The oxygen evolution reaction has
become the bottleneck of electrochemical
water splitting for its sluggish kinetics. Developing high-efficiency
and low-cost non-noble-metal oxide electrocatalysts is crucial but
challenging for industrial application. Herein, superhydrophilic/superaerophobic
hierarchical nanoneedle/microflower arrays of Ce-substituted Co3O4 (Ce
x
Co3–x
O4) in situ grown on the nickel foam are
successfully constructed. The hierarchical architecture and superhydrophilic/superaerophobic
interface can be facilely regulated by controlling the introduction
of Ce into Co3O4. The unique feature of hierarchical
architecture and superhydrophilic/superaerophobic interface is in
favor of electrolyte penetration and bubbles release. In addition,
the presence of oxygen vacancy and Ce endows the catalyst with enhanced
intrinsic activity. Benefiting from these advantages, the optimized
Ce0.12Co2.88O4 catalyst shows a superior
electrocatalytic performance for the oxygen evolution reaction (OER)
with an overpotential of 282 mV at 20 mA cm–2, and
a Tafel slope of 81.4 mV dec–1. The turnover frequency
of 0.0279 s–1 for Ce0.12Co2.88O4 is 9.3 times larger than that for Co3O4 at an overpotential of 350 mV. Moreover, the optimized Ce0.12Co2.88O4 catalyst shows a robust
long-term stability in alkaline media.