Replacing the sluggish oxidation reaction in water-splitting process with the relatively fast anodic reaction is an effective method for producing H2. Here, we designed an amorphous Ni-P/rGO/NF ...nano-microporous catalyst for fast and easy hydrogen production from water splitting assisted by hydrazine electrooxidation reaction (HzOR). Cathodic cyclic voltammetry electrodeposition of Ni-P on rGO/NF electrode results in a nano-micro porous structure with superior conductivity besides excellent stability and catalytic activity toward both HzOR and HER. The electrode due to the specific structure and surface morphology, shows excellent electrocatalytic activity achieves 10 and 100 mA cm−2 at − 117, and − 82 mV for HER and 127 and 7.34 mV for HzOR, respectively. Furthermore, the optimized electrode demonstrated high retention rates of 97.4%, and 94.8% towards HER and HzOR, respectively. In a two-electrode cell, a small cell voltage of 241 mV is required to touch a current density of 100 mA cm−2.
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•Enhancing electrocatalytic activity of Ni-P by rGO nanolayer is demonstrated.•Ni-P/rGO nano-micro porous structure is prepared by cyclic voltammetry method.•Ni-P/rGO 10-C electrode shows the best performance with η10 equal to − 82 mV and 7.34 mV toward HER and HzOR.•The largest hydrogen evolution rate of Ni-P/rGO 10-C is over 2-fold of pure Ni-P/NF.
•Nanonetwork wrapped graphite felt is prepared by in situ electrodeposition.•A VRFB dual-function electrode wrapped with carbon nano-network is prepared.•There is excellent connectivity between ...wrapped nano-network and graphite felt.•Binder-free nano-network enables graphite felt show excellent cycling stability.
In this work, nitrogen-doped carbon nanonetwork wrapped dual-function electrode is fabricated in-situ by a simple electrodeposition method. By changing the electrodeposition time and calcination temperature, the morphology of carbon nanonetwork and the presence of nitrogen on graphite felt are controlled. The in-situ wrapped nanonetwork can increase the specific surface area of graphite felt electrode, improve the connectivity between graphite felt and carbon nanonetwork, and reduce the electrode resistance. The composite electrode is prepared without the involvement of adhesive, which enables the carbon nanofibers to exist stably on the graphite felt surface during charging and discharging. At 100 mA cm–2, the energy efficiency of modified cell is 79.2%, which is 8.8% higher than that of blank cell. Using the prepared electrode, VRFB has a discharge capacity of 350 mA h at 250 mA cm–2, while the blank cell cannot work normally. This work proposes a method for preparing a high-performance, high-stability composite electrode, which enables the carbon nanonetwork stably exist on the surface of graphite felt without a binder.
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Dynamic windows based on reversible metal electrodeposition (RME) can electronically adjust light transmission from ≈70% to <0.1% to improve building aesthetics and energy efficiency by controlling ...light and heat flow. For RME devices using Cu and Bi, the windows reach “privacy state” (<0.1% transmission) when ≈180 nm of metal is electrodeposited on the transparent conducting electrode. When films with a plated atomic Cu–Bi ratio of ≈2:1 rest in the privacy state, sinusoidal cracks form across the entire film, and the metal delaminates in <1 day. This mechanical failure renders the window unusable as specks of metal are visually unattractive and reduce the dynamic range of the window. The Cu–Bi film is stress free upon deposition, but after 4 h of resting, 38 MPa of tensile stress develops. The tension in Cu–Bi and Cu films combined with the Cu(ClO4)2 in the electrolyte results in severe, widespread fractures and delamination due to stress corrosion cracking. In contrast, electrodeposited Bi films have compressive stress, likely due to high self‐diffusion and insertion of atoms into grain boundaries while plating, which results in a Bi‐based dynamic window with crack‐free resting stability that exceeds 9 weeks.
Mechanical reliability of electrodeposited films is critical for practical device design. This work systematically describes the failure of Cu–Bi and Cu films in <1 day from tension and stress corrosion cracking (SCC) and demonstrates a Bi film with >2 months resting stability (resistant to SCC) for dynamic windows.
Hydrogen technology is widely considered a novel clean energy source, and electrolysis is an effective method for hydrogen evolution. Therefore, efficient hydrogen evolution reaction (HER) catalysts ...are urgently needed to replace precious metal catalysts and meet ecological and environmental protection standards. Herein, Ni–Mn–P electrocatalysts are synthesized using facile electrodeposition technology. The influence of the Mn addition on the catalytic behavior is studied by the comprehensive analysis of catalytic performance and morphology of the catalysts. Among them, the Ni–Mn–P0.01 catalyst exhibits small coral-like structures, greatly improving the adsorption and desorption of hydrogen ions and reducing the overpotential hydrogen evolution. Consequently, overpotential at 10 mA cm−2 electric current density is 113 mV, and the value of the Tafel slope achieves 74 mV/dec. Furthermore, the Ni–Mn–P catalyst shows long-time (20 h) stability at current densities of 10 and 60 mA/cm2. The results confirm that the synergistic effect of Ni, Mn, and P accelerates the electrochemical reaction. Meanwhile, the addition of manganese element can change the micromorphology of the catalyst, thereby exposing more active sites to participate in the reaction, enhancing water ionization, improving the catalytic performance. This study opens a new way toward improving the activity of the catalyst by adjusting Mn concentration during the electrodeposition process.
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•Ni–Mn–P electrocatalysts are synthesized by facile electrodeposition technology.•3D spherical microstructure Ni–Mn–P catalyst can be formed.•3D spherical microstructure improves the adsorption and desorption of hydrogen ions.•Ni–Mn–P catalyst improves the hydrogen evolution reaction and longtime stability.
The characteristics of electrodeposition and recent transition metal-based catalysts synthesized by electrodeposition are reviewed comprehensively, which guide for developing advanced ...electrodeposition technology and preparing new generation catalysts to achieve efficient hydrogen production via water splitting.
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Developing lower-cost and higher-effective catalyst to support hydrogen (H2) production by electrochemical water-splitting has been recognized as a preferred strategy to drive the clean energy utilization. As a credible technology for the synthesis of functional materials, electrodeposition has attracted widespread attention, especially suitable for non-noble transition metal-based catalysts (TMCs). Recently, lots of researchers have been devoted to this hot research direction with plentiful achievements, however, a comprehensive review towards this area is still missing. Hence, we summarize the past research progress, presents the technical characteristics of electrodeposition from the viewpoint of fundamental theory and influence factors for the electrochemical deposition behavior, and introduce its application in various of TMCs with versatile nanostructures and compositions. Except a deeper and more comprehensive cognition of electrodeposition, we further discuss the catalyst's optimized hydrogen evolution reaction (HER), oxygen evolution reaction (OER) performance as well as overall water splitting that combined with the synthetic process. Finally, we conclude the technical advantages towards electrodeposition, propose challenge and future research directions in this promising field. This timely review aims to promote a deeper understanding of effective catalysts obtained via electrodeposition strategy, and provide new guidance for the design and synthesis of future catalysts for hydrogen production.
Abstract
Performing CO
2
reduction in acidic conditions enables high single-pass CO
2
conversion efficiency. However, a faster kinetics of the hydrogen evolution reaction compared to CO
2
reduction ...limits the selectivity toward multicarbon products. Prior studies have shown that adsorbed hydroxide on the Cu surface promotes CO
2
reduction in neutral and alkaline conditions. We posited that limited adsorbed hydroxide species in acidic CO
2
reduction could contribute to a low selectivity to multicarbon products. Here we report an electrodeposited Cu catalyst that suppresses hydrogen formation and promotes selective CO
2
reduction in acidic conditions. Using in situ time-resolved Raman spectroscopy, we show that a high concentration of CO and OH on the catalyst surface promotes C-C coupling, a finding that we correlate with evidence of increased CO residence time. The optimized electrodeposited Cu catalyst achieves a 60% faradaic efficiency for ethylene and 90% for multicarbon products. When deployed in a slim flow cell, the catalyst attains a 20% energy efficiency to ethylene, and 30% to multicarbon products.
•An environmentally friendly superhydrophobic film was constructed on mild steel for corrosion protection.•The superhydrophobic film could greatly improve the anti-corrosion performance of the ...substrate in 3.5 wt.% NaCl solution.•The superhydrophobic film exhibited long-term stability even after stored indoor for one year.
In this work, non-particle and fluorine-free superhydrophobic films were constructed on mild steel (MS) for corrosion protection by one-step electrodeposition from dodecyltrimethoxysilane (DTMS)-contained precursor solution. The superhydrophobicity was achieved by the generated micro/nanostructure of hydrophobic DTMS during electrodeposition. The superhydrophobic films exhibited long-term stability to air atmosphere. The protective performance in 3.5 wt. % NaCl solution was estimated by potentiodynamic polarization technique, by electrochemical impedance spectroscopy, by monitoring water contact angle changes and by iron dissolution examination. The results show that the superhydrophobic films exhibit remarkable enhanced anticorrosion performance for MS with a promising inhibition efficiency of 99.74%.
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•Non-volatile BmimPF6 as solvent of the mixed ILs system.•The electrodeposition process replaces the traditional chemical stripping agents.•The mixed ILs exhibits high stability and ...excellent electrochemical properties.•Ir(0) was obtained through the selective extraction combining electrodeposition.•The non-extractability of Ir(III) was revealed by DFT calculations.
In this work, a novel extraction–electrodeposition process is employed to separate and recover Ir(IV) from a multi-metal mixed solution comprising Ir(IV), Pt(IV), Fe3+, Al3+, Cu2+, Mg2+, and Ca2+. The mixed ionic liquid (EBTOABr/BmimPF6) can efficiently separate Pt(IV) from Ir(III) once Ir(IV) has been reduced to Ir(III). The separation coefficient of βPt(IV)/Ir(III) was higher than 1.0 × 104. Following Pt(IV) extraction, 30% (w/w) H2O2 was added to the extraction raffinate to oxidize Ir(III) to Ir(IV). The same mixed ILs system was adopted to select IV ely extract Ir(IV) from the extraction raffinate. The electrochemical window of mixed ILs and the optimum Ir(IV) deposition voltage are investigated using cyclic voltammetry (CV). Ir(IV) can be reduced to Ir(0) at an optimal potential voltage of −1.72 V using EBTOABr-Ir(IV)/BmimPF6 as an electrolyte. SEM-EDS, TEM, and XPS analysis demonstrate that a black coating of iridium metal has been deposited on the copper surface. In addition to its excellent extraction efficiency, the proposed method offers low volatility and good stability. Furthermore, DFT calculations have been used to examine the platinum and iridium separation mechanism, as well as to determine the key factors affecting extraction, including bond length, charge density, molecular polarity, and electrostatic potential. The electrostatic potential surface models indicate that the EBTOABr/BmimPF6 system is not capable of extracting Ir(III). This technique has enormous potential for separating and recovering iridium from wasted catalyst leaching liquor.
Cathodic electrodeposition lends itself to the formation of biphasic metal-organic framework thin films at room temperature from single deposition baths using potential bias as the main user input. ...Depending on the applied potential, we selectively deposit two different phases as either bulk mixtures or bilayer films.
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