Abstract
The photocatalytic activity of a material is contingent on efficient light absorption, fast electron excitation, and control of the recombination rate by effective charge separation. Inorganic materials manufactured in unique shapes via controlled synthesis can exhibit significantly improved properties. Here, n-type Bi2S3 nanorods (with good optical activity) were wrapped with two-dimensional (2D) p-type MoS2 sheets, which have good light absorption properties. The designed p-n junction Bi2S3/MoS2 composite exhibited enhanced light absorption over the entire wavelength range, and higher carbon dioxide adsorption capacity and photocurrent density compared to the single catalysts. Consequently, the activity of the 1Bi2S3/1MoS2 composite catalyst for the photocatalytic reduction of carbon dioxide was more than 20 times higher than that of the single catalysts under visible-light irradiation at ≤400 nm, with partial selectivity for CO conversion. This is attributed to the p-n heterojunction Bi2S3/MoS2 composite designed in this study, the high light absorption of n-Bi2S3, accelerated electron excitation, and the electron affinity of the 2D sheet-p-MoS2, which quickly absorbed excited electrons, resulting in effective charge separation. This ultimately improved the catalytic performance by continuously supplying catalytically active sites to the heterojunction interfaces.
Highlights
The greatest challenge for an eco-friendly CO2 -to-fuel system, which produces fuel by photocatalytically reducing carbon dioxide under visible light, is the development of stable and highly efficient photocatalysts
In this study, we propose that p-type MoS2 particles, which lack electrons, will accept electrons excited by n-type Bi2 S3 particles that have a narrow band-gap
The XRD profile of the heterojunction Bi2 S3 /MoS2 catalysts clearly showed the characteristic peaks of Bi2 S3, but the peak assigned to the (002) plane of MoS2 was hardly visible
Summary
The greatest challenge for an eco-friendly CO2 -to-fuel system, which produces fuel by photocatalytically reducing carbon dioxide under visible light, is the development of stable and highly efficient photocatalysts. Chalcogenides are currently highly topical as candidate materials for this purpose and extensive studies of these materials have been conducted. Chalcogenides are an attractive research theme because their physicochemical properties vary with their unique shape and size. Chalcogenides have small band-gaps and large extinction coefficients, and can be utilized in various applications such as batteries [3], gas sensors [4], and photodetectors [5]. Due to their wide light absorption ability, the application of chalcogenides as photocatalysts that are active under visible-light irradiation has been actively studied
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