1. Interfacial electric field optimization and co-catalyst free LaFeO3-based p-p-type homojunction for efficient PEC water splitting.
- Author
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Li, Yanxin, Hao, Zhichao, Wang, Ruikai, Wang, Guangyao, Li, Haiyan, Li, Can, Xia, Chenghui, Dong, Bohua, and Cao, Lixin
- Abstract
The Cu-LFO/Ni-LFO homojunction reduces the defects caused by the lattice mismatch at the interface and the recombination of photogenerated carriers. In addition, the relative positions of the Fermi energy levels of Cu-LFO and Ni-LFO are adjusted by ion doping to achieve the synergistic enhancement of photogenerated carrier separation by the triple synergy of applied voltage, energy band potential and built-in electric field. Meanwhile, Ni-LFO modulates the adsorption and desorption of water molecules and reduction reaction intermediates to accelerate the reaction kinetics at the semiconductor-electrolyte interface. [Display omitted] • Modulation of built-in electric field direction by metal ion doping; • Synergistic enhancement of photogenerated carrier separation; • Reduction of interfacial defects and photogenerated carrier recombination; • Ni-LFO served as co-catalyst-like agent to optimize HER reaction kinetics. LaFeO 3 (LFO), a typical p-type semiconductor, is considered as a promising material for photoelectric conversion because of its flexible composition and structure. However, its severe photogenerated carrier recombination and surface reaction kinetic hysteresis greatly limit its application in photoelectrochemistry (PEC) water splitting. Here, for the first time, a LFO p-p-type homojunction (Cu-LFO/Ni-LFO) formed by Cu-doped LFO and Ni-doped LFO is reported. Experimental investigation and density functional theory (DFT) calculations reveal that Cu and Ni doping forms a built-in electric field directed from Ni-LFO to Cu-LFO, which effectively improves the carrier separation and transport efficiency. The comparable crystal structure at the interface minimizes the photogenerated carrier recombination due to the interface lattice mismatch. In addition, Ni-LFO in contact with the electrolyte served as a co-catalyst like role in this PEC system, improving the kinetic properties of the surface reaction significantly by optimizing the adsorption and desorption of H 2 O molecules and HER reaction intermediates on the Fe in the active center whilst significantly reducing the energy barrier. As a result, the photocurrent density of the Cu-LFO/Ni-LFO photocathode reaches 5.94 mA cm2, which is 11 times higher than that of Cu-LFO and surpasses all LFO-based photocathodes reported so far. The LFO-based p-p homo-junction synthesized in this work is instructive for improving the carrier separation efficiency and surface reaction kinetics of LFO. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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