N-doped Graphene Research Articles

N-Doped Graphene Quantum Dots Confined within Silica Nanochannels for Enhanced Electrochemical Detection of Doxorubicin.

Herein, we describe a fast and highly sensitive electrochemical sensor for doxorubicin (DOX) detection based on the indium tin oxide (ITO) modified with a binary material consisting of vertically-ordered mesoporous silica films (VMSFs) and N-doped graphene quantum dots (NGQDs). VMSFs, with high permeability and efficient molecular transport capacity, is attached to the ITO electrode via a rapid and controllable electrochemical method, which can serve as a solid template for the confinement of numerous NGQDs through facile electrophoresis. By virtue of the excellent charge transfer capacity, π-π and electrostatic preconcentration effects of NGQDs, as well as the electrostatic enrichment ability of VMSF, the presented NGQDs@VMSF/ITO shows amplified electrochemical signal towards DOX with a positive charge, resulting in good analytical performance in terms of a wide linear range (5 nM~0.1 μM and 0.1~1 μM), high sensitivity (30.4 μA μM-1), and a low limit of detection (0.5 nM). Moreover, due to the molecular sieving property of VMSF, the developed NGQDs@VMSF/ITO sensor has good selectivity and works well in human serum and urine samples, with recoveries of 97.0~109%, thus providing a simple and reliable method for the direct electrochemical analysis of DOX without complex sample pretreatment procedures.

Sonoelectrochemical nitrided graphene nanosheets with vacancies and their applications for catalysis and sensing of uric acid oxidation

A sonoelectrochemical method for preparing N-doped defective graphene nanosheets (N/O-dGNs) with point defects and 5-9 or 5-8-5 vacancies and oxygen-containing groups was successfully demonstrated. In this one-pot approach, the N-bonding configuration and N content of N/O-dGNs were finely tuned by the ultrasonic power (192, 320, and 640 W). The N content in atomic percentage (at%) for N/O-dGN (N/O-dGN320W) with point defects and 5-8-5 vacancy prepared at 320 W power was 5.6 at%, greater than 3.0 at% and 2.6 at% for N/O-dGN with point defects and 5-9 vacancies at 192 W and 640 W power (N/O-dGN192W and N/O-dGN640W), respectively. N-bonding sites on N/O-dGN320W were dominantly amine N (2.1 at%) and pyrrolic N (2.4 at%). Additionally, the electrocatalytic activity of N/O-dGN192W, N/O-dGN320W, and N/O-dGN640W was successfully demonstrated for the sequential uric acid (UA) oxidation reaction (UOR), in which N/O-dGN320W displayed a significant mass activity (2.51 A/g). As in the transient catalysis of UOR, N/O-dGN320W with amine N showed 400.8 μA mM−1 cm−2 in sensitivity within a wide linear analysis range (1.5 × 10–2–6 mM) for amperometrically sensing UA. The results of real sample experiments using serum samples further demonstrated the potential of N/O-dGN320W as a non-enzymatic UA sensor.

Tuning dual-atom mediator toward high-rate bidirectional polysulfide conversion in Li-S batteries

An emerging practice in the realm of Li-S batteries lies in the employment of single-atom catalysts (SACs) as effective mediators to promote polysulfide conversion, but monometallic SACs affording isolated geometric dispersion and sole electronic configuration limit the catalytic benefits and curtail the cell performance. Here, we propose a class of dual-atom catalytic moieties comprising hetero- or homo-atomic pairs anchored on N-doped graphene (NG) to unlock the liquid–solid redox puzzle of sulfur, readily realizing Li-S full cell under high-rate-charging conditions. As for Fe-Ni-NG, in-depth experimental and theoretical analysis reveal that the hetero-atomic orbital coupling leads to altered energy levels, unique electronic structures, and varied Fe oxidation states in comparison with homo-atomic structures (Fe-Fe-NG or Ni-Ni-NG). This would weaken the bonding energy of polysulfide intermediates and thus enable facile electrochemical kinetics to gain rapid liquid-solid Li2S4 ↔ Li2S conversion. Encouragingly, a Li-S battery based on the S@Fe-Ni-NG cathode demonstrates unprecedented fast-charging capability, documenting impressive rate performance (542.7 mA h g−1 at 10.0 C) and favorable cyclic stability (a capacity decay of 0.016% per cycle over 3000 cycles at 10.0 C). This finding offers insights to the rational design and application of dual-atom mediators for Li-S batteries.

Insights into the mechanism of electric field regulating hydrogen adsorption on Li-functionalized N-doped defective graphene: A first-principles perspective

The hydrogen storage properties of lithium functionalized graphene under external electric fields have been studied in this work employing density functional theory (DFT) calculations. Lithium modified nitrogen doped double-vacancy graphene (Li_NDVG) was constructed as hydrogen storage material. It is examined in terms of the system’s electronic properties, H2 adsorption energy, and stable configuration. The results demonstrate that Li atoms can be distributed on the substrate surface and incorporated into defect centers without producing metal clusters. In comparison to pristine graphene, the adsorption energy of H2 on Li_NDVG is four times higher. The Coulomb force between Li atom and H2 molecule grows as the positive electric field’s strength increases, and the adsorption distance shrinks. On the contrary, the H2 adsorption energy decreases as the negative electric field’s strength increases, and the adsorption distance expands. Furthermore, adsorption occurs spontaneously within the range of 0–300 K and 1–100 atm, and the promoting effect of a positive electric field on adsorption only occurs in the temperature range of 0–140 K. Hydrogen storage properties of functionalized graphene modified with lithium trimer and tetramer respond to the electric field in the same way as single atom. And the presence of clusters and positive electric field increases the bond length of the H2 molecule, causing a tendency for the H2 molecule to dissociate.

Long-Lived Photo-Response of Multi-Layer N-Doped Graphene-Based Films.

New insights into the mechanism of the improved photo(electro)catalytic activity of graphene by heteroatom doping were explored by transient transmittance and reflectance spectroscopy of multi-layer N-doped graphene-based samples on a quartz substrate prepared by chitosan pyrolysis in the temperature range 900-1200 °C compared to an undoped graphene control. All samples had an expected photo-response: fast relaxation (within 1 ps) due to decreased plasmon damping and increased conductivity. However, the N-doped graphenes had an additional transient absorption signal of roughly 10 times lower intensity, with 10-50 ps formation time and the lifetime extending into the nanosecond domain. These photo-induced responses were recalculated as (complex) dielectric function changes and decomposed into Drude-Lorentz parameters to derive the origin of the opto(electronic) responses. Consequently, the long-lived responses were revealed to have different dielectric function spectra from those of the short-lived responses, which was ultimately attributed to electron trapping at doping centers. These trapped electrons are presumed to be responsible for the improved catalytic activity of multi-layer N-doped graphene-based films compared to that of multi-layer undoped graphene-based films.

(Invited) Modification of Properties of N- and B-Doped Graphene by Heteroatom Functionalization

Since its discovery in 2004, the graphene has attracted great attention owing to its unique chemical bonding structure, which has excellent chemical, thermal, mechanical, electrical and optical properties. Due to the graphene being a zero band-gap material, it has a limited development in the field of nano electronics. Therefore, to broaden its application scope, it is very important to carry out a study on opening the band gap of graphene. One general strategy for achieving this goal is doping graphene with heteroatoms; in this approach, the properties of graphene are controlled by the nature of the dopant elements and by the percentage of doping being N-doped graphene is of n-type doping, while B-doped graphene is of p-type doping. Compared with that of the intrinsic graphene, the Fermi level of N doped graphene moves up 5 eV; on the contrary, the Fermi level of B doped graphene moves down 3 eV.However, it would be convenient to develop additional tools to achieve further control of the electronic properties of graphene materials. In this context, one of the possibilities would be to functionalize those dopant elements on the graphene sheet in such a way that the electron density and electronegativity of the heteroatom are effectively controlled. This objective could, in principle, be achieved by applying concepts from organic chemistry. Organic synthesis offers proven chemical reactions that are applicable to different types of nitrogen and boron compounds.In the work described here, we´ll present our results on the covalent functionalization of the nitrogen atom or boron atom of N-doped and B-doped graphene. In a simple strategy, electron-donating and -withdrawing groups present on aromatic rings can be used to modulate the electronic properties of the material.

Effects of Nitrogen-Doping or Alumina Films on Graphene as Anode Materials of Lithium-Ion Batteries Verified by in Situ XRD

First, graphene is directly grown on nickel foil without additional catalysts by chemical vapor deposition (CVD). Next, the graphene is modified by nitrogen-doping and alumina is deposited onto the graphene by magnetron sputtering. The charge specific capacity of N-doped graphene is higher than that of graphene since 2 Theta of in situ XRD characteristic peaks for N-doped graphene moves toward a lower angle (about 24) which is smaller than that (about 25) for graphene, then the gap between graphene layers for N-doped graphene is larger than that for graphene according to Bragg’s Law and N-doped graphene demonstrates the additional in situ XRD characteristic peak (LiC6) in comparison to graphene only with the in situ XRD characteristic peak (LiC12). Furthermore, because 2 Theta of in situ XRD characteristic peaks for Al2O3/graphene also moves toward a lower angle (about 24) and Al2O3/graphene also shows the additional in situ XRD characteristic peak (LiC6), the charge specific capacity of Al2O3/graphene is also higher than that of graphene.

(Invited) Synthesis, Characterization and Quality Control of Heteroatom-Doped Graphene

Heteroatom doped graphene materials have gained attention as promising candidates for a variety of energy-related applications. Addition of heteroatoms in the graphene lattice is a powerful tool to modify their electronic, electrochemical, and catalytic properties. This presentation focusses on N-doped reduced graphene oxide and summarizes strategies to engineer the structure and properties of the material through control of the synthetic conditions. The produced N-doped graphene materials are characterized to determine their chemical composition, nitrogen content, degree of graphitization, surface area, electronic and electro-chemical properties. The scalability and manufacturability of the N-doped graphene materials are assessed and various examples of their current and future applications in batteries and supercapacitors are discussed.

Oxide-mediated nitrogen doping of CVD graphene and their subsequent thermal stability.

Heteroatom doping of graphene is a promising approach for tailoring its chemical and electronic properties - a prerequisite for many applications such as sensing, catalysis, and energy storage. Doping chemical vapour deposition (CVD) graphene with nitrogen during growth (in-situ doping) is a common strategy, but it produces a distribution of inequivalent dopant sites and requires substantial modifications to the CVD growth process. In this study, we demonstrate a novel and simple oxide-mediated approach to introduce nitrogen dopants into pre-existing CVD graphene (ex-situ doping) which achieves comparable doping densities to in-situ doping methodologies. Furthermore, we demonstrate that thermal annealing of N-doped graphene can selectively remove pyridinic, retaining graphitic and pyrrolic nitrogen dopants, offering an attractive route to further modify graphene functionality. The methodologies we present are simple and scalable to precisely tailor graphene properties without the need to alter CVD growth protocols.

Modification of In-situ N-doped graphene coated ZnO composites as anode for high performance lithium-ion batteries

The application of ZnO with high theoretical specific capacity as anode material for lithium-ion batteries is severely limited due to volume expansion during continuous cycling, slow lithium-ion diffusion, and poor conductivity. Here, ZnO nanoparticles were wrapped in N-doped multilayer graphene (ZnO@C) by chemical vapor deposition to improve specific capacity, rate performance, cycle stability, and conductivity. The thickness of the graphene layer and filling rate of ZnO in yolk-shell structure were investigated for the best electrochemical performance. The ZnO@C of yolk-shell structure with filling rate of 28% has a reversible specific capacity of 390 mAh/g after 200 cycles at 0.25 A/g, and achieves a capacity of 204.6 mAh/g at a high current of 1 A/g. The results show that N-doped porous graphene coated ZnO yolk-shell structure composites with etching treatment have good rate performance and cycle stability. The performance of electronic conductivity and lithium-ion diffusion is greatly improved, and the pseudocapacitive effect in the lithium storage mechanism is enhanced.

Employing novel N-doped graphene quantum dots to improve chloride binding of cement

One of the most primary reasons for durability deterioration of reinforced concrete (RC) structures is reinforcement corrosion caused by chloride ion invasion. However, there is still a lack of efficient additives to enhance the anti-chloride-corrosion behavior of RC structures. Herein, highly dispersed and cost-efficient N-doped graphene quantum dots (N-GQDs) are firstly applied to significantly increase the chloride binding performance of cement. Specifically, N-GQDs with high dispersity and low cost are successfully synthesized by one-step hydrothermal method. And the typical equilibrium test determines that after 14-day exposure to 3 M NaCl solution, the incorporation of 0.2 wt% (by weight of cement) N-GQDs makes the chloride binding ability of cement paste sharply boost by 134%. Moreover, in light of phase compositions analyses from XRD, TGA and SEM, the chloride binding mechanism of cement pastes modified by N-GQDs is rationally ascribed to the fact that the addition of N-GQDs enormously increases the physically adsorbed chloride ions and slightly promotes chemically bound chloride ions. This work firstly provides a novel carbon-based nanomaterial to efficiently enhance the chloride binding of cement, expected to improve the durability of RC structures.

Synergistic effect of nickel and calcium dual-atomic sites to facilitate electrochemical CO2 reduction to methanol: Combining high activity and selectivity

Atomically dispersed transition metal sites embedded into nitrogen-doped graphene provide promising potential for the electrochemical CO2 reduction to CO, but the catalytic efficiency for further hydrogenation to methanol is seriously restricted. Herein, combining the advantage of single transition metal, alkaline-earth metal, and multiple active sites, we designed nickel and calcium dual-atomic site catalysts (Ni-Ca DACs) supported on N-doped graphene to enable CO2 hydrogenation. First-principles calculations reveal that the electron-rich Ni atom serves as the carbon adsorption site, and the adjacent Ca atom with electron-deficient properties acts as the oxygen adsorption site, which largely stabilizes many CHxOy species through the O-Ca bond, especially the *OCHO, thus facilitating CO2 reduction. More importantly, a synergistic adsorption process on Ni-Ca sites promote the formation of *CHO species that is considered as the key intermediate for generation of multi-electron products. Different from the single Ni or Ca catalysts that produce mainly CO or HCOOH, the Ni-Ca DACs can selectively catalyze CO2 reduction to CH3OH, with a low limiting potential of −0.52 V, while suppressing the hydrogen evolution reaction. The outstanding catalytic activity originates from the tuned polarized charge and d-band center of active sites by synergistic interaction of adjacent Ni and Ca atoms.

Mechanistic understanding of the electrocatalytic conversion of CO into C2+ products by double-atom catalysts

Electrocatalytic CO reduction reaction (CORR) has gained increasing attentions to generate valuable multi-carbon (C2+) products, and designing high-performance electrocatalysts for CORR presents a great challenge for realizing its practical application. With the unique dual-atom site, double-atom catalyst (DAC) can provide enough geometric space to bind two CO molecules simultaneously for the key C–C coupling reaction. Herein, taking the typical 3d transition metal (TM) dimer anchored N-doped graphene (denoted as M1M2@NG) as representative, using first-principles calculations we theoretically investigate the catalytic mechanism and activity origin of CORR on DACs. It is found that the metal sites with higher d-band centers can effectively bind CO molecule, and further the d-band centers can be used as descriptors to predict the coupling free energy and coupling energy barrier for the key C–C coupling step of CO dimers. Intriguingly, among 21 candidates, CrCo and MnCo@NG DACs exhibit excellent performance for selectively generating ethanol (CH3CH2OH), with small C–C coupling energy barriers of 0.52 and 0.57 eV and ultralow limiting potentials of only −0.20 and −0.34 V, respectively, which has been further confirmed by the constant-potential simulations. Moreover, both heteronuclear CrCo and MnCo@NG exhibit significantly enhanced CORR performance compared with their homonuclear counterparts, which is ascribed to the unique d orbital synergy effect of the two different TM atoms. Our work provides rational guidelines for the design of efficient DACs for CORR, and brings useful insights into the boosted CORR performance enabled by the electronic synergy effect of the heteronuclear dual-atom site.

Homonuclear dual-atom catalysts embedded on N-doped graphene for highly efficient nitrate reduction to ammonia: From theoretical prediction to experimental validation

Electrocatalytic reduction of nitrate (NO3−) to ammonia (NRA) is emerging as an attractive strategy to attain valuable NH3 synthesis and harmful NO3− removal, but developing efficient electrocatalysts remains challenging. Herein, taking homonuclear dual metal catalysts (DACs) embedded on N-doped graphene as the example, we proposed a three-step strategy to theoretically evaluate their NRA catalytic performance by means of density functional theory (DFT) computations, which enables us to rapidly identify Cu2@N3−6 as the most promising NRA catalyst with a low limiting potential (−0.14 V). More importantly, such theoretical prediction was further validated by our proof-of-concept experiment: the NH3 yield rate of ∼18.2 mg h−1 cm−2 at − 0.8 V vs RHE and the Faradaic efficiency of 97.4% were achieved. Our studies may offer a feasible avenue to rapidly and precisely achieve efficient NRA catalysts by using theoretical prediction as a guideline for experimentalists to avoid the traditional “trial and error method”.

Facile synthesis of N-doped graphene oxide decorated with copper ferrite as an electrode material for supercapacitor with enhanced capacitance

In the past decade, enormous attempts have been made to modify the effective electrode materials for the construction of supercapacitors. Here, we report a cost-effective, simple, and one-pot hydrothermal technique to fabricate a new nanocomposite based on nitrogen-doped graphene oxide (NGO) nanosheets twisted with copper ferrite nanoparticles (CuFe2O4 NPs) as a new supercapacitor material with outstanding performance. A concurrent synthetic route takes advantage of the synergetic impact caused by the high pseudo-capacitance of CuFe2O4 and the superior electrical conductivity of NGO, resulting in a larger performance improvement of the nanocomposite than that of blank CuFe2O4. The as-prepared NGO/ CuFe2O4 electrode significantly shows an excellent specific capacitance of 348 F/g at 1 A/g current density with superior cycling stability, saving 87% of its first capacitance over 2000 GCD cycles. The electrochemical analysis revealed that the NGO provides a continuous conductive pathway for electron/ion transport and a large surface area and alleviates the significant strain resulting from the volume expansion of CuFe2O4. Furthermore, an asymmetrical supercapacitor is produced by NGO/CuFe2O4 as the positive electrode and activated carbon as the negative electrode, which shows superior electrochemical performance, producing a high energy density (35.79 Wh/kg) and a high-power density (883.09 W/kg) with excellent cycling stability. This article aims to provide a rapid and scalable hydrothermal approach for synthesizing NGO/CuFe2O4 nanocomposites with increased electrochemical efficiency for supercapacitor applications.

Activating the PdN4 single-atom sites for 4 electron oxygen reduction reaction via axial oxygen ligand modification

The absence of Pd ensemble sites and weak affinity for O-intermediates in tetracoordinate planar PdN4 sites inhibit O-O bond dissociation and restrict 4e- oxygen reduction reaction (ORR) pathway. Optimizing the adsorption energy between O-intermediates and PdN4 sites is a rational approach for selectively promoting 4e- ORR electrocatalysis. Herein, we propose a molten-salt strategy for introducing axial oxygen ligand into the PdN4 sites to manipulate the electronic structure and create catalytic O-PdN4 sites (one subsurface axial Pd-O configuration on PdN4 plane) on N-doped graphene nanosheets (O-PdN4-NGS). Density functional theory calculations revealed that the axial Pd-O coordination can induce charge redistribution, downshift the d-band center of Pd and enhance the adsorption affinity of PdN4 site for O-intermediates, thereby leading to superior electrocatalysis activity and selectivity for 4e- ORR process compared to conventional PdN4 sites in 0.1 M KOH (with a positive half-wave potential E1/2 of 0.90 V vs RHE). Moreover, zinc-air battery featuring with O-PdN4 sites delivers a peak power density of 178 mW cm−2 at 227.5 mA cm−2 and stable long-term cycling performance, effectively showcasing the advantages of the axial O ligand modification in practical application. This work provides a constructive strategy to activate the reaction activity and specificity of PdN4 single-atom sites by precisely-tuning the local coordination environment of Pd.

Dried figs like nitrogen-doped graphene oxide anchored cobalt-doped Fe3O4 nanoparticle as sulfur host for high performance Li-S battery

Lithium-sulfur batteries (LSBs) represent a prospective energy storage device because of their low cost and high theoretical energy density. However, the performance of LSBs was largely constrained by the kinetics of polysulfides (LiPSs) conversion and shuttle effect. Thus, a metal-doped metal oxide is proposed as an efficient adsorbent and catalyst for LiPSs. We designed cobalt-doped Fe3O4 nano-catalysts which was in situ grown on the N-doped graphene conductive network as a multifunctional sulfur host. Evidenced by experimental characterization, it is demonstrated that due to the appropriate doping amount (EGO/Co-Fe3O4 (700)), the host exhibits efficient adsorption and rapid catalytic conversion of LiPSs. Compared with the undoped Co catalyst (S@EGO/Fe3O4), The S@EGO/Co-Fe3O4 (700) electrode possesses high initial discharge specific capacity (1488.4 mAh/g, 0.2 C), and superior cycle stability (900.8 mAh/g after 100 cycles). Impressive performances are also attained at lean electrolyte conditions (electrolyte-to-sulfur (E/S) ratio ∼ 7 μL mg−1).

Efficient pH-universal aqueous supercapacitors enabled by an azure C-decorated N-doped graphene aerogel

Current aqueous supercapacitors (SCs) possess the relative low energy density, and there is therefore widespread interest in cost-effective fabrication of capacitive materials with promoted specific capacitance and/or broadened voltage window. Here, a redox-active azure C-decorated N-doped graphene aerogel (AC − NGA) is fabricated using a simple hydrothermal self-assembly method through strong noncovalent π-π interaction. AC − NGA highlights an excellent charge storage performance (a high 591F g−1 gravimetric capacitance under a current density of 1.0 A g-1 and ultrahigh voltage window of 2.3 V) under pH-universal conditions. The capacitive contribution of charge storage is 91.7%, exceeding or comparable to those of the best pseudocapacitors known. Furthermore, a symmetric AC − NGA//AC − NGA device realizes high energy and power densities (15.2–60.2 Wh kg−1 at 650–23,000 W kg−1) and excellent cycling stability in acidic, neutral, and basic aqueous solutions. This work offers a cost-effective strategy to combine redox dye molecules with heteroatom-doped graphene aerogel for building green efficient pH-universal aqueous supercapacitors.

Synergy of dual-atom catalysts deviated from the scaling relationship for oxygen evolution reaction.

Dual-atom catalysts, particularly those with heteronuclear active sites, have the potential to outperform the well-established single-atom catalysts for oxygen evolution reaction, but the underlying mechanistic understanding is still lacking. Herein, a large-scale density functional theory is employed to explore the feasibility of *O-*O coupling mechanism, which can circumvent the scaling relationship with improving the catalytic performance of N-doped graphene supported Fe-, Co-, Ni-, and Cu-containing heteronuclear dual-atom catalysts, namely, M'M@NC. Based on the constructed activity maps, a rationally designed descriptor can be obtained to predict homonuclear catalysts. Seven heteronuclear and four homonuclear dual-atom catalysts possess high activities that outperform the minimum theoretical overpotential. The chemical and structural origin in favor of *O-*O coupling mechanism thus leading to enhanced reaction activity have been revealed. This work not only provides additional insights into the fundamental understanding of reaction mechanisms, but also offers a guideline for the accelerated discovery of efficient catalysts.

Theoretical Insights on ORR Activity of Sn-N-C Single-Atom Catalysts.

The advancement of efficient and stable single-atom catalysts (SACs) has become a pivotal pursuit in the field of proton exchange membrane fuel cells (PEMFCs) and metal-air batteries (MABs), aiming to enhance the utilization of clean and sustainable energy sources. The development of such SACs has been greatly significant in facilitating the oxygen reduction reaction (ORR) process, thereby contributing to the progress of these energy conversion technologies. However, while transition metal-based SACs have been extensively studied, there has been comparatively less exploration of SACs based on p-block main-group metals. In this study, we conducted an investigation into the potential of p-block main-group Sn-based SACs as a cost-effective and efficient alternative to platinum-based catalysts for the ORR. Our approach involved employing density functional theory (DFT) calculations to systematically examine the catalyst properties of Sn-based N-doped graphene SACs, the ORR mechanism, and their electrocatalytic performance. Notably, we employed an H atom-decorated N-based graphene matrix as a support to anchor single Sn atoms, creating a contrast catalyst to elucidate the differences in activity and properties compared to pristine Sn-based N-doped graphene SACs. Through our theoretical analysis, we gained a comprehensive understanding of the active structure of Sn-based N-doped graphene electrocatalysts, which provided a rational explanation for the observed high four-electron reactivity in the ORR process. Additionally, we analyzed the relationship between the estimated overpotential and the electronic structure properties, revealing that the single Sn atom was in a +2 oxidation state based on electronic analysis. Overall, this work represented a significant step towards the development of efficient and cost-effective SACs for ORR which could alleviate environmental crises, advance clean and sustainable energy sources, and contribute to a more sustainable future.