电催化剂
材料科学
析氧
氢氧化物
催化作用
复合数
化学工程
扩展X射线吸收精细结构
电导率
层状双氢氧化物
电化学
氧烷
吸附
无机化学
物理化学
电极
复合材料
化学
吸收光谱法
工程类
物理
量子力学
生物化学
光谱学
作者
Kassa Belay Ibrahim,Wei‐Nien Su,Ming‐Jong Tsai,Amaha Woldu Kahsay,Soressa Abera Chala,Mulatu Kassie Birhanu,J.-F. Lee,Bing‐Joe Hwang
标识
DOI:10.1016/j.mtchem.2022.100824
摘要
Developing oxygen evolution reaction (OER) electrocatalyst based on earth-abundant materials holds great promise for ascertaining water-splitting to surmount its deprived kinetics. In this regard, NiFe-LDH (layered double hydroxide) receives considerable attention owing to their layered structure. However, they still suffer from poor electronic conductivity and structural stability. We combined NiFe-LDH nanosheets with Magnéli phase Ti4O7 into a heterostructured composite. A series of analyses reveal that decorating Ti4O7 facilitates charge transfer to enhance the conductivity of NiFe-LDH-Ti4O7. During electrochemical measurement, Ni2+ is transformed to metastable Ni3+ (Ni (OH)→ NiOOH) before the OER onset potential. Thus, the presence of Ni3+ as the main active sites could improve the chemisorption of OH− to facilitate OER. As a result, the NiFe-LDH-Ti4O7 catalyst delivers as low as onset potential (1.43 V). Combining the holey structure (NiFe-LDH and Ti4O7) and the defect engineering generated on NiFe-LDH-Ti4O7 as a synergistic effect improves the OER performance. The inclusion of Ti4O7 in the composite leads to more vacancy sites, as evidenced by the extended X-ray absorption fine structure (EXAFS) analysis. The obtained defective structure with a low coordination environment would improve the electronic conductivity and facilitate the adsorption process of H2O onto metal cations, thereby increasing the intrinsic catalytic activity of NiOOH. The strong coupling of NiFe-LDH and Ti4O7 also increases the stability, and the heterostructured composite helps maintain the structural robustness of the LDH.
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