Nitrogen-doped carbon nanotubes and graphene composite structures for energy and catalytic applications

Abstract

Substitutional heteroatom doping is a promising route to modulate the outstanding material properties of carbon nanotubes and graphene for customized applications. Recently, (nitrogen-) N-doping has been introduced to ensure tunable work-function, enhanced n-type carrier concentration, diminished surface energy, and manageable polarization. Along with the promising assessment of N-doping effects, research on the N-doped carbon based composite structures is emerging for the synergistic integration with various functional materials. This invited feature article reviews the current research progress, emerging trends, and opening opportunities in N-doped carbon based composite structures. Underlying basic principles are introduced for the effective modulation of material properties of graphitic carbons by N-doping. Composite structures of N-doped graphitic carbons with various functional materials, including (i) polymers, (ii) transition metals, (iii) metal oxides, nitrides, sulphides, and (iv) semiconducting quantum dots are highlighted. Practical benefits of the synergistic composite structures are investigated in energy and catalytic applications, such as organic photovoltaics, photo/electro-catalysts, lithium ion batteries and supercapacitors, with a particular emphasis on the optimized interfacial structures and properties.

Straightforward synthesis of nitrogen-doped carbon nanotubes as highly active bifunctional electrocatalysts for full water splitting

“…It has been reported in the literature that graphitic N serves as the active site for other catalytic reactions, such as oxygen reduction reaction [54,56] while pyridinic N is active toward OER [33,37]. Depending on the N dopant configurations, electron transfer mechanism in Ndoped carbon nanomaterials can be either p-or n-type [58,59] as has been shown both theoretically and experimentally [33,37,56,60]. Pyridinic N can accept electrons (p-type doping) from adjacent C atoms, facilitating the adsorption of water oxidation intermediates (OH À , OOH À ) as the rate-determining steps for OER in alkaline solution [37].…”

Controlling the Incorporation of Phosphorus Functionalities on Carbon Nanofibers: Effects on the Catalytic Performance of Fructose Dehydration

“…The introduction of heteroatoms (N, O, P, and S) has been reported to confer higher hydrophilicity, enhanced metal-support interactions, and additional acidic or basic sites [23][24][25][26][27][28][29][30][31][32]. Obviously, the distribution, the amount, the location, and the specific binding forms of the heteroatoms on the surface strictly depend on the nature of the carbonaceous substrate.…”

Nitrogen-Doped Carbon Nanotube and Graphene Materials for Oxygen Reduction Reactions

“…Furthermore, when the nitrogen with excessive valence is introduced to the graphitic plane, more π-electrons can be obtained [10]. This feature, together with the significant difference in the electronegativity of N and C, leads to many unique properties to graphitic carbons, including increased n-type carrier concentration, high surface energy, reduced work-function, as well as tunable polarization [11][12][13][14]. As schematically illustrated in Figure 2, three common bonding configurations of N atoms in graphene are demonstrated, including pyrrolic, pyridinic, and graphitic (or quaternary) N [15].…”

“…The basic principles and mechanisms behind N doping effectively tailoring the electrical and surface properties of graphitic carbons have been reviewed in some excellent papers [14,17,18]. Here in this review, we place emphasis on the synthesis of NCNTs and NG, and their applications for ORR.…”

“…Graphitic (or quaternary) N refers to the N atoms that replace the carbon atoms in the graphene plane. Such doped N atoms can change the local density state around the Fermi level of N-doped graphitic carbons, which may play a vital role in tailoring the electronic properties and improving their ORR performance [14,16].…”