| 摘 要： | The design and fabrication of low-cost,high-efficiency,and stable oxygen-evolving catalysts are essential for promoting the overall efficiency of water electrolysis.In this study,mesoporous Ni1-xFexOy (0 ≤ x ≤ 1,1 ≤ y ≤ 1.5) nanorods were synthesized by the facile thermal decomposition of Ni-Fe-based coordination polymers.These polymers passed their nanorod-like morphology to oxides,which served as active catalysts for oxygen evolution reaction (OER).Increasing the Fe-doping amount to 33 at.％ decreased the particle size and charge-transfer resistance and increased the surface area,resulting in a reduced overpotential (～302 mV) at 10 mA/cm2 and a reduced Tafel slope (～42 mV/dec),which were accompanied by a far improved OER activity compared with those of commercial RuO2 and IrO2 electrocatalysts.At Fe-doping concentrations higher than 33 at.％,the trend of the electrocatalytic parameters started to reverse.The shift in the dopant concentration of Fe was further reflected in the structural transformation from a NiO (＜33 at.％ Fe) rock-salt structure to a biphasic NiO/NiFe2O4 (33 at.％ Fe) heterostructure,a NiFe2O4 (66 at.％ Fe) spinel structure,and eventually to α-Fe2O3 (100 at.％ Fe).The efficient water-oxidation activity is ascribed to the highly mesoporous one-dimensional nanostructure,large surface area,and optimal amounts of the dopant Fe.The merits of abundance in the Earth,scalable synthesis,and highly efficient electrocatalytic activity make mesoporous Ni-Fe binary oxides promising oxygen-evolving catalysts for water splitting.
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