Spinel cobalt–manganese oxide supported on non-oxidized carbon nanotubes as a highly efficient oxygen reduction/evolution electrocatalyst,Inorganic Chemistry Frontiers

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Spinel cobalt–manganese oxide supported on non-oxidized carbon nanotubes as a highly efficient oxygen reduction/evolution electrocatalyst
Inorganic Chemistry Frontiers ( IF 6.1 ) Pub Date : 2017-08-16 00:00:00 , DOI: 10.1039/c7qi00367f
Ting Ma _{1,

2,

3,

4,

5} , Chun Li _{1,

2,

3,

4,

5} , Xiang Chen _{1,

2,

3,

4,

5} , Fangyi Cheng _{1,

2,

3,

4,

5} , Jun Chen _{1,

2,

3,

4,

5}

Affiliation

We report an in situ preparation of ultrasmall Co–Mn–O spinel nanoparticles (4.4 nm) supported on non-oxidized carbon nanotubes (denoted as CMO@CNTs) as a bifunctional catalyst for oxygen reduction and evolution reactions (ORR/OER). The preparation process involves the oxidization of divalent metal ions under alkaline conditions and the decomposition of nitrates in aqueous solution containing dispersed non-oxidized CNTs. The synthesized CMO nanoparticles strongly couple with the non-oxidized CNTs, which facilitates electron transfer and improves the catalytic activity. Other composites such as CMO@reduced graphene oxide, CMO@Vulcan X-72R, CMO@oxidized CNTs, and a physical mixture of CMO and CNTs were also prepared for comparison. Remarkably, CMO@CNTs exhibit a half wave potential of 0.91 V in 1 M KOH and higher kinetic current and better catalytic durability than Pt/C. Moreover, CMO@CNTs afford an electrocatalytic OER current density of 10 mA cm⁻² at a low potential of 1.5 V and a small Tafel slope of 81.1 mV dec⁻¹. Furthermore, CMO@CNTs display lower discharge/charge overpotential and more stable voltage plateau on cycling than that of Pt/C when employed as a cathode material in rechargeable Zn–air cells. This work indicates that CMO@CNTs are a promising, cheap and efficient bifunctional ORR/OER electrocatalyst for rechargeable metal–air batteries.

中文翻译：

尖晶石钴锰氧化物负载在非氧化碳纳米管上，是一种高效的氧还原/释放电催化剂

我们就地报告在非氧化碳纳米管（表示为CMO @ CNTs）上担载的超小型Co-Mn-O尖晶石纳米颗粒（4.4 nm）的制备，作为双功能催化剂，用于氧还原和放出反应（ORR / OER）。制备过程涉及在碱性条件下氧化二价金属离子和在含有分散的非氧化碳纳米管的水溶液中硝酸盐的分解。合成的CMO纳米粒子与未氧化的CNT牢固结合，从而促进了电子转移并提高了催化活性。还准备了其他复合材料，例如CMO还原的氧化石墨烯，CMOVulcan X-72R，CMO氧化的CNT，以及CMO和CNT的物理混合物，以进行比较。值得注意的是，CMO @ CNTs的半波电势为0。在1 M KOH中为91 V，比Pt / C具有更高的动电流和更好的催化耐久性。此外，CMO @ CNT可提供10 mA cm的电催化OER电流密度^-1在1.5 V的低电势和81.1 mV dec^-1的小Tafel斜率下产生。此外，当CMO @ CNT用作可充电Zn-空气电池的阴极材料时，其循环放电比Pt / C更低的放电/电荷超电势和更稳定的电压平稳性。这项工作表明，CMO @ CNTs是一种有前景的，廉价且有效的双功能ORR / OER电催化剂，用于可充电金属-空气电池。

更新日期：2017-08-16

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