A Soluble Cu(II) Complex of Sodium 1, 4-Dihydroxy-9, 10-Anthraquinone-2-Sulphonate Electrocatalyzes Water Oxidation with a Large Turn over Frequency

摘要

The electro- and photo-catalytic generations of H_2 and O_2 from water have been explored as inexpensive ways of producing a carbon-neutral fuel. Though various metals have-shown significant catalytic activity, however, efforts are still on to find out cheap, efficient and robust water soluble catalysts in this regards. In the present study we reported a soluble and inexpensive copper(II) complex of sodium 1, 4-dihydroxy-9, 10-anthraquinone-2-sulphonate (CuA_2) as an electro-catalyst for water oxidation. Cyclic voltammetry measurements of CuA_2 solutions at pH range 11.4 - 12.5 showed a large and irreversible current in the potential range between +1.3 and +1.7 V indicating a catalytic production of O_2. The study showed that the turnover frequency of this process is 2927 s~(-1) at pH 11.90 which is the highest in magnitude in comparison to that of other copper(II) complexes reported earlier. The over potential was observed as ～972 mV vs. standard hydrogen electrode.