Hierarchical CoNiO₂ Microflowers Assembled by Mesoporous Nanosheets as Efficient Electrocatalysts for Hydrogen...

In order to alleviate the energy crisis and propel a low-carbon economy, hydrogen (H₂) plays an important role as a renewable cleaning resource. To break the hydrogen evolution reaction (HER) bottleneck, we need high-efficiency electrocatalysts. Based on the synergistic effect between bimetallic oxides, hierarchical mesoporous CoNiO₂ nanosheets can be fabricated. Combining physical representations with electrochemical measurements, the resultant CoNiO₂ catalysts present the hierarchical microflowers morphology assembled by mesoporous nanosheets. The ultrathin two-dimensional nanosheets and porous surface characteristics provide the vast channels for electrolyte injection, thus endowing CoNiO₂ the outstanding HER performance. The excellent performance with a fewer onset potential of 94 mV, a smaller overpotential at 10 mA cm^-2, a lower Tafel slope of 109 mV dec^-1 and better stability after 1000 cycles makes CoNiO₂ better than that of metallic Co and metallic Ni.