Non-precious Electrocatalysts Research Articles

Non-precious metal high-entropy electrocatalysts (Al0.5NiCoCr-X0.5) for OER application

The high entropy alloy electrocatalysts demonstrate exceptional efficiency in the production of hydrogen through water electrolysis. Consequently, the development of durable and economically efficient electrocatalysts has become an urgent objective to accomplish. In order to achieve this goal, a bulk non-precious metal high-entropy alloy, Al0.5NiCoCr-X0.5 (Mo, Mn, Cu, V, Fe), was synthesized and characterized in this study through physical phase analysis and electrochemical property test. To explore the reasons for the influence of the five added elements on the catalytic performance of high entropy alloys in this system and to find the OER electrocatalyst with the best catalytic performance. Electrochemical performance tests were performed in 1 M KOH electrolyte. At a current density of 10 mA·cm−2, the overpotential of the high-entropy alloy catalyst Al0.5NiCoCrMo0.5 was lower than that of the high-entropy alloy with the addition of the other four elements respectively, which was only 327 mV, and lower than that of the conventional noble metal catalyst RuO2, which had an overpotential of 342 mV. This is attributed to the addition of Mo element, which makes Al0.5NiCoCr produce a large number of HCP phases on top of the original FCC phase and a very small number of BCC phases, which is more conducive to the generation of active sites on the surface of the catalysts, and thus improves the OER activity, and the stability can be maintained for at least 20 hours. Therefore, Al0.5NiCoCrMo0.5 high-entropy alloy catalysts can be used in industrial hydrogen production instead of the traditional precious metal catalysts, and it has a rather broad application prospect, and at the same time, it lays a solid foundation for the application of transition metals in catalysts.

Low-temperature plasma-assisted synthesis of iron and nitrogen co-doped CoFeP-N nanowires for high-efficiency electrocatalytic water splitting

Designing efficient, stable, and low-cost non-precious metal electrocatalysts is critical for gainful utilization of renewable resources and effective water splitting. The catalytic efficiency is determined by interactions between the multiple main constituent elements and dopants. However, achieving performance-boosting synergistic interactions between different species in the catalyst is challenging. This work demonstrates such effect using low-temperature plasma-enhanced hydrothermal-phosphorization synthesis of Fe, N co-doped CoFeP-N nanowires. Nickel foam was utilized as the substrate to prepare CoFe-LDH precursor by hydrothermal method and CoFeP nanoparticles were obtained by phosphorization in a tube furnace. The N element was further doped into CoFeP using a low-temperature plasma discharge. The produced CoFeP-N nanowires exhibit far superior hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities in an alkaline medium compared to the original CoP due to the incorporation of Fe and N elements, with overpotentials of 64 mV and 219 mV at 10 mA cm−2 respectively, and excellent cycling stability. When CoFeP-N is used as both the cathode and anode of a two-electrode water splitting device, low voltages of only 1.516 V and 1.636 V were needed to achieve current density of 10 mA cm−2 and100 mA cm−2 respectively, which are better than that of Pt/C||RuO2 and most non-precious metal-based electrocatalysts reported to date. These experimental results provide new insights and strategies for developing efficient, stable, and low-cost bifunctional water splitting electrocatalysts.

Tuning the electrocatalytic activity of MoS2 nanosheets via the in situ hybridization with ruthenium and graphene network

The quest for highly efficient, stable, and non-precious electrocatalysts as alternatives to Pt in the hydrogen evolution reaction (HER) at ambient temperature is paramount. Two-dimensional (2D) layered transition metal dichalcogenides (TMDs), notably MoS2, have emerged as promising noble-metal-free candidates. However, MoS2′s limited active edge sites and sluggish electron transfer kinetics present challenges in achieving efficient HER activity under both acidic and basic conditions. In this study, we introduce a composite catalyst composed of 2D MoS2 nanosheets enveloped by graphene networks, with uniform dispersion of ruthenium (Ru) nanoparticles within the extended 2D structure. This ternary hybrid catalyst exhibits excellent catalytic activity, with a low onset overpotential of 60 mV at 10 mA cm−2, a small Tafel slope of 38 mV dec-1, and remarkable durability during continuous 10-hour operation at 100 mV potential in 1.0 M KOH, without substantial activity loss. The conductive graphene support effectively prevents the restacking of exfoliated MoS2 nanosheets, enhancing mass transport and charge transfer kinetics. Ru incorporation induces the partial phase transformation of MoS2 from its trigonal (2H) to octahedral (1 T) phase, concurrently generating sulfur vacancies. The induced phase transformation not only activates the inert basal planes of MoS2 but also reduces the energy barrier for the adsorption/desorption of H* intermediates. Beyond the structural advantages, the intrinsic synergistic effects, primarily related to electronic structure modulation and defect engineering, contribute significantly to the enhanced electrochemical HER performance. In summary, this study not only introduces an efficient, cost-effective alternative to Pt-based electrocatalysts but also lays the foundation for designing other TMD-based hybrid catalysts, characterized by abundant exposed active sites and reduced barriers for hydrogen binding energy, thereby advancing electrochemical hydrogen production.

Facile synthesis of Co-Cu metal organic framework as efficient non-noble bifunctional electrocatalysts for overall water splitting

The rapid development of superior, highly stable, alkaline-medium-compatible, and nonprecious earth-abundant bifunctional electrocatalysts has garnered significant research interest. This interest aims to replace the costliest noble metals (Pt, Ir/IrO2, and Ru/RuO2) in renewable and green energy technologies for overall water splitting. However, there are still important limitations, such as lower stability and higher energy consumption. In this work, we report the synthesis of Cu-Co metal-organic frameworks (MOFs) as a bifunctional electrocatalyst using a simple chemical precipitation technique. Especially, when 11.5 mM of Co is combined with Cu MOF, it exhibits excellent bifunctional activity for overall water splitting with a lower overpotential of 0.21 V (OER) and -0.71 V (HER) at a current density of 10 mA cm−2, which exhibits nearly several times more enhancement than that of pristine Cu and Co MOFs in a 1 M KOH electrolyte solution. The Tafel slope value of 130 mV/dec and the lower charge transfer resistance, along with relatively high stability for up to 12 h at the onset potential of OER and HER, are observed for the 11.5 mM Cu-Co MOF electrocatalyst. The present results open an alternative pathway for developing a novel design of highly efficient and scalable bifunctional electrocatalysts for overall water splitting.

Synergistic heterointerface engineering of Co9S8/Ni(OH)2 hierarchical nanosheets for remarkable overall water splitting

Sustainable production of hydrogen from electrochemical water spitting by cost-effective and non-precious bifunctional electrocatalyst is of remarkable interest and extremely desirable. Here, a novel hierarchical Co9S8/Ni(OH)2 heterostructure with porous nanosheets was fabricated as the heterogeneous bifunctional electrodes to achieve remarkable water electrolysis. Synergistic coexistence of Co9S8 and Ni(OH)2 nanostructure with crystalline-amorphous feature can induce a large number of chemically coupled heterointerfaces as catalytically accessible active sites to accelerate electron transfer kinetics and enable a super-hydrophilic feature to contact electrolyte and release gas bubbles. Thus, such Co9S8/Ni(OH)2 heterostructure electrode verifies a remarkable electrocatalytic activity with low overpotentials of 274 mV at 100 mA cm−2 for OER and 109 mV at 10 mA cm−2 for HER. As assembled in a lab-made electrolyzer, the Co9S8/Ni(OH)2 heterostructures as bifunctional electrodes enable 1.51 V to achieve an overall water splitting at 10 mA cm−2, along with the outstanding stability at about 100 mA cm−2 up to 55 h. This work paves a bright way to design and construct non-precious materials as effective and advanced electrocatalysts for electrolysis in water.

In situ generation of oxyanions-decorated cobalt(nickel) oxyhydroxide catalyst with high corrosion resistance for stable and efficient seawater oxidation

The development of efficient and robust anode materials for stable alkaline seawater electrolysis is severely limited by chlorine evolution reaction and chloride corrosion. Here, the sulfur-doped cobalt-nickel bimetallic phosphides (CoNiPS) are specifically designed as a pre-catalyst for navigating a surface reconstruction to fabricate the anions (PO43− and SO42−)-decorated Co(Ni)OOH catalyst (R-CoNiPS) with exceptional durability and high activity for stable alkaline seawater oxidation (ASO). Various experiment techniques together with theoretical simulations both demonstrate that the in situ-generated PO43− and SO42− anions on catalyst surface can improve the oxygen evolution reaction (OER) activity, regulating and stabilizing the catalytic active species Co(Ni)OOH, as well as make a critical role in inhibiting the adsorption of chloride ions and extending the service life of electrode. Therefore, this R-CoNiPS electrode exhibits superb OER activity toward ASO and stands out among the non-precious ASO electrocatalysts reported recently, requiring low overpotentials of 420 and 440 mV to attain large current densities of 500 and 1000 mA cm−2 in an alkaline natural seawater electrolyte, respectively. Particularly, the catalyst displays a negligible chloride corrosion at room temperature during ASO operation (>200 h) at 500 mA cm−2. This work opens up a new viewpoint for designing high-activity and durable electrocatalysts for seawater electrolysis.

FeNi2S4-A Potent Bifunctional Efficient Electrocatalyst for the Overall Electrochemical Water Splitting in Alkaline Electrolyte.

For a carbon-neutral society, the production of hydrogen as a clean fuel through water electrolysis is currently of great interest. Since water electrolysis is a laborious energetic reaction, it requires high energy to maintain efficient and sustainable production of hydrogen. Catalytic electrodes can reduce the required energy and minimize production costs. In this context, herein, a bifunctional electrocatalyst made from iron nickel sulfide (FeNi2S4 [FNS]) for the overall electrochemical water splitting is introduced. Compared to Fe2NiO4 (FNO), FNS shows a significantly improved performance toward both OER and HER in alkaline electrolytes. At the same time, the FNS electrode exhibits high activity toward the overall electrochemical water splitting, achieving a current density of 10mAcm-2 at 1.63V, which is favourable compared to previously published nonprecious electrocatalysts for overall water splitting. The long-term chronopotentiometry test reveals an activation followed by a subsequent stable overall cell potential at around 2.12V for 20h at 100mAcm-2.

Tensile nanostructured hierarchically porous non-precious transition metal-based electrocatalyst for durable anion exchange membrane-based water electrolysis

Electrochemical water electrolysis is a promising method for sustainable hydrogen production while transiting towards hydrogen economy. Among many, the Anion Exchange Membrane (AEM) based water electrolyzer is an emerging yet potentially affordable technology on maturity for producing large-scale hydrogen accommodating the usage of Non-Platinum Group Metal (non-PGM) based inexpensive electrocatalysts. Herein, we demonstrate the excellent performance of a bifunctional Nickel Copper Phosphide-Nickel sulphide (NCP-NS) electrocatalyst with a unique tensile nanostructure obtained via a facile, controlled ambient galvanic displacement route. An AEM electrolyzer with a larger active area of 10 cm2 stacked with the symmetric NCP-NS electrodes and a membrane demonstrates scalability with a requirement of a mere 1.66 V to reach a current density of 10 mA cm−2. The nickel-copper phosphide boosts the kinetics of charge transfer between the electrode and electrolyte interface, while a unique combination of a few nickel sulphide phases present in the catalyst provides sufficiently appropriate active sites for the overall water electrolysis. For the first time, we report a room temperature performance of ∼ 230 mA cm−2 at 2 V for a non-PGM-based bifunctional electrocatalyst with exceptional durability for over 300 h of operation in an AEM water electrolyser with a retention rate of 95 %-97 % at a current density range of 80–800 mA cm−2.

Oxygen Vacancy and Heterostructure Modulation of Co2P/Fe2P Electrocatalysts for Improving Total Water Splitting.

Designing a stable and highly active catalyst for hydrogen evolution and oxygen evolution reactions (HER/OER) is essential for the industrialization of hydrogen energy but remains a major challenge. This work reports a simple approach to fabricating coupled Co2P/Fe2P nanorod array catalyst for overall water decomposition, demonstrating the source of excellent activity in the catalytic process. Under alkaline conditions, Co2P/Fe2P heterostructures exhibit an overpotential of 96 and 220 mV for HER and OER, respectively, at 10 mA cm-2. For total water splitting, a low voltage of 1.56 V is required to provide a current density of 10 mA cm-2. And the catalyst exhibits long-term durability for 30 h at a high current density of 250 mA cm-2. The analysis of the results revealed that the presence of interfacial oxygen vacancies and the strong interaction between Co2P/Fe2P provided the catalyst with more electrochemically active sites and a faster charge transfer capability, which improved the hydrolysis dissociation process. Electrochemically active metal (oxygen) hydroxide phases were produced after OER stability testing. The results of this study prove its great potential in practical industrial electrolysis and provide a reasonable and feasible strategy for the design of nonprecious metal phosphide electrocatalysts.

A facile approach to construct Co2P@Fe(PO3)2-NCNT heterojunction with highly dispersed active sites for photosensitive oxygen reduction reaction and oxygen evolution reaction

A facile pre-anchored approach is employed to prepare a non-precious bifunctional electrocatalyst Co2P@Fe(PO3)2-NCNT with a p−n heterojunction structure for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Firstly, a well-designed Co3O4/Fe(CN)64−@PPy-CNT precursor is synthesized via an one-pot method, in which Fe(CN)64− and Co3O4 are pre-anchored on polypyrrole (PPy) chains that in-situ formed on carbon nanotubes (CNTs). Subsequent pyrolysis and phosphating of the precursor resulted in the Co2P@Fe(PO3)2-NCNT catalyst, which contains highly dispersed Co2P and Fe(PO3)2 nanoparticles within N-doped carbon (NCNT). Compared to Co2P-NCNT with only n-type Co2P, introducing p-type Fe(PO3)2 into Co2P@Fe(PO3)2-NCNT leads to not only its Fermi level (EF) closer to Pt, but a larger energy gap between EF and the conduction band. This makes it a higher half-wave potential (E1/2) of 0.85 V for ORR, and a lower overpotential (η10) of only 300 mV for OER, superior to both Co2P-NCNT (E1/2 = 0.76 V,η10 = 510 mV), the commercial 20% Pt/C (E1/2 = 0.84 V) and RuO2 (η10 = 360 mV). Impressively, the unique p−n heterojunction structure of Co2P@Fe(PO3)2-NCNT is resulted in the significant improvement on both ORR with E1/2 increased by 10 mV and OER with overpotential decreased by 20 mV under visible light.

Optimized W-d band configuration in porous sodium tungsten bronze octahedron enabling Pt-like and wide-pH hydrogen evolution

Metal d-band configuration is decisive to the interaction of metals with reactants and intermediates, therefore often governs the catalytic activity. Herein, we for the first time demonstrate a family of alkali tungsten bronzes (MxWO3, M = Na, K, Rb, Cs and 0<x<1) for efficient hydrogen evolution reaction (HER) by modulating the W-d band configuration. Experimental and theoretical investigations on the newly-reported alkali tungsten bronzes reveal a linear relationship between the W-5d band center and the HER activity. Guided by this, the introduction of sodium ions endows NaxWO3 with optimized electronic structure and W-d band configuration, leading to not only superior charge-transfer ability but also promoted H2O adsorption/dissociation kinetics and moderate hydrogen adsorption energy for wide-pH HER. As a result, NaxWO3 exhibits Pt-like activity in a wide-pH range, delivering an overpotential as low as 37, 48 and 226 mV at 10 mA cm−2 in acid, alkaline and neutral seawater, respectively. This work provides the first insight into the role of alkali metal ions in tungsten bronzes towards HER, which thus is expected to open up a new class of non-precious metal-based electrocatalysts for the HER and other energy storage and conversion reactions.

Rational Construction of 3D Self-Supported MOF-Derived Cobalt Phosphide-Based Hollow Nanowall Arrays for Efficient Overall Water Splitting At large Current Density.

Developing efficient nonprecious bifunctional electrocatalysts for hydrogen and oxygen evolution reactions (HER and OER) in the same electrolyte with a low overpotential and large current density presents an appealing yet challenging goal for large-scale water electrolysis. Herein, a unique 3D self-branched hierarchical nanostructure composed of ultra-small cobalt phosphide (CoP) nanoparticles embedded into N, P-codoped carbon nanotubes knitted hollow nanowall arrays (CoPʘNPCNTs HNWAs) on carbon textiles (CTs) through a carbonization-phosphatization process is presented. Benefiting from the uniform protrusion distributions of CoP nanoparticles, the optimum CoPʘNPCNTs HNWAs composites with high abundant porosity exhibit superior electrocatalytic activity and excellent stability for OER in alkaline conditions, as well as for HER in both acidic and alkaline electrolytes, even under large current densities. Furthermore, the assembled CoPʘNPCNTs/CTs||CoPʘNPCNTs/CTs electrolyzer demonstrates exceptional performance, requiring an ultralow cell voltage of 1.50V to deliver the current density of 10mAcm-2 for overall water splitting (OWS) with favorable stability, even achieving a large current density of 200mAcm-2 at a low cell voltage of 1.78V. Density functional theory (DFT) calculation further reveals that all the C atoms between N and P atoms in CoPʘNPCNTs/CTs act as the most efficient active sites, significantly enhancing the electrocatalytic properties. This strategy, utilizing 2D MOF arrays as a structural and compositional material to create multifunctional composites/hybrids, opens new avenues for the exploration of highly efficient and robust non-noble-metal catalysts for energy-conversion reactions.

Electronic Modulation in Cu Doped NiCo LDH/NiCo Heterostructure for Highly Efficient Overall Water Splitting.

Layered double hydroxides (LDHs), promising bifunctional electrocatalysts for overall water splitting, are hindered by their poor conductivity and sluggish electrochemical reaction kinetics. Herein, a hierarchical Cu-doped NiCo LDH/NiCo alloy heterostructure with rich oxygen vacancies by electronic modulation is tactfully designed. It extraordinarily effectively drives both the oxygen evolution reaction (151mV@10mAcm-2) and the hydrogen evolution reaction (73mV@10mAcm-2) in an alkaline medium. As bifunctional electrodes for overall water splitting, a low cell voltage of 1.51V at 10mAcm-2 and remarkable long-term stability for 100h are achieved. The experimental and theoretical results reveal that Cu doping and NiCo alloy recombination can improve the conductivity and reaction kinetics of NiCo LDH with surface charge redistribution and reduced Gibbs free energy barriers. This work provides a new inspiration for further design and construction of nonprecious metal-based bifunctional electrocatalysts based on electronic structure modulation strategies.

A Highly Active Porous Mo2C-Mo2N Heterostructure on Carbon Nanowalls/Diamond for a High-Current Hydrogen Evolution Reaction

Developing non-precious metal-based electrocatalysts operating in high-current densities is highly demanded for the industry-level electrochemical hydrogen evolution reaction (HER). Here, we report the facile preparation of binder-free Mo2C-Mo2N heterostructures on carbon nanowalls/diamond (CNWs/D) via ultrasonic soaking followed by an annealing treatment. The experimental investigations and density functional theory calculations reveal the downshift of the d-band center caused by the heterojunction between Mo2C/Mo2N triggering highly active interfacial sites with a nearly zero ∆GH* value. Furthermore, the 3D-networked CNWs/D, as the current collector, features high electrical conductivity and large surface area, greatly boosting the electron transfer rate of HER occurring on the interfacial sites of Mo2C-Mo2N. Consequently, the self-supporting Mo2C-Mo2N@CNWs/D exhibits significantly low overpotentials of 137.8 and 194.4 mV at high current densities of 500 and 1000 mA/cm2, respectively, in an alkaline solution, which far surpass the benchmark Pt/C (228.5 and 359.3 mV) and are superior to most transition-metal-based materials. This work presents a cost-effective and high-efficiency non-precious metal-based electrocatalyst candidate for the electrochemical hydrogen production industry.

The influence of nanostructure and electrolyte concentration on the performance of nickel sulfide (Ni3S2) catalyst for electrochemical overall water splitting

Developing non-precious nanostructured electrocatalysts, exhibiting high catalytic activity in combination with excellent stability, has an enormous potential to replace noble-metal-based catalysts for Hydrogen production through electrochemical water splitting. In this study, a facile method is used for the synthesis of three different hierarchical nanostructures of nickel sulfide (Ni3S2) including nanosheets, nanorods, and multiconnected nanorods that are directly grown on 3D nickel foam (NF). These nanostructured electrocatalysts are evaluated for electrochemical water splitting in alkaline media using four different concentrations to understand the effect of nanostructure and ion concentration on the efficiency. Among different combinations of structure and electrolyte concentration, the Ni3S2 in the form of nanosheets exhibited the best electrocatalytic performance for hydrogen evolution reaction (HER) as well as oxygen evolution reaction (OER) in 3.0 M alkaline solution. The hierarchical Ni3S2 nanosheets exhibited a high electrochemically active surface area, which facilitated the charge transport phenomenon along the electrode–electrolyte interface in a higher electrolyte concentration that improved the reaction kinetics so as overall water splitting. The developed Ni3S2 nanosheets required an overpotential of 110 mV (@10 mA cm−2) and 211 mV (@100 mA cm−2) for HER and OER, respectively in 3.0 M electrolyte concentration. This work provides insight into how the materials’ nanostructures and electrolyte concentration could be utilized to improve the electrocatalytic performance for an overall water-splitting process, and the concept could be applied for material designing and conditions optimization for other catalytic applications.

Hierarchically structured Mo1–2C/Co-encased carbon nanotubes with multi-component synergy as bifunctional oxygen electrocatalyst for rechargeable Zn-air battery

The development of efficient and durable non-precious metal-based bifunctional oxygen electrocatalysts is pivotal in realizing cost-effective and high-performance rechargeable Zinc-Air Batteries (ZABs). In this study, a straightforward hydrothermal-melamine-assisted carbonization method is employed to synthesize a hierarchical core-shell structure comprising Mo2C/MoC intertwined with cobalt-incorporated N-doped carbon nanotubes (Mo2C/MoC/Co@CNTs). The synergy between Mo2C/MoC and Co@CNTs is harnessed to achieve remarkable bifunctional OER/ORR activities, as evidenced by a small potential gap (ΔE = Ej = 10 – E1/2) of 0.74 V between OER and ORR. When integrated into a liquid ZAB, the assembled battery delivers a remarkable peak power density of 134 mW cm−2 and exhibits a robust cycling performance, sustaining continuous operation for 275 h at a current density of 10 mA cm−2. This work not only presents a strategic approach to developing electrocatalysts with specific components, but also underscores the significance of multi-component synergy in electrocatalytic applications.

In-based coordination polymer-derived carbon nanoribbons with abundant CoP nanoparticles in carbon nanotubes for water oxidation.

The sluggish oxygen evolution reaction (OER) in overall electrocatalytic water splitting poses a significant challenge in hydrogen production. A series of transition metal phosphides are emerging as promising electrocatalysts, effectively modulating the charge distribution of surrounding atoms for OER. In this study, a highly efficient OER electrocatalyst (CoP-CNR-CNT) was successfully synthesized through the pyrolysis and phosphatization of a Co-doped In-based coordination polymer, specifically InOF-25. This process resulted in evenly dispersed CoP nanoparticles encapsulated in coordination polymer-derived carbon nanoribbons. The synthesized CoP-CNR-CNT demonstrated a competitive OER activity with a smaller overpotential (η10) of 295.7 mV at 10 mA cm-2 and a satisfactory long-term stability compared to the state-of-the-art RuO2 (η10 = 353.7 mV). The high OER activity and stability can be attributed to the high conductivity of the carbon network, the abundance of CoP particles, and the intricate nanostructure of nanoribbons/nanotubes. This work provides valuable insights into the rational design and facile preparation of efficient non-precious metal-based OER electrocatalysts from inorganic-organic coordination polymers, with potential applications in various energy conversion and storage systems.

Constructing delocalized electronic structures to motivate the oxygen reduction activity of zinc selenide for high-performance zinc-air battery

Rechargeable zinc-air battery (ZAB) typically necessitates highly efficient, durable, and cost-effective electrocatalysts to accelerate oxygen reduction reaction (ORR). Zinc selenide (ZnSe) has been demonstrated as a superior energy storage material due to its unique electronic structure for various energy-related applications but is still rarely developed in electrocatalysis field. Herein, the efficient interfacial engineering is reported to motivate and sufficiently boost the ORR performances of ZnSe to an unprecedented level. Density functional theory (DFT) calculations demonstrate that the introduction of robust Se-C interactions and N species regulation could efficiently modulate the local electronic structure of ZnSe and improve the interaction with oxygen-containing intermediate, thus producing lower reaction energy barrier of O2 → OOH* conversion. The optimized ZnSe@PNC catalyst manifests remarkable ORR activity with a half-wave potential of 0.905 VRHE in alkaline. Furthermore, the assembled Zn-air batteries with ZnSe@PNC cathodes show large peak power density (126 mW cm−2), high specific capacity (818 mAh/g) and long cycling life (200 h). This work provides more possibilities for the electrocatalytic applications of nonprecious metal selenide electrocatalyst for future energy storage.

Engineering Non-precious Trifunctional Cobalt-Based Electrocatalysts for Industrial Water Splitting and Ultra-High-Temperature Flexible Zinc-Air Battery.

Developing efficient, robust, and cost-effective trifunctional catalysts for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) at high current density and high temperature is crucial for water splitting at industry-level conditions and ultra-high-temperature Zinc-air battery (ZAB). Herein, cobalt nanoparticles well-integrated with nitrogen-doped porous carbon leaves (Co@NPCL) by direct annealing of core-shell bimetallic zeolite imidazolate frameworks is synthesized. Benefiting from the homogeneous distribution of metallic Co nanoparticles, the conductive porous carbon, and the doped N species, the as-fabricated Co@NPCL catalysts exhibit outstanding trifunctional performances with low overpotentials at 10mAcm-2 for HER (87mV) and OER (276mV), long-lasting lifetime of over 2000h, and a high half-wave potential of 0.86V versus RHE for ORR. Meanwhile, the Co@NPCL catalyst can serve as both cathode and anode for water splitting at industrial conduction, and exhibit a stable cell voltage of 1.87V to deliver a constant catalytic current of 500mAcm-2 over 60h. Moreover, the excellent trifunctional activity of Co@NPCL enables the flexible ZAB to operate efficiently at ultra-high temperature of 70°C, delivering 162mWcm-2 peaks power density and an impressive stability for 4500min at 2mAcm-2.

MoP nanocrystals encapsulated in N-doped three-dimensional carbon networks for efficient hydrogen evolution electrocatalysis

An efficient HER electrocatalyst, in which MoP nanocrystals are encapsulated in N-doped carbon networks, has been prepared successfully via a hard template-assisted freeze-drying and subsequent carbonization–phosphorization process.