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The development of a cost‐competitive and efficient electrocatalyst is both attractive and challenging for hydrogen production by hydrogen evolution reaction (HER). Herein, a facile glycol reduction method to construct Ru nanoclusters coupled with hierarchical exfoliated‐MXene/reduced graphene oxide architectures (Ru‐E‐MXene/rGA) is reported. The hierarchical structure, formed by the self‐assembly of graphene oxides, can effectively prohibit the self‐stacking of MXene nanosheets. Meanwhile, the formation of the MXene/rGA interface can strongly trap the Ru3+ ions, resulting in the uniform distribution of Ru nanoclusters within Ru‐E‐MXene/rGA. The boosted catalytic activity and underlying catalytic mechanism during the HER process are proved by density functional theory. Ru‐E‐MXene/rGA exhibits overpotentials of 42 and 62 mV at 10 mA cm−2 in alkaline and acidic electrolytes, respectively. The small Tafel slope and charge transfer resistance (Rct) values elucidate its fast dynamic behavior. The cyclic voltammetry (CV) curves and chronoamperometry test confirm the high stability of Ru‐E‐MXene/rGA. These results demonstrate that coupling Ru nanoclusters with the MXene/rGA heterostructure represents an efficient strategy for constructing MXene‐based catalysts with enhanced HER activity. [ABSTRACT FROM AUTHOR]

The mechanically and electrochemically stable and ionically conducting solid electrolyte interphase (SEI) is important for the stabilization of metal anodes. Since SEIs are originally absent in aqueous zinc metal batteries (AZMBs), it is very challenging to suppress water‐induced side reactions and dendrite growth of Zn metal anodes (ZMAs). Herein, a gradient‐structured and robust solid gradient SEI, consisting of B,O‐inner and F,O‐exterior layer, in situ formed by hydrated eutectic electrolyte for the homogeneous and reversible Zn deposition, is demonstrated. Moreover, the molar ratio of acetamide to Zn salt is modulated to prohibit the water activity and the hydrolysis of BF4− as well as to achieve high ionic conductivity owing to the regulation of the solvation sheath of Zn2+. Consequently, the eutectic electrolyte allows Zn||Zn symmetric cells to achieve a cycling lifespan of over 4400 h at 0.5 mA cm−2 as well as Zn||PANI full cells to deliver a high capacity retention of 73.2% over 4000 cycles at 1 A g−1 and to demonstrate the stable operation at low temperatures. This work provides the rational design for the hydrated eutectic electrolyte and the corresponding gradient SEIs for dendrite‐free and stable Zn anodes even under harsh conditions. [ABSTRACT FROM AUTHOR]

Doping Co atoms into Ru lattices can tune the electronic structure of active sites, and the conductive MXene can adjust the electrical conductivity of catalysts, which are both favorable for improving the electrocatalytic activity of the catalyst for water splitting. Here, ruthenium‐cobalt bimetallic nanoalloys coupled with exfoliated Ti3C2Tx MXene (RuCo−Ti3C2Tx) have been constructed by ice‐templated and thermal activation. Due to the strong interaction between the RuCo nanoalloys and conductive MXene, RuCo−Ti3C2Tx not only exhibits an excellent hydrogen evolution reaction (HER) performance with a low overpotential and Tafel slope (60 mV, 34.8 mV dec−1 in 0.5 M H2SO4 and 52 mV, 38.7 mV dec−1 in 1 M KOH), but also good oxygen evolution reaction (OER) performance in an alkaline electrolyte (266 mV, 111.1 mV dec−1 in 1 M KOH). The assembled RuCo−Ti3C2Tx||RuCo−Ti3C2Tx electrolyzer requires a lower potential (1.56 V) than does the Pt/C||RuO2 electrolyzer at 10 mA cm−2. A boosted catalytic HER activity from immobilizing the RuCo nanoalloys on MXene was unveiled by density functional theory calculations. This study provides a feasible and efficient strategy for developing MXene‐based catalysts for overall water splitting. [ABSTRACT FROM AUTHOR]

The development of an efficient pH‐universal hydrogen evolution reaction (HER) electrocatalyst is essential for practical hydrogen production. Here, an efficient and stable pH‐universal HER electrocatalyst composed of the strongly coupled 2D NiCo2S4 and 2D ReS2 nanosheets (NiCo2S4/ReS2) is demonstrated. The NiCo2S4/ReS2 2D–2D nanocomposite is directly grown on the surface of the carbon cloth substrate, which exhibits excellent HER performance with overpotentials of 85 and 126 mV at a current density of 10 mA cm−2 and Tafel slopes of 78.3 and 67.8 mV dec−1 under both alkaline and acidic conditions, respectively. Theoretical and experimental characterizations reveal that the chemical coupling between NiCo2S4 and ReS2 layers induces electron transfer from Ni and Co to interfacial Re‐neighbored S atoms, enabling beneficial H atom adsorption and desorption for both acidic and alkaline HER. Simultaneously, an electron transfer‐induced spin‐crossover generates high‐spin interfacial Ni and Co atoms that promote water dissociation kinetics at the NiCo2S4/ReS2 interface, which is the origin of the superior alkaline HER activity. NiCo2S4/ReS2 also shows decent catalytic activity and long‐term durability for oxygen evolution reaction, and finally bifunctionality for overall water splitting. This study suggests a rational strategy to enhance water dissociation kinetics by inducing spin‐crossover via electron transfer. [ABSTRACT FROM AUTHOR]

Transition bimetallic alloy-based catalysts are regarded as attractive alternatives for the oxygen evolution reaction (OER), attributed to their competitive economics, high conductivity and intrinsic properties. Herein, we prepared FeNi3/C nanorods with largely improved catalytic OER activity by combining hydrothermal reaction and thermal annealing treatment. The temperature effect on the crystal structure and chemical composition of the FeNi3/C nanorods was revealed, and the enhanced catalytic performance of FeNi3/C with an annealing temperature of 400 °C was confirmed by several electrochemical tests. The outstanding catalytic performance was assigned to the formation of bimetallic alloys/carbon composites. The FeNi3/C nanorods showed an overpotential of 250 mV to afford a current density of 10 mA cm−2 and a Tafel slope of 84.9 mV dec−1, which were both smaller than the other control samples and commercial IrO2 catalysts. The fast kinetics and high catalytic stability were also verified by electrochemical impendence spectroscopy and chronoamperometry for 15 h. This study is favorable for the design and construction of bimetallic alloy-based materials as efficient catalysts for the OER. [ABSTRACT FROM AUTHOR]

Highly active and durable electrocatalysts are essential for producing hydrogen fuel through the hydrogen evolution reaction (HER). Here, a uniform deposition of Ru nanoparticles strongly interacting with oxygen‐rich carbon nanotube architectures (Ru‐OCNT) through ozonation and hydrothermal approaches has been designed. The hierarchical structure of Ru‐OCNT is made by self‐assembly of oxygen functionalities of OCNT. Ru nanoparticles interact strongly with OCNT at the Ru/OCNT interface to give excellent catalytic activity and stability of the Ru‐OCNT, as further confirmed by density functional theory. Owing to the hierarchical structure and adjusted surface chemistry, Ru‐OCNT has an overpotential of 34 mV at 10 mA cm−2 with a Tafel slope of 27.8 mV dec−1 in 1 M KOH, and an overpotential of 55 mV with Tafel slope of 33 mV dec−1 in 0.5 M H2SO4. The smaller Tafel slope of Ru‐OCNT than Ru‐CNT and commercial Pt/C in both alkaline and acidic electrolytes indicates high catalytic activity and fast charge transfer kinetics. The as‐proposed chemistry provides the rational design of hierarchically structured CNT/nanoparticle electrocatalysts for HER to produce hydrogen fuel. [ABSTRACT FROM AUTHOR]

Electrolytes play a crucial role in facilitating the ionic movement between cathode and anode, which is essential for the flow of electric current during the charging and discharging process of the rechargeable batteries. In particular, electrolyte additives are considered as effective and economical approaches into the advancements of the battery technologies in both the conventional non‐aqueous and burgeoning aqueous electrolyte systems. Herein, a systematic and comprehensive review of the electrolyte additives is reported for the interfacial engineering of Li and Zn metal anodes in the non‐aqueous and aqueous electrolytes, respectively. The types of electrolyte additives and their corresponding functionalities for the protection of these two metal anodes are discussed along with the electrochemical features of solid electrolyte interphase (SEI) derived from electrolyte additives. The recent progress on electrolyte additives for these two battery systems are also addressed from the perspectives of electrode, electrolyte, and the associated SEI. Finally, the outlook and perspective on the current issues and future directions in the field of electrolyte additive engineering are presented for next‐generation battery technologies beyond the conventional Li‐ion batteries. [ABSTRACT FROM AUTHOR]

The development of a cost-competitive and efficient electrocatalyst is both attractive and challenging for hydrogen production by hydrogen evolution reaction (HER). Herein, a facile glycol reduction method to construct Ru nanoclusters coupled with hierarchical exfoliated-MXene/reduced graphene oxide architectures (Ru-E-MXene/rGA) is reported. The hierarchical structure, formed by the self-assembly of graphene oxides, can effectively prohibit the self-stacking of MXene nanosheets. Meanwhile, the formation of the MXene/rGA interface can strongly trap the Ru 3+ ions, resulting in the uniform distribution of Ru nanoclusters within Ru-E-MXene/rGA. The boosted catalytic activity and underlying catalytic mechanism during the HER process are proved by density functional theory. Ru-E-MXene/rGA exhibits overpotentials of 42 and 62 mV at 10 mA cm -2 in alkaline and acidic electrolytes, respectively. The small Tafel slope and charge transfer resistance (R ct ) values elucidate its fast dynamic behavior. The cyclic voltammetry (CV) curves and chronoamperometry test confirm the high stability of Ru-E-MXene/rGA. These results demonstrate that coupling Ru nanoclusters with the MXene/rGA heterostructure represents an efficient strategy for constructing MXene-based catalysts with enhanced HER activity., (© 2024 The Authors. Advanced Science published by Wiley‐VCH GmbH.)

Doping Co atoms into Ru lattices can tune the electronic structure of active sites, and the conductive MXene can adjust the electrical conductivity of catalysts, which are both favorable for improving the electrocatalytic activity of the catalyst for water splitting. Here, ruthenium-cobalt bimetallic nanoalloys coupled with exfoliated Ti 3 C 2 T x MXene (RuCo-Ti 3 C 2 T x ) have been constructed by ice-templated and thermal activation. Due to the strong interaction between the RuCo nanoalloys and conductive MXene, RuCo-Ti 3 C 2 T x not only exhibits an excellent hydrogen evolution reaction (HER) performance with a low overpotential and Tafel slope (60 mV, 34.8 mV dec -1 in 0.5 M H 2 SO 4 and 52 mV, 38.7 mV dec -1 in 1 M KOH), but also good oxygen evolution reaction (OER) performance in an alkaline electrolyte (266 mV, 111.1 mV dec -1 in 1 M KOH). The assembled RuCo-Ti 3 C 2 T x ||RuCo-Ti 3 C 2 T x electrolyzer requires a lower potential (1.56 V) than does the Pt/C||RuO 2 electrolyzer at 10 mA cm -2 . A boosted catalytic HER activity from immobilizing the RuCo nanoalloys on MXene was unveiled by density functional theory calculations. This study provides a feasible and efficient strategy for developing MXene-based catalysts for overall water splitting., (© 2023 Wiley-VCH GmbH.)

Highly active and durable electrocatalysts are essential for producing hydrogen fuel through the hydrogen evolution reaction (HER). Here, a uniform deposition of Ru nanoparticles strongly interacting with oxygen-rich carbon nanotube architectures (Ru-OCNT) through ozonation and hydrothermal approaches has been designed. The hierarchical structure of Ru-OCNT is made by self-assembly of oxygen functionalities of OCNT. Ru nanoparticles interact strongly with OCNT at the Ru/OCNT interface to give excellent catalytic activity and stability of the Ru-OCNT, as further confirmed by density functional theory. Owing to the hierarchical structure and adjusted surface chemistry, Ru-OCNT has an overpotential of 34 mV at 10 mA cm -2 with a Tafel slope of 27.8 mV dec -1 in 1 M KOH, and an overpotential of 55 mV with Tafel slope of 33 mV dec -1 in 0.5 M H 2 SO 4 . The smaller Tafel slope of Ru-OCNT than Ru-CNT and commercial Pt/C in both alkaline and acidic electrolytes indicates high catalytic activity and fast charge transfer kinetics. The as-proposed chemistry provides the rational design of hierarchically structured CNT/nanoparticle electrocatalysts for HER to produce hydrogen fuel., (© 2021 Wiley-VCH GmbH.)