Exploring highly efficient and non-noble-metal-based electrocatalysts for oxygen evolution reaction (OER) is of great importance not only for water splitting but also for rechargeable metal-air batteries and fuel cells. Herein, we describe a simple strategy to prepare hierarchical Ni@Mn-doped NiO hybrids using flower-like Ni-Mn layered double hydroxides (NiMn-LDHs) as a precursor. After calcination at 400 ℃ for an hour under N2 atmosphere, the flower-like NiMn-LDHs transform to porous microspheres consisting of nanoparticles, in which Ni cores are encapsulated by Mn-doped NiO shells (denoted as Ni@Mn-NiO-400). Benefiting to this unique porous, core-shell structures and element doping, the as-prepared Ni@Mn-NiO-400 hybrid shows a low overpotential of 178 mV at the current density of 10 mA/cm2 and Tafel slope of 52.7 mV/dec in 1 mol/L KOH solution. More significantly, the Ni@Mn-NiO-400 hybrid also demonstrates superior stability of 98.6% after 50 h continuously testing, much higher than pristine NiMn-LDHs and commercial IrO2 catalyst. In addition, theoretical simulation shows that Ni core and Mn doping greatly affect the electronic states and electronic structure of NiO. As a result, Ni@Mn-doped NiO hybrid possesses an optimal adsorption activity towards oxygen species than NiO and undoped Ni@NiO hybrid. Considering the compositional and structural flexibility of LDHs, this work may offer a simple method to prepare other non-noble metal-based electrocatalysts for OER.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |