Evolution Reaction Performance Research Articles

Hierarchical Architectures by Hybridizing Ru Nanoparticles with Nitrogen/Oxygen Dual‐Doped Carbon Nanotubes for Advanced Hydrogen Evolution Reaction Performance

AbstractDeveloping highly efficient and stable electrocatalysts is critical for advancing hydrogen evolution reactions (HER) for hydrogen production. Herein, we report a facile approach to fabricating a hierarchical catalyst featuring ruthenium (Ru) nanoparticles uniformly integrated with nitrogen/oxygen co‐doped carbon nanotube aerogels (Ru‐NOCAs). Heteroatoms N and O‐modified CNTs can result in a negatively charged surface to effectively trap Ru3+ ions. Ru‐NOCAs exhibit a well‐defined hierarchical morphology facilitated by the self‐assembly of functional groups on the surface of CNTs, which enhances the interaction between Ru nanoparticles and CNTs. Due to the synergistic effect of hierarchical structure and strong interaction formation, Ru‐NOCAs show excellent catalytic activity and stability. Ru‐NOCAs catalyst demonstrates a remarkable overpotential of 41 mV at 10 mA cm−2 with a Tafel slope of 57 mV dec−1 in 1 M KOH and an overpotential of 68 mV with a Tafel slope of 65.8 mV dec−1 in 0.5 M H2SO4. These results indicate superior catalytic efficiency and enhanced charge transfer kinetics compared to the control samples. This study highlights the effectiveness of incorporating hierarchical structures and tailored surface chemistries in electrocatalyst design, offering new avenues for optimizing HER performance and advancing hydrogen fuel technology.

Comparative Study on the Electrocatalytic Performance of ABO3-Based Hexagonal Perovskite Oxides with Different [AO3] Layers.

To systematically investigate the influence of the number of [AO3] layers in the unit cell of hexagonal perovskite oxide on the oxygen evolution reaction performance, we successfully synthesized the three new hexagonal perovskite oxides 2H-BaCo0.9Ru0.1O3-δ, 6H-BaCo0.9Ru0.1O3-δ, and 10H-BaCo0.9Ru0.1O3-δ with the same element composition but different [BaO3] layers via the sol-gel method. Here, 2H, 6H, and 10H refer to the number of [BaO3] layers contained in the unit cell of the BaCo0.9Ru0.1O3-δ system. Experimentally, 10H-BaCo0.9Ru0.1O3-δ, featuring ten layers of [BaO3], exhibits optimal electrochemical activity among the three oxide catalysts, and in situ Raman results under various bias voltages confirm its ability to maintain a high surface crystal structural stability. Notably, as the number of [BaO3] layers increases, the effective magnetic moments and the valence state of surface Co ions in these three catalysts also increase, with the spin configuration of the surface Co ions being in a high-spin state. More importantly, DFT calculations provide the evolution rules of the p-band center (εp) with the number of [BaO3] layers, predicting the electrochemical performance of the BaCo0.9Ru0.1O3-δ system with different [BaO3] layers. Our experimental results offer a distinctive perspective for the future design, synthesis, and application of hexagonal perovskite oxides in electrocatalysis.

Utilizing reconstruction achieves ultrastable water electrolysis

The dissolution of active atoms under operating potential will lead to a decline in their oxygen evolution reaction (OER) performance, thus preventing the current highly active catalysts from being practically applicable in industrial water electrolysis. Here, we propose a sequential leaching strategy to utilize the dynamic restructuring and enhance the chemical bond strength for highly active and stable OER. Modeling on nickel-iron sulfides (NiFe-S), we introduced and utilized foreign Mo dopant preleaching as the sacrificial agent to alleviate the oxidation corrosion of partial M─S bonds. Operando spectroscopic reveal that foreign Mo dopant leach from the matrix and then adsorb on the surface of NiFe O(S)OH as molybdate at lower OER potential. The crystal occupation hamiltonian population analysis uncovers that the charge transfer from molybdate into NiFe O(S)OH will enhance bond energy of M─S, thus preventing further S and Fe/Ni leaching. By manipulating ion leaching, the resulting active phase achieves an ultralow overpotential of 250 mV at 400 mA cm −2 and high stability of more than 3,700 h at 100 mA cm −2 . An industrial water electrolysis equipment using our catalysts delivered ultralow energy consumption of 4.30 kWh m −3 H2 and record stability over 250 h (2,300 h lifetime by epitaxial method with 10% attenuation) under a high working current of 8,000 mA. The hydrogen production cost of US$2.46/kg H2 aligns with the green hydrogen cost target set by the European Commission for the coming decade.

A novel CoCuNi-sulfide nanocatalyst derived from trimetallic zeolitic imidazolate framework for boosting oxygen evolution reaction performance: comparison study of sulfides and oxides

The investigation of multi-component transition metals has been undertaken as a means to enhance the oxygen evolution reaction (OER) performance contrasted with single-component transition metals. In this study, we prepare a series of monometallic (ZIF-67), bimetallic (ZIF-CoCu), and novel trimetallic zeolitic imidazolate frameworks (ZIF-CoCuNi) via a facile one-step room-temperature solution precipitation method. The optimized CoCuNi-sulfide nanoparticles with amorphous structure and rough surface exhibit superior catalytic activity for OER in 1 mol L-1 KOH with a low overpotential of 210 mV at a current density of 10 mA.cm−2 and negligible reduction in operational capabilities following a stability test lasting 24 hours. This study showcases that both the sulfidation process and the synergy of multiple components yield favorable outcomes in terms of enhancing the activity and stability of OER. These findings present a new approach to fabricating and developing high-efficiency and low-cost electrocatalysts, which have an essential part in the conversion of energy.

Strengthening heterogeneous strain in FeCoNiMo-based high-entropy alloys for advanced energy conversion

Inducing lattice distortion and applying strain between atoms to regulate the electronic structure is an effective strategy for optimizing catalytic activity; however, several challenges still remain. Herein, heterogeneous strain triggered by large-radius atoms is proposed to effectively optimize the electronic structure and energy level of FeCoNiMo-based HEAs, thereby significantly enhancing alkaline hydrogen evolution and triiodide reduction reaction performance. Following the introduction of large-radius atoms such as Nb, W or Ta into FeCoNiMo-based HEA catalysts, the overpotential at η10 was reduced by more than half (from 172 to 84 mV). Using FeCoNiMoNb/C as the counter electrode in photovoltaic devices, 8.50% PCE was achieved, which is higher than that of FeCoNiMo- and Pt-based photovoltaic devices. This study leverages large-radius atoms to trigger strengthened heterogeneous strain within HEA catalysts, providing an innovative approach to effectively regulate their electronic structures and develop high-performance, low-cost bifunctional HEA catalysts.

Enhanced oxygen evolution reaction performance of flower-like CoHS @NCDs through in-situ coupling of Nitrogen-Doped carbon dots and cobalt hydroxide nanosheets

Enhanced oxygen evolution reaction performance of flower-like CoHS @NCDs through in-situ coupling of Nitrogen-Doped carbon dots and cobalt hydroxide nanosheets

Oxygen evolution reaction performance misjudgment caused by the self-oxidation process

Oxygen evolution reaction performance misjudgment caused by the self-oxidation process

Ru-M (Fe, Co, Ni) onto Nitrogen-doped Two-dimensional Carbon Nanosheets through Microwave Approach with Strong Metal-support Interactions for overall Water-splitting

Developing Ru-based catalysts with strong metal-support interactions (SMSI) is a significant approach to achieve highly-efficient catalytic activity and satisfactory stability. Nevertheless, the current strategies to construct SMSI are generally time-consuming and tedious, and then leading to aggregation. In this research, ultrafast microwave (45 s) is employed to affix small Ru-M (Fe, Co, Ni) nanoparticles onto nitrogen-doped two-dimensional (2D) carbon nanosheets (NCN, Ru-M/NCN), leading to robust metal-support interactions that enhance reaction kinetics and boost stability. Furthermore, the electronic interplay between Ru and M is pivotal in augmenting catalytic efficacy. The small size of the Ru-M nanoparticles and high specific surface area also favor exposing active sites and abundant interconnected channels to accelerate mass transport. Subsequent low-temperature oxidation process, to prepare RuM@RuOx/NCN, which is conducted to achieve oxygen evolution reaction (OER) performance. Thus, the as-synthesized RuCo/NCN only requires 65 mV, 58 mV, and 98 mV to achieve 10 mA cm-2 for hydrogen evolution reaction (HER) in 0.5 M H2SO4, 1 M KOH and alkaline seawater. RuM@RuOx/NCN is obtained by low-temperature oxidation to achieve excellent oxygen reduction reaction performance in 1 M KOH, the low overpotential of only 273 mV, 256 mV and 284 mV can reach 10 mA cm-2 and satisfactory stability. Moreover, the prepared electrocatalysts also achieve satisfactory electrocatalytic activity for overall water-splitting in alkaline freshwater/seawater electrolytes. This work provides a superior pathway for multifunctional nanomaterials for sustainable energy storage and conversion.

Hydrogen evolution performance of single atom catalyst supported on holey graphdiyne

Abstract Electrocatalytic hydrogen production is an effective method to solve environmental issues and energy crisis. However, cheap and high performance electrocatalysts are still very scarce. In this work, the hydrogen evolution reaction performance of holey graphdiyne supported transition metals single-atom catalysts (TM-SAC-HGY) were investigated by first-principles study. It is found that TM atoms are stably anchored on monolayer HGY by forming TM-C bonds. Meanwhile, TM atoms transfer electrons to both HGY and H atom. More importantly, the H adsorption free energy (ΔGH) of Cu-SAC-HGY is 0.028 eV, which is very close to 0 eV. Therefore, Cu-SAC-HGY has excellent HER activity. By analyzing the results of partial density of states, it can be concluded that the orbital hybridization strength of TM and H plays a decisive role in affecting HER activity. This work could contribute to the development of more efficient HER electrocatalysts.

Prominence of copper in AuCu alloy towards enhance surface plasmon resonance-driven water oxidation

To fully harness the potential of surface plasmon resonance (SPR) in augmenting photocatalytic water oxidation, a comprehensive exploration of structure-activity relationship of metal nanoparticles is essential. This work presents a wrap-bake-peel (WBP) strategy designed to stabilize AuCu/TiO2 nanostructures while preserving SPR absorption and refining the metal-semiconductor interfaces. Through strategically incorporating trace Cu into Au (Cu/Au = 0.06), we achieved a 2.6-fold enhancement of SPR-induced oxygen evolution reaction (OER) performance compared to pristine Au/TiO2. This enhancement is due to the synergistic effect of SPR and a well-defined Schottky barrier, which improves plasmonic hot carrier charge separation, as verified by detailed spectroscopic analyses. The incorporation of copper plays a critical role, acting as an electron shuttle that facilitates the transfer of hot electrons from photoexcited gold to the AuCu NP surface, thereby reducing recombination. This process, driven by SPR-induced hot electrons from Au, also extends electron-phonon (τ0e-ph), interactions by 138 %, significantly prolonging hot carrier lifetimes. Mechanistic insights reveal that d-band onset potentials (Ed-AuCu∼-0.9 V/ Ed-Au∼-1.2 V) and increased hot hole d-band occupancy in AuCu further enhance the overall SPR-induced water oxidation performance. Simulated electron distributions and quantum confinement in AuCu vs. Au critically dictate SPR characteristics, enabling precise modulation of plasmonic responses. These findings underscore the crucial role of Cu in fine-tuning the properties of plasmonic photocatalysts, demonstrating a significant advancement in the rational design of efficient solar-to-fuel conversion systems.

Sulfur-doped FeCoNiOx nanosheets improve their catalytic oxygen evolution reaction performance

Developing efficient and easily synthesized oxygen evolution catalysts is crucial for generating clean energy. A low-sulfur (S) doped FeCoNiOx flower-like nanosheet (denoted as S-FeCoNiOx) grown on nickel foam (NF) is presented. The porous structure of the NF, combined with the electronic structure modification from S doping, results in the nanosheets featuring numerous active sites and optimal adsorption strength. Electrochemical tests reveal that the catalyst demonstrates outstanding performance in alkaline electrolytes, characterized by a low overpotential (221 mV @ 10 mA cm−2) and a small Tafel slope of 29.19 mV dec−1, indicating favorable reaction kinetics. A two-electrode system comprising S-FeCoNiOx and Pt/C for water splitting, it exhibits low voltage (1.49 V @ 10 mA cm−2) and superior stability over 40 h. This research emphasizes significant potential applications and offers fresh guidance for creating additional high-efficiency S-doped electrocatalysts for oxygen evolution reactions (OER).

Mn‐Doped CoFeP Nanosheets as Effective Electrocatalysts for Superior Overall Water Splitting

For green hydrogen, the exploitation of advanced electrocatalysts is crucial, and transition metal phosphides have great potential in water splitting due to their abundant reserves and optimized electronic structure. Herein, a synergistic approach involving Mn doping and phosphorization is applied to CoFe‐layered double hydroxide nanoflowers to produce a series of bifunctional catalysts Mn‐doped CoFeP (Mn‐CoFeP). Electrochemical evaluations demonstrate that the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance of Mn(10%)‐CoFeP both have notable improvement in 1 M KOH, with the overpotentials of only 160 and 239 mV to achieve current densities of 10 and 100 mA cm−2, respectively. Comparative electrocatalytic analysis indicates that moderate Mn doping mainly contributes to improve the OER performance, while the phosphorization significantly enhances the HER activity, resulting in effective bifunctional catalysis. For overall water decomposition, a total hydrolysis electrolysis cell equipped with the Mn(10%)‐CoFeP bifunctional catalyst requires only 1.64 V to reach a current density of 10 mA cm−2. Furthermore, it performs stable operation for 10 h at a current density of 10 mA cm−2 with a current maintenance rate of 83.6%. This work offers new insights into preparing effective bifunctional electrocatalysts, advancing clean energy development.

Boosting the Oxygen Evolution Reaction Performance of Inert ZnO by Incorporating Ni and Trace-Level Ir for Scalable and Industrial-Level Water-Splitting Catalysts

Boosting the Oxygen Evolution Reaction Performance of Inert ZnO by Incorporating Ni and Trace-Level Ir for Scalable and Industrial-Level Water-Splitting Catalysts

Study on the Hydrogen Evolution Reaction Performance of Graphene Synthesized by Detonation Approach

Study on the Hydrogen Evolution Reaction Performance of Graphene Synthesized by Detonation Approach

Testing and assessment of various catalysts for uniquely designed cathodes for hydrogen evolution reactions

This study reports the electrodeposition of various unique catalysts for 3D-printed cathodes for alkaline water electrolysis. This paper explores hydrogen evolution reaction performance for nickel, nickel-copper, nickel-iron, and nickel-molybdenum 3D-printed electrodes. In particular, this study reports a novel electrodeposition of nickel-iron and nickel-molybdenum on conductive PLA 3D-printed electrode surfaces. The performance of the electrodes is assessed through electrochemical models, including cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). The results of the study show considerable differences at a standard current density of 10 mA/cm2. The nickel-iron and nickel-copper coated 3D-printed electrodes are found to have an overpotential of 270 mV and 275 mV, respectively. The nickel-copper and nickel-iron coated electrodes also showed to have a low resistance. The amount of metal deposited also showed to have an important role. At a potential of −2.5 V, nickel coated electrode Ni4x, with four times the nickel mass deposition (0.178 g/cm2) of another nickel coated electrode Ni1x (0.044 g/cm2), is found to have a current density of −106 mA/cm2 in comparison to −44 mA/cm2, respectively. These findings provide important insights for optimizing additive manufacturing for electrochemical systems.

Efficient hydrogen evolution reaction performance of Ni substituted WS2 nanoflakes

Efficient hydrogen evolution reaction performance of Ni substituted WS2 nanoflakes

Tailoring of electrocatalytic oxygen evolution reaction performance of 2D conductive Co-catecholate metal-organic frameworks

Herein, we report the microwave hydrothermal synthesis of highly porous and conductive 2D Co-catecholate MOFs (Co-CATs) in the absence (Co-CAT-WO) and presence (Co-CAT-W) of N-methyl-2-pyrrolidone (NMP) polar solvent, and the study of these Co-CATs as electrocatalysts for oxygen evolution reaction (OER). The OER performance of Co-CAT-WO and Co-CAT-W is compared. The as-synthesized Co-CATs exhibit a 2D layered hexagonal structure. The electrical conductivity of Co-CAT-WO and Co-CAT-W is 6.9 and 5.8 S/m, respectively. The good conductivity and porous structure can initiate charge transport to achieve better OER performance under the 4e--transfer process. The as-prepared Co-CAT-WO and Co-CAT-W, respectively, show an overpotential of 455 and 424 mV at 10 mA/cm2 after performing the durability and chronoamperometry experiments for 13 h in 1 M KOH. From the electrochemical studies, it is apparent that the Co-CAT-W exhibits better OER performance with low overpotential, high current density, and excellent stability over extended cycling. Moreover, the lower HOMO-LUMO gap for Co-CAT-W than that of the Co-CAT-WO endorses its better electrocatalytic activity. The post-OER results show that the Co-CAT-W electrocatalyst acts as a "precatalyst" rather than the original catalyst, and it undergoes electrochemical transformation to metal hydroxide and metal oxyhydroxide after the OER studies, promoting the OER kinetics. The findings of this work offer valuable insights into the synthetic strategies for developing 2D conducting metal-catecholate MOF catalysts for efficient and sustainable OER processes, which is crucial in water splitting for sustainable energy production.

Ternary ZnO/Co3O4/CuO heterostructure nanocomposites derived from trimetallic metal-organic frameworks for efficient electrocatalytic water oxidation

Enhancing the electrocatalytic performance of transition-metal oxide catalysts by optimizing the active center at the multi-component heterointerface is a daunting task. Herein, the three-component ZnO/Co3O4/CuO heterostructure composite catalyst was effectively produced through a room-temperature precipitation reaction, followed by calcination in air. The ZnO/Co3O4/CuO ternary heterostructure catalyst showed superior oxygen evolution reaction (OER) performance, characterizedby a low overpotential (312 mV at 10 mA cm−2) and Tafel slope (83.5 mV dec-1) compared to the ZnO, Co3O4, ZnO/CuO, ZnO/Co3O4, and Co3O4/CuO catalysts. The research shows that the property of electrocatalytic oxygen evolution is greatly enhanced due to the combined impact of each component.

Synthesis of Co/Ni-MOFs with mixed ligands and their Oxygen Evolution Reaction (OER) performance

Two new transition metal–organic framework (MOF) complexes, Co-MOF (C28H17CoN6O9S2) and Ni-MOF (C28H6NNi8O2S0.06), were synthesized using a hydrothermal method. Upon characterization and analysis, Co-MOF and Ni-MOF showed similar structures, in which Co2+ or Ni2+ coordinated with two pyridine-2,6-dicarboxylic acid ligands to form octahedral geometric configurations, which in turn formed one-dimensional layered structure, while Py2TTz ligands existed between these layers to enlarge the pore size of MOFs. Co-MOF showed superior performance than Ni-MOF in the OER process, with a low overpotential (227 mV) and Tafel slope (51.4 mV dec‑1) at 10 mA cm-2 current density. This work provided new insight into designing transition MOFs for electrocatalytic water splitting.

Rational Design of Diatomic Active Sites for Elucidating Oxygen Evolution Reaction Performance Trends.

Diatomic catalysts, especially those with heteronuclear active sites, have recently attracted significant attention for their advantages over single-atom catalysts in reactions with relatively high energy barrier, e.g. oxygen evolution reaction. Rational design and synthesis of heteronuclear diatomic catalysts are of immense significance but have so far been plagued by the lack of a definitive correlation between structure and catalytic properties. Here, we report macrocyclic precursor constrained strategy to fabricate series of transition metal (MT, Ni, Co, Fe, Mn, or Cu)-noble (MN, Ir or Ru) centers in carbon material. One notable performance trend is observed in the order of Cu-MN<Mn-MN<Fe-MN<MN<Co-MN<Ni-MN. Meanwhile, the pathway has been not altered, still following the traditional adsorption reaction mechanism. The effect of the MT atoms on the performances could possibly originate from the distinct adsorption/desorption behaviors of key intermediates (i.e. *OH, *O and/or *OOH), strongly implying that ΔG*OOH-ΔG*OH could be used as the performance descriptor. We believe that our work provides useful strategy for synthesis of diatomic active sites with sole coordination configuration and varied composition, and in-depth insight to their catalytic mechanism, which could be used for further optimization of diatomic catalysts towards oxygen electrocatalysis.