N-, P-, and O-Tridoped Carbon Hollow Nanospheres with Openings in the Shell Surfaces: A Highly Efficient Electrocatalyst toward the ORR

Abstract

Recently, carbon nanomaterials doped with nonmetallic atoms have been used as electrocatalysts involved in oxygen reduction reactions (ORRs) because of the lack of degradation and contamination problems caused by metal dissolution, low cost, sustainability, and multifunctionality. In this study, the metal-free N-, P-, O-tridoped carbon hollow nanospheres (N, P, O-Carbon) with openings in the shell surfaces have been developed, where poly­(o-phenylenediamine) hollow nanospheres with openings in the shell surfaces were chosen as a nitrogen-rich polymer, and then different phosphorus sources (such as NaH2PO2, H3PO4, and phytic acid (PA)) were introduced for heat treatment. When used as electrocatalysts, N, P, O-Carbon-PA showed the best ORR electroactivity with an onset potential (E onset ) of 0.98 V and the limit current density of 5.39 mA cm–2. The origin of high activity associated with heteroatom doping was elucidated by X-ray photoelectron spectroscopy and density functional theory. The results evidenced the high potential of N, P, O-Carbon as highly active nonmetal ORR electrocatalysts. It can be expected that the conclusions rendered herein will provide guidance for the reasonable design of other heteroatom-doped carbon for wider applications.

Exploring the structural dependence of metal-free carbon electrocatalysts on zinc-based metal–organic framework types

“…3f) were fit to CO (530.7 eV), C–O–C (532.2 eV), and C–O–H (533.8 eV). 37,75,76 The relative content of electrocatalytically active CO species of N1OC, N2OC and N3OC are 19.0%, 25.6% and 23.5%, respectively (Fig. S8, ESI†).…”

Synthesis of Iron and Phosphorous‐Embedded Nitrogen‐Containing Porous Carbon as an Efficient Electrocatalyst for Microbial Fuel Cells

“…[32] The existence of P atom in PÀ O species can enhance the electronegativity of the O atom, which further promotes the charge delocalization of the adjacent C atoms and benefits for the adsorption of O 2 . [33] In addition, the P atoms embedded in carbon lattice can facilitate the highly distorted carbon layer, thus generating more open edge sites [34] that further enhanced the electrochemical activity. Noticeably, small peaks at 129.7 and 130.3 eV corresponding to P 2p in PÀ Fe phase [10] appeared in the spectrum of P/Fe-SS 900, and their peak intensities gradually enhanced with the increasing pyrolysis temperature, which was consistent with the XRD results.…”

Carbon-Based Electrocatalyst Design with Phytic Acid—A Versatile Biomass-Derived Modifier of Functional Materials

“…In another approach, o -phenylenediamine was polymerized in the presence of an oxidant to produce hollow nanospheres, which were further treated with an aqueous solution of PA [ 63 ]. The subsequently dried materials were subjected to carbonization at 900 °C.…”