Role of Surfactants on Electrocatalytic Activity of Co/Al Layered Double Hydroxides For Hydrogen and Oxygen Generation

Abstract

Layered double hydroxides (LDHs) have recently attracted much attention in the scientific community as a prominent catalyst for oxygen evolution reaction (OER) because they are economical, extremely stable and highly active. Here, we synthesized Co/Al based LDH systems that efficiently perform as bi‐functional electrocatalysts for both HER and OER. Exfoliation of this layered material via anion intercalation into a few layers further enhanced its activity. In this work, we reported the synthesis of Co/Al LDHs via co‐precipitation followed by hydrothermal method and different surfactant functionalized LDHs (with anionic surfactant –SDS, cationic surfactant – CTAB and non‐ionic surfactant – PEG 4000). SDS modified LDH (s LDH) showed notable stability and competent results in hydrogen evolution in addition to oxygen evolution. The exfoliation of s LDH caused enhancement in the high specific surface area about 6.8 times compared to pristine LDH, as evident from BET data. The onset potential for HER as obtained from the polarisation curve for s LDH is ‐0.41 V vs RHE with Tafel slope of 67.4 mV/dec. Similarly, OER onset potential and corresponding Tafel slope are 1.53 V vs RHE at 10 mA/cm2 and 90.2 mV/dec, respectively.