Crystal phase-dependent electrocatalytic hydrogen evolution performance of ruthenium–boron intermetallics

Abstract

Four crystal phases of ruthenium–boron intermetallics, including Ru7B3, RuB, Ru2B3 and RuB2, are selectively synthesized and their activity trends toward the HER are investigated.

One-step integration of amorphous RuBx and crystalline Ru nanoparticles into B/N-doped porous carbon polyhedra for robust electrocatalytic activity towards the HER in both acidic and basic media

“…Based on the above results of BET, ESA and EIS analysis, due to the porous structure and great specic surface area of the B/N-doped carbon polyhedra, augmented exposure of active sites of the uniform amorphous RuB x and crystalline Ru nanoparticles, and decreased chargetransfer resistance on account of the crystalline Ru nanoparticles and B, N doping, RuB x -Ru@BNPCH exhibited a high HER activity. In addition, according to the literature, Ru species are benecial for a low energy barrier to break the H-OH bond of water moleculars, 50,51 and Ru-B sites possess the optimal balance of H*-adsorption-H 2 -desorption capacity 32,52 , so the integration of amorphous RuB x and crystalline Ru nanoparticles induced excellent HER performance.…”

Intermetallic borides: structures, synthesis and applications in electrocatalysis

“…Our group comparatively investigated the HER catalytic activities of four Ru-B intermetallics with different crystal structures, including Ru 7 B 3 , RuB, Ru 2 B 3 and RuB 2 . 42 The HER activities of RuB, Ru 2 B 3 and RuB 2 are close to that of Pt in acidic solution and little better than that of Pt in alkaline solution, while Ru 7 B 3 has a moderate activity similar to metallic Ru. Among them, the RuB 2 material exhibits not only the optimal HER activity, but also the best stability in both acidic and alkaline solutions.…”

“…7c). 42 This is because stronger B-B interactions in more boron-rich environments weaken the orbital hybridization between Ru 4d and B 2sp states.…”

“…7e, demonstrate that the Ru-B interaction in RuB 2 is metallic. 42 The electronic structure plays a fundamental role in determining the surface adsorption energy and catalytic properties of borides toward various reactions. Several recent studies have found that the HER activities of borides are strongly related to metal d-band properties (i.e., d-band center, d-band width) which influence the adsorption strength of key hydrogen intermediates.…”

“…Several recent studies have found that the HER activities of borides are strongly related to metal d-band properties (i.e., d-band center, d-band width) which influence the adsorption strength of key hydrogen intermediates. [41][42][43] The metal d-band properties of boride catalysts depend on many factors including metal-boron orbital hybridization, metal-metal bond length and metal-boron charge transfer. For example, the position of the metal d-band center in RuB 2 is close to that of the benchmark Pt catalyst, leading to optimal hydrogen adsorption and Pt-like activity for the HER.…”