Use of Rotating Ring‐Disk Electrodes to Investigate Graphene Nanoribbon Loadings for the Oxygen Reduction Reaction in Alkaline Medium

Cardoso, Eduardo S. F.; Fortunato, Guilherme V.

doi:10.1002/celc.201800331

Cited by 36 publications

(38 citation statements)

References 62 publications

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“…Figures and S7 show the results of the XPS survey analysis along with the high‐resolution XPS (HR‐XPS) spectra for the non‐electrochemically stabilized Pt−Pd/GNR and Ti/Pt−Pd/GNR nanocomposites, and the electrochemically stabilized Ti/Pt−Pd/GNR nanocomposite. Detailed interpretation from the results of XPS survey spectra (Figure S7A and Table S2), atomic percentages of C, N, O, Pt, Pd, and Ti (Table S2), C 1s HR‐XPS spectra attributions (Figure S7B and Table S3), N 1s HR‐XPS spectra attributions (Figure S7C and Table S3), O 1s HR‐XPS spectra attributions (Figure S7D and Table S3), and Ti 2p HR‐XPS spectrum attributions (Figure S7E and Table S3) are presented at section S1 in SI.…”

Section: Resultsmentioning

confidence: 99%

Ti/Pt−Pd‐Based Nanocomposite: Effects of Metal Oxides on the Oxygen Reduction Reaction

2020

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Over the last few years, there has been an intensive search for stable and highly active electrocatalysts, which are intended to be applied in oxygen reduction reaction (ORR) preferably without the use of noble metals or with the application of a very small quantity of these metals in the process. Electrocatalysts that satisfy these conditions can be composed of Ti and other metals, supported or not by carbonaceous materials. The present work reports the application of synthesized threedimensional Ti/PtÀ Pd nanoparticles with highly rough surfaces supported on graphene nanoribbons (Ti/PtÀ Pd/GNR nanocomposite) by a single one-pot reaction, and applied in ORR. Unlike the effect of strong metal-support interaction (SMSI), which favors electrons transfer from the metal support to the catalyst, the mechanism employed in this study favored the transfer of electrons from the catalyst to the metal support; in other words, the mechanism led to the oxidation of Pt and Pd. Pt, which exhibited PtÀ Pd type alloy features, was found to be more externally distributed at the rough surface of the metallic structures. Additionally, Ti, which presented oxide features, was found to be even more externally distributed at the surface of PtÀ Pd on non-electrochemically and electrochemically stabilized Ti/PtÀ Pd/GNR nanocomposite electrodes. Since all these metals have great amounts of different oxides (i. e. are highly oxidized), the oxides are found to be energetically responsible for the improvement in ORR electrocatalytic activity and stability of Ti/PtÀ Pd/GNR/GC electrodes in comparison with the ORR responses for PtC TKK/GC and PtÀ Pd/GNR/GC modified electrodes. To Ti-containing catalysts, the high activity is attributable to enhancing the intrinsic activity and the high selectivity to 4-electron ORR is due to the fact that presence of Ti contributes to oxygen-binding energy of these nanocomposites shifts toward more positive values (weakening oxygen bonding).[a] G.

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Section: Resultsmentioning

confidence: 99%

Ti/Pt−Pd‐Based Nanocomposite: Effects of Metal Oxides on the Oxygen Reduction Reaction

2020

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“…The C 1s HR-XPS spectra (Figures A and S4) showing a visible narrow peak and a small shoulder were deconvoluted in three peaks related to the following groups: sp 2 - (CC) and sp 3 -hybridized carbon (C–C) at 284.3 eV (Table S3); ,,,, alcohol and ether (C–OH, C–O–C) at around 285 eV (Table S3); ,,,, and carbonyl (CO, COOH) at around 288 eV (Table S3). ,,,, The two small peaks at 292.9 and 295.8 eV are attributed to K 2p, which is derived from the KOH solution employed during the electrochemical measurements and remained in the structure of GNR and GONR after electrochemical stabilization. For both GNR and GONR samples, there was an increase in the percentage content of C bonded to O (oxidation of C–C or CC bonds) and a displacement of the peak position of C (bonded to O) to lower energy (Table S3) after electrochemical stabilization.…”

Section: Resultsmentioning

confidence: 99%

Modification of C, O, and N Groups for Oxygen Reduction Reaction on an Electrochemically Stabilized Graphene Nanoribbon Surface

Cardoso

Fortunato

2019

J. Phys. Chem. C

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There has been a huge debate in the literature over the past few years regarding the groups (C, O, and N groups and their quantities) involved in oxygen reduction reaction on metal-free carbonaceous nanostructured surfaces. The present study shows that the electrochemical stabilization of graphene oxide nanoribbons (GONRs) leads to an increase in the number of quinone groups on the surface of GONR electrodes. These quinone groups are responsible for the high production of HO2 –. The percentage decrease observed in HO2 – production (in a region of defined potential) is attributed to the presence of pyrrolic-N groups along with epoxy groups on the electrochemically stabilized surface of graphene nanoribbon (GNR) electrodes. The presence of pyrrolic-N groups along with epoxy groups on the electrochemically stabilized surface of GNR electrodes is observed concomitantly with a decrease in the amount of pyridinic-N groups oxidized to N oxides from pyridinic-N groups in addition to a significant decrease in the percent concentration of quinone groups. The combination of pyrrolic-N groups (without ruling out the contribution of pyridinic-N groups, which presented very low percentage content with a total N atomic concentration of only 0.7%) with quinone groups on a nonelectrochemically stabilized GNR surface is responsible for the high production of HO2 –.

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“…Other suitable catalysts can be found through DFT computations [53]. In addition, further attention should be given to topological structure design for active catalysts (actual determination of selectivity should be noted [54]) with high-current density, long-term run, and depressing the decomposition of H 2 O 2 at high overpotentials. The catalysts may be low stability at high-current density, and reasonable experiments and characterization techniques should be applied to find the factors of material degradation [14] and provide targeted solutions.…”

Section: Discussionmentioning

confidence: 99%

Recent Progress on Carbonaceous Material Engineering for Electrochemical Hydrogen Peroxide Generation

Zhang

et al. 2020

Trans. Tianjin Univ.

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Electrochemical synthesis of hydrogen peroxide (H 2 O 2) provides a clean and safe technology for large-scale H 2 O 2 production. The core of this project is the development of highly active and highly selective catalysts. Recent studies demonstrate that carbonaceous materials are favorable catalysts because of their low-cost and tunable surface structures. This brief review first summarizes the strategies of carbonaceous material engineering for selective two-electron O 2 reduction reaction and discusses potential mechanisms. In addition, several device designs using carbonaceous materials as catalysts for H 2 O 2 production are introduced. Finally, research directions are proposed for practical application and performance improvement.

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Use of Rotating Ring‐Disk Electrodes to Investigate Graphene Nanoribbon Loadings for the Oxygen Reduction Reaction in Alkaline Medium

Cited by 36 publications

References 62 publications

Ti/Pt−Pd‐Based Nanocomposite: Effects of Metal Oxides on the Oxygen Reduction Reaction

Ti/Pt−Pd‐Based Nanocomposite: Effects of Metal Oxides on the Oxygen Reduction Reaction

Modification of C, O, and N Groups for Oxygen Reduction Reaction on an Electrochemically Stabilized Graphene Nanoribbon Surface

Recent Progress on Carbonaceous Material Engineering for Electrochemical Hydrogen Peroxide Generation

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