Hydrogen production through dry reforming of biogas using a porous electrochemical cell: Effects of a cobalt catalyst in the electrode and mixing of air with biogas

Abstract This paper reports the performance of porous Gd-doped ceria (GDC) electrochemical cells with Co metal in both electrodes (cell No. 1) and with Ni metal in the cathode and Co metal in the anode (cell No. 2) for CO 2 decomposition, CH 4 decomposition, and the dry reforming reaction of a biogas with CO 2 gas (CH 4 + CO 2 → 2H 2 + 2CO) or with O 2 gas in air (3CH 4 + 1.875CO 2 + 1.314O 2 → 6H 2 + 4.875CO + 0.7515O 2 ). GDC cell No. 1 produced H 2 gas at formation rates of 0.055 and 0.33 mL-H 2 /(min m 2 -electrode) per 1 mL-supplied gas/(min m 2 -electrode) at 600 °C and 800 °C, respectively, by the reforming of the biogas with CO 2 gas. Similarly, cell No. 2 produced H 2 gas at formation rates of 0.40 mL-H 2 /(min m 2 ) per 1 mL-supplied gas/(min m 2 ) at 800 °C from a mixture of biogas and CO 2 gas. The dry reforming of a real biogas with CO 2 or O 2 gas at 800 °C proceeded thermodynamically over the Co or Ni metal catalyst in the cathode of the porous GDC cell. Faraday's law controlled the dry reforming rate of the biogas at 600 °C in cell No. 2. This paper also clarifies the influence of carbon deposition, which originates from CH 4 pyrolysis (CH 4 → C + 2H 2 ) and disproportionation of CO gas (2CO → C + CO 2 ), on the cell performance during dry reforming. The dry reforming of a biogas with O 2 molecules from air exhibits high durability because of the oxidation of the deposited carbon by supplied air.