期刊
CHEMICAL ENGINEERING JOURNAL
卷 403, 期 -, 页码 -出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.cej.2020.126297
关键词
Electrocatalysis; Tantalum; Layered double hydroxide; Oxygen evolution reaction
资金
- National Natural Science Foundation of China [21805308]
- Taishan Scholar Project of Shandong province
- Key Research and Development Program of Shandong Province [2019GSF109075]
- Fundamental Research Funds for the Central Universities [19CX05001A]
Structural manipulation of electrocatalysts by doping high-valence Ta into NiFe layered double hydroxide enhances OER activity through lattice expansion and electronic structure modification. The optimized Ta-NiFe LDH exhibits superior OER performance with lower overpotential and smaller Tafel slope. This work provides a theoretical basis for enhancing OER activity by doping LDH with high-valence foreign metals.
Structural manipulation of electrocatalyst via doping strategy has always held great interests for developing advanced and stable non-noble metal electrocatalyst for oxygen evolution reaction (OER). Herein, a high-valence state tantalum (Ta) was incorporated into the pristine NiFe layered double hydroxide (LDH) by hydrothermal method. Interestingly, as revealed by structural characterizations, Ta doping causes the lattice expansion of LDH and electronic structure modification through electron transfer from Fe to Ta. DFT calculations further verified that the modulated electronic structure among Ni, Fe and Ta and the modified e(g) orbital of Ta induced by charge transfer are beneficial for the adsorption of OH species on Ta site in Ta-doped NiFe LDH and increasing the intrinsic metallic property of NiFe LDH. Consequently, the Ta site has lower overpotential compared with other sites on NiFe LDH including the pristine oxygen vacancies, which can improve the electrocatalytic activity for OER. Furthermore, the optimized Ta-NiFe LDH (0.5:6:1.5) exhibited a superior OER activity in contrast to bimetallic LDH, with a low overpotential of 260 mV to drive the current density of 50 mA.cm(-2) and a small Tafel slope of 58.95 mV.dec(-1). This work provides the theoretical basis for the enhancement of electrochemical OER activity by doping LDH with high-valence state foreign metal.
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