Downshifted d‐Band Center of Ru/MWCNTs by Turbostratic Carbon Nitride for Efficient and Robust Hydrogen Evolution in Alkali

Abstract

Ru, unlike Pt, is seldom considered as the effective electrocatalyst for hydrogen evolution reaction (HER) due to the strong binding of hydrogen species on metal surface as well as the serious metal bleaching. Herein, the amorphous turbostratic‐phased carbon nitride (t‐CNx) layer was utilized to downshift the d‐band center of the Ru/multi‐walled carbon nanotubes (Ru/MWCNTs) hybrids to achieve the optimized hydrogen species adsorption for subsequent efficient and stabilized hydrogen evolution in alkali. The catalysts with a low Ru loading of 8 wt % presented the high HER activity with a low overpotential of 39 mV for a catalytic current density of 10 mA cm−2, a small Tafel slope of 28 mV dec−1 and a stabilized catalytic performance over a period of 14 h in 1.0 M KOH, outperforming the 20 wt % Pt/C benchmarks. The thin t‐CNx layer play dual roles: (1) as the modulator of electronic structures for Ru with lower d‐band position for the enhanced activity and (2) as the protective layer to avoid the metal aggregation/bleaching and improve the catalytic stability of the hybrid catalysts subsequently.

Ruthenium Nanoparticles for Catalytic Water Splitting

“…At horough comparison with the corresponding undopeds ystems highlightst he importance of nitrogen for avoiding aggregation and boostingt he electrocatalytic activity.A nalogously,t he use of NGCi sa ne xcellent strategy to boost the HER activity of Ru NPs at acidic and basic pH ( Table 3, entry 15, and Ta ble 4, entry 16), [79] and the beneficial effect of ac arbon nitride coating on Ru NPs deposited on MWCNTsw as recently reported at pH 14 ( Table 4, entry 17). [80] However, in ar ecent paper,t he HER activity of Ru@GnP (Table 3, entry 16;T able 4, entry 18) [81] has been shown to decreasea fter Nd oping due to the blockingo fR ua ctive sites by Na toms. Excellent HER performance under alkalinec onditions was also recently reported by Yamauchia nd co-workers for a hierarchically ordered system.…”

Room‐Temperature Morphology‐Controlled Synthesis of Nickel and Catalytic Properties of Corresponding Ru/Ni Catalysts

“…The Ru 3p XPS spectrum had two prominent bands at high binding energy values, 464.2 eV (Ru 3p 3/2 ) and 486.2 eV (Ru 3p 1/2 ), attributable to RuO 2 (Figure e–g), respectively. Two additional bands with lower energy (462 eV and 484 eV) coincides well with Ru(0) species . The intensity of position of the two peaks of RuO 2 is obviously higher than that of the additional two peaks of Ru(0), indicating that most Ru atoms are present in the form of oxidation state ruthenium on their surface.…”

“…Two additional bands with lower energy (462 eV and 484 eV) coincides well with Ru(0) species. [39][40][41][42] The intensity of position of the two peaks of RuO 2 is obviously higher than that of the additional two peaks of Ru (0), indicating that most Ru atoms are present in the form of oxidation state ruthenium on their surface. It was mainly because Ru atoms were supported on their surface via galvanic replacement reaction method and readily oxidized upon exposure to air.…”

pH universal Ru@N-doped carbon catalyst for efficient and fast hydrogen evolution

“…Overall, the above results clearly indicate that Ru@NC(1 : 5) is a highly efficient electrocatalyst for HER in alkaline media and is comparable to the other excellent Ru-based electrocatalysts (Table 2). 19,21,23,[26][27][28][29][30]39 The other important criterion of a good catalyst is the stability during the catalytic process. Therefore, we carried out a long-term durability test of Ru@NC(1 : 5) using cyclic voltammetry (CV) initially.…”

“…[16][17][18][19][20][21][22][23][24] In particular, a number of electrocatalysts based on Ru nanoparticles (NPs) have been recently shown to exhibit similar or even better HER performance compared to the Pt/C benchmark. [25][26][27][28][29][30] However, the preparation of Ru NPs usually requires a strong reducing reagent such as NaBH 4 , and the direct loading of Ru NPs on the surface of the supports may be not enough to guarantee the sufficient interactions with the supports. Thermolysis of a Ru precursor with a carbon source seems to be a potential way for the in situ generation of Ru NPs embedded in a carbon matrix, though it is still a challenge to control the uniform particle size and the homogenous distribution of NPs during the high temperature pyrolysis process.…”