Abstract
Photocatalysis is attracting enormous interest driven by the great promise of addressing current energy and environmental crises by converting solar light directly into chemical energy. However, efficiently harvesting solar energy for photocatalysis remains a pressing challenge, and the charge kinetics and mechanism of the photocatalytic process is far from being well understood. Here we report a new full solar spectrum driven photocatalyst in the system of a layered oxyselenide BiCuSeO with good photocatalytic activity for degradation of organic pollutants and chemical stability under light irradiation, and the photocatalytic performance of BiCuSeO can be further improved by band gap engineering with introduction of La. Our measurements and density-functional-theory calculations reveal that the effective mass and mobility of the carriers in BiCuSeO can be tuned by the La-doping, which are responsible for the tunable photocatalytic activity. Our findings may offer new perspectives for understanding the mechanism of photocatalysis through modulating the charge mobility and the effective mass of carriers and provide a guidance for designing efficient photocatalyts.
Highlights
Absorbance spectra of Bi1−xLaxCuSeO (x = 0, 0.04, 0.08) powder samples
We demonstrate a new Bi-based layered structured BiCuSeO oxyselenides with good photocatalytic activity and chemical stability in the full solar light spectrum for degradation of organic contaminants (Congo Red being used as model pollutants) in aqueous solution, and present a comprehensive study on the role of effective mass on the photocatalytic properties in a series of Bi1−xLaxCuSeO samples (La doping being employed for tailoring the energy band structure of BiCuSeO) both experimentally based on Hall measurements on the bulk samples and theoretically by Density Functional Theory (DFT) calculations
Oxyselenide compound BiCuSeO has been extensively investigated as a promising oxide-based thermoelectric material in the moderate temperature range in recent years triggered by Zhao’s work in 201032
Summary
Oxyselenide compound BiCuSeO has been extensively investigated as a promising oxide-based thermoelectric material in the moderate temperature range in recent years triggered by Zhao’s work in 201032. With smaller effective mass (higher mobility) of holes, La doped BiCuSeO show stronger photocurrent density as well as higher photocatalytic activity of degrading CR solution than pristine one in UV, visible and NIR light under the same intensity of irradiation. This can be considered as direct evidence of more efficient migration of carriers to surface over La doped BiCuSeO than pure sample. These results may present a new research direction of investigating charge kinetics which is a key factor of determining the photocatalytic activity and provide new perspectives for deep understanding of the mechanism of photocatalysis in semiconductor material systems
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