Different Interlayer Anions Controlled Zinc Cobalt Layered Double Hydroxide Nanosheets for Ethanol Electrocatalytic Oxidation

Abstract

Layered double hydroxides (LDHs) have been known as highly desired anode materials in the alkaline electrolyte. With regard to non-noble metal electrocatalysts, the interlayer spacing of LDHs has important influences on the electrocatalytic activity toward ethanol oxidation. Herein, ZnCo-LDHs with different interlayer spacing controlled by different interlayer anions (NO3–, Cl–, and CH3COO–) are used as effective non-noble metal electrocatalysts for the ethanol oxidation reaction (EOR). The interlayer spacing of three non-noble metal electrocatalysts follows the order: ZnCo-LDH-CH3COO– (0.763 nm) > ZnCo-LDH-Cl– (0.733 nm) > ZnCo-LDH-NO3– (0.719 nm). ZnCo-LDH-CH3COO– exhibits the highest mass activity (345.4 mA mg–1) for the EOR, which is 1.22 and 1.37 times higher than that of ZnCo-LDH-Cl– (283.8 mA mg–1) and ZnCo-LDH-NO3– (252.8 mA mg–1), respectively, attributed to the enlarged interlayer space. This work proposes a potential mechanism of the catalytic process toward the EOR, which may provide a new idea to design non-noble metal electrocatalysts with high catalytic activity in direct ethanol fuel cells (DEFCs).