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

Abstract

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 –.

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

“…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.…”

Recent Progress on Carbonaceous Material Engineering for Electrochemical Hydrogen Peroxide Generation

“…To amplify the synergistic effect, they also designed metal-free carbon aerogel integrated with nitrogen dopants and surface -COOH groups for H 2 O 2 production, which exhibited complete 100% selectivity to H 2 O 2 with high yields and stability [25]. Furthermore, Cardoso et al [50] discussed the performance varieties before and after electrochemically stabilized measurements on the N and O group-modified graphene and graphene oxide nanoribbons. The varieties of activity could be attributed to the changes of active functional groups in the process of long-term test.…”

Rotating Ring‐Disc Electrode Method: Dissecting Oxygen Reduction Reaction Through a Different Lens

“…With the differences in mind, two important questions arise as to which deconvolution method is more suitable for reaction selectivity analysis, and what extra information or insight can they together provide in regard to electrocatalysis. Intriguingly, both the product path‐based analysis, [14–17] and the step process‐based analysis, [18–22] have received good attention with a similar level of adoption for reaction selectivity analysis, without their differences elucidated. So, which analysis would be more appropriate?…”

“…Direct analysis on the overall envelope gives a value of 66 mV dec −1 , as an interfered result due to the large slope (119 mV dec −1 ) of the more sluggish P2H reaction. Other successful examples of the detailed Tafel analysis on decoupled reactions can be found in the works by Maia and his co‐workers [20–22] . One may stretch the reaction analysis further to extrapolate the intrinsic kinetic parameters of each reaction.…”