Fe induced nanostructure reorganization and electronic structure modulation over CoNi (oxy)hydroxide nanorod arrays for boosting oxygen evolution reaction

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2021-01, Vol.403, p.126304, Article 126304
• Main Authors: Huang, Chuqiang, Zhong, Yuhong, Chen, Junxuan, Li, Jian, Zhang, Wei, Zhou, Jianqing, Zhang, Yuanlu, Yu, Luo, Yu, Ying
• Format: Article
• Language: English
• Subjects: Electrolyzer; Fe-incorporated CoNi (oxy)hydroxide; Nanosheet-assembled nanorod; Oxygen evolution reaction; Self-template
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2020.126304

[Display omitted] •A strategy to fabricate Fe-containing hierarchical structured catalysts was reported.•Introducing Fe induces structure reorganization and electronic structure modulation.•Fe-CoNi-OH exhibits enhanced activity and stability for oxygen evolution reaction.•Fe-CoNi-OH//CoP deliver 10 and 100 mA cm−2 at 1.506 and 1.623 V, respectively. Ni- and Co-based (oxy)hydroxides are promising candidates for oxygen evolution reaction (OER), but their limited specific surface area and poor intrinsic conductivity lead to unsatisfied OER activity. Herein, a unique and universal self-template strategy has been developed to fabricate Fe-incorporated CoNi (oxy)hydroxide (Fe-CoNi-OH) nanosheet-assembled nanorod arrays toward OER. The reorganized nanosheet-assembled nanorod hierarchical structure induced by Fe incorporation exposes more active sites and facilitates mass transfer. Furthermore, Fe incorporation modifies the electron structure of CoNi (oxy)hydroxide (CoNi-OH), and enhances its electronic conductivity for rapid electron transport, thus intrinsically enhancing the OER activity. Consequently, the Fe-CoNi-OH possesses excellent OER activity with low overpotentials of 210, 248, 304, and 349 mV to achieve current densities of 10, 100, 500, and 1000 mA cm−2, respectively, along with a very small Tafel slope of 28.0 mV dec−1, which are superior to the CoNi-OH and benchmark RuO2. By paring the Fe-CoNi-OH anode with a CoP cathode, an outstanding alkaline electrolyzer has been constructed, which only requires cell voltages of 1.506 and 1.623 V to deliver current densities of 10 and 100 mA cm−2, respectively, and can stably work for 100 h. This work provides a universal strategy to synthesize Fe-containing hierarchical nanostructured catalysts for energy conversion application.