A Robust One‐Compartment Fuel Cell with a Polynuclear Cyanide Complex as a Cathode for Utilizing H2O2 as a Sustainable Fuel at Ambient Conditions. Issue 35 (19th July 2013)

• Record Type: Journal Article
• Authors: Yamada, Yusuke; Yoneda, Masaki; Fukuzumi, Shunichi
• Is Part Of: Chemistry. Volume 19:Issue 35(2013)
• Page Start: 11733
• Page End: 11741
• Publication Date: 2013-07-19
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201300783
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A robust one‐compartment H<sub>2</sub>O<sub>2</sub> fuel cell, which operates without membranes at room temperature, has been constructed by using a series of polynuclear cyanide complexes that contain Fe, Co, Mn, and Cr as cathodes, in sharp contrast to conventional H<sub>2</sub> and MeOH fuel cells, which require membranes and high temperatures. A high open‐circuit potential of 0.68 V was achieved by using Fe<sub>3</sub>[{Co<sup>III</sup>(CN)<sub>6</sub>}<sub>2</sub>] on a carbon cloth as the cathode and a Ni mesh as the anode of a H<sub>2</sub>O<sub>2</sub> fuel cell by using an aqueous solution of H<sub>2</sub>O<sub>2</sub> (0.30 <sc>M</sc>, pH 3) with a maximum power density of 0.45 mW cm<sup>−2</sup>. The open‐circuit potential and maximum power density of the H<sub>2</sub>O<sub>2</sub> fuel cell were further increased to 0.78 V and 1.2 mW cm<sup>−2</sup>, respectively, by operation under these conditions at pH 1. No catalytic activity of Co<sub>3</sub>[{Co<sup>III</sup>(CN)<sub>6</sub>}<sub>2</sub>] and Co<sub>3</sub>[{Fe<sup>III</sup>(CN)<sub>6</sub>}<sub>2</sub>] towards H<sub>2</sub>O<sub>2</sub> reduction suggests that the N‐bound Fe ions are active species for H<sub>2</sub>O<sub>2</sub> reduction. H<sub>2</sub>O<sub>2</sub> fuel cells that used Fe<sub>3</sub>[{Mn<sup>III</sup>(CN)<sub>6</sub>}<sub>2</sub>] and Fe<sub>3</sub>[{Cr<sup>III</sup>(CN)<sub>6</sub>}<sub>2</sub>] as the cathode exhibited lower performance compared with that using Fe<sub>3</sub>[{Co<sup>III</sup>(CN)<sub>6</sub>}<sub>2</sub>] as a cathode, because ligand isomerization of Fe<sub>3</sub>[{M<sup>III</sup>(CN)<sub>6</sub>}<sub>2</sub>] into (FeM<sub>2</sub>)[{Fe<sup>II</sup>(CN)<sub>6</sub>}<sub>2</sub>] (M=Cr or Mn) occurred to form inactive FeC bonds under ambient conditions, whereas no ligand isomerization of Fe<sub>3</sub>[{Co<sup>III</sup>(CN)<sub>6</sub>}<sub>2</sub>] occurred under the same reaction conditions. The importance of stable Fe<sup>2+</sup>N bonds was further indicated by the high performance of the H<sub>2</sub>O<sub>2</sub> fuel cells with Fe<sub>3</sub>[{Ir<sup>III</sup>(CN)<sub>6</sub>}<sub>2</sub>] and Fe<sub>3</sub>[{Rh<sup>III</sup>(CN)<sub>6</sub>}<sub>2</sub>], which also contained stable Fe<sup>2+</sup>N bonds. The stable Fe<sup>2+</sup>N bonds in Fe<sub>3</sub>[{Co<sup>III</sup>(CN)<sub>6</sub>}<sub>2</sub>], which lead to high activity for the electrocatalytic reduction of H<sub>2</sub>O<sub>2</sub>, allow Fe<sub>3</sub>[{Co<sup>III</sup>(CN)<sub>6</sub>}<sub>2</sub>] to act as a superior cathode in one‐compartment H<sub>2</sub>O<sub>2</sub> fuel cells.</p> </abstract>