Facile one-pot synthesis of layered double hydroxides nanosheets with oxygen vacancies grown on carbon nanotubes for efficient oxygen evolution reaction

Abstract

Developing efficient and durable electrocatalysts toward oxygen evolution reaction is vital for energy conversion technologies. Herein, we present a facile one-pot synthesis of defect-rich heterojunction electrocatalysts composed of ultrathin cobalt nickel layered double hydroxides nanosheets with oxygen vacancies (OV), and covering on carbon nanotubes (CNT@NiCo LDH-OV) for the oxygen evolution reaction (OER). The synthesized CNT@NiCo LDH-OV nanosheets possess a thickness ranges from 0.86 to 2.05 nm. The CNT@NiCo LDH-OV displays outstanding OER performance with an overpotential of 257 mV at 10 mA cm−2 and a low Tafel slope for 51 mV dec−1. Moreover, water splitting catalyzed by CNT@NiCo LDH-OV delivers 1.54 V to reach a current density of 10 mA cm−2. Density functional theory (DFT) calculations reveal that oxygen vacancy and CNT can greatly reduce the band gap of the catalyst, making it has excellent conductivity. Simultaneously, the calculated (ΔGO – ΔGOH) for CNT@NiCo LDH-OV is closer to 1.23 eV, which is more efficient for OER. This work develops a simple strategy to fabricate high catalytic activity composite material rich in oxygen vacancies toward OER.