In situ formation of low-valence state cobalt cation in octahedral sites of Co9S8 for highly efficient electrocatalytic hydrogen evolution
In situ formation of low-valence state cobalt cation in octahedral sites of Co9S8 for highly efficient electrocatalytic hydrogen evolution
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DOI：
10.1016/j.mtener.2024.101494
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发表时间：
2024-01-19
影响因子：
9.3
通讯作者：
Zhao，Yongfeng
中科院分区：
文献类型：
--
作者：
Tian，Bin;Cheah，Pohlee;Zhao，Yongfeng
电催化剂中元素的价态对其催化能力有重要影响。然而，通过控制元素价态和精确的掺杂位置来提高性能仍然具有挑战性。这项工作致力于探索一种可控的电子结构，能够通过操纵特定位置元素的价态来提高电催化析氢活性。这是通过使用硼氢化钠还原Co 9 S8的八面体位置中的高价态Co 3+以形成低价态Co 2+来证明的。Co ~（2+）在Co ~（3+）位的占据引起了晶格局部畸变，从而为析氢反应（HER）提供了更有效的活性位。另外，八面体位置的Co ~（2+）为吸附的水分子提供了更多的电子，有利于HO-H解离和H ~+吸附。在500 mA/cm 2电流密度下，该催化剂的过电位为301 mV，是目前报道的单组分Co 9 S8基催化剂中性能最好的。这项工作铺平了道路，通过精确地调整在特定位置的元素的价态的HER电催化剂的合理设计。
The elementary valence state in electrocatalysts has been demonstrated to significantly affect their catalytic ability. However, enhancing performance by controlling the elemental valence state and the precise doping location remains challenging. This work is devoted to exploring a controllable electronic structure that is capable of improving electrocatalytic hydrogen evolution activity by manipulating the valence state of an element at a specific location. This is demonstrated by reducing the high valence state Co3+in octahedral sites of Co9S8to form low valence state Co2+using sodium borohydride. The occupation of Co2+in the Co3+site gives rise to the generation of local lattice distortion, which provides more efficient active sites for the hydrogen evolution reaction (HER). Additionally, Co2+in octahedral sites donates more electrons to adsorbed water molecules, which facilitates HO–H dissociation and H∗ adsorption. The resulting electrocatalyst exhibits a low overpotential of 301 mV at 500 mA/cm2for the HER, which is the best performance among all reported single-component Co9S8-based catalysts. This work paves an avenue for the rational design of HER electrocatalysts by precisely tuning the valence state of elements at specific locations.