Highly Efficient Alkaline Water Splitting with Ru‐Doped Co−V Layered Double Hydroxide Nanosheets as a Bifunctional Electrocatalyst

Abstract

Active electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are decisive for achieving efficient energy conversion from electricity to hydrogen fuel through water electrolysis. In this study, tremella‐like Ru‐doped Co‐V layered double hydroxide nanosheets on Ni Foam (Ru‐CoV‐LDH@NF) was fabricated by a one‐pot solvothermal reaction. As‐prepared Ru‐CoV‐LDH@NF, with a nominal Ru loading of around 51.6 μg cm−2 exhibits excellent bifunctional catalytic activity towards HER and OER in alkaline media. To accomplish a current density of 10 mA cm−2, it demands 32 mV and 230 mV overpotentials for HER and OER, respectively. The alkali electrolyzer utilizing Ru‐CoV‐LDH/NF as bifunctional electrocatalyst affords 10 mA cm−2 electrolytic current density at an extremely low cell voltage of 1.50 V, showing excellent performance compared to a Pt/C−RuO2‐based electrolyzer and many other bifunctional electrocatalyst‐based ones. The incorporation of Ru changes the morphology of the resultant nanosheets to offer high electrochemical surface areas for electrocatalysis; at the same time, it significantly boosts the intrinsic HER/OER electrocatalytic activity. For HER, the energy barrier of the Volmer step is efficiently reduced upon Ru doping, whereas the Ru dopants optimize the absorption strength of *O intermediates to facilitate the OER process. This work offers a feasible means to optimize the Co‐based hydroxide materials for improved electrocatalysis in overall water splitting.

Metal single‐atom‐confined electrocatalysts to water oxidation: Development, innovation, and challenges

“…Ni alloy LDH can be obtained with Ni foam as the substrate. [ 31,38,44 ] With a Cl ‒ corrosion strategy, NiCoRu alloy LDH on Ni foam was formed. Ni foams were soaked into an aqueous solution containing NaCl, CoCl 2 , and RuCl 3 , and the solution was heated at 80°C in a water bath for 6 h. [ 38 ] An overpotential as 270 mV at 100 mA/cm 2 and Tafel slope of 40 mV/dec were obtained by NiCoRu LDH in KOH electrolyte, which surpassed IrO 2 catalysts.…”

“…Similarly, RuCoV alloy LDH on Ni foam were formed by reducing metal ions in a solvothermal strategy, and an overpotential as 230 mV at 10 mA/cm 2 in KOH electrolyte was achieved (Table 1). [ 31 ] These LDH electrocatalysts were not superior to Ru single atom Ru SAs/AC‐FeCoNi, demonstrating the key role of the SA state of Ru in OER catalysis.…”

The Central Role of Nitrogen Atoms in a Zeolitic Imidazolate Framework‐Derived Catalyst for Cathodic Hydrogen Evolution

“…Renewable electric energy from solar, wind, hydro, and other sources can be transformed into storable hydrogen by water electrolysis [1] . Precious metals such as Pt, Pd, Ru, Rh and Ir‐based materials are among the most effective electrocatalyst for the hydrogen evolution reaction (HER) [1c,2] . The HER mechanism on Pt has been studied in detail based on the Sabatier's principle, which states that the best catalysts should bind the intermediate species with a moderate strength, neither too weakly in order to be able to activate the reactants, nor too strongly to allow the products to desorb [3] .…”

Rational Construction of Ruthenium‐Cobalt Oxides Heterostructure in ZIFs‐Derived Double‐Shelled Hollow Polyhedrons for Efficient Hydrogen Evolution Reaction

“…[2,3] Therefore, exploiting efficient cathodic active electrocatalyst is significantly critical to accelerate the HER process that has sluggish kinetics and large overpotentials. [4][5][6] Although the platinum (Pt)-based materials possess the fascinating catalytic activity for HER, high price and low reserves are still obstacles to their large-scale application. [7] Intensive research on Pt-free electrocatalysts for effective HER has been conducted with the purpose of replacing expensive Pt-based materials in the last few decades.…”

“…[7] Intensive research on Pt-free electrocatalysts for effective HER has been conducted with the purpose of replacing expensive Pt-based materials in the last few decades. [4,6,7] Particularly, transition metal oxides (TMOs)based materials as an emerging family of HER electrocatalysts have attracted widespread attention due to the merits of facile synthesis, earth-abundance, compositional and structural diversity, and flexible tunability. [8] However, pure metal oxides with inappropriate hydrogen adsorption ability, limited catalytic-active sites and poor electrical conductivity, are generally considered as inactive for HER.…”