Abstract:Pd-coated Ru nanocrystals supported on N-doped graphene (Pd–Ru@NG) are obtained via electroless deposition of Pd on Ru nanocrystals which shows efficient bifunctional HER and ORR electrocatalytic activity.
“…Second, the nitrogen heteroatoms can induce charge redistribution and facilitate the adsorption of oxygen and the consequent reduction reaction on carbon. The proposed materials’ composition is their advantage, because generally structures described for ORR application tend to be decorated with expensive, precious, or environmentally-unfriendly metals or metal oxides, e.g., Pd, Ru 53 , perovskie oxides 54 , Fe(II) 55 , Fe 7 C 3 56 , or Au 57 . Figure 7 ( a ) CV curves with a scan speed of 100 mV s −1 in O 2 -saturated electrolyte for the 1A-T series and the Pt/C catalyst; ( b ) LSV curve of the obtained samples and Pt/C catalysts (5 V s −1 , 1600 rpm); ( c ) Onset potential of 1A-T and the commercial catalyst; ( d ) Koutecky–Levich plot for the samples at 0.45 V. …”
The synthesis of metal-free but electrochemically active electrode materials, which could be an important contributor to environmental protection, is the key motivation for this research approach. The progress of graphene material science in recent decades has contributed to the further development of nanotechnology and material engineering. Due to the unique properties of graphene materials, they have found many practical applications: among others, as catalysts in metal-air batteries, supercapacitors, or fuel cells. In order to create an economical and efficient material for energy production and storage applications, researchers focused on the introduction of additional heteroatoms to the graphene structure. As solutions for functionalizing pristine graphene structures are very difficult to implement, this article presents a facile method of preparing nitrogen-doped graphene foam in a microwave reactor. The influence of solvent type and microwave reactor holding time was investigated. To characterize the elemental content and structural properties of the obtained N-doped graphene materials, methods such as elemental analysis, high-resolution transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy were used. Electrochemical activity in ORR of the obtained materials was tested using cyclic voltamperometry (CV) and linear sweep voltamperometry (LSV). The tests proved the materials’ high activity towards ORR, with the number of electrons reaching 3.46 for tested non-Pt materials, while the analogous value for the C-Pt (20 wt% loading) reference was 4.
“…Second, the nitrogen heteroatoms can induce charge redistribution and facilitate the adsorption of oxygen and the consequent reduction reaction on carbon. The proposed materials’ composition is their advantage, because generally structures described for ORR application tend to be decorated with expensive, precious, or environmentally-unfriendly metals or metal oxides, e.g., Pd, Ru 53 , perovskie oxides 54 , Fe(II) 55 , Fe 7 C 3 56 , or Au 57 . Figure 7 ( a ) CV curves with a scan speed of 100 mV s −1 in O 2 -saturated electrolyte for the 1A-T series and the Pt/C catalyst; ( b ) LSV curve of the obtained samples and Pt/C catalysts (5 V s −1 , 1600 rpm); ( c ) Onset potential of 1A-T and the commercial catalyst; ( d ) Koutecky–Levich plot for the samples at 0.45 V. …”
The synthesis of metal-free but electrochemically active electrode materials, which could be an important contributor to environmental protection, is the key motivation for this research approach. The progress of graphene material science in recent decades has contributed to the further development of nanotechnology and material engineering. Due to the unique properties of graphene materials, they have found many practical applications: among others, as catalysts in metal-air batteries, supercapacitors, or fuel cells. In order to create an economical and efficient material for energy production and storage applications, researchers focused on the introduction of additional heteroatoms to the graphene structure. As solutions for functionalizing pristine graphene structures are very difficult to implement, this article presents a facile method of preparing nitrogen-doped graphene foam in a microwave reactor. The influence of solvent type and microwave reactor holding time was investigated. To characterize the elemental content and structural properties of the obtained N-doped graphene materials, methods such as elemental analysis, high-resolution transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy were used. Electrochemical activity in ORR of the obtained materials was tested using cyclic voltamperometry (CV) and linear sweep voltamperometry (LSV). The tests proved the materials’ high activity towards ORR, with the number of electrons reaching 3.46 for tested non-Pt materials, while the analogous value for the C-Pt (20 wt% loading) reference was 4.
“…As an oxophilic metal, Ru is active to catalyze the dissociation of water and holds great potential as highly efficient electrocatalysts for HER in an alkaline solution. The strong electron coupling between Pd, Cu and Ru could optimize the binding energy of Ru-H, which results in a weak hydrogen adsorption on the surface of the PdCuRu nanoplates [50]. On the other hand, Cu could accelerate the electron transfer between Ru and the adsorbate.…”
Ru is a key component of electrocatalysts for hydrogen evolution reaction (HER), especially in alkaline media. However, the catalytic activity and durability of Ru-based HER electrocatalysts are still far from satisfactory. Here we report a solvothermal approach for the synthesis of PdCuRu porous nanoplates with different Ru compositions by using Pd nanoplates as the seeds. The PdCuRu porous nanoplates were formed through underpotential deposition (UPD) of Cu on Pd, followed by alloying Cu with Pd through interdiffusion and galvanic replacement between Cu atoms and Ru precursor simultaneously. When evaluated as HER electrocatalysts, the PdCuRu porous nanoplates exhibited excellent catalytic activity and durability. Of them, the Pd24Cu29Ru47/C achieved the lowest overpotential (40.7 mV) and smallest Tafel slope (37.5 mV dec−1) in an alkaline solution (much better than commercial Pt/C). In addition, the Pd24Cu29Ru47/C only lost 17% of its current density during a stability test for 10 h, while commercial Pt/C had a 59.5% drop under the same conditions. We believe that the electron coupling between three metals, unique porous structure, and strong capability of Ru for water dissociation are responsible for such an enhancement in HER performance.
“…10–14 Currently, precious metal catalytic materials, such as Pt, Pd, Ru, and Ir, are the state-of-the-art oxygen electrode catalysts. 15–17 However, their high prices and limited reserves greatly restrict their commercial viability. 18,19 For this reason, it is desirable and ambitious to develop non-precious metal catalysts with high catalytic properties to substitute precious catalysts.…”
Reasonable design of bifunctional catalysts for oxygen reduction reactions (ORR) and oxygen evolution reactions (OER) is of great importance for the large-scale deployment of metal-air batteries. Herein, we developed a...
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