Interlayer Expansion of Layered Cobalt Hydroxide Nanobelts to Highly Improve Oxygen Evolution Electrocatalysis

The water oxidation reaction is known to be energy-inefficient and generally considered as a major bottleneck for water splitting. Exploring electrocatalysts with high-efficiency and at low cost is vital to widespread utilization of this technology, but is still a big challenge. Here we report an effective strategy based on an expanding interlayer of layered structures to realize a great enhancement of the catalytic performance of the oxygen evolution reaction from water splitting. Well-defined nanobelts of layer-structured cobalt benzoate hydroxide (Co(OH)(C₆H₅COO)·H₂O) are successfully prepared in terms of a simple hydrothermal process. Intercalation with benzoate ions induces the interlayer expansion of the cobalt hydroxide, which is useful for the accommodation of more electrolyte ions and favorable for their diffusion and transport. The as-prepared Co(OH)(C₆H₅COO)·H₂O nanobelts need significantly smaller overpotential (∼0.36 V) to reach 10 mA·cm^-2 of current density compared with their Co(OH)₂ (∼0.44 V) and Co₃O₄ (∼0.387 V) counterparts, and even favorably compare with most of the layered hydroxide-based electrocatalysts. Moreover, the Co(OH)(C₆H₅COO)·H₂O nanobelts retain a much higher stability than the RuO₂ reference in alkaline solution. This approach would be utilized to design and develop high-performance layered hydroxide-based electrocatalysts.