An oxygen reduction reaction electrocatalyst tuned for hydrogen peroxide generation based on a pseudo-graphite doped with graphitic nitrogen

Abstract

The carbon material, GUITAR (pseudo-graphite from the University of Idaho thermolyzed asphalt reaction) can be doped with nitrogen in two prevalent forms. In a previous study N(py)-GUITAR had a predominance of pyridinic and pyrrolic moieties with no graphitic nitrogen. In this study N(g)-GUITAR contains a 9.7 % N atomic abundance, with that fraction consisting of 72.3 % graphitic, 23.7 % pyridinic, and 0 % pyrrolic nitrogen. The two materials allow for the examination of hypotheses regarding the importance of the three different nitrogen moieties in the oxygen reduction reaction (ORR). In the previous investigation, the lack of graphitic nitrogen of N(py)-GUITAR gave a preferred pathway of 4e- ORR to H2O. In this investigation, N(g)-GUITAR gave a 2e- ORR pathway to H2O2. This was elucidated by current efficiency and hydrodynamic voltammetry studies. The high predominance of graphitic nitrogen confirms the hypothesis regarding 2e- vs. 4e- ORR pathways with N-doped carbon materials. N(g)-GUITAR was also evaluated for parasitic pathways for H2O2 production. At -0.95 V vs. Ag/AgCl the combination of current efficiency for H2O2 is 96 % in 0.05 M Na2SO4 with a production rate of 4.9 mg cm-2 h-1, is the highest reported in the literature. This indicates possibilities for water purification and treatment applications, which require 10 to 250 mg L-1, depending on conditions.

Hydrogen peroxide electrosynthesis using commercial carbon blacks as catalysts: the influence of surface properties and adsorption performance

“…31 Hamal et al mixed N-doped Ketjen black with Nafion solution and coated it on a rotating ring disk electrode, and the cumulative H 2 O 2 concentration reached 106 mg L −1 . 32 Lei et al found that 194 mg L −1 of H 2 O 2 was produced at 60 min in a trickle bed electrochemical reactor using carbon black VXC 72-PTFE coated graphite sheet as cathode, and the current efficiency reached 63.7%. 33 Liao et al prepared a three-layer air diffusion cathode modified with carbon black BP-2000 and polytetrafluoroethylene (PTFE), which had abundant mesopores and micropores, high hydrophobicity and numerous C O groups, and the H 2 O 2 production reached 119 mg L −1 and current efficiency reached 90.6%.…”

“…Hamal et al . mixed N‐doped Ketjen black with Nafion solution and coated it on a rotating ring disk electrode, and the cumulative H 2 O 2 concentration reached 106 mg L −1 32 . Lei et al .…”

Superhydrophilicity and Antifouling Behavior in Electrochemically Oxidized Nanocrystalline Pseudographite

“…GUITAR (pseudoGraphite from the University of Idaho Thermalized Asphalt Reaction) is a thin film electrode material best classified as a nanocrystalline graphite-like hydrogenated amorphous carbon. , X-ray photoelectron spectroscopy (XPS), X-ray diffraction, and elemental analysis studies indicate a composition of 85/15 mole ratio of sp 2 /sp 3 carbon, an interlayer d spacing of 0.350 nm (vs 334 nm for graphite), and a crystallite grain size of 1.5 nm. − The Raman I (D)/ I (G) ratio of 1.16 indicates a high density of structural defects . Defects in graphite-like carbons commonly include grain boundaries, vacancies, interplanar bonds, and Stone–Wales and step defects .…”