Nitrogen-doped graphene microtubes with opened inner voids: Highly efficient metal-free electrocatalysts for alkaline hydrogen evolution reaction

Abstract

A facile method was developed to fabricate nitrogen-doped graphene microtubes (N-GMT) with ultra-thin walls of 1-4 nm and large inner voids of 1-2 μm. The successful introduction of nitrogen dopants afforded N-GMT more active sites for significantly enhanced hydrogen evolution reaction (HER) activity, achieving a current density of 10 mA·cm -2 at overpotentials of 0.464 and 0.426 V vs. RHE in 0.1 and 6 M KOH solution, respectively. This HER performance surpassed that of the best metal-free catalyst reported in basic solution, further illustrating the great potential of N-GMT as an efficient HER catalyst for real applications in water splitting and chlor-alkali processes.

Optimized Nickel-Cobalt and Nickel-Iron Oxide Catalysts for the Hydrogen Evolution Reaction in Alkaline Water Electrolysis

“…If Reaction 11 is the rds the Tafel slope is trivially equal to b = −RT /αF (or b = − ln 10RT /αF = −2.303RT /αF for a base-10 logarithm) and the reaction order with respect to OH − , OH − , is OH − = 0 at all (negative) values of E . 41,46 With α = 0.5 this would give a Tafel slope of 118 mV at room 298 K. The current is, according to this mechanism and and rds, independent of pH.…”

“…13, involves chemical desorption. 41,46 The rate constants in Eqs. 11 and 12 are potential dependent and take the form…”

Recent Studies on Bifunctional Perovskite Electrocatalysts in Oxygen Evolution, Oxygen Reduction, and Hydrogen Evolution Reactions under Alkaline Electrolyte

“…However, the stability of the material is not addressed. [63] The category (iii) materials are earth-abundant elements and intensively studied. Particularly POs based materials have been the prime focus due to the virtue of structural and compositional flexibility for HER activity.…”

Quantum Effects Allow the Construction of Two‐Dimensional Co3O4‐Embedded Nitrogen‐Doped Porous Carbon Nanosheet Arrays from Bimetallic MOFs as Bifunctional Oxygen Electrocatalysts

“…[14][15][16] Among 2D materials, carbon-based 2D materials display superior electrical conductivity,h igh carrierm obility,a nd strong structures tability,a nd have great potentials as electrocatalysts. [17][18][19][20][21][22] For example, phosphorus-doped ordered mesoporous carbons, [23] polyaniline-derived N-and O-doped mesoporous carbons, [24] and metal-free electrocatalysts assembled from carbon nanotubes andg raphene [25] have been reported to promote ORR activities. Meanwhile, nitrogen-doped graphene frameworks, [26] nitrogen and oxygen dual-doped carbon hydrogel films, [27] and Fe 3 O 4 -decorated Co 9 S 8 nanoparticles in situ grown on reduced graphene oxide [28] have also been used to improveO ER performances.…”