Modulating Electronic Environment of Ru Nanoclusters via Local Charge Transfer for Accelerating Alkaline Water Electrolysis

Electronic structure optimizing of Ru nanoclusters via Co single atom and N, S co-doped reduced graphene oxide for accelerating water electrolysis

The development of efficient and stable electrocatalysts for hydrogen evolution reaction (HER) is impending for the advancement of water-splitting. In this study, we developed a novel electrocatalyst consisting of highly dispersed Ru nanoclusters ameliorated by cobalt single atoms and N, S co-doped reduced graphene oxide (CoSARuNC@NSG). Benefitted from the optimized electronic structure of the Ru nanoclusters induced by the adjacent single atomic Co and N, S co-doped RGO support, the electrocatalyst exhibits exceptional HER performance with overpotentials of 15 mV and 74 mV for achieving a current density of 10 mA cm-2 in alkaline and acidic water. The catalyst outperforms most noble metal-based HER electrocatalysts. Furthermore, the electrolyzer assembled with CoSARuNC@NSG and RuO2 demonstrated an overall voltage of 1.56 V at 10 mA cm-2 and an excellent operational stability for over 25 h with almost no attenuation. Theoretical calculations also deduce its high HER activity demonstrated by the smaller reaction energy barrier due to the optimized electronic structure of Ru nanoclusters. This strategy involving the regulation of metal nanoparticles activity through flexible single atom and GO support could provide valuable insights into the design of high-performance and low-cost HER catalysts.

Metal Alloys-Structured Electrocatalysts: Metal-Metal Interactions, Coordination Microenvironments, and Structural Property-Reactivity Relationships

Metal alloys-structured electrocatalysts (MAECs) have made essential contributions to accelerating the practical applications of electrocatalytic devices in renewable energy systems. However, due to the complex atomic structures, varied electronic states, and abundant supports, precisely decoding the metal-metal interactions and structure-activity relationships of MAECs still confronts great challenges, which is critical to direct the future engineering and optimization of MAECs. Here, this timely review comprehensively summarizes the latest advances in creating the MAECs, including the metal-metal interactions, coordination microenvironments, and structure-activity relationships. First, the fundamental classification, design, characterization, and structural reconstruction of MAECs are outlined. Then, the electrocatalytic merits and modulation strategies of recent breakthroughs for noble and non-noble metal-structured MAECs are thoroughly discussed, such as solid solution alloys, intermetallic alloys, and single-atom alloys. Particularly, unique insights into the bond interactions, theoretical understanding, and operando techniques for mechanism disclosure are given. Thereafter, the current states of diverse MAECs with a unique focus on structural property-reactivity relationships, reaction pathways, and performance comparisons are discussed. Finally, the future challenges and perspectives for MAECs are systematically discussed. It is believed that this comprehensive review can offer a substantial impact on stimulating the widespread utilization of metal alloys-structured materials in electrocatalysis.

Ru nanoclusters anchored on boron- and nitrogen-doped carbon for a highly efficient hydrogen evolution reaction in alkaline seawater

Electrochemical seawater splitting is an intriguing strategy for green hydrogen production. Constructing advanced electrocatalysts for the hydrogen evolution reaction (HER) in seawater is extremely demanded for accelerating the sluggish kinetic process. Herein, a Ru nanocluster anchored on boron- and nitrogen-doped carbon (Ru/NBC) catalyst was successfully synthesized for the HER in alkaline/seawater electrolytes. Remarkably, Ru/NBC exhibits outstanding activity and durability, delivering low overpotentials@10 mA cm-2 in 1.0 M KOH (30 mV) and 1.0 M KOH + seawater electrolyte (35 mV), outperforming Pt/C, Ru/NC, Ru/BC and Ru/C. Additionally, Ru/NBC also provides a high specific activity of 0.093 mA cm-2ECSA at an overpotential of 150 mV, which is higher than those of Ru/NC, Ru/BC and Ru/C, respectively. Density functional theory calculation results demonstrate that the Ru-B formed interfacial chemical bond can regulate the electronic structure of Ru active sites of Ru/NBC, which can facilitate the adsorption of water and hydrogen in alkaline media. This work provides a feasible strategy to fabricate outstanding electrocatalysts for the HER in alkaline/alkaline seawater electrolytes.

Synthesis of Fe Atom-Doped Monodisperse Co2P Nanorods with a Dual-Ligand Strategy for Excellent Electrocatalytic Hydrogen Evolution Performance

Cobalt phosphide has been widely used in various catalytic reactions due to its excellent catalytic activity and stability. In contrast to the conventional synthesis of Co2P nanorods using expensive and toxic trioctylphosphine (TOP), this study employs a dual-ligand strategy to prepare iron-atom-doped monodisperse Co2P nanorods. The strategy involves the use of triphenylphosphite (TPOP) as a cost-effective and relatively less toxic strong ligand, alongside hexadecylamine (HDA) as a weaker ligand. The resultant atom-doped Co2P nanorods exhibited a large aspect ratio, providing a plentiful supply of active sites for electrocatalytic hydrogen evolution. In both alkaline and acidic electrolytes, achieving a current density of 10 mA cm-2 required overpotentials of 91 and 141 mV, respectively, with the optimal Co:Fe molar ratio of 1:0.2. The introduction of Fe atoms through doping increased the electron density at the Co atom sites, thereby enhancing H adsorption. This research offers a cost-effective and relatively low-toxicity method for the controlled fabrication of monodisperse transition-metal phosphide nanorods, enabling efficient catalytic reactions.