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Germanium (Ge) has become a promising anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity and decent electron/ion conductivity, but it exhibits inferior lifespan caused by dramatic volume variations during the (de)lithiation process. Herein, hierarchically, nanoporous Ge (np-Ge) was fabricated by the combination of selective phase corrosion with chemical dealloying. As an anode for LIBs, the np-Ge electrode exhibits marvelous cycling stability with capacity retentions of 1060.0 mA h g−1 at 0.2 A g−1 and 767.1 mA h g−1 at 1 A g−1 after 100 cycles. Moreover, the electrode shows excellent rate capability with a capacity retention of 844.2 mA h g−1 at 5 A g−1. Noticeably, the (de)lithiation mechanisms of np-Ge and porous Si–Ge (p-Si6Ge4) were unveiled by operando X-ray diffraction. [ABSTRACT FROM AUTHOR]

Antimony (Sb) as a low-toxic and cost-effective metal is a promising material to catalyse CO 2 electroreduction to formate with practical viability. However, monometallic Sb suffers from intrinsically low catalytic activity and the competing hydrogen evolution. Here, we report nanoporous Sb-Bi alloys for substantially improving the catalytic activity of Sb and suppressing hydrogen evolution. The optimal Sb-Bi alloy exhibits a maximum Faradaic efficiency of 95.8 % toward formate production, surpassing the 11.6 % of monometallic Sb counterpart. Operating the catalyst in the flow cell demonstrates a formate partial current density of 734 mA cm−2 and cathodic energy efficiency of 59 % at a moderate overpotential of 800 mV, representing a record formate-production performance so far. Experimental and theoretical studies indicate that the Sb-Bi interactions activate Sb sites to selectively stabilize *OCHO intermediates, facilitating CO 2 -to-formate conversion. This work offers insights in manipulating bimetallic interactions to transform inert materials into active catalysts for efficient electrocatalysis. [Display omitted] • Sb-Bi interactions induce electrocatalytic switching from HER to CO 2 ER. • Sb 2 Bi 6 exhibits a maximum formate selectivity of 95.8 % in an H-type cell. • Sb 2 Bi 6 achieves a record formate activity of 734 mA cm−2 in a flow cell. • Sb-Bi interactions facilitate Sb sites to stabilize *OCHO for formate formation. [ABSTRACT FROM AUTHOR]

• A simple liquid Ga assisted-alloying/dealloying strategy to fabricate nanoporous Ag. • The thickness of alloy layer/nanoporous Ag varies with the mass loading of Ga. • The bimodal wire-like and unimodal bulk-like nanoporous Ag is obtained. • The substrate-supported nanoporous Ag exhibits excellent mechanical properties. The substrate-supported nanoporous Ag with controllable thickness and different morphologies (bulk-like and wire-like) is fabricated via the liquid Ga-assisted alloying/dealloying strategy. [Display omitted] Nanoporous metals show great potentials in various applications including catalysis, sensing, actuation and supercapacitors. The liquid Ga-assisted alloying/dealloying strategy is a feasible and scalable way to fabricate substrate-supported nanoporous metals. However, the influence of intrinsic alloying mode and mechanism on the formation and modulation of nanoporous structure has not been thoroughly explored before. In this work, after painting liquid Ga on Ag foil, both the bulk-like Ag 3 Ga (in the Ag-rich zone) and wire-like Ag 3 Ga (in the liquid Ga-rich zone) form owing to the interdiffusion of Ag and Ga atoms. Correspondingly, the bimodal wire-like and unimodal bulk-like nanoporous Ag is obtained because of the structure inheritance during dealloying. In addition, the thickness of alloy layer (nanoporous layer) versus mass loading of liquid Ga follows a good linear relationship. The in-situ X-ray diffraction of dealloying from Ag 3 Ga to nanoporous Ag illustrates no other intermetallic phase appears and the dealloying process can be described by the dissolution-surface diffusion model. More importantly, the substrate-supported nanoporous Ag exhibits excellent mechanical properties which are of great importance to the future applications of nanoporous metals. [ABSTRACT FROM AUTHOR]

Metallic actuators have received a wide range of attention in the past two decades because of their larger strains than piezoelectric ceramics and higher strength relative to conducting polymers. However, the metallic actuators composed of noble metals are limited to the high material cost for further development and practical applications. Here, nanoporous CuMnNi (np‐CMN) alloys are fabricated from a ternary Mn70Cu20Ni10 precursor through an electrochemical dealloying method, and their microstructures/compositions are further regulated through different electrochemical processes (multi‐step and two‐step). The np‐CMN alloys show good electrochemical actuation properties in 1 m NaOH solution, and the sample obtained from two‐step dealloying exhibits much better actuation performance than that from multi‐step dealloying. The maximum strain amplitude of np‐CMN could reach up to 0.46%, which is comparable to or even better than that of noble metal‐based actuators. Our work indicates that the low‐cost np‐CMN alloy could be a competitive material among electrochemical metallic actuators. [ABSTRACT FROM AUTHOR]

Cobalt (Co) mainly exists in two allotropic forms: a low temperature hexagonal close-packed (HCP) structure and a high temperature face-centered cubic (FCC) structure. However, annealing at high temperature only induces the formation of FCC-Co on the surface of a bulk sample and fabrication of bulk FCC-Co is still a great challenge. In this work, nanoporous FCC-Co with a macroscopic dimension is successfully fabricated via a vapor phase alloying (VPA)–vapor phase dealloying (VPD) strategy using zinc (Zn) as the vapor source. Moreover, the thickness of the nanoporous layer could be modulated by adjusting the VPA time. The bulk nanoporous FCC-Co with different shapes and sizes can be fabricated owing to the flexibility and reactivity of the Zn vapor. Both the temperature effect and the size influence contribute to the formation of bulk FCC-Co during the VPD process. In addition, nanoporous FCC-Co shows different magnetic properties as benchmarked with pristine HCP-Co. Our findings provide a new methodology for the preparation of bulk nanoporous FCC-Co which may exhibit unique properties and potential applications. [ABSTRACT FROM AUTHOR]

Ag-Zn alloys are identified as highly active and selective electrocatalysts for CO2 reduction reaction (CO2RR), while how the phase composition of the alloy affects the catalytic performances has not been systematically studied yet. In this study, we fabricated a series of Ag-Zn alloy catalysts by magnetron co-sputtering and further explored their activity and selectivity towards CO2 electroreduction in an aqueous KHCO3 electrolyte. The different Ag-Zn alloys involve one or more phases of Ag, AgZn, Ag5Zn8, AgZn3, and Zn. For all the catalysts, CO is the main product, likely due to the weak CO binding energy on the catalyst surface. The Ag5Zn8 and AgZn3 catalysts show a higher CO selectivity than that of pure Zn due to the synergistic effect of Ag and Zn, while the pure Ag catalyst exhibits the highest CO selectivity. Zn alloying improves the catalytic activity and reaction kinetics of CO2RR, and the AgZn3 catalyst shows the highest apparent electrocatalytic activity. This work found that the activity and selectivity of CO2RR are highly dependent on the element concentrations and phase compositions, which is inspiring to explore Ag-Zn alloy catalysts with promising CO2RR properties. [ABSTRACT FROM AUTHOR]

A class of ruthenium-nickel alloy catalysts featured with nanoporous nanowires (NPNWs) were synthesized by a strategy combining rapid solidification with two-step dealloying. RuNi NPNWs exhibit excellent electrocatalytic activity and stability for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in which the RuNi-2500 NPNWs catalyst shows an OER overpotential of 327 mV to deliver a current density of 10 mA cm−2 and the RuNi-0 NPNWs catalyst requires the overpotential of 69 mV at 10 mA cm−2 showing the best HER activity in alkaline media. Moreover, the RuNi-1500 NPNWs catalyst was used as the bifunctional electrocatalyst in a two-electrode alkaline electrolyzer for water splitting, which exhibits a low cell voltage of 1.553 V and a long-term stability of 24 h at 10 mA cm−2, demonstrating that the RuNi NPNWs catalysts can be considered as promising bifunctional alkaline electrocatalysts. A class of ruthenium-nickel alloy catalysts featured with nanoporous nanowires (NPNWs) was synthesized by a strategy combined rapid solidification with two-step dealloying, in which the total cell voltage of RuNi-1500 NPNWs electrolyzer for water splitting is 1.553 V to deliver a current density of 10 mA cm−2. [Display omitted] • A two-step dealloying strategy was used to prepare RuNi catalysts. • RuNi catalysts exhibit a unique nanoporous nanowires (NPNWs) morphology. • RuNi NPNWs catalysts show excellent electrocatalytic performance for OER and HER. • RuNi NPNWs catalysts can be used as bifunctional catalysts for water splitting. [ABSTRACT FROM AUTHOR]

The synthesis of cost-effective and high-performance electrocatalysts for water splitting is the main challenge in electrochemical hydrogen production. In this study, we adopted a high throughput method to prepare bi-metallic catalysts for oxygen/hydrogen evolution reactions (OER/HER). A series of Ni–Mo alloy electrocatalysts with tunable compositions were prepared by a simple co-sputtering method. Due to the synergistic effect between Ni and Mo, the intrinsic electrocatalytic activity of the Ni–Mo alloy electrocatalysts is improved, resulting in excellent HER and OER performances. The Ni 90 Mo 10 electrocatalyst shows the best HER performance, with an extremely low overpotential of 58 mV at 10 mA cm−2, while the Ni 40 Mo 60 electrocatalyst shows an overpotential of 258 mV at 10 mA cm−2 in OER. More significantly, the assembled Ni 40 Mo 60 //Ni 90 Mo 10 electrolyzer only needs a cell voltage of 1.57 V to reach 10 mA cm−2 for overall water splitting. [Display omitted] • A high throughput method was used to prepare Ni–Mo alloy catalysts. • Ni–Mo alloy catalysts exhibit remarkable activity and stability for HER and OER. • The Ni–Mo alloy acts as a bifunctional catalyst for overall water splitting. • The synergistic effect between Ni and Mo leads to the excellent performances. [ABSTRACT FROM AUTHOR]

Transition metal nitrogen carbon based single‐atom catalysts (SACs) have exhibited superior activity and selectivity for CO2 electroreduction to CO. A favorable local nitrogen coordination environment is key to construct efficient metal‐N moieties. Here, a facile plasma‐assisted and nitrogen vacancy (NV) induced coordinative reconstruction strategy is reported for this purpose. Under continuous plasma striking, the preformed pentagon pyrrolic N‐defects around Ni sites can be transformed to a stable pyridinic N dominant Ni‐N2 coordination structure with promoted kinetics toward the CO2‐to‐CO conversion. Both the CO selectivity and productivity increase markedly after the reconstruction, reaching a high CO Faradaic efficiency of 96% at mild overpotential of 590 mV and a large CO current density of 33 mA cm‐2 at 890 mV. X‐ray adsorption spectroscopy and density functional theory (DFT) calculations reveal this defective local N environment decreases the restraint on central Ni atoms and provides enough space to facilitate the adsorption and activation of CO2 molecule, leading to a reduced energy barrier for CO2 reduction. [ABSTRACT FROM AUTHOR]

Alloying Ni with Pd lowers the overpotential of benzaldehyde hydrogenation and obtains a reaction rate 20 times higher than that of Ni at 0.1 V vs. RHE, which is ascribed to the lower binding energy of benzaldehyde on the metal surface revealed by the in-situ IR study. [Display omitted] • Nanoporous nanowire NiPd alloys were synthesized using a dealloying method. • Alloying Ni and Pd lowers the overpotential of ECH of benzaldehyde. • The activity of NiPd alloy is comparable with Pd. • In-situ IR study reveals that Pd tunes the binding strength of adsorbed benzaldehyde. Ni is one of the most promising catalysts in aldehydes hydrogenation, although the high overpotential and low Faradaic efficiency limit its electrocatalytic performances. Here we introduce an effective and facile alloying strategy to tune the electronic structure of Ni. We demonstrate that alloying Pd to Ni can significantly boost the electrocatalytic performances of benzaldehyde hydrogenation and lower the overpotential to the level of pure Pd. Pd introduction enhances the electrocatalytic hydrogenation process over hydrogen evolution reaction (HER), and results in an increased Faradaic efficiency. The npnw-Ni 82 Pd 18 catalyst shows the optimal atomic ratio of Ni and Pd among the explored catalysts, and achieved a turnover frequency (TOF) value of 1387 mol mol metal -1h-1 at -0.1 V vs. reversible hydrogen electrode (RHE), higher than that of npnw-Ni (60 mol mol metal -1h-1) and comparable to np-Pd (1306 mol mol metal -1h-1) under the same reaction conditions. In-situ surface-enhanced infrared absorption spectroscopy study reveals that the electronic interactions between Ni and Pd would activate the adsorbed benzaldehyde, and therefore result in an enhanced activity in benzaldehyde hydrogenation. [ABSTRACT FROM AUTHOR]

A room-temperature Ag 3 Ga-mediated liquid EGaSn anode with improved wettability for advanced Mg ion batteries. [Display omitted] • The room-temperature Ag 3 Ga-mediated liquid EGaSn anode was simply prepared for MIBs. • Ag 3 Ga can improve the wettability of EGaSn on the substrate and provide capacity. • ssm-Ag 3 Ga-EGaSn shows superior electrochemical performance in half and full cells. • Reaction mechanism of the Ag 3 Ga-mediated liquid EGaSn anode was unveiled. Liquid metals with a self-healing property can address the passivation issue of Mg metal and the huge volume variation problem of solid alloy-type anodes in rechargeable magnesium ion batteries (MIBs). Liquid Ga-based anodes show great potentials in MIBs, however, being operated at room temperature is a great challenge. Herein, a novel strategy is proposed to enhance the room-temperature Mg storage performance of liquid eutectic GaSn (EGaSn) alloy through constructing a bifunctional intermetallic compound (Ag 3 Ga) layer on the current collector. This Ag 3 Ga layer could greatly improve the wettability of EGaSn on the substrate in the electrolyte environment. Moreover, operando X-ray diffraction confirms that Ag 3 Ga could participate the reversible alloying/dealloying reactions during the discharge/charge processes and thus provide an extra capacity. Eventually, the Ag 3 Ga-mediated EGaSn anode exhibits outstanding electrochemical performance towards Mg storage in both half and full cells at room temperature (∼24 and 21 °C), as benchmarked with state-of-the-art anodes in MIBs. Specially, the MIBs could be stably cycled up to 600 cycles in the half cell configuration, and 100 cycles in the full cell assembly. This work provides useful information on the development of advanced anodes for MIBs. [ABSTRACT FROM AUTHOR]

• 3D Cu current collectors were gained by painting-alloying-dealloying and annealing. • The porous structure of 3D Cu was regulated by altering Ga mass and annealing. • The relationships between porous layer depth and performance were explored. • The Li deposition behaviors on 3D/2D Cu were clarified. Lithium metal anode has shown great potentials for achieving high energy density due to its high theoretical capacity and low redox potential, but its application is impeded by the dendrite proliferation and unstable solid electrolyte interface. Herein, three-dimensional (3D) porous Cu current collectors were fabricated via the combination of painting-alloying-dealloying with subsequent annealing, where the depth and length scale of the porous layer can be facilely regulated by controlling the alloying and annealing processes. In lithium metal batteries, the relationship between the Li deposition behavior and the porous layer depth was explored in detail via electrochemical measurements and ex-situ scanning electron microscopy. Notably, the A-3D Cu-14 current collector with the porous layer depth of around 34.5 µm exhibits long lifespan over 430 h at 1 mA cm−2 and low voltage hysteresis, in comparison with the pristine Cu foil and the porous Cu with thinner porous layers. The superior electrochemical performance of A-3D Cu-14 can be attributed to the enhanced suppression effect upon the Li dendrite deriving from the more accommodation capability of its thick porous layer, as well as the better homogenization of the Li+ ion flux caused by the porous structure. Furthermore, the Li@A-3D Cu-14 | LiFePO 4 full cell shows excellent cycling stability and rate capability in full battery tests. Dealloying-induced modulation upon porous layer depth of three-dimensional copper current collector to stabilize the lithium batteries. [Display omitted] [ABSTRACT FROM AUTHOR]

A self-healing room-temperature liquid eutectic GaSn anode with improved wettability for advanced Mg ion batteries. [Display omitted] • ∙ Self-healing room-temperature liquid EGaSn anodes were simply prepared for MIBs. • ∙ The wettability of liquid EGaSn on ssm-CuGa 2 substrate was significantly improved. • ∙ The ssm-CuGa 2 -EGaSn shows greatly enhanced cycling stability and rate performance. • ∙ Reaction mechanism and self-healing feature of liquid EGaSn anodes were unveiled. Using alloy-type anodes offers an effective method to address the incompatibility issue between Mg metal anodes and conventional electrolytes and also facilitates the development of high performance magnesium ion batteries (MIBs). But the huge volume variations of alloy-type anodes during cycling impair the electrochemical performance of MIBs. Herein, a liquid eutectic GaSn (EGaSn) electrode with a low melting point (20.5 °C) and self-healing property was fabricated through simply painting onto stainless steel mesh (ssm). But the ssm-EGaSn electrode shows unsatisfactory electrochemical performance due to poor wettability of liquid EGaSn on ssm. To overcome this problem, a CuGa 2 layer was constructed to enhance the wettability of liquid EGaSn on the ssm substrate. The modified liquid EGaSn electrode delivers much better electrochemical performance (specific capacity, cycling stability and rate performance) either at ∼ 38 or 28 °C. Furthermore, operando X-ray diffraction and ex situ scanning electron microscopy were conducted to reveal the Mg storage mechanism and self-healing feature of the liquid EGaSn electrode. Noticeably, the liquid EGaSn electrode displays well compatibility with simple Mg salt electrolytes like Mg(TFSI) 2 and the full cell could display stable electrochemical behavior over dozens of cycles. [ABSTRACT FROM AUTHOR]

• Nanoporous NiSb (np-NiSb) alloy was fabricated by a facile dealloying strategy. • The np-NiSb anode exhibits good cycling stability and superior rate capability. • Operando XRD reveals the sodiation/desodiation mechanism of the np-NiSb anode. • On-line DEMS verifies the gas release of half cells with NiSb anode during cycling. Engineering Sb-based anode materials is the key to enhance their electrochemical performance for sodium ion batteries (SIBs) by solving the issues of the rapid capacity decay and poor rate capability. In this work, a nanoporous NiSb alloy (np-NiSb) with a three-dimensionally interconnected ligament-channel structure was synthesized by a facile dealloying strategy. As an anode for SIBs, the np-NiSb alloy exhibits excellent cycling performance, rate capability and stability with a reversible capacity of 334.6 mAh g −1 at 0.2 A g −1 after 100 cycles, 155.6 mAh g −1 at 20 A g −1 and a capacity retention rate of 97% after 100 cycles at 1 A g −1. The nanoporous structure and the introduction of inactive Ni effectively tolerate the dramatic volume changes during the charge/discharge processes, restraining the pulverization of np-NiSb. The unique ligament-channel network structure with an average size of about 30 nm significantly shortens the ion transmission distance, ensuring the fast charge transfer at high rates. Operando X-ray diffraction reveals the sodiation/desodiation mechanism of the np-NiSb anode during the discharge/charge processes. In addition, on-line differential electrochemical mass spectrometry further explores the reaction mechanism of np-NiSb. This work highlights constructing nanoporous Sb-based alloys as an effective strategy to improve the performance of SIBs. [Display omitted] As an anode for SIBs, the np-NiSb alloy with bicontinuous ligament-channel structure exhibits good cycling stability with capacity retention rate of 97% over 100 cycles at 1 A g −1 (279.7 mAh g −1). [ABSTRACT FROM AUTHOR]