Excellent Hydrogen Evolution Reaction Research Articles

RuSe2 and CoSe2 Nanoparticles Incorporated Nitrogen-Doped Carbon as Efficient Trifunctional Electrocatalyst for Zinc-Air Batteries and Water Splitting.

The development of affordable, highly active, and stable trifunctional electrocatalysts is imperative for sustainable energy applications such as overall water splitting and rechargeable Zn-air battery. Herein, we report a composite electrocatalyst with RuSe2 and CoSe2 hybrid nanoparticles embedded in nitrogen-doped carbon (RuSe2CoSe2/NC) synthesized through a carbonization-adsorption-selenylation strategy. This electrocatalyst is a trifunctional electrocatalyst with excellent hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) activities. An in-depth study of the effect of Se on the electrocatalytic process was conducted. Notably, the incorporation of Se moderately adjusted electronic structure of Ru and Co, enhancing all three types of catalytic performance (HER, η10 = 31 mV; OER, η10 = 248 mV; ORR, E1/2 = 0.834 V) under alkaline condition with accelerated kinetics and improved stability. Density functional theory (DFT) calculation reveals that the (210) crystal facet of RuSe2 is the dominant HER active site as it exhibited the lowest ΔGH* value. The in situ Raman spectra unravel the evolution process of the local electronic environment of Co-Se and Ru-Se bonds, which synergistically promotes the formation of CoOOH as the active intermediate during the OER. The superior catalytic efficiency and remarkable durability of RuSe2CoSe2/NC as an electrode for water splitting and zinc-air battery devices demonstrate its great potential for energy storage and conversion devices.

Efficient Hydrogen Evolution Electrocatalyst: MoN/Ni3N/NF Coupled with Methanol Oxidation Reaction for Formate Production in Alkaline Media

Abstract Electrocatalytic water splitting for hydrogen production is promising, but its practical application is limited by the sluggish kinetics of the anodic oxygen evolution reaction (OER) and the less valuable oxygen by-product. Hence, replacing OER with a thermodynamically favorable methanol oxidation reaction (MOR) and coupling with value-added formate generation on the anode is an energy-saving and effective scheme. In this work, we report a self-supporting bifunctional electrocatalyst MoN/Ni3N/NF, which exhibits excellent hydrogen evolution reaction catalytic activity and stability, requiring overpotentials of only 18 and 68 mV to reach current densities of −10 and −100 mA cm−2, respectively. Moreover, the catalyst’s performance minimally deteriorates after long-standing chronopotentiometry measurements (−100 mA cm−2@150h). When MOR is used instead of OER, the required potential drops by 200 mV to 1.38 V at a current density of 100 mA cm−2 and MoN/Ni3N/NF also demonstrates splendid catalytic stability towards OER and MOR. Finally, a two-electrode system employing MoN/Ni3N/NF as a bifunctional electrocatalyst only requires a cell voltage of 1.40, 1.68 V to achieve current densities of 10 and 100 mA cm−2, respectively. The coupled electrolyzer also exhibits high faradaic efficiency for producing cathodic H2 (100%) and anodic formate (90%).

Theoretical study of electrochemical hydrogen evolution reaction of Pt–Co diatomic sites catalyst

Hydrolytic Hydrogen is a clean hydrogen production method. To mitigate the substantial costs associated with water electrolysis, electrocatalysts are crucial in decreasing the cathodic reaction involved in hydrogen hydrolysis, specifically, the overpotential for hydrogen evolution reaction (HER). Compared to traditional catalysts and single-atom catalysts, Pt–Co diatomic sites catalyst exhibit excellent hydrogen evolution reaction activity and stability. We have established eight different structures of dual-center metal catalysts based on graphene planes. A systematic study was conducted on the catalytic performance and mechanism of these configurations, among which the structure with the best hydrogen evolution reaction activity was CoN4/PtC2N2, with a Gibbs free energy (ΔG) of 0.004 eV. Electronic structure analysis confirms that H follows the Sabatier mechanism on diatomic catalysts, and the catalyst exhibits excellent HER performance for moderate adsorption strength of H atoms. The d-band centers of Co and Pt atoms in the electrocatalyst CoN4–PtC2N2 are lower than those of a single system, indicating that the electronic effect between the CoN4 and PtC2N2 sites can enhance the inherent HER activity of the catalyst. This study expands the application scope of dual-site catalysts and provides new insights for the design and synthesis of dual-site hydrogen evolution catalysts.

Silk derived electrospun carbon nanofibers loaded with CoS nanoparticles as efficient hydrogen evolution reaction catalysts in acidic and alkaline media

The design of a stable and efficient hydrogen evolution catalyst across the entire pH range is of significant importance for the development of hydrogen production technology by electrocatalytic water splitting. This study chose biomass silk fibroin protein as the electrospinning raw material, synthesizing a hybrid membrane of CoS@carbon nanofibers (CNF) with a layered core–shell structure through simple carbonization and hydrothermal treatment. The CoS nanoparticles can grow uniformly and densely on the CNF. By varying the concentrations of hexahydrate cobalt nitrate (Co(NO3)2·6H2O) and thiourea (CH4N2S), the morphology of the synthesized CoS nanoparticles on CNF can be controlled. Different microscopic morphologies lead to differences in the activity of the hydrogen evolution reaction (HER), attributed to variations in the exposed active sites for different morphologies. Compared to pure CNF, the CoS-2@CNF hybrid membrane exhibits excellent HER activity in both acidic and alkaline electrolytes. This highlights the synergistic catalytic effect between CNF and CoS particles. This work provides guidance for the rational design of bio-based catalysts with excellent performance.

Superior MoTiN and NiMoTiN coating electrode with platinum-like catalytic activity fabricated by plasma electrolytic oxidation

Electrolyzing water is an effective and feasible technology to achieve a large-scale hydrogen production in industry. However, it is still challenging to develop an efficient approach to fabricate a superior and stable hydrogen evolution reaction (HER) electrodes with low cost and outstanding catalytic efficiency. This work presents an innovative surface modification technique of plasma electrolytic oxidation (PEO) to fabricate superior MoN based coating electrodes. By simply introducing Na2MoO4 and NiAc2 into the electrolyte, a novel MoTiN and NiMoTiN coatings were successfully achieved on the surface of a titanium substrate by PEO and annealing treatments, which exhibits excellent mechanical adhesion and platinum-like catalytic properties. Importantly, it has been demonstrated that the newly formed MoTiN solid solution combined by active Mo2N and conductive TiN can contribute the superior catalytic activity and the subsequent Ni doping can effectively stabilize the structure and activity of MoTiN. Under the alkaline environment of 1 M KOH, the MoTiN and NiMoTiN coated electrodes require only 126 and 121 mV overpotential, respectively, to achieve a current density of 10 mA cm−2. Additionally, under the same test conditions, NiMoTiN can operate stably for over 24 h, demonstrating excellent HER catalytic activity and stability. This work provides new insights into the preparation of HER electrodes with superior mechanical properties and excellent catalytic performance towards industrial hydrogen production.

A general strategy for Ni0–NiOOH hybrid catalyst of high hydrogen evolution activity

Ni-based hybrid catalysts consisting of different components in variant valence state have the synergistic effect on boosting hydrogen evolution reaction (HER) activity. A general strategy is developed to achieve a Ni0–NiOOH HER hybrid catalyst, which needs to produce metal Ni0 and Ni(OH)2 concurrently. The strategy is demonstrated by two approaches, both of which include two electrochemical steps. To regular the content of the components in the hybrid catalyst, l-histidine and nitrate ions are introduced to the electrolyte in order to controlling the generation rate of Ni0 and Ni(OH)2. In terms of the two-step electrochemical technology, the pre-catalyst Ni0–Ni(OH)2 is electrochemically deposited firstly, and then electrochemical oxidized to Ni0–NiOOH, wherein Ni0 and NiOOH in different valence act as *H and *OH absorption sites, respectively. The XRD, TEM and XPS results demonstrate the coexistence of Ni0 and Ni(OH)2 in the pre-catalyst and the conversion of Ni(OH)2 to NiOOH in the final catalyst. Electrochemical tests show that the Ni0–NiOOH hybrid catalysts exhibit excellent HER activity. The overpotentials at 10 and 50 mA cm−2 are 39 mV and 88 mV, respectively, and the catalyst keeps a durable stability at 50 mA cm−2 for over 100 h. The present results suggest that the structure-performance correlations of the Ni0–NiOOH hybrid catalyst could be manipulated implementing this general deposition strategy.

A facile dual isolation and protection strategy for preparation of PtFe intermetallic compound in biomass-derived carbon with high activity and durability for pH-universal bifunctional electrocatalysts

A facile dual isolation and protection strategy is developed to prepare PtFe intermetallic electrocatalyst (PtFe–N–C@bioC) on porous biomass carbon (bioC) derived from peanut shell. In preparation, meso-tetraphenylporphyrine (H2TPP) together with platinum (II)-tetraphenylporphyrin (PtTPP) are in-situ fabricated on the porous peanut shell-derived bioC matrixes and then further absorbed Fe (III) tetraphenyl porphyrin (FeTPP) molecules through π−π interactions between PtTPP/H2TPP and FeTPP to form a mixed precursor of FeTPP/PtTPP/TPP-bioC. Upon pyrolysis of FeTPP/PtTPP/TPP-bioC, PtFe bimetallic-containing N-doped carbon formed on bioC (PtFe–N–C@bioC). The resultant PtFe–N–C@bioC showed excellent oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) activity across a wide pH range. In particular, under alkaline medium, PtFe–N–C@bioC shows the ORR performance with an onset potential (Eonset) of 0.989 V, a half-wave potential (E1/2) of 0.901 V and a limiting current density (JL) of −6.214 mA cm−2. Meanwhile, PtFe–N–C@bioC delivers an enhanced mass activity (1.197 A mg−1Pt), which is 13 times larger than commercial Pt/C. For HER, PtFe–N–C@bioC shows an impressive overpotential (η10) of 17 mV at a current density of 10 mA cm−2 under acidic medium. Further, it is applied to Zn-Air batteries with a power density performance of 98.7 mW cm−2 and good durability.

Ordered PtNiTiZrHf nanoparticles on carbon nanotubes catalyze hydrogen evolution reaction with high activity and durability

With the scarcity of the earth's natural resources, hydrogen production from electrolyzing water is seen as an alternative energy source. Although platinum (Pt) is an advanced catalyst for hydrogen evolution reaction (HER), its application is limited by high cost and limited electrocatalytic performance. In this article, the five-element alloy nanoparticles are successfully synthesized on carbon nanotubes (CNT) by employing liquid-phase reduction and gas-phase sintering to reduce Pt utilization and improve catalytic performance. For comparison, a series of ordered and disordered (PtNi)x(TiZrHf)100-x/CNT catalysts are obtained. Results show that the ordered samples have more excellent HER catalytic performance and stability than disordered samples in 0.5 M H2SO4 and 1 M KOH electrolytes. In particular, when the electrolyte is acidic, the overpotentials of ordered (PtNi)55(TiZrHf)45/CNT at 10 and 100 mA cm−2 are 11 and 52 mV, with low Tafel slope of 37.73 mV dec−1. At 10 mA cm−2, the stabilization time can reach 58 h, which is much better than commercial Pt/C (20 wt.%). Density functional theory (DFT) calculation shows that ordered (PtNi)55(TiZrHf)45/CNT has lower hydrogen adsorption energy and activated water adsorption energy than disordered one, indicating better performance in both acidic and alkaline electrolytes. It is mainly attributed to the electronic coupling effect after ordering that makes the overall D-band center decrease. This work presents a cost-effective approach to optimize the structural design for acid-base HER electrocatalysts.

Boost alkaline hydrogen evolution reaction by intermetallic charge transfer in perovskite ruthenate encapsulated in ZIF-67 derived cobalt sulfide nanoparticles

Constructing and manipulating heterostructure is an effective strategy to prepare electrocatalysts with excellent performance for water electrolysis. Herein, an efficient alkaline hydrogen evolution reaction (HER) electrocatalysts, Co3S4-embedded in carbon-encapsulated BaRuO3 (BaRuO3@CS-0.1), was synthesized through the sacrificial template method of ZIF-67 encapsulated BaRuO3 precursors. By inheriting the exceptional merits of different ingredients, this heterostructure catalyst BaRuO3@CS-0.1 enables intermetallic charge transfer between Ru and Co with boosted HER kinetics, and thus displaying higher catalytic activity towards HER, as evidenced by the intensively theoretical calculations and experimental measurements. BaRuO3@CS-0.1 exhibits excellent HER performance, with the lowered overpotentials of 26 mV to achieve 10 mA cm−2 in comparison to the pristine BaRuO3 (51 mV), which is also superior to Pt/C catalyst at large current density. Moreover, this heterostructure also demonstrates comparable oxygen evolution reaction (OER) activities with the representative electrocatalysts, delivering current densities of 10 mA cm−2 at a potential of 1.546 V for overall water splitting. These findings provide a rational route to optimize the performance of bulk electrocatalysts and endow them with richer electrochemical activity through this composite strategy.

Self-supported monometallic FeS2/FeOOH-ZnO@NF with abundant oxygen vacancies as efficient and stable electrocatalysts for the OER and HER

The construction of heterogeneous interfaces and oxygen vacancy (Ov) is a very useful method to enhance the catalytic activity performance of catalysts. In this work, the high-performance a monometallic iron based bifunctional electrocatalyst FeS2/FeOOH-ZnO@NF with oxygen vacancy (Ov) and heterogeneous interface is prepared by the ZnO template induced deposition method for the first time. Due to the synergistic effect of the heterogeneous interface of FeS2/FeOOH-ZnO@NF and the oxygen vacancies of the ZnO, the FeS2/FeOOH-ZnO@NF catalysts exhibited excellent hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activity in alkaline media, with a low overpotential of 74 mV and 177 mV at 10 mA cm−2, respectively. It should be emphasized that the FeS2/FeOOH-ZnO@NF || FeS2/FeOOH-ZnO@NF electrolytic cell has an ultra-low decomposition voltage, only 1.41 V at 10 mA cm−2 and 1.49 V at 20 mA cm−2, which is much lower than that currently reported in most literatures. This work will provide a new strategy and idea for the improvement of HER and OER electrocatalytic performance of transition metal-based catalyst.

Boosting electrocatalytic activity of Ru for hydrogen evolution through engineering Ru on multiple interfaces of 1T-MoS2 and carbon

Ru is considered as highly efficient Pt-free catalyst in hydrogen evolution reaction (HER) due to its fast water dissociation kinetics. However, its strong affinity to OH* and H* greatly limits its HER performance. Herein, Ru nanoparticles (NPs) anchored on the mixed substrates of MoS2 (different 1T contents) and carbon fiber paper (Ru@MoS2-1T%/CFP) is designed and synthesized with three kinds of interfaces (MoS2/CFP, Ru/CFP, and Ru/MoS2) as excellent electrocatalyst for HER. Particularly, the Ru2@MoS2-85%/CFP presents superb HER performance with overpotential of 19 mV at 10 mA cm−2, a low Tafel slope of 29 mV dec–1 and stability of up to 10 days, outperforming reported Ru-based catalysts and Pt/C. The experimental and DFT studies disclose that the hydroxyl migration-assisted dissociation of water and interface-engineering desorption of H2 process, occurring at the mutually hybridized interface sites of Ru/MoS2/CFP, simultaneously speed Volmer/Tafel processes. Compared to Ru, the stronger interaction of 1T-MoS2 to OH* makes OH* migrate from Ru to MoS2, alleviating the poisoning of Ru sites. Also, only Ru NPs close to the interface of 1T-MoS2/CFP can achieve an optimal hydrogen adsorption energy for high HER performance. This designed strategy provides a novel idea for preparing supported Ru catalysts for excellent HER performance.

Theoretical Calculation Assisted by Machine Learning Accelerate Optimal Electrocatalyst Finding for Hydrogen Evolution Reaction

AbstractElectrocatalytic hydrogen evolution reaction (HER) is a promising strategy to solve and mitigate the coming energy shortage and global environmental pollution. Searching for efficient electrocatalysts for HER remains challenging through traditional trial‐and‐error methods from numerous potential material candidates. Theoretical high throughput calculation assisted by machine learning is a possible method to screen excellent HER electrocatalysts effectively. This will pave the way for high‐efficiency and low‐price electrocatalyst findings. In this review, we comprehensively introduce the machine learning workflow and standard models for hydrogen reduction reactions. This mainly illustrates how machine learning is used in catalyst filtration and descriptor exploration. Subsequently, several applications, including surface electrocatalysts, two‐dimensional (2D) electrocatalysts, and single/dual atom electrocatalysts using machine learning in electrocatalytic HER, are highlighted and introduced. Finally, the corresponding challenge and perspective for machine learning in electrocatalytic hydrogen reduction reactions are concluded. We hope this critical review can provide a comprehensive understanding of machine learning for HER catalyst design and guide the future theoretical and experimental investigation of HER catalyst findings.

Self-assembled PtNi layered metallene nanobowls for pH-universal electrocatalytic hydrogen evolution

Compared with layered materials such as graphite and transition metal disulfide compounds with highly anisotropic in-plane covalent bonds, it is inherently more challenging to obtain independent metallic two-dimensional films with atomic thickness. In this study, PtNi layered metallene nanobowls (LMBs) with multilayer atomic-scale nanosheets and bowl-like structures have been synthesized in one step using structural and electronic effects. The material has the advantage of catalyzing pH-universal hydrogen evolution reaction (HER). Compared with Pt/C, PtNi LMBs exhibited excellent HER activity and stability under all pH conditions. The overpotentials of 10 mA cm−2 at 0.5 M H2SO4, 1.0 M phosphate buffer and 1.0 M KOH were 14.8, 20.3, and 34.0 mV, respectively. Under acidic, neutral and alkaline conditions, the HER Faraday efficiencies reach 98.97%, 98.85%, and 99.04%, respectively. This study provides an example for the preparation of unique multilayer nanobowls, and also provides a basic research platform for the development of special HER materials.

Rational Design of Dynamic Interface Water Evolution on Turing Electrocatalyst toward the Industrial Hydrogen Production.

Manipulating the structural and kinetic dissociation processes of water at the catalyst-electrolyte interface is vital for alkaline hydrogen evolution reactions (HER) at industrial current density. This is seldom actualized due to the intricacies of the electrochemical reaction interface. Herein, this work introduces a rapid, nonequilibrium cooling technique for synthesizing ternary Turing catalysts with short-range ordered structures (denoted as FeNiRu/C). These advanced structures empower the FeNiRu/C to exhibit excellent HER performance in 1 m KOH with an ultralow overpotential of 6.5 and 166.2 mV at 10 and 1000 mA cm-2, respectively, and a specific activity 7.3 times higher than that of Pt/C. Comprehensive mechanistic analyses reveal that abundant atomic species form asymmetric atomic electric fields on the catalyst surface inducing a directed evolution and the dissociation process of interfacial H2O molecules. In addition, the locally topologized structure effectively mitigates the high hydrogen coverage of the active site induced by the high current density. The establishment of the relationship between free water population and HER activity provides a new paradigm for the design of industrially relevant high performance alkaline HER catalysts.

Enhancing electrocatalytic hydrogen evolution of MoS2 enabled by electrochemical cation implantation for simultaneous surface-defect and phase engineering

The increasing demand for energy-efficient and cost-effective water-splitting systems has prompted research on non-precious-metal-based electrocatalysts for the hydrogen evolution reaction (HER) over a wide pH range. Molybdenum sulfide (MoS2) has received considerable attention owing to its excellent HER activity in acidic media. However, its competitive HER properties must be improved to achieve better performance in alkaline or neutral environments. In this study, we introduced an electrochemical cation implantation (ECI) process as a versatile method to enhance the electrocatalytic properties of MoS2. By modifying the microstructure of MoS2, the ECI process induced vacancies in Mo and S, primarily in the basal planes and facilitated a gradual transition from the semiconducting (2H) to metallic (1T) phase. The optimized ECI-processed MoS2 catalysts exhibited improved HER activities and low overpotentials (η10, 144 mV) over the entire pH range compared with bare MoS2 catalysts, highlighting the potential application of the ECI process for enhanced electrocatalysts.

Coupling amorphous WO3 with WP as a cocatalyst for efficient dye-sensitizated photocatalytic hydrogen evolution

Tungsten phosphide (WP) as an excellent hydrogen evolution reactions (HER) catalyst has attracted widespread attention, but its HER activity is low in alkaline media due to high water dissociation barrier. Herein, noble-metal-free cocatalyst WP/WO3 composite was synthesized by adjusting the P/W molar ratio in the raw material using a simple solid phosphidation reaction. The structure, morphology, composition, and optoelectronic properties of the as-synthesized samples were characterized by XRD, SEM, TEM, XPS, UV–vis DRS, PL techniques, and electrochemical methods. Under visible light irradiation (λ ≥ 420 nm), the photocatalytic HER activities of the as-prepared samples using Eosin-Y (EY) dye as a sensitizer and trimethylamine (TMA) as an electron donor were investigated. The result shows that WP/WO3 composite as a cocatalyst exhibits excellent photocatalytic HER activity and good stability. The highest apparent quantum yield (AQY) reaches 32.8 %. The presence of amorphous WO3 in crystalline WP can improve the separation efficiency of photogenerated electrons and holes, reduce HER overpotential, and promote the dissociation of H2O in alkaline media. Therefore, the photocatalytic HER activity of WP/WO3 composite is higher than that of single crystalline WP.

Controllable fabrication of N-doped carbon nanotubes coated Co4N nanoparticles to boost hydrogen evolution reaction

Transition metal nitrides (TMNs) have attracted great attention as ideal active materials in the field of electrocatalysts in recent years due to their excellent electrical conductivity, wide band gap and adjustable morphology. Pure phase Co4N nanoparticles encapsulated nitrogen-doped carbon (NC) nanotubes (Co4N@NC) were in-situ synthesized by one-pot method. In this paper, the morphology of carbon nanotubes is controlled by adjusting the pyrolysis time, so that more active sites are exposed on carbon nanotubes. Thus, the cobalt nitride catalyst with excellent catalytic performance for hydrogen evolution reaction (HER) in acidic electrolyte was obtained. In summary, due to the protection of mesoporous nitrogen-doped carbon to Co4N nanoparticles, large electrochemically active surface area, good conductivity and more exposed active sites, Co4N@NC possesses excellent HER performance in acidic electrolytes. The overpotential of Co4N@NC at the current density of 10 mA cm−2 is 117 mV (η10), and it shows long-term stability in 0.5 M H2SO4 solution for 50 h. This study provides a strategy for the development of catalysts for the controllable synthesis of high-performance transition metal nitrides.

Molten Salts Etching Route Driven Construction of C@Ni Nanoparticles Loaded Carbon Nanosheet as High-Performance Electrocatalyst for Hydrogen Evolution Reaction

Developing earth-abundant, low-cost, high-efficiency electrocatalysts for hydrogen evolution reaction (HER) by structure design is still a grand challenge. Herein, we fabricated Ni nanoparticles encapsulated by carbon loaded in two-dimensional carbon nanosheets (2D Ni@C@SU) using a molten salt (NaCl)-assisted pyrolysis method. Because of the large specific surface area (262.35m²/g) and high electrical conductivity, the prepared 2D Ni@C@SU-0.75 electrocatalyst exhibits excellent HER electrocatalytic activity with the overpotential of -105 mV at -10 mA cm-2 and -367 mV at -200 mA cm-2, which is close to the commercial benchmark Pt/C (η200= -339 mV). Besides, the catalyst displays incredible durability in the electrocatalytic HER. This research indicates that the green solid-state synthetic strategy provides a new window for designing new Ni-based composite catalysts for electrocatalytic HER.

A universal and ultrafast method for fabricating a library of nanocellulose-supported metal nanoparticles

Using nanocatalysts to catalyze water electrolysis for hydrogen production is an ideal solution to address the energy crisis. The most well-adopted fabrication methods for nanocatalysts are tube furnace annealing, Hydrothermal method, etc., hardly satisfying the trade-off among coarsening, dispersity, and particle size due to mutual restrictions. Herein, a universal, ultrafast and facile cellulose nanometer whiskers-high temperature shock (CNW-HTS) method was reported for fabricating a library of ultrafine metal nanoparticles with uniform dispersion and narrow size distribution. The metal-anchor functional groups in CNW (i.e., –OH and –COOH) and the characteristics of the HTS method for ultrafast heating and powerful quenching synergistically contribute to the successful synthesis of metal nanoparticles. As an initial demonstration, the as-prepared Pt nanocatalyst (η10 ​mA ​cm−2 ​= ​51.8 ​mV) shows more excellent catalytic hydrogen evolution reaction (HER) performance than the Pt catalyst prepared in the tubular furnace (η10 ​mA ​cm−2 ​= ​169.4 ​mV). This rapid and universal CNW-HTS method can pave the way for nanomanufacturing to produce high-quality metal nanoparticles, thereby expanding applications of energy conversion and electrocatalysis.

3D-printed pyramid nickel-based electrode enabling directional bubble traffic and electrolyte flow for efficient hydrogen evolution

For efficient and stable large-scale water electrolysis, practical industrial electrodes should meet the following characteristics: high activity, structural stability, and fast bubble removal. Here we report a structured electrode (NiS–Co–NiP) prepared via 3D printing of nickel-based substrate and subsequent electrodeposition for the hydrogen evolution reaction (HER). With unique 3D nanosheets, the NiS–Co–NiP electrode exhibits large electrochemical surface area (ECSA), strong hydrophilicity, high mechanical strength and electrical conductivity, delivering outstanding HER activity. It requires low overpotentials of 134 mV and 169 mV to achieve the current densities of 100 mA cm−2 and 300 mA cm−2, respectively. Moreover, rational design of the NiS–Co–NiP electrode in pyramidal geometry facilitates directional bubble transport and electrolyte flow, resulting in superior stability of 350 h at a current density of 150 mA cm−2. This work demonstrates a new approach for manufacturing binder-free structured electrode of excellent HER performance at high current densities.