Layered double hydroxides with atomic-scale defects for superior electrocatalysis
selective defect engineering, atomic vacancy, layered double hydroxide, electrocatalysis, oxygen evolution reaction
ABSTRACT Atomic composition tuning and defect engineering are effective strategies to enhance the catalytic performance of multicomponent catalysts by improving the synergetic effect; however, it remains challenging to dramatically tune the active sites on multicomponent materials through simultaneous defect engineering at the atomic scale because of the similarities of the local environment. Herein, using the oxygen evolution reaction (OER) as a probe reaction, we deliberately introduced base-soluble Zn(II) or Al(III) sites into NiFe layered double hydroxides (LDHs), which are one of the best OER catalysts. Then, the Zn(II) or Al(III) sites were selectively etched to create atomic M(II)/M(III) defects, which dramatically enhanced the OER activity. At a current density of 20 mA·cm−2, only 200 mV overpotential was required to generate M(II) defect-rich NiFe LDHs, which is the best NiFe-based OER catalyst reported to date. Density functional theory (DFT) calculations revealed that the creation of dangling Ni–Fe sites (i.e., unsaturated coordinated Ni–Fe sites) by defect engineering of a Ni–O–Fe site at the atomic scale efficiently lowers the Gibbs free energy of the oxygen evolution process. This defect engineering strategy provides new insights into catalysts at the atomic scale and should be beneficial for the design of a variety of catalysts.
Tsinghua University Press
Qixian Xie,Zhao Cai,Pengsong Li,Daojin Zhou,Yongmin Bi,Xuya Xiong,Enyuan Hu,Yaping Li,Yun Kuang,Xiaoming Sun, Layered double hydroxides with atomic-scale defects for superior electrocatalysis. NanoRes.2018, 11(9): 4524–4534