High-performance Electrocatalysts Research Articles

Fabrication of Platinum-Decorated NiCo-Layered Double Hydroxide Nanoflowers for Electrocatalytic Ammonia Oxidation Reaction

The complete anodic oxidation of ammonia is an important part of direct ammonia fuel cells. Fabricating a high-performance electrocatalyst for ammonia oxidation reaction is meaningful for developing a direct ammonia fuel cell. Herein, we designed one platinum-decorated NiCo-layered double hydroxide nanoflower on Ni foam (Pt-NiCo-LDH-Ni foam) and measured the electrocatalytic performance via the cyclic voltammetry (CV) technique. The experimental results demonstrated that the optimized Pt-NiCo-LDH-Ni foam showed great electrocatalytic performance, with a low overpotential with a value of −0.573 V, a high current density of 17.75 mA cm−2 for the ammonia oxidation reaction, and good stability.

Highly Efficient CoFeP Nanoparticle Catalysts for Superior Oxygen Evolution Reaction Performance.

Developing effective and long-lasting electrocatalysts for oxygen evolution reaction (OER) is critical for increasing sustainable hydrogen production. This paper describes the production and characterization of CoFeP nanoparticles (CFP NPs) as high-performance electrocatalysts for OER. The CFP NPs were produced using a simple hydrothermal technique followed by phosphorization, yielding an amorphous/crystalline composite structure with improved electrochemical characteristics. Our results reveal that CFP NPs have a surprisingly low overpotential of 284 mV at a current density of 100 mA cm-2, greatly exceeding the precursor CoFe oxide/hydroxide (CFO NPs) and the commercial RuO2 catalyst. Furthermore, CFP NPs demonstrate exceptional stability, retaining a constant performance after 70 h of continuous operation. Post-OER characterization analysis revealed transformations in the catalyst, including the formation of cobalt-iron oxides/oxyhydroxides. Despite these changes, CFP NPs showed superior long-term stability compared to native metal oxides/oxyhydroxides, likely due to enhanced surface roughness and increased active sites. This study proposes a viable strategy for designing low-cost, non-precious metal-based OER catalysts, which will help advance sustainable energy technology.

Interfacial engineering of ruthenium-nickel for efficient hydrogen electrocatalysis in alkaline medium

Developing highly efficient electrocatalyst with heterostructure for hydrogen evolution and oxidation reactions (HER/HOR) in alkaline media is crucial to the fabrication and conversion of hydrogen energy but also remains a great challenge. Herein, the synthesis of ruthenium-nickel nanoparticles (Ru3-Ni NPs) with heterostructure for hydrogen electrocatalysis is reported, and studies show that their catalytic activity is improved by electron redistribution caused by the distinctly heterogeneous interface. Impressively, Ru3-Ni NPs possess the remarkable exchange current density (2.22 mA cm−2) for HOR. Additionally, an ultra-low overpotential of 28 mV is required to attain a current density of 10 mA cm−2 and superior stability of 200 h for HER. The highly efficient catalytic activity can be attributed to the electron transfer from Ni to Ru and the optimal adsorption of H* on Ru-Ni sites. Our study showcases a reliable heterostructure that boosts the HOR/HER activity of the catalyst in alkaline environments. This work provides a new pathway for designing high-performance electrocatalyst for energy storage and conversion.

Perfect Is Perfect: Nickel Prussian Blue Analogue as A High-Efficiency Electrocatalyst for Hydrogen Peroxide Production.

Prussian blue analogues (PBA) are a large family of functional materials with diverse applications such as in electrochemical fields. However, their use in the emerging two-electron oxygen reduction reaction for clean production of hydrogen peroxide (H2O2) is lagging. Herein, a general solvent exchange induced reconstruction strategy is demonstrated, through which an abnormal NiNi-PBA superstructure is synthesized as a high-performance electrocatalyst for H2O2 generation. The resultant NiNi-PBA superstructure has a stoichiometric composition with saturated lattice water, and a leaf-like morphology composed of interconnected small-size nanosheets with identical orientation and predominate {210} side surface exposure. Our studies show that the Ni-N centers on {210} facets are the active sites, and the saturated lattice H2O favors a six-coordinated environment that results in high selectivity. The "perfect" structure including stoichiometric composition and ideal facet exposure leads to a high selectivity of ~100% and H2O2 yield of 5.7 mol g-1 h-1, superior to the reported MOF-based electrocatalysts and most other electrocatalysts.

High-Performance Low-Iridium Catalyst for Water Oxidation: Breaking Long-Ranged Order of IrO2 by Neodymium Doping.

Exploring efficacious low-Irelectrocatalysts for oxygen evolution reaction (OER) is crucial for large-scale application of proton exchange membrane water electrolysis (PEMWE). Herein, an efficient non-precious lanthanide-metal-doped IrO2 electrocatalyst is presented for OER catalysis by doping large-ionic-radius Nd into IrO2 crystal. The doped Nd breaks the long-ranged order structure by triggering the strain effect and thus inducing an atomic rearrangement of Nd─IrO2 involving the forming of Nd─O─Ir bonds along with an increased amount of oxygen vacancies (Ov), giving rise of a long-ranged disorder but a short-ranged order structure. The formed Nd─O─Ir bonds tailor the electronic structure of Ir, leading to a lowered d-band center that weakens intermediates absorption on Ir sites. Moreover, doping Nd triggers Nd─IrO2 to catalyze OER mainly through lattice oxygen mechanism (LOM) by activating lattice oxygen owing to abundant Ov. The optimal catalyst only requires a relatively low overpotential of 263 mV@10mA cm-2 with a high mass activity of 216.98 A gIr -1 (at 1.53V) (eightfold of commercial IrO2), and also shows a superior durability at 50mA cm-2 (20h) than commercial IrO2 (3h) due to the oxidation-suppressing effect induced by Nd doping. This work offers insights into designing high-performance low-Ir electrocatalysts for PEMWE application.

Asymmetric Microenvironment Tailoring Strategies of Atomically Dispersed Dual-Site Catalysts for Oxygen Reduction and CO2 Reduction Reactions.

Dual-atom catalysts (DACs) with atomically dispersed dual-sites, as an extension of single-atom catalysts (SACs), have recently become a new hot topic in heterogeneous catalysis due to their maximized atom efficiency and dual-site diverse synergy, because the synergistic diversity of dual-sites achieved by asymmetric microenvironment tailoring can efficiently boost the catalytic activity by optimizing the electronic structure of DACs. Here, this work first summarizes the frequently-used experimental synthesis and characterization methods of DACs. Then, four synergistic catalytic mechanisms (cascade mechanism, assistance mechanism, co-adsorption mechanism and bifunction mechanism) and four key modulating methods (active site asymmetric strategy, transverse/axial-modification engineering, distance engineering and strain engineering) are elaborated comprehensively. The emphasis is placed on the effects of asymmetric microenvironment of DACs on oxygen/carbon dioxide reduction reaction. Finally, some perspectives and outlooks are also addressed. In short, the review summarizes a useful asymmetric microenvironment tailoring strategy to speed up synthesis of high-performance electrocatalysts for different reactions.

N,F co-doped carbon derived from spent bleaching earth waste as oxygen electrocatalyst support.

Affordable nitrogen and fluorine co-doped carbon nanostructure was prepared from the hazardous industrial waste of edible oil refinery, spent bleaching earth (SBE), and used as raw material for obtaining high-performance non-noble metal bifunctional oxygen electrocatalysts. Waste SBE contains 35 per cent residue non-saturated oil as a carbon source and the assistance of montmorillonite (MMT) as the template. This study converts waste SBE into a fluorine-doped carbon nanostructure through a pyrolysis process followed by removing the aluminosilicate layers of the MMT by HF etching. Furthermore, the impregnation of the support with Co and Fe nitrates readily gives rise to N, F co-doped carbon (NFC) electrocatalysts, as confirmed by XPS analysis. Electrochemical results evidenced that the Co-NFC catalyst proved to be a valuable bifunctional competitor for oxygen reduction reaction and oxygen evolution reaction in alkaline media, showing activity in both reactions and superior stability compared with the Fe-NFC catalyst in accelerated tests. This work offers a straightforward, economical and eco-friendly strategy for designing N, F co-doped carbon-based electrocatalysts for oxygen reactions in electrochemical devices.

Noble metal-modified copper surfaces for alkaline condition hydrogen evolution reaction

Cu-based materials would be attractive candidates for cost-effective alkaline hydrogen evolution reaction (HER) electrocatalysts due to high abundance, excellent conductivity, and excellent stability in alkaline environments, if not for the inherent inertness of Cu in HER. This inertness has led to a relative lack of research on Cu-based HER catalysts in both experimental and theoretical domains. Here, We report engineered Cu(111) surfaces that can significantly improve the poor activity of H2O dissociation on pure Cu(111) surface. We do this by introducing noble metal atoms (M = Ru, Rh, Pd, Ag, Os, Ir, Pt) through surface doping. These modified surfaces exhibit excellent thermodynamic and electrochemical stability, with the exception of Cu(111)-Ag. Notably, the H2O dissociation energy barrier on Cu(111)-Os (Eb) is only 0.74 eV, which is much smaller than that (1.31 eV) of pure Cu(111), and is even lower than that of Pt (Eb = 0.92 eV), which is commercially used for electrodes. The low Eb and resulting expected excellent performance of Cu(111)-Os for water splitting is related to the particular local electronic properties of doped Os atoms, specifically the electronic structure of the Os d-orbitals, which have a d-band center near Fermi level (EF) and a high density of states around EF, including just above EF. These results are expected to stimulate the investigation of surface alloyed Cu, leading to a new direction for the design of high-performance and low-cost electrocatalysts.

Surface reconstruction of hierarchical CoNiP@Ni2P nanoarray to promote overall water splitting

Efficient water splitting remains a challenge to produce clean and pure H2 in an industrial scale for the lack of high-performance cost-effective stable electrocatalysts of hydrogen and oxygen evolution (HER and OER). Surface engineering is a novel proposal to upgrade the electrocatalytic performances of HER and OER catalysts. Herein, a hierarchical architecture composed of carbon-supported CoNiP nanoplates (NPs) on Ni2P nanowire was constructed. The nanoarray of CoNiP@Ni2P heterostructure shows a high bifunctional activity of HER and OER. The overpotential is 46 mV required for HER at 10 mA·cm−2 and 292 mV for OER at 100 mA·cm−2 in 1 mol·L−1 KOH. In addition, the nanoarray of CoNiP@Ni2P heterostructure also shows a high stability for HER. The HER activity can be maintained at 11 mA·cm−2 without loss after 50 h cathode polarization at the overpotential of 100 mV, while the OER activity continuously increases from 26 to 64 mA·cm−2 at an overpotential of 400 mV after 50 h anode polarization. The enhancement of the oxygen evolution performance can be ascribed to the surface reconstruction of CoNiP/Ni2P heterostructure nanoarray, which can offer more active sites to OER. Density functional theory (DFT) reveals surface reconstruction can create an oxygen-rich surface in favor of intermediate adsorption, thus enabling a fast OER kinetics at the interface of NiCoOOH/Ni2P heterostructure. This work highlights surface reconstruction adaptability to design advanced catalysts of efficient water splitting for commercial H2 production.

Component synergistic effect of Co9S8/FeBOx composite system for efficient oxygen evolution reaction

The synergistic interaction between the components of the composites is the key to modulate the intrinsic activity and stability of oxygen evolution reaction (OER). In this study, an efficient and stable Co9S8/FeBOx composite system was constructed by combining Co9S8 with FeBOx as an OER catalyst. The synergistic effect of the components effectively promotes the interfacial charge transfer between different components, which is conducive to improving OER performance. The Co9S8/FeBOx-2 catalyst exhibits exceptional OER activity and stability, achieving a current density of 10 mA cm−2 in 1 M KOH electrolyte with an overpotential of only 214 mV. It can be stably operated for over 150 h at a current density of 200 mA cm−2. This research opens up a new avenue for designing high-performance electrocatalysts with unconventional properties for energy and environmental applications.

A high-performance electrocatalyst for sustainable ammonia synthesis via single-atom Ru-embedded Fe2O3 nitrogen-DOPED carbon

Ammonia (NH3) is an important industrial chemical, but the production of NH3 by the conventional Haber-Bosch process consumes large amounts of energy and has a serious environmental impact. Electrochemical nitrogen reduction reaction (NRR) offers a promising green alternative, but challenges remain in developing efficient catalysts. Here, we report the synthesis of single-atom Ru-embedded metal–organic framework-derived Fe2O3 nitrogen-doped carbon (Ru/Fe2O3-NC) materials via plasma-enhanced chemical vapour deposition. Under ambient conditions, the Ru/Fe2O3-NC catalyst exhibited a high NH3 yield rate of 141.18 μg h−1 mgcat.−1 in 0.1 M K2SO4 with a Faraday efficiency (FE) of 48.89 %, which was superior to the pristine Fe2O3-NC catalyst. Online differential electrochemical mass spectrometry (DEMS) analysis confirmed the selective generation of NH3 and no by-product N2H4 was detected. The Ru/Fe2O3-NC catalyst also showed remarkable stability during prolonged electrolysis. This work demonstrates the synergistic effect of incorporating single-atomic Ru in the Fe2O3-NC framework and provides a new platform for the development of advanced catalysts for the efficient and sustainable electrochemical synthesis of NH3.

First-principles study of electrochemical H2O2 production on Pd-B40 single-atom catalyst

Hydrogen peroxide (H2O2), a versatile green compound, is increasingly in demand. The electrochemical two-electron oxygen reduction reaction (2e− ORR) is a simple and environmentally friendly substitute method to the traditional anthraquinone oxidation method for H2O2 production. This study systematically investigates the 2e− ORR process on single transition metal atom-loaded boron fullerene (M − B40) using density functional theory calculations. In evaluating the stability of the catalysts, we found that Au, Pd, Pt, Rh, and Ir atoms adsorbed on hexagonal or heptagonal sites of B40 exhibit good stability. Among these, Pd-modified B40 heptagonal cavity (Pd-B40-heptagonal) demonstrates an ideal Gibbs free energy change for OOH* (4.49 eV) and efficiently catalyzes H2O2 production at a low overpotential (0.27 V). Electronic structure analysis reveals that electron transfer between Pd-B40-heptagonal and adsorbed O2 facilitates O2 activation. Additionally, the high 2e− ORR activity of Pd-B40-heptagonal is attributed to electron transfer from the Pd-d orbitals to the π* anti-bonding of p orbitals of OOH*, moderately activating the O-O bond. This study offers valuable understanding designing high-performance electrocatalysts for 2e− ORR.

Edge-Rich Pt-O-Ce Sites in CeO2 Supported Patchy Atomic-Layer Pt Enable a Non-CO Pathway for Efficient Methanol Oxidation.

Rational design of efficient methanol oxidation reaction (MOR) catalyst that undergo non-CO pathway is essential to resolve the long-standing poisoning issue. However, it remains a huge challenge due to the rather difficulty in maximizing the non-CO pathway by the selective coupling between the key *CHO and *OH intermediates. Here, we report a high-performance electrocatalyst of patchy atomic-layer Pt epitaxial growth on CeO2 nanocube (Pt ALs/CeO2) with maximum electronic metal-support interaction for enhancing the coupling selectively. The small-size monolayer material achieves an optimal geometrical distance between edge Pt-O-Ce sites and *OH absorbed on CeO2, which well restrains the dehydrogenation of *CHO, resulting in the non-CO pathway. Meanwhile, the *CHO/*CO intermediate generated at inner Pt-O-Ce sites can migrate to edge, inducing the subsequent coupling reaction, thus avoiding poisoning while promoting reaction efficiency. Consequently, Pt ALs/CeO2 exhibits exceptionally catalytic stability with negligible degradation even under 1000 s pure CO poisoning operation and high mass activity (14.87 A/mgPt), enabling it one of the best-performing alkali-stable MOR catalysts.

Co-CoSe heterogeneous fibers with strong interfacial built-in electric field as bifunctional electrocatalyst for high-performance Zn-air battery

The explorations of efficient electrocatalysts to accelerate oxygen reactions in a wide temperature range is a crucial issue to the development of zinc-air batteries (ZAB) for all-climate applications. Herein, the Co-CoSe heterogeneous furry fibers (Co-CoSe@NHF) are developed as a bifunctional oxygen electrocatalyst for ZAB towards wide-temperature range applications. The Co-CoSe heterostructure with large work function difference (ΔWF) endows interfacial electron redistribution, which builds strong interfacial built-in electric field (BIEF) and improves the oxygen reactions. Meanwhile, the Co-CoSe heterostructure is encapsulated by in-situ grown carbon nanotubes, and forms the hollow fiber (NHF) with furry surface and beads-on-string configuration. The highly porous and conductive NHF configuration facilitates the fast kinetics and favors to accommodates volume change during cycling. As a result, the Co-CoSe@NHF achieves the superior bifunctional properties and good reliability for oxygen reactions. Integrated with the Co-CoSe@NHF fiber, the ZAB cell delivers the superior power density (301 mW cm−2) and long-term cycling stability over 280 h at 25 °C, and maintains the power densities of 126 mW cm−2 even the temperature decreases to −25 °C. Moreover, the solid-state ZAB exhibits significant flexibility and superior properties in a wide temperature range. Therefore, this work not only proposes a new strategy to design the high-performance bifunctional electrocatalysts, but also propels the development of flexible power sources for all-climate applications.

Tri-Electrode Structured Zinc-Air Batteries: A Leap in Energy Storage Efficiency and Stability

Rechargeable zinc-air batteries (ZABs) are gaining attention as a potent solution for large-scale energy storage, offering high capacity and an environmentally friendly profile. Utilizing zinc, an abundant and cost-effective alternative to lithium, ZABs capitalize on the plentiful oxygen in ambient air, presenting a more sustainable option than traditional lithium-ion batteries. In this work, we address the operational challenges of ZABs, primarily focusing on the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) that occur during the discharge and charge cycles. ORR, a three-phase reaction, necessitates efficient water management and high-performance electrocatalysts, while OER is a two-phase reaction prone to creating oxygen bubbles that can damage the electrode structure. A critical issue in ZABs is the instability of ORR catalysts during the OER phase, and vice versa. To counter this, we propose a tri-electrode cell structure that separates the ORR and OER electrodes, allowing each to be optimized independently. This design enhances the stability and overall efficiency of the batteries. In our study, MnO2/C deposited on nickel foam was employed as the ORR electrode, and layered double hydroxides (LDHs) deposited directly on stainless steel mesh served as the OER electrode. A graphite electrode was used as the common negative electrode. Our proposed system, tested at 100 mAh/cm² and 25 mA/cm², demonstrated remarkable durability, sustaining at least 100 cycles with a Coulombic efficiency of 98% and a 60% roundtrip efficiency. These findings offer valuable insights into the future design of stable, high-efficiency rechargeable zinc-air batteries, marking a significant step forward in sustainable energy storage technology.

Scaling-up a Photo-Electrocatalytic Reactor for CO2 Capture and Conversion to Syngas

The most challenging deal we face today is the need to lower greenhouse gas (GHG) emissions and tackle climate change. Though calls to reduce them are growing louder yearly, emissions remain unsustainably high. CO2 is the key contributor to global climate change in the atmosphere. Electrochemical CO2 reduction (EC CO2R) into chemicals or fuels holds great research interest as a promising approach to mitigate CO2 emissions and reach a carbon-neutral future.1 In this regard, an extraordinary effort has been made to discover new efficient and sustainable catalysts at the laboratory level over recent years. High-performance electrocatalysts in aqueous electrolytes often rely on noble metals, which may hinder their industrial applications. Herein, we successfully synthesized core-shell Cu2O/SnO2 nanoparticles2–4 functionalized with a silane group, using a simple and versatile methodology based on a three-step scalable synthesis method involving wet precipitation followed by salinization and, finally, a rhenium-based complex has been assembled by electro-polymerization.5 The carbon paper-supported Cu2O/SnO2-Re electrocatalyst was characterized at 10 cm2 scale achieving a CO:H2 ratio from 3 to 9, and demonstrating an stable syngas production up to 24 hours at -20 mA·cm-2. To translate those developments from the laboratory level to a higher TRL towards the practical application of CO2 capture and utilization6, an additional chamber was added to the system for the continuous CO2 capture and electrochemical conversion, increasing the electrode area from 10 cm2 to 100 cm2. Captured CO2 co-electrolysis to syngas (H2:CO ratio of 5) in one step was demonstrated with a high CO2 conversion at a current up to -2 A, indicating the scale-up potential of this intensified system. The technology is currently under validation in a TRL4 reactor composed of an array of 5 modules (i.e., 4 x 5 cells x 100 cm2) with a total active area of or 0.2m2 for direct CO2 conversion from simulated anthropogenic sources. The design integrates low-cost photovoltaic (PV) cells to provide any required additional bias to drive the reaction, thus, Perovskite PV panels with a cost of up to 5 times lower (10 €/m2) than Si PV cells were used. The TRL5 demonstration of the developed technology will be done with real flue gas emissions the first semester of 2024. Acknowledgements The financial support of the SUNCOCHEM project (Grant Agreement No 862192) of the European Union’s Horizon 2020 Research and Innovation Action programme is acknowledged. References Guzmán, H., Russo, N. & Hernández, S. CO2 valorisation towards alcohols by Cu-based electrocatalysts: challenges and perspectives. Green Chemistry vol. 23 1896–1920 Preprint at https://doi.org/10.1039/d0gc03334k (2021).Cuatto, G. et al. Standardization of Cu2O nanocubes synthesis: Role of precipitation process parameters on physico-chemical and photo-electrocatalytic properties. Chemical Engineering Research and Design 199, 384–398 (2023).Zoli, M., Guzmán, H., Sacco, A., Russo, N. & Hernández, S. Cu2O/SnO2 Heterostructures: Role of the Synthesis Procedure on PEC CO2 Conversion. Materials 16, (2023).Zoli, M. et al. Facile and scalable synthesis of Cu2O-SnO2 catalyst for the photoelectrochemical CO2 conversion. Catal Today 413–415, 113985 (2023).Miró, R. et al. Solar-driven CO2 reduction catalysed by hybrid supramolecular photocathodes and enhanced by ionic liquids. Catal Sci Technol 13, 1708–1717 (2023).Sullivan, I. et al. Coupling electrochemical CO2 conversion with CO2 capture. Nat Catal 4, 952–958 (2021). Figure 1

Enhanced Local Ion Transport in High-Performance Anion Exchange Membrane Water Electrolyzers Via Quaternary Ammonium-Functionalized Metal-Organic Framework Electrocatalysts

Anion-exchange membrane water electrolyzers (AEMWEs) present a multitude of advantages, particularly in the utilization of non-platinum group (non-PGM) catalysts. While diverse catalysts have demonstrated notable electrocatalytic activity in alkaline conditions, the integration of the ionomer with the electrocatalyst at the active catalyst layer is crucial for enhancing overall AEMWE performance in practical device demonstrations by improving mass transport. However, the intrinsic instability of polymeric ionomers, leading to physical detachments or alkaline (chemical) degradation, poses a challenge that can potentially diminish performance. In this study, drawing inspiration from the aforementioned ionomer chemistry, we introduce non-PGM NiFe-based metal-organic frameworks (MOFs) incorporating quaternary ammonium (QA) cation moieties covalently functionalized to benzenedicarboxylic acid (BDC) ligands as promising electrocatalysts for the oxygen evolution reaction (OER) in alkaline environments. Three specifically designed functional groups with varying ion exchange capacities (IEC) and alkaline stability—trimethylamine (TMA), N-methylpyrrolidine (C4N), and N-methylpiperidine (C5N)—were directly tethered to BDC ligands. The alkaline OER activity of Ni2Fe1-QA-MOF was meticulously assessed using rotating disk electrodes and AEMWE devices. These directly tethered QA groups markedly facilitated improved ionic transport of OH- ions at the catalyst/electrolyte interfaces compared to BDC ligands, ultimately leading to a significant enhancement in half-cell activity and AEMWE performance. In-situ IR/RAMAN spectroscopy revealed that QA moieties highly promoted local ionic transport at the interfaces, as evidenced by characteristic peaks indicating a robust interaction between QA and OH- ions. Unexpectedly, QA moieties not only contributed to ionic transport in local environments but also induced oxidation states of Ni metal sites, while Fe sites exhibited no changes during the applied potential in the OER region, as comprehensively revealed by synchrotron X-ray absorption spectroscopy (XAS). In comparison with conventional NiFe layered double hydroxide (LDH) structures, we posit that the substantial structural transformation of Ni moieties can be attributed to an increased degree of M-O bond interaction, enhanced by the local interaction between QA and OH- ions. Density functional theory (DFT) calculations also validate the balanced adsorption of OER intermediates on QA-MOFs. Finally, QA-NiFe-MOF was directly synthesized on a porous transport layer (PTL), and its AEMWE performance was evaluated without the use of any ionomer. At 1.0 M KOH, C4N, C5N, and TMA-based NiFe MOFs exhibited current densities of 9.35 A/cm2, 9.11 A/cm2, and 7.6 A/cm2, respectively. These current densities surpassed those of bare BDC-NiFe MOF and commercial IrO2 anode catalysts, which exhibited only 7.39 A/cm2 and 6.4 A/cm2, respectively. Consequently, we emphasize that the facilitation of local ionic transport could yield remarkable AEMWE performance, even in the absence of conventional polymeric ionomers.

MOF-Derived Selenium-Enriched Hollow NiCo2O4/NiO Nanocages for Enhanced Oxygen Evolution Reaction

Finding clean, sustainable, and environmentally friendly technologies is especially crucial in addressing both energy and environmental challenges. Intending to accelerate the oxygen evolution reaction (OER) which happens at the anode and and to decrease the energy consumption for water-splitting at a large scale, exploring high-performing electrocatalysts is an imperative undertaking essential to maximize the practical applicability of water splitting. Developing electrocatalysts through strategic surface modifications represents a significant approach to the deliberate creation of exceptionally active catalytic centers through rational means. Considerable attention has been focused on the advancement of mixed oxides based on transition metals as highly active electrocatalysts. In the present work, we have successfully synthesized electrocatalysts for the OER as elemental selenium incorporated hollowed NiCo2O4/NiO nanocages by employing precise control over the structure and composition of the material. The findings demonstrated that the surface reconstructed hollowed structure with plenty of thin nanocages enhancement of 5 wt% Se-NiCo2O4/NiO resulted in an increased quantity of corresponding edge active sites. This structural achievement further expedited mass transport and due to increased conductivity sped up the charge transfer processes within the system, exhibited remarkable activity for the OER, displaying a low overpotential (η=288 mV) at a current density (j) of 10 mA cm−2 and a Tafel slope (66.7 mV dec−1) including better stability. This work offers a viable and versatile method for fabricating a range of functional coordinated MOF compounds that hold potential for utilization across diverse energy applications including storage, conversion, and environmental purposes. Figure 1

Rapid Synthesis of Ruthenium-Copper Nanocomposites as High-Performance Bifunctional Electrocatalysts for Electrochemical Water Splitting.

Development of high-performance, low-cost catalysts for electrochemical water splitting is key to sustainable hydrogen production. Herein, ultrafast synthesis of carbon-supported ruthenium-copper (RuCu/C) nanocomposites is reported by magnetic induction heating, where the rapid Joule's heating of RuCl3 and CuCl2 at 200A for 10s produces Ru-Cl residues-decorated Ru nanocrystals dispersed on a CuClx scaffold, featuring effective Ru to Cu charge transfer. Among the series, the RuCu/C-3 sample exhibits the best activity in 1m KOH toward both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), with an overpotential of only -23 and +270mV to reach 10mAcm-2, respectively. When RuCu/C-3 is used as bifunctional catalysts for electrochemical water splitting, a low cell voltage of 1.53V is needed to produce 10mAcm-2, markedly better than that with a mixture of commercial Pt/C+RuO2 (1.59V). In situ X-ray absorption spectroscopy measurements show that the bifunctional activity is due to reduction of the Ru-Cl residues at low electrode potentials that enriches metallic Ru and oxidation at high electrode potentials that facilitates the formation of amorphous RuOx. These findings highlight the unique potential of MIH in the ultrafast synthesis of high-performance catalysts for electrochemical water splitting.

Valence band-tunable NiFe electrocatalyst triggered by the dynamic Mo exudation and re-deposition for superior high current density oxygen evolution reaction.

Developing energy- and time-efficient strategies to derive high-performance non-precious electrocatalysts for anodic oxygen evolution reaction (OER), especially stably working at industrial-demanding current density, is still a big challenge. In this work, a concise molten salt erosion scenario was devised to rapidly modulate the smooth surface of the commercial NiMo foam substrate into the rough, electronically coupled, and hierarchically porous Ni/Fe/Mo(oxy)hydroxide catalyst layer assembled by the nanosphere array. This self-supported catalyst is super-hydrophilic for the alkaline electrolyte and distinguished by a balanced Mo leaching/surface-readsorption process to tune the metal d band center and electronic perturbation. The altered electronic environment with the favored OER intermediate adsorption behavior attains the outstanding OER activity in terms of a very small overpotential of 230.21 mV at 10 mA cm-2 and an ultra-long stability for 1179.45 h to sustain the initial commercial-level current density of ca. 1000 mA cm-2. This superb performance transcends most of the edge-cutting transition metal peers reported recently and can satisfy the standards of industrial applications. This industrial-compatible synthesis technology holds profound implications for hydrogen production via water splitting and other electrochemical applications.