Amorphous/Crystalline Heterophase Ruthenium Nanosheets for pH‐Universal Hydrogen Evolution

Abstract

Recently, constructing noble metals in heterogeneous phases, denoted as phase engineering of nanomaterials, has attracted great attention. [7,8] In particular, developing amorphous/crystalline heterophase is explored to regulate the microstructure and properties, and the products exhibit desirable functionalities in energy conversion and storage applications, such as in catalysis, [9][10][11] battery, [12,13] solar cell, [14] electrochromic device, [15] and supercapacitor. [16] Although some progresses have been achieved, the development of individual nanostructure composed of both amorphous and crystalline phases is still in its fancy stage, with many challenges remained.Crystalline phase engineering requires a large portion of atoms to rearrange in a new distribution, which is distinguished from the shape control with only surface atoms involved, and thus is quite challenging. [17] Connected by the strong metallic bonds, noble metal atoms tend to form long range order with high degree of crystallization. Nevertheless, the glassy structure allows a number of dangling bonds to be exposed, providing more defect sites which can serve as trap sites to capture electrons and inert molecules. [18,19] As such, it is intensively expected to prepare new noble metals with amorphous/crystalline heterophase for promising use. Specific to the catalysis field, the presence of amorphous/crystalline heterophase allows more atoms to be exposed and activated at the phase boundaries, serving as new active sites for promoting the catalytic reaction. Meanwhile, the heterophase structure offers distinctive atomic arrangement with unique coordinated environment, which tremendously affects the ion adsorption and transport. Moreover, the synergism between different phase domains can enrich its electronic characters, modulate the interaction between active centers and reacting species, as well as the intermediates, and thus leading to a higher catalytic capability. Recently, Zhang and his co-authors have reported amorphous/ crystalline heterophase palladium (Pd) Nanosheets, [20] ultrathin amorphous/crystalline heterophase rhodium, [9] aging amorphous/crystalline heterophase Pd-copper [21] for catalytic reactions. However, to the best of our knowledge, preparing amorphous/crystalline heterophase ruthenium (Ru), accompanied by its catalytic application is rarely reported.Ru is the most inexpensive element among the noble metals, with the price approximately a quarter of that for Pt. It shows a To design and synthesize heterophase noble-metal materials is of crucial importance owing to their unique structure and apparent properties. Ruthenium (Ru) is one of the most active candidates for hydrogen evolution reaction because of its low price compared with other precious metals, which is favorable for industrial hydrogen cycle operation. In this study, free-standing amorphous/crystalline Ru nanosheets are facilely synthesized through a controlled annealing method. Charge redistribution occurs at the phase interface because of the work function ...

Fe Engineering on Ru Nanosheets for Enhanced Hydrogen Evolution in pH-Universal Media

“…Both pristine Ru and RuAl illustrated a distinct peak at 181 cm –1 (Figure c), attributed to the metallic Ru–Ru bond . Meanwhile, relatively weak Ru–O bond signals appeared at 266, 512, and 634 cm –1 , inferring a partial surface oxidation due to the high sensitivity of the Ru surface. ,, The Ru–Ru peak of RuAl exhibited a slight positive shift to 183 cm –1 , confirming a stronger reduction capacity caused by Al incorporation. In comparison, the Ru–Ru vibration became rather weak on the Ru (Al) Fe catalyst, suggesting a significant loss of crystallinity accompanied by defects and lattice distortions generated in the Ru matrix.…”

“…Ruthenium (Ru) is the most inexpensive element among noble metals. , Moreover, Ru possesses a comparable binding for hydrogen (65 kcal mol –1 ) as Pt (62 kcal mol –1 ). − Prior investigations suggest that engineering on size, dimension, and composition are effective to optimize the Ru property, for expediting hydrogen generation. − Volmer and Heyrovsky processes are the general rate-determining steps for nonacidic hydrogen production, which typically depend on the ability of water dissociation and hydrogen binding, respectively . Henceforth, ration design is desirable to reach high-performance Ru-based HER catalysts.…”

Amorphous-crystalline PdRu bimetallene for efficient hydrogen evolution electrocatalysis

“…Two-dimensional (2D) materials have been demonstrated as promising electrocatalysts for the HER thanks to their special physical and chemical properties. [10][11][12] As a member of the 2D materials, metallene with atomic-layer thickness has rich unsaturated bonds, large specific surface area, high electrical conductivity and sufficient active sites, and is considered as a potential candidate in electrocatalytic fields. 13,14 Recently, amorphous catalysts have shown excellent HER performance compared to crystalline ones because they can enable surface and volume constrained electrocatalysis.…”

Interface functionalization of mesoporous ruthenium films with polyaniline for enhanced hydrogen evolution electrocatalysis at all pH values

“…21,22 Recently, Ru-based nanocatalysts have been demonstrated as efficient HER catalysts with high intrinsic activities over a wide pH range, due to their Pt-like bond strength to hydrogen. [23][24][25] Furthermore, the relatively low price of Ru (about 1/4 of Pt) makes it promising for industrial HER applications. 26,27 To enhance the atomic utilization and electroactivity of Ru, much effort has been devoted to modulating the size and morphology of Ru-based nanocatalysts.…”