carbon-based materials are effective catalysts for fuel cells. However, the durability of the carbon supports in acidic media needs to be improved. Platinum/polypyrrole (PPy) nanotubes have emerged as promising catalysts for the oxygen reduction reaction (ORR) due to their high surface area and good electrocatalytic activity. Furthermore, the nitrogen atoms within the chemical structure of PPy nanotubes are expected to improve their durability.In this study, we investigated the performance and durability of Pt catalysts during ORR by decorating different carbon-based materials with Pt nanoparticles. The catalytic activity and durability were analyzed using the rotation ring-disk electrode (RRDE) technique. We also examined the influence of the different supports on the electrochemical degradation of the catalysts.Our results showed that Pt/PPy nanotubes exhibited high activity and durability in ORR reactions. We paid particular attention to the chemical changes of the catalysts' surfaces, including both the metal and support components, during the ex-situ electrochemical measurements. The surface of the catalysts was characterized using photoelectron X-ray spectroscopy (XPS), synchrotron radiation photoelectron spectroscopy (SRPES), and near-edge X-ray absorption fine structure (NEXAFS) analysis before and after electrochemical degradation. Based on our findings, we proposed degradation mechanisms of the Pt/PPy nanotubes catalysts.In addition, we tested the Pt/PPy nanotubes catalysts in fuel cells and observed their high performance. These findings suggest that Pt/PPy nanotubes catalysts can serve as durable and effective catalysts for ORR reactions, even under harsh conditions. Further research is needed to optimize the synthesis conditions and operating parameters of these catalysts to improve their performance and durability.

Non-PGM Cathode Electrocatalysts for PEM Fuel Cells

Polymer electrolyte membrane fuel cells, PEMFCs, are considered the most ideal next generation energy conversion device, able to provide power to a broad range of applications; automotive, combined heat and power, portable electronic devices. Pt-based electrocatalysts are regarded as ideal for promoting the desired redox reactions of a fuel cell, especially the sluggish oxygen reduction at the cathode, ORR. High expense and scarcity of Pt are the greatest impediments to successful commercialization of this technology. The replacement of unsustainable noble-metal catalysts with platinum group metal (PGM)-free catalysts for oxygen reduction reaction (ORR) is essential for material wise and market value viable PEMFCs.Among the different attempts towards non-PGM catalysts, incorporating atomically dispersed transition metal atoms (Fe, Mn, etc.) and heteroatoms (N, S, etc.) into carbon frameworks is the most promising [1,2]. Large specific surface area, high intrinsic ORR electrocatalytic activity, efficient porosity and sufficient stability in acid media and/or in the actual working environment are the least requirements to consider when designing the catalysts. So far, despite the tremendous efforts, many drawbacks still persist that include poor understanding of the nature of active centres and their control over the synthesis, as well as fast decay of the structure under operation.In this work, we will present a rationally designed strategy to prepare hybrid composite catalysts by developing Fe–N–C materials onto different 2D and 3D templates [3,4] with differentiated surface chemistry (silicon and heteroatom-doped carbon structures). Despite structural and physicochemical characterization, the study includes extensive electrochemical characterization in terms of activity and durability in relative to the application conditions. An example is depicted in Figure 1 for a single atom Fe-N-C catalyst synthesized using porous silica nanotubes as the sacrificial template resulting in a hierarchically porous structure with a surface area of 370 m2/g. Electrochemical study revealed a half-wave potential of 0.72 V and an onset potential of 0.88 V with high stability in acidic environment.Very importantly, the different findings are correlated to one another, thereby establishing a composition to function relationship to provide a pathway for the integrated engineering of novel structures with improved performance. Acknowledgments Funding from the Operational Program “Competitiveness, Entrepreneurship & Innovation” (EPAnEK), NSRF 2014-2020 through the project Solar2HyP Τ2ΕΔΚ-01877 References [1] L. Osmieri, et al., Current Opinion in Electrochemistry 25 (2020) 100627.[2] T. Asset, et al., Joule 4 (2019) 33-44.[3] Jin-Cheng Li et al., Asia Materials 10 (2018) e461[4] Nan Zhang et al., Energy Environ. Sci. 13 (2020) 111-118 Figure 1

(Invited) Materials Challenges for the Green Hydrogen Economy at Scale

Research and development projects over the last 30 years have successfully shown the value of hydrogen as a fuel and energy storage medium, and now hydrogen is seen as a key solution to decarbonization. Green hydrogen can be made by electrolysis anywhere that there is ample hydroelectric, solar and wind electric power. The hydrogen energy can be converted back to useful work in a fuel cell, turbine, or engine, or directly to manufacture products such as ammonia, cement, and steel. However, world decarbonization at scale also requires the demonstration of hydrogen at scale, and the widescale adoption of hydrogen for a green economy requires a reimagining of how energy is created, stored and used.Leading technologies for the green hydrogen economy include proton exchange membrane fuel cells (PEMFCs) and PEM water electrolyzers (PEMWE), both which operate under acidic conditions. In addition to high electrocatalytic activity, the electrode materials must be designed for two- phase flow of water and gas. All of the materials should be durable, low cost, manufacturable, recyclable, and have the appropriate electronic and thermal properties.This talk will describe some of the materials challenges needed to meet commercialization goals for PEMFCs and PEMWEs, and some of the constraints of manufacturing and recycling.

Oxygen Reduction Reaction Activity of Platinum Nanosheets Derived from Layered Platinic Acid

Platinum nanoparticles are mainly utilized as the cathode catalyst for polymer electrolyte fuel cells. However, the utilization of platinum for the oxygen reduction reaction (ORR) is insufficient and one must tackle the trade-off between high surface area and high stability. We have previously shown that metallic nanosheets such as ruthenium nanosheets exhibit high electrocatalytic activity and stability owing to the two-dimensional structure with an atomic scale thickness.1, 2 Platinum nanosheets, if available, should also have the potential to increase the utilization of the atoms and durability. While a few studies have reported the synthesis of platinum nanosheets,3 the thickness of the nanosheets is more than 1 nm, and the utilization of platinum has so far been lower than that of the Pt nanoparticles.In this study, we report double-layered platinum nanosheets derived from layered platinic acid.4 Layered platinic acid was synthesized through a solid-state-reaction and subsequent acid treatment. From the layered platinic acid, platinum oxide nanosheets were obtained as a colloid via chemical exfoliation. The thickness of the platinum oxide nanosheet was ~0.9 nm, consistent with the thickness of a single PtO6 octahedron. The platinum oxide nanosheets on silicon wafer were topotactically reduced to platinum nanosheets by mild thermal treatment in hydrogen. The thickness of the platinum nanosheet was ~0.5 nm, corresponding to a two atomic layer platinum nanosheet.Carbon supported platinum nanosheets were prepared by the reduction of platinum oxide nanosheets supported on carbon. The electrochemically active surface area (ECSA) of the carbon supported platinum nanosheets was 100 to 120 m2 (g-Pt)-1, which was considerably larger than that of 3 nm platinum nanoparticle (80 m2 (g-Pt)-1). In addition, the platinum nanosheet showed 1.7 times higher mass activity towards the oxygen reduction reaction compared to that of 3 nm platinum nanoparticles.Various methods for the topotactic reduction of platinum oxide nanosheets on carbon was studied. In addition to the mild thermal treatment in hydrogen gas, electrochemical reduction was also conducted. The ECSA of the platinum nanosheet prepared by electrochemical reduction at constant potential was 100 to 120 m2 (g-Pt)-1, which was almost same as the platinum nanosheet reduced by the mild thermal treatment in hydrogen. The specific activity was 1.2 to 1.3 times higher than that of the platinum nanosheet reduced by the mild thermal treatment in hydrogen. Therefore, the platinum nanosheet reduced by electrochemical reduction showed high mass activity for ORR.AcknowledgementThis work was supported as part of the “Polymer Electrolyte Fuel Cell Program” and the FC-Platform projects from the New Energy and Industrial Technology Development Organization (NEDO) of Japan (20001201-0, 22101136-0).

Interface engineering of N, P and S-doped hollow/porous Co3O4@Co3V2O8 heterostructure nanocube for high-activity supercapacitor and oxygen evolution reaction

Cobalt-based materials exhibit high theoretical specific capacitance and desirable electrocatalytic activity. However, their practical specific capacitance and electrocatalytic activity are significantly constrained by a lack of active sites and limited conductivity. Herein, N, P and S-doped hollow Co3O4@Co3V2O8 heterostructure nanocube is reasonably constructed via in-situ ion exchange method combined with calcination strategy. Besides, the relationship of heterogeneous interface and heteroatom doping on electrochemical performance is explored. The heterogeneous interface provides rich active sites and accelerates electron transfer. Additionally, N, P, and S-doping regulate the internal electronic structures, boost ion transfer rates, and increase active sites. The hollow structure accelerates the adsorption and desorption processes due to the increased electrochemical reaction sites. Benefiting from internal electronic structure and structural advantages, N, P, S-Co3O4@Co3V2O8 exhibits low overpotentials (561 mV and 649 mV at the current density of 50 mA/cm2 and 100 mA/cm2), low Tafel slopes (100.9 mV/dec), prospective specific capacitance (550.2 F/g) and outstanding charge/discharge behavior with remarkable life span. N, P, S-Co3O4@Co3V2O8 based device delivers favorable energy density (21.3 Wh/kg at 802.3 W/kg), which surpasses most of the latest cobalt-based materials. Overall, this work provides novel insights into the development of highly active and durable bifunctional electrode materials.

Functionally Graded Infiltration Triggering Ultrahigh Electrolytic Current in Robust Reversible Solid Oxide Cells

The reversible solid oxide cell (ReSOC) offers the dual capability to store electricity as chemical fuels and convert fuels to electricity, thereby enabling carbon neutral cycling. The nickel‐cermet fuel electrode exhibits high electrocatalytic activity for redox reactions while being particularly vulnerable to carbon deposition and nickel coarsening, especially at high current densities. Herein, a novel approach involving a graded infiltration onto a dendritic Ni–YSZ (yttria‐stabilized zirconia) skeleton with Pr6O11 nanoparticles/films is presented, demonstrating remarkable electrolytic current and coke tolerance in CO–CO2 conversion. At 800 °C, the current densities achieve approximately −2.0 and +2.0 A cm−2 under 1.3 and 0.6 V, respectively, showcasing robust cycling stability switching between two operational modes within 20 cycles. Notably, the attained electrolytic current density reaches an unprecedented −3.06 A cm−2 under 1.6 V. Furthermore, the button cell runs smoothly at ultrahigh electrolytic current densities ranging from −0.5 to −3.0 A cm−2 for nearly 270 h. The mechanism of high‐performance CO2 reduction is elucidated by in/ex situ experimental characterizations and theoretical calculations. These results indicate the viability of employing Ni–YSZ‐supported ReSOC for stable renewable electricity storage at previously unattainable reaction rates, and have implications for fundamental understanding of designing robust ReSOC based on the nickel‐cermet fuel electrode.

Enhanced electrocatalytic hydrodechlorination of 2,4-dichlorophenol over palladium nanoparticles loading on dendrite-like Ni-Cu-P interlayer

A new electrode with high electrocatalytic hydrodechlorination activity was prepared by pulse electrodeposition of Pd nanoparticles on a dendrite-like Ni-Cu-P interlayer with foam nickel as the substrate. The physical and chemical properties of the composite electrode were systematically investigated by various characterizations. The dechlorination performance was evaluated with 2,4-dichlorophenol as the model pollutant. The results indicated that in 150 min the dechlorination efficiency over the electrode without the Ni-Cu-P interlayer was only 52.7 %, while 100 % of 2,4-dichlorophenol could be removed by the composite electrode. The enhanced dechlorination performance was mainly attributed to the synergic effect between Pd nanoparticles and the Ni-Cu-P interlayer. The dendrite morphology of Ni-Cu-P facilitated Pd nanoparticle dispersion, thus providing more active sites and reducing the consumption of Pd. Furthermore, the Ni-Cu-P interlayer assisted Pd0 to produce more active hydrogen and increased the content of Pd2+ to promote CCl bond cleavage. Consequently, the dechlorination performance was improved.

Design and catalytic performance of Cu/γ-Al2O3 for electrocatalytic methanol oxidation reaction by using density functional theory and molecular dynamics

The electrocatalytic activity of methanol oxidation reaction (MOR) on Cu/γ-Al2O3 and the growth behavior of Cu on γ-Al2O3 are investigated by using density functional theory and molecular dynamics. It is found that the interaction between the Cu3 cluster and γ-Al2O3(110) is stronger than that between the Cu4 cluster and γ-Al2O3(110). Consequently, the d-band center of the Cu3 cluster locates close to the Fermi level compared to the d-band center of the Cu4 cluster, resulting in high electrocatalytic MOR activity on Cu3/γ-Al2O3(110). The electrocatalytic MOR pathway is non-CO pathway on Cu3/γ-Al2O3(110). The highest Gibbs free energy pathway is CH3O* → CH2O*, which the Gibbs free energy is 0.53 eV. To achieve a high proportion of 2D Cu cluster on γ-Al2O3, it is recommended to prepare the catalyst at temperatures below 500 K with Cu loading below 21.78 wt%. These findings provide valuable insights into the design of MOR catalysts.

Machine Learning-Assisted Automatically Electrochemical Addressable Cytosensing Arrays for Anticancer Drug Screening.

The high-throughput and accurate screening of anticancer drugs is crucial to the preclinical assessment of candidate drugs and remains challenging. Herein, an automatically electrochemical addressable cytosensor (AEAC) for the efficient screening of anticancer drugs is reported. This sensor consists of sectionalized laser-induced graphene arrays decorated by the rhombohedral TiO2 and spherical Pt nanoparticles (LIG-TiO2-Pt) with high electrocatalytic activity for H2O2 and a homemade Ag/Pt electrode couple fixed onto the robot arm. The immobilization of laminin on the surface of LIG-TiO2-Pt can promote its biocompatibility for the growth and proliferation of various tumor cells, which empowers the in situ monitoring of H2O2 directly released from these live cells for drug screening. A machine learning (ML) algorithm is employed to eliminate the possible random or systematic errors of AEAC, realizing rapid, high-throughput, and accurate prediction of different types of anticancer drugs. This ML-assisted AEAC provides a powerful approach to accelerate the evolution of sensing-served tumor therapy.

Surface-Modified Carbon Nanotubes with Ultrathin Co3O4 Layer for Enhanced Oxygen Evolution Reaction.

Alkaline water electrolysis is a vital technology for sustainable and efficient hydrogen production. However, the oxygen evolution reaction (OER) at the anode suffers from sluggish kinetics, requiring overpotential. Precious metal-based electrocatalysts are commonly used but face limitations in cost and availability. Carbon nanostructures, such as carbon nanotubes (CNTs), offer promising alternatives due to their abundant active sites and efficient charge-transfer properties. Surface modification of CNTs through techniques such as pulsed laser ablation in liquid media (PLAL) can enhance their catalytic performance. In this study, we investigate the role of surface-modified carbon (SMC) as a support to increase the active sites of transition metal-based electrocatalysts and its impact on electrocatalytic performance for the OER. We focus on Co3O4@SMC heterostructures, where an ultrathin layer of Co3O4 is deposited onto SMCs using a combination of PLAL and atomic layer deposition. A comparative analysis with aggregated Co3O4 and Co3O4@pristine CNTs reveals the superior OER performance of Co3O4@SMC. The optimized Co3O4@SMC exhibits a 25.6% reduction in overpotential, a lower Tafel slope, and a significantly higher turnover frequency (TOF) in alkaline water splitting. The experimental results, combined with density functional theory (DFT) calculations, indicate that these improvements can be attributed to the high electrocatalytic activity of Co3O4 as active sites achieved through the homogeneous distribution on SMCs. The experimental methodology, morphology, composition, and their correlation with activity and stability of Co3O4@SMC for the OER in alkaline media are discussed in detail. This study contributes to the understanding of SMC-based heterostructures and their potential for enhancing electrocatalytic performance in alkaline water electrolysis.

Graphitic carbon nitride and its nanocomposites-based sensors for detection of pharmaceutical effluents in food, ecological and biological samples: A mini-review

Pharmaceutical effluents (PEs) have emerged as a global threat to mankind owing to their adverse health effects on humans. Generally, PEs are acquainted with the environment via direct emissions from drug manufacturing plants, unplanned disposal of unused or expired medicines, unprocessed patient/animal excretion, aquafarming, etc. Unlike other pollutions, PE-based contaminations can lead to catastrophic consequences via genotoxic, ecotoxicological, mutagenic effects, etc., causing behavioural changes, reproductive damage, and chronic damage. Therefore, a susceptible detection platform for PE traces in different sources like water bodies, human biofluids, etc., is in high demand. Owing to their high surface area, chemical stability, and electrocatalytic activity, the 2D graphitic carbon nitride (gCN) has gathered significant research interest. It has been examined for the electrochemical detection of PE traces in different ecological and biological samples. In this mini-review, we discuss the exciting advancements in the design and fabrication of gCN and its nanocomposite-based electrochemical sensors for other trace-level detection of different PEs in ecological and biological systems. The table in this review provides a clear insight into the reported gCN-based electrochemical sensors and their performance analysis towards sensing of EFs. The anticipated developments are discussed with current limitations in gCN-based electrochemical sensors for PE detection.

Three-dimensional Electrocatalytic Degradation of Tetracycline by Nano-Feooh

Nano-FeOOH catalysts were prepared by a co-precipitation method and characterized by XRD, SEM, XPS and BET to analyze the phase composition, surface morphology, elemental composition and specific surface area of FeOOH. Results showed that the FeOOH catalyst had large pore volume and surface area, providing more active sites for catalytic reactions. A 3D electrocatalytic system EC/PS/FeOOH was established to degrade tetracycline (TC), and the contributions of FeOOH adsorption, PS activation and electrocatalysis were investigated. It was found that the adsorption rate of TC on sole FeOOH was 42%, the degradation rate of TC in the PS/FeOOH system was 63.80%, and the degradation rate of TC in the 3D EC/PS/FeOOH system reached 72.97%, indicating the high electrocatalytic activity of FeOOH. Surface catalysis mechanism studies showed that the high catalytic activity of FeOOH could be attributed to electron transfer between Fe(II) and Fe(III) and adsorbed oxygen on its surface.