Cation and anion modulation activates lattice oxygen for enhanced oxygen evolution

Abstract

Oxygen evolution reaction (OER) is often regarded as a crucial bottleneck in the field of renewable energy storage and conversion. To further accelerate the sluggish kinetics of OER, a cation and anion modulation strategy is reported here, which has been proven to be effective in preparing highly active electrocatalyst. For example, the cobalt, sulfur, and phosphorus modulated nickel hydroxide (denoted as NiCoPSOH) only needs an overpotential of 232 mV to reach a current density of 20 mA cm^–2, demonstrating excellent OER performances. The cation and anion modulation facilitates the generation of high-valent Ni species, which would activate the lattice oxygen and switch the OER reaction pathway from conventional adsorbate evolution mechanism to lattice oxygen mechanism (LOM), as evidenced by the results of electrochemical measurements, Raman spectroscopy and differential electrochemical mass spectrometry. The LOM pathway of NiCoPSOH is further verified by the theoretical calculations, including the upshift of O 2p band center, the weakened Ni–O bond and the lowest energy barrier of rate-limiting step. Thus, the anion and cation modulated catalyst NiCoPSOH could effectively accelerate the sluggish OER kinetics. Our work provides a new insight into the cation and anion modulation, and broadens the possibility for the rational design of highly active electrocatalysts.