[15p-D505-1~14] 1.4 Energy conversion, storage, resources and environment

▲ [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)

Keywords: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.