Hu Songhan, Wang Kai, Xu Xinxin, Wang Qiang
Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819, China.
School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China.
Dalton Trans. 2024 Nov 12;53(44):17819-17828. doi: 10.1039/d4dt01625d.
Although Ni-based materials are widely used as electrocatalysts, it remains necessary to further explore their selectivity towards the four- or two-electron oxygen reduction reaction (ORR). Herein, it is proposed to synthesize NiO@NCNTs (NCNTs = N-doped carbon nanotubes) using a metal-organic framework (MOF), [Ni(BZIDA)(HO)] (NiMOF, BZIDA = benzimidazole-5,6-dicarboxylic acid), as a precursor after calcination with dicyandiamide (DCDA). Regarding NiO@NCNTs, small NiO particles are distributed in NCNTs derived from DCDA homogeneously. NiO@NCNTs act as a typical two-electron electrocatalyst. The HO production rate of NiO@NCNTs reaches 0.5 mol g h at 0.46 V ( RHE). After the doping of Co in NiMOF, Co/NiO@NCNTs were synthesized using a similar method, with the four-electron character shown in ORR. A Zn-air battery was assembled by applying Co/NiO@NCNTs as the cathode material. When discharge occurs at 5 and 10 mA cm, its specific capacitance reaches 779.3 and 832.2 mA h g with an energy density of 928.6 and 948.5 W h kg, respectively. Theoretical calculations suggest a variation in ORR selectivity between NiO@NCNTs and Co/NiO@NCNTs, which results from their different interactions with OOH*. This study demonstrates the effect of the structure on ORR selectivity for Ni-based electrocatalysts.
尽管镍基材料被广泛用作电催化剂，但仍有必要进一步探索它们对四电子或两电子氧还原反应（ORR）的选择性。在此，有人提出使用金属有机框架（MOF）[Ni(BZIDA)(HO)]（NiMOF，BZIDA = 苯并咪唑-5,6-二羧酸）作为前驱体，在与双氰胺（DCDA）煅烧后合成NiO@NCNTs（NCNTs = N掺杂碳纳米管）。对于NiO@NCNTs，小的NiO颗粒均匀分布在由DCDA衍生而来的NCNTs中。NiO@NCNTs作为一种典型的两电子电催化剂。在0.46 V（相对于可逆氢电极）时，NiO@NCNTs的过氧化氢生成速率达到0.5 mol g h。在NiMOF中掺杂Co后，采用类似方法合成了Co/NiO@NCNTs，其在ORR中表现出四电子特性。通过将Co/NiO@NCNTs用作阴极材料组装了锌空气电池。当在5和10 mA cm下放电时，其比电容分别达到779.3和832.2 mA h g，能量密度分别为928.6和948.5 W h kg。理论计算表明，NiO@NCNTs和Co/NiO@NCNTs之间的ORR选择性存在差异，这是由于它们与OOH*的相互作用不同所致。这项研究证明了结构对镍基电催化剂ORR选择性的影响。
