Electrocatalysts For Water Splitting Research Articles

Bifunctional Ni4MoW PMEC electrocatalyst for efficient overall water splitting

Bifunctional Ni4MoW PMEC electrocatalyst for efficient overall water splitting

3D volcanic-rock-like structure of Co-doped Ni/MoNi4 heterostructure with corallite pattern surface as bifunctional electrocatalysts for urea-assisted water splitting

3D volcanic-rock-like structure of Co-doped Ni/MoNi4 heterostructure with corallite pattern surface as bifunctional electrocatalysts for urea-assisted water splitting

High-performance NiMo@Co@NSC electrocatalyst for efficient overall water splitting

High-performance NiMo@Co@NSC electrocatalyst for efficient overall water splitting

Cu-doped SnS/Sn2S3 electrocatalyst for high-performance methanol-mediated overall water splitting

Cu-doped SnS/Sn2S3 electrocatalyst for high-performance methanol-mediated overall water splitting

Constructing Mo-Co2P/Ni12P5 heterostructures as highly efficient electrocatalysts for overall water splitting

Constructing Mo-Co2P/Ni12P5 heterostructures as highly efficient electrocatalysts for overall water splitting

Atom doping and alkali etching to construct defect-rich electrocatalysts for efficient overall water splitting

Atom doping and alkali etching to construct defect-rich electrocatalysts for efficient overall water splitting

Enhancing hydrogen evolution by heterointerface engineering of Ni/MoN catalysts.

Enhancing hydrogen evolution by heterointerface engineering of Ni/MoN catalysts.

Leafy ZIF-Derived Bi-Metallic Phosphate-Mxene Nanocomposites for Overall Water Splitting.

Electrocatalytic water splitting is a significant method of hydrogen production to overcome energy scarcity and tackle the environmental pollution caused by the extreme consumption of fossil fuels. This work directs the focus on the development of an efficient catalyst toward hydrogen and oxygen evolution reactions (HER and OER). Herein, a highly active and robust bi-metallic phosphate nanocomposite supported on Mxene is derived from an in situ technique, using a 2D (leafy) zeolitic imidazolate framework (ZIF 67) and phosphorus-doped nickel hydroxide [P-Ni(OH)2] as a primary precursor for the first time. The synergy between the reaction mechanism leads to the formation of highly porous, needle-like morphology with a layer boundary interface. A remarkable performance of the catalyst is obtained with significantly low overpotential and excellent stability toward HER and OER. In conjunction with structural merits and catalytic activity, excellent performance is attributed to the optimized porosity owing to the 2D/3D conducting interface channel. The theoretical and experimental insights on the study affirm the conducive nature of the catalyst for overall water splitting. This finding exposed a new avenue for the chemistry between MOF and phosphate with conducting substrate to develop a highly active electrocatalyst for HER and overall water splitting.

Preparation of Highly Efficient All-pH Bifunctional Water Electrolysis Catalysts Through a Surface Modification Strategy.

Electrolytic hydrogen production from water is a very promising technology, and catalysts capable of efficient operation over a wide pH range are essential for energy storage and conversion. Herein, a trace Ru catalytic core restructures nickel foam (NF) under polymeric protection, with temperature gradient control forming HER-active metal monomers at low temperatures and OER-suitable oxides at high temperatures. It is demonstrated that the surface modification strategy can help NF to maintain its own backbone structure during the carbonation process and that the resulting catalysts possess excellent properties. The synthesized catalysts-Ru@NF-KPDA-550 exhibit the lowest OER overpotentials of 183mV in 0.5M H2SO4 and 151mV in 1.0M KOH, and Ru@NF-KPDA-350 exhibits the lowest HER overpotentials of 11.8mV in 0.5M H2SO4 and 13.4mV in 1.0M KOH for Ru@NF-KPDA-350 at 10mA cm-2. The DFT simulations show that the synergistic interaction between Ru and Ni components, which optimizes their d-band centers, enhances the HER and OER pathways, thereby lowering activation barriers and boosting catalytic performance. This work provides a viable strategy for the design of pH-universal electrocatalysts for the overall water splitting.

Robust Oxygen Evolution on Ni-Doped MoO3: Overcoming Activity-Stability Trade-Off in Alkaline Water Splitting.

Electrochemical water splitting using earth-abundant materials is crucial for enabling green hydrogen production and energy storage. In recent years, molybdenum trioxide (MoO3), a semiconducting material, has been proposed as a candidate catalyst for the oxygen evolution reaction (OER). Here, we advance nickel (Ni) doping of MoO3 as a strategy to increase the activity and stability of the material during alkaline electrochemical water splitting, thereby overcoming the typical activity-stability trade-off encountered with OER catalysts. The instability of MoO3 in alkaline media can be mitigated by doping with Ni, whose oxide is stable under such conditions. Using density functional theory (DFT) with Hubbard corrections, we show that Ni doping reduces the thermodynamic OER overpotential on the MoO3 basal plane to 0.64 V. Experiments demonstrate that Ni-doped MoO3 requires an overpotential of 0.34 V for an OER current density of 10 mA/cm2 (and 0.56 V at 100 mA/cm2), as opposed to a value of 0.40 V for pure MoO3. Further, Ni-doped MoO3 exhibits a lower Tafel slope of 74.8 mV/dec, compared to 98.3 mV/dec for the pristine material under alkaline conditions. While Mo leaches in alkaline conditions, X-ray photoelectron spectroscopy reveals enhanced stability with Ni doping. Overall, our work advances Ni-doped MoO3 as a promising water-splitting electrocatalyst and provides new insights into its OER mechanism and stability in alkaline media. More generally, the work sheds light on choosing a dopant to increase a material's activity and stability, which will also find applications in other catalytic materials.

Detection and Measurement of Interfacial Charge Transfer Relaxation Time: FeNi/NF Electrocatalysts for Water Splitting to Hydrogen.

A cost-effective nickel-iron (Ni-Fe) alloy with a predominant face-centered cubic(111) crystallographic orientation is demonstrated as a high-performance electrocatalyst for the hydrogen evolution reaction (HER). This alloy demonstrates mutual hybridization of Ni and Fe d-orbitals, bringing its valence energy level close to the Fermi level, comparable to that of the benchmark Pt/C catalyst. While water-splitting electrocatalysts typically undergo surface structural evolution after each reaction cycle, the time scale of surface reconstruction during HER remains uncharted. This study presents a NiFe/NF alloy with an enriched (111) orientation, an active surface area of 24,217 ± 0.1 cm2, an average crystallite size of 14.5 nm, and 0.634% lattice strain as an HER electrocatalyst. The electrocatalyst exhibits excellent performance towards HER, achieving a current density exceeding 800 mA/cm2, an overpotential of -133 mV, and a hydrogen turnover frequency of 2.8 × 1012 s-1, and maintaining stable operation over 100 h. The distribution of relaxation time (DRT) analysis is introduced to deconvolute the HER process. A distinct high-frequency peak is attributed to interfacial charge transfer with a 2.38 × 10-6 s relaxation time. Additionally, medium- and low-frequency peaks represent ion transport and hydrogen adsorption/desorption at 277.4 × 10-6 and 905.1 × 10-6 s relaxation times, respectively. The assignments can serve as a reference on the bulk and interfacial relaxation times critical for understanding electrocatalyst surface evolution using the DRT method, regardless of the material or type of electrochemical reaction. These findings are useful for advancing the design of low-cost, transition-metal-based alloys as catalysts for clean energy systems.

Heterointerface engineering of vanadium oxide/cobalt nitride as efficient electrocatalysts for alkaline overall water splitting.

A triangular plate-shaped vanadium oxide/cobalt nitride (VO/CoN) heterostructure was constructed and used as an effective bifunctional electrocatalyst for alkaline water electrolysis. The VO/CoN-based electrolyzer exhibits a low cell voltage of 1.587 V at 10 mA cm-2 and presents remarkable stability over 100 h of operation.

Defect-Engineered Multi-Intermetallic Heterostructures as Multisite Electrocatalysts for Efficient Water Splitting.

Efficient water splitting for renewable hydrogen production requires the development of highly active and stable electrocatalysts. This study investigates the design and synthesis of defect-engineered multimetallic heterostructures as advanced electrocatalysts for overall water splitting. A synergistic approach combining atomic-scale defect engineering and multiphase heterostructures is employed to enhance catalytic activity. A series of highly porous intermetallic alloys (CoCuMoNi) with abundant defect sites are synthesized using a high-temperature alloying-dealloying technique. Due to the synergistic effect of multiphase interfaces, built-in electric fields, and defect engineering, the CoCuMoNi catalyst exhibits excellent bifunctional activity for water splitting (Hydrogen evolution reaction: 14mV@10 mA cm-2; Oxygen evolution reaction (OER): 211mV@10mAcm-2; Overall water splitting: 1.559V@100mAcm-2), with significantly enhanced activity compared to pure metals and conventional materials. Additionally, these structures demonstrate excellent stability and durability. Advanced characterization techniques and density functional theory (DFT) reveal that the formation of defect sites and heterojunctions not only induces electronic modulation but also enhances intermetallic interactions and charge transfer from Ni and Mo to Cu and Co, facilitating intermediate formation and transformation, thereby boosting intrinsic activity. This work highlights the potential of defect-engineered multimetallic heterostructures as scalable and efficient electrocatalytic platforms, paving the way for their practical applications in clean energy technologies.

Machine-Learning-Assisted Synthesis of Bimetallic Metal-Organic Frameworks for the Optimized Oxygen Evolution Reaction.

Although a wide range of bimetallic metal-organic frameworks (MOFs) have been reported as electrocatalysts for the oxygen evolution reaction (OER), there is still a need for precise tuning of the metal precursors and composite ratios to minimize the overpotential and design highly efficient electrocatalysts. To achieve this, we applied machine learning (ML) algorithms to optimize the metal precursor and composite ratios, identifying the key factors that govern the OER performance. We first synthesized a bimetallic FeCo squarate-based MOF (FeCo-Sq MOF) using a solvothermal method and then optimized the metal precursor ratios using ML algorithms to achieve a low overpotential. To further enhance the OER efficacy, the ML-optimized FeCo-Sq MOF was coated with S-doped graphitic carbon nitride (SCN) and wrapped with polydopamine (PDA). The PDA wrapping not only increased the number of binding/adsorption sites for -OH but also enhanced the stability, charge/electron transfer kinetics, and effective anchoring of SCN on the MOF surface. To obtain optimal OER catalysts, the SCN loading was further fine-tuned through ML. The ML-optimized PDA-SCN@FeCo-Sq MOF exhibited high electrocatalytic performance, achieving a low overpotential of 310 mV and a Tafel slope of 56 mV/dec at a current density of 10 mA cm-2 in 1 M KOH. This study presents a promising ML-assisted strategy for designing high-performance PDA-SCN@FeCo-Sq MOF electrocatalysts for efficient water splitting.

Fullerene‐Buffered Electron Shuttle of Ru/RuO2 with Switchable Active Sites Enables Robust and Efficient Bifunctional Alkaline Water Electrolysis

AbstractDeveloping highly‐efficient and robust bifunctional electrocatalyst for overall water splitting (OWS) is desirable, but it confronts long‐term challenge in the local structural reconstruction of catalyst during the hydrogen and oxygen evolution reaction (HER and OER). As inspired by the stable acid–base buffer system in human life, here we construct an electron buffer system to well address the key issue of structural reconstruction, in which the charge‐buffered fullerene renders Ru‐based active species to be reversibly shuttled between Ru and RuO2 during HER and OER. Consequently, the as‐prepared Ru‐RuO2/C60‐x catalyst exhibits overpotentials of merely 7 and 194 mV at 10 mA cm−2 for HER and OER in alkaline conditions, respectively. The photovoltaic‐driven OWS device with a solar‐to‐hydrogen (STH) efficiency of 18.9% and an anion exchange membrane water electrolysis (AEMWE) system with good robustness was fabricated based on Ru‐RuO2/C60‐x. It was unraveled by in situ/operando spectroscopy and theoretical calculation that the significantly promoted performance of water electrolysis benefits from the fullerene‐based electron shuttle effect on inhibition of structural reconstruction and electronic structural modulation of active sites as well as adsorption energy of the reaction intermediates. Our work may open an avenue to develop efficient and robust bifunctional electrocatalyst for promising industrial water electrolysis.

Enhanced electrocatalytic performance of carbon-coated NiCoO2/NiCo composites for efficient water splitting

The urgent need for sustainable energy conversion technologies has propelled the development of efficient and cost-effective electrocatalysts for water splitting. In this study, we synthesize carbon-coated NiCoO2/NiCo@C composites through the calcination of CoNi Prussian Blue Analogues nanocubes, aiming to enhance the electrocatalytic performance for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Our findings demonstrate that the NiCoO2/NiCo@C composites exhibit outstanding catalytic activity, achieving low overpotentials of 329 mV for OER and 61.9 mV for HER at a current density of 10 mA cm−2, with robust stability under prolonged operational conditions. The enhanced activity is attributed to the large interface area and high density of exposed active sites facilitated by the unique heterojunction structure of NiCoO2/NiCo particles embedded in carbon frameworks and nanotubes. This architecture not only prevents the agglomeration of metal nanoparticles but also promotes efficient electron and proton transfer, significantly boosting electrochemical performance. This study introduces a promising approach for designing high-performance, cost-effective electrocatalysts, paving the way for their application in industrial water electrolysis.

Fullerene-Buffered Electron Shuttle of Ru/RuO2 with Switchable Active Sites Enables Robust and Efficient Bifunctional Alkaline Water Electrolysis.

Developing highly-efficient and robust bifunctional electrocatalyst for overall water splitting (OWS) is desirable, but it confronts long-term challenge in the local structural reconstruction of catalyst during the hydrogen and oxygen evolution reaction (HER and OER). As inspired by the stable acid-base buffer system in human life, here we construct an electron buffer system to well address the key issue of structural reconstruction, in which the charge-buffered fullerene renders Ru-based active species to be reversibly shuttled between Ru and RuO2 during HER and OER. Consequently, the as-prepared Ru-RuO2/C60- x catalyst exhibits overpotentials of merely 7 and 194mV at 10mA cm-2 for HER and OER in alkaline conditions, respectively. The photovoltaic-driven OWS device with a solar-to-hydrogen (STH) efficiency of 18.9% and an anion exchange membrane water electrolysis (AEMWE) system with good robustness was fabricated based on Ru-RuO2/C60- x. It was unraveled by in situ/operando spectroscopy and theoretical calculation that the significantly promoted performance of water electrolysis benefits from the fullerene-based electron shuttle effect on inhibition of structural reconstruction and electronic structural modulation of active sites as well as adsorption energy of the reaction intermediates. Our work may open an avenue to develop efficient and robust bifunctional electrocatalyst for promising industrial water electrolysis.

Ni-Doped Co-Based Metal–Organic Framework with Its Derived Material as an Efficient Electrocatalyst for Overall Water Splitting

Composite catalysts combining a metal–organic framework (MOF) with its derivatives have attracted significant attention in electrocatalysis due to their unique properties. In this study, we report the synthesis of a Ni-doped Co-1,4-benzenedicarboxylate (defined as Co3Ni1BDC) metal–organic framework via a straightforward solvothermal method, aiming to enhance oxygen evolution reaction (OER) activity. The introduction of Ni modulated the electronic structure, yielding high catalytic activity with an overpotential (η100) of 300 mV and excellent stability for the OER. The Co3Ni1BDC material was further encapsulated with Co2P nanoparticles via a controlled phosphating annealing process, forming a hybrid electrocatalyst (Co3Ni1BDC@Co2P) to boost hydrogen evolution reaction (HER) performance. The Co3Ni1BDC@ Co2P catalysts exhibited superior HER performance with low overpotentials of η10 = 20 mV and η100 = 127 mV, outperforming the Co3Ni1BDC precursor. An alkaline electrolyzer assembled with Co3Ni1BDC//Co3Ni1BDC@Co2P achieved a cell voltage of 1.70 V at a current density of 20 mA cm−2. This work provides a valuable idea for designing efficient electrocatalysts for overall water splitting.

CeF3-Accelerated surface reconstruction of MoO2 nanosheets into coral-like CeF3/MoO2 composites enhances the oxygen evolution reaction for efficient water splitting.

CeF3-Accelerated surface reconstruction of MoO2 nanosheets into coral-like CeF3/MoO2 composites enhances the oxygen evolution reaction for efficient water splitting.

Engineering electron redistribution of CeO2/Ni(OH)2@Mo-NiS nanorod composites with rich oxygen vacancies for overall water splitting.

Engineering electron redistribution of CeO2/Ni(OH)2@Mo-NiS nanorod composites with rich oxygen vacancies for overall water splitting.