Water Electrolysis Using Thin Pt and RuO(x) Catalysts Deposited by a Flame-Annealing Method on Pencil-Lead Graphite-Rod Electrodes

[Image: see text] An inexpensive, simple, and high-activity catalyst preparation method has been introduced in this work. Pt and RuO(x) catalysts were fabricated by soaking inexpensive graphite electrodes (pencil-lead graphite rod: PGR) in catalyst precursor solutions and using a simple flame-annealing method, which results in lower amount of Pt and RuO(x) catalyst layers. From X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure analysis, it has been found that platinum and ruthenium were deposited as zero-valence metal (Pt) and oxide (RuO(x)), respectively. Catalytic activities of Pt/PGR and RuO(x)/PGR for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were evaluated using neutral 1 M Na(2)SO(4) aqueous electrolyte, respectively. Although HER and OER currents using PGR without catalysts were −16 mA cm(–2) (at −1.5 V vs Ag/AgCl) and +20 mA cm(–2) (at +2.0 V vs Ag/AgCl), they were improved to −110 and +80 mA cm(–2) with catalysts (Pt and RuO(x)), respectively. Such an inexpensive and rapid catalyst electrode preparation method on PGR using flame-annealing is a very significant method in the initial catalyst activity evaluation requiring a large amount of trial and error.