Reduction to CO and HCOOH

Similarly, the kinetics and mechanism of C02 reduction to formic acid has been studied by Vassiliev et al. over a wide range of metal electrodes with high or moderate hydrogen overpotentials (e.g., Cu, Sn, In, Sb, Bi, In, Zn, Pb) [48]. The best 

Reduction at Pt electrodes and Pt group metals of Ir and Rh in aqueous solution has led to CO production [56-58]. Intermediate-adsorbed species have been studied by Giner in acidic solution at Pt [59], while similar spectroscopic experiments at Pt electrodes have also been conducted by Nicolic et al. [60], It appears that the reduction of C02 occurs by reaction with adsorbed hydrogen atoms to produce both linear and bridge-bonded CO. The reduced C02 species at Pt electrodes, however, caused a rapid poisoning of the electrodes to further C02 reduction [61]. 

---

Electrochemical reduction to CO and HCOOH over Fe or Ni catalysts supported on activated carbon fibres131... 

---