Nitrogen-doped carbon nanomaterials as non-metal electrocatalysts for water oxidation

Abstract

Efficient and low-cost electrocatalysts for the oxygen evolution reaction are essential components of renewable energy technologies, such as solar fuel synthesis and providing a hydrogen source for powering fuel cells. Here we report that the nitrogen-doped carbon materials function as the efficient oxygen evolution electrocatalysts. In alkaline media, the material generated a current density of 10 mA cm À 2 at the overpotential of 0.38 V, values that are comparable to those of iridium and cobalt oxide catalysts and are the best among the non-metal oxygen evolution electrocatalyst. The electrochemical and physical studies indicate that the high oxygen evolution activity of the nitrogen/carbon materials is from the pyridinic-nitrogen-or/and quaternary-nitrogen-related active sites. Our findings suggest that the non-metal catalysts will be a potential alternative to the use of transition metal-based oxygen evolution catalysts.

Origin and Perspectives of the Photochemical Activity of Nanoporous Carbons

“…Further analysis of the anodes after illumination corroborated the photo‐electrocorrosion due to the occurrence of redox reactions involving the O‐, N‐, and S‐surface groups of the carbon matrix 70, 139, 143. Several complementary techniques confirmed the reduction of quaternary nitrogen, carboxylic acid groups, sulfonic acids, and sulfones, due to the side reaction of the photogenerated electrons with the carbon surface.…”

“…In the field of water splitting, despite carbon nanomaterials gained popularity in electrocatalysis as low cost and metal‐fee materials, their use as photoelectrodes has not been much explored, with all the studies focused on their role as photoanodes for the OER,139, 140, 141, 142 while nonporous carbon nanomaterials have been investigated for the HER.…”

Anchoring CoFe2O4 Nanoparticles on N‐Doped Carbon Nanofibers for High‐Performance Oxygen Evolution Reaction

“…To address these issues, one of the effective strategies is to hybridize the AB 2 O 4 nanocatalysts with conductive carbon‐based substrates (i.e., activated carbon, carbon nanotubes/nanofibers, and graphene) in order to improve their conductivity and electrochemical stability, as well as facilitate charge transfer of the integrated system, thus giving rise to an enhanced OER performance 18, 19, 20, 21, 22, 23, 24. Moreover, heteroatom‐doping, such as N‐doping, into nanocarbon could effectively improve the electronic conductivity and modulate the electronic structures of the carbon matrix, which is beneficial to boost the OER activity 25, 26. Among various carbon‐based supports, 1D carbon nanofibers have been attracting enormous attention in electrochemical energy‐related fields due to their large exposed surfaces, shortened distance for mass diffusion and direct efficient pathway for electron transport 27, 28, 29.…”

Paper‐Based N‐Doped Carbon Films for Enhanced Oxygen Evolution Electrocatalysis

“…Because of its sluggish kinetics, OER usually proceeds on various electrocatalysts such as noble metal (irrinium oxide IrO 2 and ruthinium oxide RuO 2 ),14, 15 nonprecious metal (manganese dioxide MnO 2 ,16 cobalt oxide Co 3 O 4 ,17 and perovskite Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3–δ ),3 and nonmetal materials (nitrogen‐doped graphite18 and carbon nanotube11). Commonly, two strategies have been utilized to enhance the performances of these electrocatalysts: to modify their chemical compositions by element doping18/hybridization,11 or tailor their micro/nanostructures, for example, by assembly into 1D nanowires,10 2D sheets,9 or 3D hollow spheres 8. Besides these strategies, it would be also useful to tailor the interfacial chemistry of electrode supports for elevated catalytic efficiency.…”

“…Thus far, there are only a few illustrations of nonmetallic OER electrocatalysts, for example, N(5)‐ethylflavinium,28 N‐doped graphite,18 and graphene‐CNTs hybrid 22. However, most of their activities are still inferior to IrO 2 .…”