Active and stable electrocatalysts made from earth‐abundant elements are key to water splitting for hydrogen production through electrolysis. The growth of NiSe nanowire film on nickel foam (NiSe/NF) ...in situ by hydrothermal treatment of NF using NaHSe as Se source is presented. When used as a 3D oxygen evolution electrode, the NiSe/NF exhibits high activity with an overpotential of 270 mV required to achieve 20 mA cm−2 and strong durability in 1.0 M KOH, and the NiOOH species formed at the NiSe surface serves as the actual catalytic site. The system is also highly efficient for catalyzing the hydrogen evolution reaction in basic media. This bifunctional electrode enables a high‐performance alkaline water electrolyzer with 10 mA cm−2 at a cell voltage of 1.63 V.
NiSe nanowire films grown hydrothermally in situ on nickel foam (NiSe/NF) were used as a 3D bifunctional electrode for both the oxygen evolution reaction and hydrogen evolution reaction in a strongly alkaline electrolyte. The films exhibit high catalytic activity and superior stability, and a cell voltage of only 1.63 V is required for the alkaline water electrolyzer to deliver 10 mA cm−2 water‐splitting current.
To restore the natural nitrogen cycle (N-cycle), artificial N-cycle electrocatalysis with flexibility, sustainability, and compatibility can convert intermittent renewable energy (e.g., wind) to ...harmful or value-added chemicals with minimal carbon emissions. The background of such N-cycles, such as nitrogen fixation, ammonia oxidation, and nitrate reduction, is briefly introduced here. The discussion of emerging nanostructures in various conversion reactions is focused on the architecture/compositional design, electrochemical performances, reaction mechanisms, and instructive tests. Energy device advancements for achieving more functions as well as in situ/operando characterizations toward understanding key steps are also highlighted. Furthermore, some recently proposed reactions as well as less discussed C–N coupling reactions are also summarized. We classify inorganic nitrogen sources that convert to each other under an applied voltage into three types, namely, abundant nitrogen, toxic nitrate (nitrite), and nitrogen oxides, and useful compounds such as ammonia, hydrazine, and hydroxylamine, with the goal of providing more critical insights into strategies to facilitate the development of our circular nitrogen economy.
In this Communication, we report the topotactic fabrication of self-supported nanoporous cobalt phosphide nanowire arrays on carbon cloth (CoP/CC) via low-temperature phosphidation of the ...corresponding Co(OH)F/CC precursor. The CoP/CC, as a robust integrated 3D hydrogen-evolving cathode, shows a low onset overpotential of 38 mV and a small Tafel slope of 51 mV dec–1, and it maintains its catalytic activity for at least 80 000 s in acidic media. It needs overpotentials (η) of 67, 100, and 204 mV to attain current densities of 10, 20, and 100 mA cm–2, respectively. Additionally, this electrode offers excellent catalytic performance and durability under neutral and basic conditions.
Electrochemical carbon monoxide reduction is a promising strategy for the production of value-added multicarbon compounds, albeit yielding diverse products with low selectivities and Faradaic ...efficiencies. Here, copper single atoms anchored to Ti
C
T
MXene nanosheets are firstly demonstrated as effective and robust catalysts for electrochemical carbon monoxide reduction, achieving an ultrahigh selectivity of 98% for the formation of multicarbon products. Particularly, it exhibits a high Faradaic efficiency of 71% towards ethylene at -0.7 V versus the reversible hydrogen electrode, superior to the previously reported copper-based catalysts. Besides, it shows a stable activity during the 68-h electrolysis. Theoretical simulations reveal that atomically dispersed Cu-O
sites favor the C-C coupling of carbon monoxide molecules to generate the key *CO-CHO species, and then induce the decreased free energy barrier of the potential-determining step, thus accounting for the high activity and selectivity of copper single atoms for carbon monoxide reduction.
Electrochemical nitrogen reduction reaction (NRR) is considered as an alternative to the industrial Haber-Bosch process for NH
3
production due to both low energy consumption and environment ...friendliness. However, the major problem of electrochemical NRR is the unsatisfied efficiency and selectivity of electrocatalyst. As one group of the cheapest and most abundant transition metals, iron-group (Fe, Co, Ni and Cu) electrocatalysts show promising potential on cost and performance advantages as ideal substitute for traditional noble-metal catalysts. In this minireview, we summarize recent advances of iron-group-based materials (including their oxides, hydroxides, nitrides, sulfides and phosphides, etc.) as non-noble metal electrocatalysts towards ambient N
2
-to-NH
3
conversion in aqueous media. Strategies to boost NRR performances and perspectives for future developments are discussed to provide guidance for the field of NRR studies.
Industrial-scale ammonia (NH
3
) production mainly relies on the energy-intensive and environmentally unfriendly Haber-Bosch process. Such issue can be avoided by electrocatalytic N
2
reduction which ...however suffers from limited current efficiency and NH
3
yield. Herein, we demonstrate ambient NH
3
production via electrochemical nitrite (NO
2
−
) reduction catalyzed by a CoP nanoarray on titanium mesh (CoP NA/TM). When tested in 0.1 M PBS (pH = 7) containing 500 ppm NO
2
−
, such CoP NA/TM is capable of affording a large NH
3
yield of 2,260.7 ± 51.5 µg·h
−1
·cm
−2
and a high Faradaic efficiency of 90.0 ± 2.3% at −0.2 V vs. a reversible hydrogen electrode. Density functional theory calculations reveal that the potential-determining step for NO
2
−
reduction over CoP (112) is *NO
2
→ *NO
2
H.
Searching for inexpensive hydrogen evolution reaction (HER) electrocatalysts with high activity has attracted considerable research interest in the past years. Reported herein is the topotactic ...fabrication of self‐supported Cu3P nanowire arrays on commercial porous copper foam (Cu3P NW/CF) from its Cu(OH)2 NW/CF precursor by a low‐temperature phosphidation reaction. Remarkably, as an integrated three‐dimensional hydrogen‐evolving cathode operating in acidic electrolytes, Cu3P NW/CF maintains its activity for at least 25 hours and exhibits an onset overpotential of 62 mV, a Tafel slope of 67 mV dec−1, and a Faradaic efficiency close to 100 %. Catalytic current density can approach 10 mA cm−2 at an overpotential of 143 mV.
Down to the wire: Self‐supported Cu3P nanowire arrays on porous copper foam (Cu3P NW/CF) were derived from topotactic low‐temperature phosphidation of its Cu(OH)2 NW/CF precursor. As an integrated hydrogen‐evolving cathode, Cu3P NW/CF exhibits excellent catalytic activity and durability with nearly 100 % Faradaic efficiency in acidic aqueous electrolytes.
It is highly attractive to develop non-noble-metal nanoarray architecture as a high-active catalyst electrode for molecular detection due to its large specific surface area and easy accessibility to ...target molecules. In this paper, we demonstrate the development of cobalt nitride nanowire array on Ti mesh (Co3N NW/TM) as an efficient catalyst electrode for glucose oxidation in alkaline solutions and H2O2 reduction in neutral solutions. Electrochemical tests suggest that such Co3N NW/TM possesses superior non-enzymatic sensing ability toward rapid glucose and H2O2 detection. As a glucose sensor, this fabricated electrode offers a high sensitivity of 3325.6μAmM−1cm−2, with a wide linear range from 0.1μM to 2.5mM, a low detection limit of 50nM (S/N=3), and satisfactory stability and reproducibility. Its application in determining glucose in human blood serum is also successful. Amperometric H2O2 sensing can also been realized with a sensitivity of 139.9μAmM−1cm−2, a linear range from 2μM to 28mM, and a detection limit of 1μM (S/N=3). This nanoarray architecture holds great promise as an attractive sensing platform toward electrochemical small molecules detection.
A closely interconnected network of MoP nanoparticles (MoP‐CA2) with rich nanopores, large specific surface area, and high conductivity can function as a highly active non‐noble metal catalyst for ...electrochemically generating hydrogen from acidic water. The network exhibits nearly 100% Faradaic efficiency and needs overpotentials of 125 and 200 mV to attain current densities of 10 and 100 mA cm−2, respectively. The catalytic activity is maintained for at least 24 h.
Water electrolysis is considered as the most promising technology for hydrogen production. Much research has been devoted to developing efficient electrocatalysts for hydrogen production via the ...hydrogen evolution reaction (HER) and oxygen production via the oxygen evolution reaction (OER). The optimum electrocatalysts can drive down the energy costs needed for water splitting via lowering the overpotential. A number of cobalt (Co)‐based materials have been developed over past years as non‐noble‐metal heterogeneous electrocatalysts for HER and OER. Recent progress in this field is summarized here, especially highlighting several important bifunctional catalysts. Various approaches to improve or optimize the electrocatalysts are introduced. Finally, the current existing challenges and the future working directions for enhancing the performance of Co‐implicated electrocatalysts are proposed.
Electrochemical water splitting is a well‐established technology with which to produce high‐purity hydrogen. Recent progress in cobalt‐based heterogeneous electrocatalysts for water splitting is reviewed. Strategies to obtain optimized or enhanced performance are introduced through specific examples. The current existing challenges and future working directions for enhancing the performance of Co‐implicated electrocatalysts are discussed.
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