Bubble Template Method Research Articles

Nanoporous Gold-Modified Screen-Printed Electrodes for the Simultaneous Determination of Pb2+ and Cu2+ in Water.

In this study, nanoporous gold (NPG) was deposited on a screen-printed carbon electrode (SPCE) by the dynamic hydrogen bubble template (DHBT) method to prepare an electrochemical sensor for the simultaneous determination of Pb2+ and Cu2+ by square wave anodic stripping voltammetry (SWASV). The electrodeposition potential and electrodeposition time for NPG/SPCE preparation were investigated thoroughly. Scanning electron microscopy (SEM) and energy-dispersive X-ray diffraction (EDX) analysis confirmed successful fabrication of the NPG-modified electrode. Electrochemical characterization exhibits its superior electron transfer ability compared with bare and nanogold-modified electrodes. After a comprehensive optimization, Pb2+ and Cu2+ were simultaneously determined with linear range of 1-100 μg/L for Pb2+ and 10-100 μg/L for Cu2+, respectively. The limits of detection were determined to be 0.4 μg/L and 5.4 μg/L for Pb2+ and Cu2+, respectively. This method offers a broad linear detection range, a low detection limit, and good reliability for heavy metal determination in drinking water. These results suggest that NPG/SPCE holds great promise in environmental and food applications.

Leaded Bronze Foams As Innovative Electrodes for Organic Electrosynthesis

The electrification of organic synthesis represents an outstanding green alternative to prepare valuable and fine chemicals. However, the design of electrode materials for organic electrosynthesis remains as an open field to investigate. Motivated by the superior performance of leaded bronzes as electrodes for reductive transformations,[1, 2, 3] we have developed highly porous binary and ternary leaded metal foams through the dynamic hydrogen bubble template method [4] and tested them as cathodes in the electro-organic synthesis of 2,6-dichlorobenzonitrile from 2,6-dichlorobenzaldoxime.[5]The electrocatalytic performance of the novel leaded foams was compared to the one of the planar CuSn7Pb15 leaded bronze. The novel porous leaded foams outperformed the CuSn7Pb15 electrodes in terms of chemical yield and energy efficiency. Furthermore, due to their highly crystalline surface, these materials are mechanically more stable and less prone to cathodic corrosion than flat Pb and CuSn7Pb15 electrodes.

Tailoring the Active Sites of Nanosheet NiSe/NiSe2 Catalyst by Pulse Electrodeposition on the 3D Microporous Ni-Cu/NF Substrate for both Hydrogen and Oxygen Evolution Reactions

Establishing proper intrinsic catalysts with nanostructured high active surfaces endows the paramount electrocatalytic activity. A Ni-Se@Cu-Ni/NF catalyst for hydrogen and oxygen evolution reactions (HER and OER) is prepared via an efficient two-step pulse current (PC) electrodeposition method. The initial 3D film of Cu-Ni is synthesized via the dynamic hydrogen bubble template (DHBT) method to attain further active surface area. Then, Ni-Se film is prepared by direct current (DC) and PC electrodeposition. Morphological, chemical, and electrocatalytic characteristics of the Ni-Se electrodeposited films are evaluated. X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy results show a NiSe/NiSe2 nanofilm on the 3D microporous nanostructured Cu-Ni substrate which reveals an efficient bifunctional electrocatalytic behavior with overpotentials of 74 and 272 mV in the current density of 10 mA cm−2, and Tafel slopes of 78 and 50 mV dec−1 for HER and OER, respectively. The two-electrode examination with NiSe/NiSe2@Cu-Ni/NF catalyst in overall water splitting indicates a required potential of 1.57 V in the current density of 10 mA cm−2.

Nanoengineered Cobalt Electrocatalyst for Alkaline Oxygen Evolution Reaction.

The alkaline oxygen evolution reaction (OER) remains a bottleneck in green hydrogen production owing to its slow reaction kinetics and low catalytic efficiencies of earth abundant electrocatalysts in the alkaline OER reaction. This study investigates the OER performance of hierarchically porous cobalt electrocatalysts synthesized using the dynamic hydrogen bubble templating (DHBT) method. Characterization studies revealed that electrocatalysts synthesized under optimized conditions using the DHBT method consisted of cobalt nanosheets, and hierarchical porosity with macropores distributed in a honeycomb network and mesopores distributed between cobalt nanosheets. Moreover, X-ray photoelectron spectroscopy studies revealed the presence of Co(OH)2 as the predominant surface cobalt species while Raman studies revealed the presence of the cubic Co3O4 phase in the synthesized electrocatalysts. The best performing electrocatalyst required only 360 mV of overpotential to initiate a current density of 10 mA cm-2, exhibited a Tafel slope of 37 mV dec-1, and stable OER activity over 24 h. The DHBT method offers a facile, low cost and rapid synthesis approach for preparation for highly efficient cobalt electrocatalysts.

Achieving Long Cycle Life of Zn-Ion Batteries through Three-Dimensional Copper Foam.

Metallic zinc anodes in aqueous zinc-ion batteries (ZIBs) suffer from dendritic growth, low Coulombic efficiency, and high polarization during cycling. To mitigate these challenges, current collectors based on three-dimensional (3D) commercial copper foam (CCuF) are generally preferred. However, their utilization is constrained by their thickness, low electroactive surface area, and increased manufacturing expenses. In this study, the synthesis of cost-effective current collectors with exceptionally large surface areas designed for ZIBs that can be cycled hundreds of times is reported. A zinc-coated CuF anode (Zn/CuF) was prepared with a 3D porous CuF current collector produced by the dynamic hydrogen bubble template (DHBT) method. Electrochemically generated copper foam could be obtained within seconds while offering a thickness as low as 30-40 μm (CuF5 achieved a thickness of ∼38 μm in 5 s) via the DHBT method. The excellent electrical conductivity and open pore structure of the 3D porous copper scaffold ensured the uniform deposition/stripping of Zn during cycling. During the 500 h Zn deposition/stripping process, the as-synthesized CuF5 current collector offered fast electrochemical kinetics and low polarization as well as a relatively high average Coulombic efficiency of 99% (at a current density of 5 mA cm-2 and a capacity of 1 mAh cm-2). Furthermore, the symmetric cell exhibited low voltage polarization and a stable voltage profile for 1000 h at a current density of 0.1 mA cm-2. In addition, full cells containing the Zn/CuF anode coupled with an as-synthesized α-MnO2 nanoneedle cathode in aqueous electrolyte were also prepared. Capacities of 266 mAh g-1 at 0.1 A g-1 and 94 mAh g-1 at 2 A g-1 were achieved after 200 charge/discharge cycles with a stable Coulombic efficiency value close to 99.9%.

Refined Pore Structure Design and Surface Modification of 3D Porous Copper Achieving Highly Stable Dendrite‐Free Lithium‐Metal Anode

Abstract3D porous copper is anticipated to serve as an ideal current collector for lithium‐metal anodes (LMAs) owing to its excellent conductivity, huge surface area, and cost‐effectiveness. However, most pertinent studies center around commercial copper foams, where their notable large pore size (150–400 µm) is identified as a primary inducement for dendrite formation and ultimate battery failure. Hence, ensuring the appropriate pore structure in 3D porous copper for achieving highly reversible lithium deposition/stripping process plays a pivotal role in stabilizing LMAs. Herein, the hydrogen bubble template method is employed to fabricate five distinct types of 3D porous copper. Among them, the one with an average surface pore diameter of 25.18 µm and the lowest probability of macropores distribution within the pore walls demonstrates optimal electrochemical performance. To further improve the inherent lithiophobicity of copper, Cu2Se/Cu2O heterostructure nanowires are loaded as kinetic enhanced nucleation sites. Benefiting from the synergistic effect of optimized pore structure and heterostructure nanowires, the Cu2Se/Cu2O@3D Cu composite current collector exhibits excellent dendrite‐free characteristics and outstanding electrochemical performance, showcasing an ultra‐long symmetrical‐cell lifespan of 3000 h at 1 mA cm−2 and stability for 300 h even under 20 mA cm−2.

Superhydrophilic/superaerophobic NiFe with internal bubble flow channels for electrocatalytic water splitting

The generation and detachment of gas bubbles from electrodes have a substantial impact on mass transfer in electrocatalytic water splitting and superwetting electrodes have emerged as promising solution for addressing such challenge. However, the superhydrophilic or superaerophobic property was mainly related to the structure on the electrode surface, while the bubbles detachment behavior within the bulk space was less investigated. In this study, a three-dimensional NiFe electrode with superhydrophilic/superaerophobic surface and abundant gas channels was constructed via an in-situ bubble template method. The superwetting and hierarchical NiFe/NF can reduce the cumulative adhesion force of bubbles and the gas channels inside the electrode facilitated the transport and release of bubbles driven by the capillary effect. The released bubbles with an average diameter of 30 μm were observed at a current density of 100 mA cm−2. The optimized Ni0.75Fe0.25/NF electrode exhibited promising catalytic activities for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), and a high current density of 500 mA cm−2 was achieved with overpotentials of 214 mV and 327 mV, respectively.

Construction of carbon-doped mesoporous g-C3N4 catalytic nanoreactor via bubble template method for visible-light photocatalysis

Morphological control of photocatalysts is an important way to improve photocatalytic activity. Herein, we design a carbon-doped mesoporous g-C3N4 nanoreactor by combining the self-assembly method of supramolecular precursors with the bubble template method. The mesoporous structure can increase the utilization rate of light absorption. Furthermore, the C atoms replace the position of bridging N atoms may generate delocalized large π bonds, both of which can facilitate photocatalysis. This nanoreactor coupled with larger specific surface area and faster electronic transmission efficiency shows an outstanding performance in photocatalytic RhB degradation (97%, 15 min) and reducing CO2 into CO (60.82 μmol/g, 5h). The C-doped mesoporous g-C3N4 nanoreactor would provide some practical reference for environmental improvements and clean energy production.

Performance enhanced Ti-based thin film getter with porous nickel as scaffold

n order to meet the requirement of high vacuum in MEMS devices, an improved Ti-based thin film getter with porous nickel scaffold was prepared by using dynamic hydrogen bubble template (DHBT) method, which finally effectively increased the specific surface area (SSA) and improved the adsorption performance. The microstructure and adsorption performance of the getter were studied by scanning electron microscope, BET, thermogravimetric analysis (TGA) and hydrogen adsorption test. The results show that the SSA of the prepared porous nickel scaffold can reach up to 11.622 m2/g. The aspect ratio of mesopores is around 2. The Ti film deposited on the scaffold have a good coating effect on the porous structure and have little effect on the aspect ratio. When the deposition thickness is 300 nm, the adsorption capacity (3.51374 mg) and adsorption rate (6.507 × 10−4mg/(s∙g)) can reach the highest. Hydrogen adsorption tests also show that the Ti-based thin film getter with porous nickel scaffold has a good repeatability, and its average initial adsorption rate reaches 8.195ml/(s∙cm2), which is nearly an order of magnitude higher than that of the two-dimensional planar getter.

Effective Energy Storage Performance Derived from 3D Porous Dendrimer Architecture Metal Phosphides//Metal Nitride-Sulfides.

The present work addresses the limitations by fabricating a wide range of negative electrodes, including metal nitrides/sulfides on a 3D bimetallic conductive porous network (3D-Ni and 3D-NiCo) via a dynamic hydrogen bubble template (DHBT) method followed by vapour phase growth (VPG) process. Among the prepared negative electrodes, the 3D-Fe3S4-Fe4N/NiCo nanostructure demonstrates an impressive specificcapacitance (Cs) of 1125 F g-1 (2475 mF cm-2) at 1 A g-1 with 80% capacitance retention over 5000 cycles. Similarly, a 3D-Mn3P nanostructured positive electrode fabricated via electrodeposition followed by a phosphorization process exhibits a maximum specific capacity (Cg) of 923.04 C g-1 (1846.08 mF cm-2) at 1 A g-1 with 80% stability. A 3D-Mn3P/Ni//3D-Fe3S4-Fe4N/NiCo supercapattery is also assembled, and it shows a notable CS of 151 F g-1 at 1 A g-1, as well as a high energy density (ED) of 51Wh kg-1,a power density (PD) of 782.57W kg-1 and a capacitance efficiency of 76% over 10000 cycles. This may be ascribed to the use of a bimetallic 3D porous conductive template and the attachment of transition metal sulfide and nitride. The development of negative electrodes and supercapattery devices is greatly aided by this exploration of novel synthesis techniques and material choice.

Modulation of active surface sites on Ni–Fe–S by the dynamic hydrogen bubble template method for energy-saving hydrogen production

A porous structure was electrosynthesized via a DHBT with interconnected nanosheets. The fabricated electrode demonstrated great activity for the UOR and HER.

Breaking Free - Unlocking the Potential of Dynamic Hydrogen Bubble Templating Materials

In recent years, porous electrodes for electrochemical conversion devices, such as low-temperature fuel cells or water electrolyzers, have been engineered to address issues related to mass transport to and within the catalyst. For example, the addition of a layer with reduced pore size facing the catalyst layer (i.e., microporous layer) results in an increased performance[1–3]. Furthermore, chemical[4], as well as mechanical[5,6]. methods of creating dedicated liquid and gas pathways in the porous electrodes, have been investigated with promising results, highlighting the need for further optimization of state-of-the-art materials with regards to multi-phase transport. The range of possible modifications is intrinsically limited by the microstructure of the material they are applied to and add cost and complexity to the already costly electrode production procedure, motivating the development of novel materials which contain these desired features, offer a large morphological design space, and are cost competitive.To tackle these stringent targets, we investigate the dynamic hydrogen bubble templating (DHBT) method to generate hierarchical structures containing both a pore size gradient as well as dedicated water and gas pathways in the form of bimodal pore size distributions. It leverages simultaneous deposition of a metal and gas evolution on the same surface to form complex structures from solution using electricity. It results in a hierarchical structure of primary pores (~5-40 µm) separated by porous walls containing secondary pores (10-1000 nm) . This type of material has been used successfully to improve boiling heat transfer[7], another process limited by the counterflow of liquid and gas. They have also been investigated as high surface area material for microbial anodes[8] and have been postulated to be appealing in other electrochemical devices such as batteries or fuel cells[9]. A significant hurdle to unlock the full potential of DHBT foams is the attachment of the foam to the solid electrode surface it is generated on. The presence of the electrode blocks the transport of media in the through-plane direction of the foam and thereby prevents its use in many electrochemical applications. Due to its fragile nature, separation of the foam from this surface easily damages the structure, which is why previous research was done exclusively in the presence of the electrode. Overcoming this limitation would enable new applications for DHBT foams and has the potential to address a wide range of problems in electrochemical systems related to porous media.In this talk, I will discuss our work towards creating free-standing, hierarchically structured metal electrodes through DHBT and the developments needed to adapt this material for the use in electrochemical systems. Owing to its well-studied synthetic parameters and facile electrodeposition, we chose copper foams to advance DHBT materials in terms of characterization and mechanical properties. As a key step of the synthesis route, we realized a method to manufacture free-standing sheets from this material from copper metal while preserving its delicate microstructure. This was supported by an optimization of synthesis parameters to improve and ensure adequate mechanical stability of the freestanding foams after isolation. This development enables the application of a wide range of characterization methods such as XTM, BET, SEM and interferometry and I will discuss how the synthesis parameters link to the resulting material microstructure. Building on this initial success, current work focuses on the transferring this knowledge to the synthesis of foams made from other metals which are more relevant to electrochemical applications such as nickel for the use in alkaline electrolyzers and paves the way to develop DHBT material into the next generation transport layer for electrochemical systems.

Dynamically assisted electrodeposition by hydrogen bubbles on carbonized wood: A NiFeCo nanoflower electrocatalyst for efficient hydrogen evolution

The development of cost-effective, simple, and highly active catalysts for electrochemical water splitting in alkaline electrolytes to produce renewable source H2 is critical to solve the environmental pollution and energy crisis. In this study, a series of nanoflower-like NiFeCo/CW catalytic electrodes were prepared by a facile one-step dynamic hydrogen bubble template (DHBT) method for electrodeposition on carbonized wood (CW), which have excellent HER performance. By reasonably investigating the effects of H+ concentration and time, a catalyst with ideal deposition results was obtained. In 1 M KOH solution, the prepared NiFeCo/CW-450 catalyst exhibits a small overpotential of 37 mV to achieve a current density of 10 mA cm−2, and still possess a satisfactory low overpotential when a larger current density is reached (η400 = 238 mV, η1000 = 298 mV). Furthermore, NiFeCo/CW can keep structure and catalytic performance stable after long-term test. The remarkable HER performance results from the unique nanoflower electrode structure that is uniformly dispersed on CW to fully expose the active site. As a result, this work will provide new inspiration and strategy for the preparation of novel simple, inexpensive and efficient electrocatalytic hydrogen evolution electrodes using earth-abundant resources.

Ultra-fast electrodeposition of dynamic hydrogen bubble template nickel sulfide on a porous copper layer as an electrocatalyst toward hydrogen evolution reaction

Finding cost-effective electrocatalysts that can match the performance of noble metals like platinum is crucial for renewable hydrogen energy generation. In this study, the electrocatalytic properties of a nickel sulfide compound deposited on a porous copper network that is formed on a nickel foam substrate are investigated. To achieve this goal, the dynamic hydrogen bubble template method was employed. Copper and nickel sulfide electrodeposited in 5 s at 6 A cm−2. The presence of the copper layer resulted in a potential requirement of 98 mV, to achieve current densities of 10 mA cm−2, compared to 120 mV, when the porous copper substrate was not present. The ECSA was found to be significantly increased by the presence of the copper layer, as determined by examining the CV test and calculating the electrochemically active surface area. Ni3S2@Cu@NF is an excellent choice for electrocatalyst when it comes to HER in alkaline media.

Electrochemical detection of xylobiose in banana biomass using a 3D porous copper oxide foam electrode modified with a molecularly imprinted Poly-L-arginine film

Xylobiose (X2) presents numerous health benefits, including cancer prevention, and can be found in agro-industrial biomass, including bananas. Here, an electrochemical sensor based on molecularly imprinted poly-L-arginine film (MIP) and 3D porous copper oxide foam (3DnpCu) for the ultrasensitive detection of X2 is studied. The MIP/3DnpCu-GCE is prepared by dynamic hydrogen bubble template method, followed by electropolymerization of L-arginine in the presence of X2 as template, followed by electrochemical extraction, resulting in the formation of X2 recognition sites. The sensor was characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. MIP/3DnpCu-GCE showed a wide linear response in the concentration range of 1.0 × 10−12 to 1.0 × 10−10 mol L−1, limit of detection of 7.7 × 10−13 mol L−1 and sensibility of 1.4 µA pmol−1 L. The sensor exhibited selective X2 recognition, long-term stability (maintaining 86% of its initial current over 8 days), while inter-electrode repeatability displayed an RSD of 2.4%. The applicability of the MIP/3DnpCu-GCE in real samples is demonstrated by successfully quantifying X2 concentration in banana biomass. Furthermore, the comparison between the data obtained using this method and those found by the HPLC method confirmed the accuracy of the sensor.

Facile fabricant of slippery lubricant-infused porous foam-like surface for efficient fog harvesting

Inspired by pitcher plant, a variety of lubricant-infused surfaces have been created with unique properties. Owing to its high heat transfer performance and negligible contact angle hysteresis, the lubricant-infused surfaces are employed in fog harvesting. However, the loss of lubricant oil can result in performance degradation. Therefore, many surfaces with fine micro/nano structure have been created to increase the lubricant retention ability of lubricant-infused surface. Unfortunately, the procedures for preparing these surfaces are difficult or time-consuming. In this study, we synthesized a porous foam-like lubricant-infused surface (F-LIS). Porous copper foam was created on the surface of copper sheets through the dynamic bubble template method, and the pore walls were made of closely interlaced needle-like nano-dendrites. The fog harvesting efficiency of the surface can reach 2761.2 mgcm−2h−1. Additionally, F-LIS demonstrates excellent mechanical durability and chemical stability as a result of the micro/nano structure and the strong intermolecular force between PFPE as lubricant and the modifier layer, PFDT. After high-speed rotation, prolonged placement and UV irradiation etc., the surface still exhibits brilliant sliding ability and fog harvesting efficiency. This work offers a simple and effective approach for fabricating lubricant-infused surfaces with distinguished fog harvesting capability, providing a reference for relieving the crisis of freshwater resource scarcity.

A Suitable Porous Micro/Nanostructured Cu and Cu–Ni Film: Evaluation of Electrodeposition Behavior, Electrocatalytic Activity, and Surface Characterization of Porous Film

Selecting an appropriate catalyst with a high surface area and proper electron transfer ability can accelerate improved hierarchical catalysts. In this research, an appropriate porous film was formed by the dynamic hydrogen bubble template (DHBT) method with a pulse current (PC) electrodeposition. CH3COOH was added to the Cu electrodeposition bath as a non-ionic surfactant, CTAB was added as a cationic surfactant, and Ni was added as an alloying element. Results show the formation of a nano-dendritic porous Cu film. The presence of surfactants, especially CTAB, causes dendritic arms to be more elegant and denser, with more round voids. Furthermore, adding Ni sulfate to the bath containing both surfactants resulted in a porous Cu film with the most improved HER behavior by decreasing the overpotential (η 10) from 389 to 195 mV RHE−1 and the Tafel slope from 174 to 93 mV dec−1 in a 1.0 M KOH solution. According to the results of the electrochemical active surface area (ECSA), normalized LSV curves, and charge transfer resistances, the co-deposition of Cu and Ni revealed more active surface area and improved intrinsic HER catalytic activity. Therefore, these properties can convince researchers to utilize an improved porous Cu–Ni electrode for energy applications.

Boosting Nitrate to Ammonia Electroconversion through Hydrogen Gas Evolution over Cu-foam@mesh Catalysts.

The hydrogen evolution reaction (HER) is often considered parasitic to numerous cathodic electro-transformations of high technological interest, including but not limited to metal plating (e.g., for semiconductor processing), the CO2 reduction reaction (CO2RR), the dinitrogen → ammonia conversion (N2RR), and the nitrate reduction reaction (NO3-RR). Herein, we introduce a porous Cu foam material electrodeposited onto a mesh support through the dynamic hydrogen bubble template method as an efficient catalyst for electrochemical nitrate → ammonia conversion. To take advantage of the intrinsically high surface area of this spongy foam material, effective mass transport of the nitrate reactants from the bulk electrolyte solution into its three-dimensional porous structure is critical. At high reaction rates, NO3-RR becomes, however, readily mass transport limited because of the slow nitrate diffusion into the three-dimensional porous catalyst. Herein, we demonstrate that the gas-evolving HER can mitigate the depletion of reactants inside the 3D foam catalyst through opening an additional convective nitrate mass transport pathway provided the NO3-RR becomes already mass transport limited prior to the HER onset. This pathway is achieved through the formation and release of hydrogen bubbles facilitating electrolyte replenishment inside the foam during water/nitrate co-electrolysis. This HER-mediated transport effect "boosts" the effective limiting current of nitrate reduction, as evidenced by potentiostatic electrolyses combined with an operando video inspection of the Cu-foam@mesh catalysts under operating NO3-RR conditions. Depending on the solution pH and the nitrate concentration, NO3-RR partial current densities beyond 1 A cm-2 were achieved.

Microfluidic Platform Integrated with Carbon Nanofibers-Decorated Gold Nanoporous Sensing Device for Serum PSA Quantification.

Prostate cancer is a disease with a high incidence and mortality rate in men worldwide. Serum prostate-specific antigens (PSA) are the main circulating biomarker for this disease in clinical practices. In this work, we present a portable and reusable microfluidic device for PSA quantification. This device comprises a polymethyl methacrylate microfluidic platform coupled with electrochemical detection. The platinum working microelectrode was positioned in the outflow region of the microchannel and was modified with carbon nanofibers (CNF)-decorated gold nanoporous (GNP) structures by the dynamic hydrogen bubble template method, through the simultaneous electrodeposition of metal precursors in the presence of CNF. CNF/GNP structures exhibit attractive properties, such as a large surface to volume ratio, which increases the antibody's immobilization capacity and the electroactive area. CNFs/GNP structures were characterized by scanning electron microscopy, energy dispersive spectrometry, and cyclic voltammetry. Anti-PSA antibodies and HRP were employed for the immune-electrochemical reaction. The detection limit for the device was 5 pg mL-1, with a linear range from 0.01 to 50 ng mL-1. The coefficients of variation within and between assays were lower than 4.40%, and 6.15%, respectively. Additionally, its clinical performance was tested in serum from 30 prostate cancer patients. This novel device was a sensitive, selective, portable, and reusable tool for the serological diagnosis and monitoring of prostate cancer.

In situ fabrication of a 3D self-supported porous Ni-Mo-Cu catalyst for an efficient hydrogen evolution reaction.

It is still a challenge to develop very effective and stable non-noble catalysts for the hydrogen evolution reaction (HER). Here, a self-supported porous Ni-Mo-Cu coating is prepared by the dynamic hydrogen bubble template (DHBT) method. This three-dimensional (3D) porous Ni-Mo-Cu coating can offer a large surface area, which helps expose more active sites and promote the transmission of electrons and materials. To achieve this, the 3D porous Ni-Mo-Cu coating catalyst requires a low overpotential value of 70 mV at 10 mA cm-2 in 1 M KOH and stable catalytic properties at a high current density of 500 mA cm-2 for more than 10 h with no obvious evidence of degradation. DFT calculations show the source of the excellent catalytic performance of the 3D porous Ni-Mo-Cu catalyst in alkaline media, including the kinetic energy and adsorption energy. This work provides significant insight into the design of efficient 3D porous materials.