Electrochemical investigation of thin films of cobalt phthalocyanine and cobalt-4,4′,4″,4′″-tetracarboxyphthalocyanine and the reduction of carbon monoxide, formic acid and formaldehyde mediated by the Co(I) complexes

• Published in: Electrochimica acta 1986-06, Vol.31 (6), p.657-663
• Main Authors: Kusuda, Kousuke, Ishihara, Ryuichi, Yamaguchi, Hidemasa, Izumi, Ikuichiro
• Format: Article
• Language: English
• Subjects: Chemistry; Electrochemistry; Exact sciences and technology; General and physical chemistry; Kinetics and mechanism of reactions
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/0013-4686(86)87032-3

Cyclic voltammetric investigations of thin films of cobalt(II) phthalocyanine( 1) and cobalt(II)-4,4′,4″,4′″-tetracarboxyphthalocyanine( 2) in N 2-saturated 1 M sulfuric acid solution revealed that both compounds gave irreversibly semi-stable reduction products, R- 1 and R- 2, at around −0.70 V vs sce. Reductions of CO, formaldehyde and formic acid by R- 1 or R- 2 were conducted with vibrating carbon fiber electrode ( cfe) modified with 1 or 2. Products of the reduction of CO were mainly formaldehyde and a small amount of methanol. In the reduction of CO, R- 2/ cfe was ca 17 times more efficient than R- 1/ cfe, which was however more efficient than the former in the reduction of formaldehyde. Reduction of formic acid by R- 2 and R- 1 seemed to be difficult under the conditions. Reduction of CO on the 2/ cfe polarized with rectangular potential pulse (−0.659 V for 5s and 0.20 V vs Ag/AgCl for 85s) produced nearly quantitative yield of formaldehyde and small amount of methanol.