High Activity and Excellent Stability of Ternary Ru(CoSe₂)/C with Enhanced Ru Utilization

Abstract

A small amount of ruthenium (Ru) was introduced into binary CoSe 2 /C through chemical reduction to obtain ternary Ru(CoSe 2 )/C. The effects of heat-treatment (HT) on crystal structures and electrocatalytic activities toward oxygen reduction reaction (ORR) of binary and ternary catalysts were investigated. Upon the heat-treatment at 400 • C, a simple phase transformation from orthorhombic to cubic CoSe 2 took place in the absence of Ru, resulting in larger crystallite size and poorer ORR activity of CoSe 2 /C-HT. However, with the incorporation of Ru, a new cubic (Ru x Co y )Se 2 like phase might be formed as the Ru could enter the CoSe 2 lattice during the phase transformation, which not only prevented the grain growth and stabilized the structure, but also provided the new efficient ORR active site. Ultimately, high activity and excellent stability were achieved for Ru(CoSe 2 )/C-HT with the synergy of Ru with Co and Se, which significantly enhanced Ru utilization. The open circuit potential and maximum power density reached 0.87 V and 151 mW • cm −2 in the H 2 /O 2 single cell test, respectively, which were 24.3% and 242.5 times larger than those of CoSe 2 /C-HT (0.70 V and 0.62 mW • cm −2 ), respectively. The normalized degradation was 2.2% after 1000 cycles during the accelerated degradation test.

Achieving Increased Electrochemical Accessibility and Lowered Oxygen Evolution Reaction Activation Energy for Co2+ Sites with a Simple Anion Preoxidation

“…Figure S11 displays the Raman spectra (acquired using 488 nm laser) of both CoSeO 3 ·2H 2 O/CC (a) and CoSe 2 /CC (b) before and after OER studies. Typically, both CoSeO 3 ·2H 2 O/CC and CoSe 2 /CC before OER characterizations showed clearly distinguishable peaks for Co–Se stretching vibrations in the wavenumber ranges of 90–250 cm –1 and 370–450 cm –1 which are in close agreement with the earlier reports on cobalt selenide materials. ,, Interestingly, CoSeO 3 ·2H 2 O/CC showed strong stretching vibrations for Se–O, as it has a selenite anion, while CoSe 2 /CC showed a very week Se–O stretching vibration, as it only possessed a negligible quantity of surface-oxidized selenium oxides/oxyanions. These peaks are observed in the range of 490–540 cm –1 with CoSeO 3 ·2H 2 O/CC and at around 495 cm –1 for CoSe 2 /CC.…”

Synergistic Engineering of Se Vacancies and Heterointerfaces in Zinc‐Cobalt Selenide Anode for Highly Efficient Na‐Ion Batteries

“…The higher intensity ratio of I D / I G (1.2) compared with ZnSe/CN (Figure S11, Supporting Information) suggests the presence of abundant defects in carbon due to the attachment of ZnSe and CoSe 2 particles and the doping of N, which could enhance the chemical conductivity and further improve the Na + ‐storage of ZnSe/CoSe 2 ‐CN. Additionally, there is one peak lactated at ≈186.5 cm –1 that should be assigned to Se‐Se bond in the sample, [ 38 ] while the peaks at 471.3, 516.1, 613.7, and 680.2 cm –1 are ascribed to the Eg, F2g (1), F2g (2) and A1g modes of cubic CoSe 2 . [ 39 ] The XPS survey spectrum displayed in Figure S12, Supporting Information verifies the presence of Zn, Co, Se, C, and N in the typical sample.…”

Highly Stable and Methanol Tolerant RuTe2/C Electrocatalysts for Fuel Cell Applications

“…In this case, ternary Ru-based cobalt selenide had to be synthesized by a multi-step process. 25 Different chalcogen elements would influence the electrocatalytic activity of Ru-based chalcogenides. Through a traditional carbonyl preparation method, a family of Ru-based chalcogenide compounds, Ru x X y (X = S, Se, Te), had been previously studied.…”