Operando High‐Valence Cr‐Modified NiFe Hydroxides for Water Oxidation
Operando High‐Valence Cr‐Modified NiFe Hydroxides for Water Oxidation
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用于水氧化的 Operando 高价 Cr 改性 NiFe 氢氧化物
DOI：
10.1002/smll.202200303
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发表时间：
2022
期刊：
影响因子：
13.3
通讯作者：
Yang Hua Gui
中科院分区：
文献类型：
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作者：
Wang Ming Hua;Lou Zhen Xin;Wu Xuefeng;Liu Yuanwei;Zhao Jia Yue;Sun Kai Zhi;Li Wen Xin;Chen Jiacheng;Yuan Hai Yang;Zhu Minghui;Dai Sheng;Liu Peng Fei;Yang Hua Gui
高价金属掺杂的多金属（氧）氢氧化物在析氧反应（OER）中的性能优于贵金属电催化剂，这是由于3d金属和高价掺杂剂之间的能量学改变。然而，充分和微妙的调制器的合理设计仍然具有挑战性。本研究以多金属层状双氢氧化物（LDH）为OER催化剂，引入了一系列高价态掺杂剂（Cr、Ru、Ce和V），这些掺杂剂可以限制LDH模板中的3+价态，以防止相分离和向>3+价态的操作转移，从而在OER过程中实现充分的电子相互作用。通过密度泛函理论模拟，合成了Cr掺杂的NiFe（NiFeCr）LDH，其中Cr掺杂剂与NiFe掺杂位点之间具有强的电子相互作用，X射线吸收光谱证明了这一点。所得NiFeCr-LDH以189和284 mV的超低过电位催化OER，分别获得10和1000 mA cm-2的电流密度。此外，NiFeCr-LDH阳极耦合在阴离子交换膜电解槽中，以促进碱性水分解和CO2至CO电解，从而在高电流密度下实现低全电池电压。
High‐valence metal‐doped multimetal (oxy)hydroxides outperform noble metal electrocatalysts for the oxygen evolution reaction (OER) owing to the modified energetics between 3d metals and high‐valence dopants. However, the rational design of sufficient and subtle modulators is still challenging. With a multimetal layered double hydroxide (LDH) as the OER catalyst, this study introduces a series of operando high‐valence dopants (Cr, Ru, Ce, and V), which can restrict the 3+ valence states in the LDH template to prevent phase separation and operando transfer to the >3+ valence states for sufficient electronic interaction during the OER process. Through density functional theory simulations, ultrathin Cr‐doped NiFe (NiFeCr) LDH is synthesized with strong electronic interaction between Cr dopants and NiFe bimetallic sites, evidenced by X‐ray absorption spectroscopy. The resulting NiFeCr‐LDH catalyzes the OER with ultralow overpotentials of 189 and 284 mV, obtaining current densities of 10 and 1000 mA cm–2, respectively. Further, a NiFeCr‐LDH anode is coupled in the anion exchange membrane electrolyzers to promote alkaline water splitting and CO2‐to‐CO electrolysis, which achieves low full cell voltages at high current densities.