[15p-D505-1~14] 1.4 エネルギー変換・貯蔵・資源・環境

▲ [15p-D505-2] Suppressing the Chlorine Evolution Reaction and Increasing Hydrogen Production During Seawater Electrolysis by Controlling Electrical Current Density

John W. Koster^1,2、Soren A. Tornoe^3,4,5,2、Donald C. Potts^1,2、〇Nobuhiko P Kobayashi^3,4,5,2 (1.Ocean Science Department、2.University of California Santa Cruz、3.Nanostructured Energy Conversion Technology and Research (NECTAR)、4.Electrical and Computer Engineering Department、5.Baskin School of Engineering)

キーワード：electrolysis, seawater, high current density

Producing hydrogen via water electrolysis helps us reduce greenhouse gas emission. In water electrolysis, seawater offers advantages over fresh-water; however, using seawater faces a significant challenge that the Chlorine Evolving Reaction (CER) overwhelms the Oxygen Evolving Reaction (OER), as a result, toxic chlorine evolves at the anode. In this paper, we describe a new approach to suppressing CER and increasing the hydrogen production rate by using electrical current density J_c much larger than that conventionally used. Besides experimental demonstration, our modeling indicates that the reduction in CER is associated with establishing a steep gradient in the electric field between a pair of electrodes. Our study suggests that explicitly elevating J_c creates opportunities for generating hydrogen without producing toxic byproducts–an environmental incentive–while increasing hydrogen production rate–an economic incentive.