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Opening of Bottleneck Pores for the Improvement of Nitrogen Doped Carbon Electrocatalysts
Author(s) -
Pampel Jonas,
Fellinger TimPatrick
Publication year - 2016
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201502389
Subject(s) - materials science , mesoporous material , specific surface area , nitrogen , chemical engineering , carbon fibers , porosity , catalysis , leaching (pedology) , eutectic system , doping , reversible hydrogen electrode , inorganic chemistry , electrode , electrolyte , organic chemistry , composite material , working electrode , chemistry , microstructure , optoelectronics , composite number , engineering , environmental science , soil science , soil water
A facile synthesis strategy to control the porosity of ionothermal nitrogen doped carbons is demonstrated. Adenine is used as cheap and biomass based precursor and a mixture of NaCl/ZnCl 2 as combined solvent‐porogen. Variation of the ratio between the two salt influences the pore structure over a wide range. The eutectic mixture leads to micro‐ and mesoporous material with high total pore volume (TPV) of 3.0 cm 3 g −1 and very high surface area of 2900 m 2 g −1 essentially rendering the product an “all‐surface‐area” nitrogen doped carbon. Increasing NaCl contents cause a continuous increase of the mesopore size and the formation of additional macropores resulting in a very high maximal TPV of 5.2 cm 3 g −1 , showing 2540 m 2 g −1 specific surface area using 60 mol% NaCl. Interestingly, the electrocatalytic activity of the samples toward oxygen reduction is strongly affected by the detailed pore structure. The different—however, chemically equivalent—catalysts vary up to 70 mV in their half wave potentials ( E 1/2 ).The sample with optimized pore system shows a high selectivity toward the favored four electron process and an outstanding E 1/2 of ≈880 mV versus reversible hydrogen electrode (RHE), which is one of the best values reported for nitrogen doped carbons so far.