Boron-modified cobalt iron layered double hydroxides for high efficiency seawater oxidation

• Published in: Nano energy 2021-05, Vol.83, p.105838, Article 105838
• Main Authors: Wu, Libo, Yu, Luo, Zhu, Qiancheng, McElhenny, Brian, Zhang, Fanghao, Wu, Chunzheng, Xing, Xinxin, Bao, Jiming, Chen, Shuo, Ren, Zhifeng
• Format: Article
• Language: English
• Subjects: Hierarchical structure; Layered double hydroxide; Oxygen evolution reaction; Partially amorphous catalyst; Seawater electrolysis
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2021.105838

Developing efficient and stable oxygen evolution reaction (OER) catalysts that can work well at high current densities for seawater electrolysis is desirable but remains a significant challenge. Here a novel and scalable strategy is developed to synthesize partially amorphous boron-modified cobalt iron layered double hydroxides (B-Co2Fe LDH). Benefiting from enhanced electronic kinetics and abundant active sites, this hierarchical nanosheet-nanoflake-structured B-Co2Fe LDH catalyst shows superb OER catalytic activity, requiring overpotentials of 205 and 246 mV to drive current densities of 10 and 100 mA cm−2, respectively, in 1 M KOH, along with a small Tafel slope of 39.2 mV dec−1. Its partial amorphousness feature leads to enhanced stability and corrosion resistance, which help the B-Co2Fe LDH catalyst to work well in the critical seawater condition. It requires overpotentials of 310 and 376 mV to drive current densities of 100 and 500 mA cm−2, respectively, in 1 M KOH seawater and can work continuously for 100 h without producing any hypochlorite. This work can enable the development of LDH catalysts for highly selective seawater oxidation using a general approach. [Display omitted] •A novel strategy is developed to synthesize partially amorphous boron-modified cobalt iron layered double hydroxides.•The B-Co2Fe LDH catalyst has a hierarchical nanosheet-nanoflake structure to expose active sites with strong corrosion resistance.•It requires low overpotential and shows excellent stability for OER in alkaline seawater.•In situ Raman and post-OER analysis are applied to analyze the transformation of B-Co2Fe LDH during OER.