Open AccessCarbon Electrocatalysts For Hydrazine Oxidation: Self-Templating Design Of Hierarchical Porosity Using Barium Carbonate Nanoparticles
Author(s) -
Eliyahu M. Farber,
Kasinath Ojha,
Tomer Y. Burshtein,
David Eisenberg
Publication year - 2020
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/ab615d
Subject(s) - electrocatalyst , hydrazine (antidepressant) , materials science , chemical engineering , porosity , raman spectroscopy , nanoparticle , x ray photoelectron spectroscopy , cyclic voltammetry , inorganic chemistry , catalysis , carbon fibers , barium , agglomerate , electrochemistry , nanotechnology , chemistry , composite material , organic chemistry , metallurgy , electrode , physics , optics , chromatography , engineering , composite number
To enable hydrazine as a clean fuel in next-generation fuel cells, electrocatalysts are sought for the hydrazine oxidation reaction (HzOR). Nanostructure of the electrocatalyst plays a crucial role in electrocatalytic activity, yet rational design of surface area, hierarchical porosity, doping and conductivity is highly challenging. We now report a systematic investigation into the structural evolution of excellent HzOR electrocatalysts. This hierarchically porous, N-doped carbon was derived by the tunable self-templating strategy from a simple, well-defined metal-organic coordination polymer (barium nitrilotriacetate). To understand the evolution of structure and its effect on electrocatalytic activity, we combined XRD, HRSEM, TEM, XPS, Raman spectroscopy, elemental analysis, N 2 porosimetry, and voltammetry. The sizes, shapes and distributions of BaCO 3 nanoparticles and agglomerates were found to be temperature-dependent, and strongly correlated to the hierarchical porosity in the ultimate carbons. The final carbons display a multi-modal porosity, high surface areas (up to 1030 m 2 g −1 ), high nitrogen content (up to 2.7 at%), and excellent graphitization. The best catalysts, prepared at 700 °C and 800 °C, begin electro-oxidizing hydrazine at onset potentials as low as 0.34 V vs RHE at pH 14—within a few 10 s mVs of the best metal-free HzOR electrocatalysts ever reported.