Multi-walled carbon nanotube supported manganese selenide as a highly active bifunctional OER and ORR electrocatalyst
Multi-walled carbon nanotube supported manganese selenide as a highly active bifunctional OER and ORR electrocatalyst
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多壁碳纳米管负载硒化锰作为高活性双功能OER和ORR电催化剂
DOI：
10.1039/d1ta09864k
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发表时间：
2022
影响因子：
11.9
通讯作者：
Nath, Manashi
中科院分区：
文献类型：
--
作者：
Singh, Harish;Marley-Hines, McKenzie;Chakravarty, Shatadru;Nath, Manashi
由于可持续能源转换的持续推动，过渡金属硒化物作为氧还原反应（ORR）和析氧反应（OER）的经济高效的电催化剂引起了人们的广泛兴趣。在本文中，我们鉴定出一种锰基双功能电催化剂 MnSe，它在碱性介质中表现出高效的 OER 和 ORR 活性。通过使用多壁碳纳米管（MWCNT）可以进一步增强催化活性，这可以增加催化剂复合材料的电荷转移和电子传导性。这种 MnSe@MWCNT 催化剂复合材料在 10 mA cm−2 下表现出 290 mV 的极低过电势，优于最先进的 RuO2 以及其他氧化物基电催化剂。此外，该复合材料的轻松 OER 动力学通过其 54.76 mV dec−1 的小塔菲尔斜率和低电荷转移电阻得到证明，表明反应物在电极界面处的快速传输。 MnSe@MWCNT 还表现出高效的 ORR 电催化活性，Eonset 为 0.94 V，这是迄今为止报道的基于硫族化物的 ORR 电催化剂中最好的电催化剂之一。更重要的是，这种MnSe基ORR电催化剂表现出高度的甲醇耐受性，在大量甲醇存在下催化剂性能不会下降，从而优于最先进的Pt电催化剂。在碱性介质中长时间连续运行后，该催化剂复合材料还表现出优异的 OER 和 ORR 功能和成分稳定性。 OER 后的表面拉曼分析揭示了硒化锰表面的保留，并具有氧配位的证据，证实了（氧）硒化物的形成作为 OER 的活性表面。这种高效的双功能 OER 和 ORR 活性使得这种 MnSe 基催化剂对于再生燃料电池和直接甲醇燃料电池的整体电解具有吸引力。
Transition metal selenides have attracted intensive interest as cost-effective electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) because of the continuous thrust in sustainable energy conversion. In this article a Mn-based bifunctional electrocatalyst, MnSe, has been identified which shows efficient OER and ORR activity in alkaline medium. The catalytic activity could be further enhanced by using multiwalled carbon nanotubes (MWCNTs) which increases the charge transfer and electronic conductivity of the catalyst composite. This MnSe@MWCNT catalyst composite exhibits a very low overpotential of 290 mV at 10 mA cm−2, which outperforms state-of-the-art RuO2 as well as other oxide based electrocatalysts. Furthermore, the composite's facile OER kinetics was evidenced by its small Tafel slope of 54.76 mV dec−1 and low charge transfer resistance, indicating quick transport of the reactant species at the electrode interface. The MnSe@MWCNT also exhibited efficient electrocatalytic activity for ORR with an Eonset of 0.94 V, which is among the best reported to date for chalcogenide based ORR electrocatalysts. More importantly, this MnSe-based ORR electrocatalyst exhibits high degree of methanol tolerance, showing no degradation of catalyst performance in the presence of copious quantities of methanol, thereby out-performing the state-of-the-art Pt electrocatalyst. The catalyst composite also exhibited exceptional functional and compositional stability for OER and ORR after a prolonged period of continuous operation in alkaline medium. The surface Raman analysis after OER revealed the retention of manganese selenide surface with evidence of oxo coordination, confirming the formation of an (oxy)selenide as the active surface for OER. Such efficient bifunctional OER and ORR activity makes this MnSe based catalyst attractive for overall electrolysis in regenerative as well as direct methanol fuel cells.