High‐Index Faceted RuCo Nanoscrews for Water Electrosplitting

Abstract

catalyst surface to form the final product, which seriously hinders the progress of the reaction. [3,4] Although researchers have made significant progress in the design of catalysts, a large cell voltage is still needed to drive this process. Therefore, it is still highly desirable to design high-efficiency water-splitting electrocatalysts. Recently, ruthenium (Ru) has attracted special attention for water-splitting catalysis since its inherently excellent activity and far lower price than platinum (Pt) and iridium (Ir). [5-9] To date, various strategies have been applied to enhance the activity of the Ru-based catalysts, including turning the crystal phase, doping electrocatalysts with hetero atoms, alloying Ru with the transition metals, and so on forth. [7,10,11] In principle, since the electrocatalysis is usually carried out on the surface of a catalyst, controlling the surface structure of the catalyst is a more straightforward way to improve the catalytic performance. The high-index crystal facets have more coordination unsaturated atoms and more active sites, which is believed to be more active. [12-14] Nevertheless, there were fewer reports on controlling the Ru-based catalysts with high-index facets. To this end, the fine control of Ru-based catalysts is of great significance in both practical application and fundamental research. Shape control has realized huge success for developing efficient Pd/Ptbased nanocatalysts, but the control of Ru-based nanocrystals remains a formidable challenge due to the inherent anisotropy in hexagonal closedpacked nanocrystals. Herein, a class of unique RuCo nanoscrews (NSs) for water electrosplitting is successfully synthesized with rough surfaces and the exposure of steps and edges. Those high-index faceted RuCo NSs show superior performance for overall water electrosplitting, where a low cell voltage of 1.524 V (@ 10 mA cm −2) and excellent stability for more than 20 h (@ 10 mA cm −2) for overall water electrosplitting in 1 m KOH is achieved. The enhanced performance of RuCo NSs is due to the optimization of the binding energy with the intermediate species and the reduced energy barrier of water dissociation. Density functional theory calculations reveal that the RuCo NS structure intrinsically endows various ridges and edges, which create low coordinated Ru-and Co-sites. These active Ru-and Co-sites present high efficiencies in electronic exchange and transfer between adsorbing O species and nearby lattice sites, guaranteeing the high H 2 Osplitting activities. This present work opens up a new strategy for creating high-performance electrocatalysts for water splitting.

Synergistic Cascade Hydrogen Evolution Boosting via Integrating Surface Oxophilicity Modification with Carbon Layer Confinement

“…[ 11,17 ] Meanwhile, another pair of small peaks with a binding energy of 465.4 and 486.9 eV corresponding to the positively charged Ru species were also observed, suggesting the oxidation of metallic Ru upon exposed to oxygen. [ 18 ] Given that the positively charged Ru species could be reduced into metallic status under HER‐relevant potential, the trace amount of ruthenium oxides was not taken into consideration in our catalyst system. It is worth noting that the binding energy of Ru 3p in both RuCr@C and Ru@C catalyst were positively shifted compared with commercial Ru/C catalyst (Figure 1g), confirming the strong interaction between metal cores and the carbon layers.…”

Nanostructured RuO2–Co3O4@RuCo-EO with low Ru loading as a high-efficiency electrochemical oxygen evolution catalyst

“…[21][22][23][24][25] The introduction of abundant transition metal elements can improve the composition and structural of electrocatalysts, thereby improving OER activity and reducing costs. [26][27][28][29][30] Early literature reports have proved that the doping/alloying of transition metals such as Fe, Co, Ni, and Cu can optimize the local electronic and geometric structure of the original metal through the strain/ligand effect. [31][32][33][34] These changes will facilitate the chemical adsorption of intermediate adsorbed species (OH* and OOH*) on the surface of the electrocatalyst, which can increase the catalytic activity in an alkaline solution.…”

Co(OH)2 Nanosheets Array Doped by Cu2+ Ions with Optimal Electronic Structure for Urea‐Assisted Electrolytic Hydrogen Generation

“…Hydrogen has been considered as one of the most captivating substitute energy carriers for conventional fuels due to its high energy density and eco-friendly characteristics. [1,2] Water electrolysis is a sustainable and promising route for commercial hydrogen production. [3] However, this strategy is hampered by a large overpotential that required by sluggish OER dynamics on the anode.…”