American Chemical Society
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In-Plane Axially Enhanced Photocatalysis by Re4 Diamond Chains in Layered ReS2

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journal contribution
posted on 2018-07-25, 00:00 authored by Perumalswamy Sekar Parasuraman, Jhih-Hao Ho, Min-Han Lin, Ching-Hwa Ho
Two-dimensional (2D) semiconductors play a crucial role in high-efficiency photocatalysts because of their high surface-to-volume ratio. The surface property is a key part of photocatalysis. In this work, the enhanced photocatalytic behavior of the layered ReS2 with optical polarization along the Re4 nano-diamond-chain (DC) direction (b axis) has been demonstrated. The unpolarized photoconductivity (PC) response of ReS2 with an applied bias along the b axis is approximately 1 order higher than that of the applied bias perpendicular to the b axis. The polarization-dependent PC spectra of Eb also reveal a higher photoresponsivity with respect to those measured along the Eb polarization for the layered ReS2. This result indicates that stronger polarization dipoles as well as a larger amount of photogenerated carriers and surface states can contribute to the C-plane ReS2 under the illumination of Eb polarized photons. With the special axial effect, the layered ReS2 2D photocatalyst shows much faster degradation rates of 5.6 and 12.3 than the other transition-metal dichalcogenides of TaS2 and MoS2 for the degradation of methylene blue (MNB) solution. For the polarization-dependent photodegradation test, the degradation rate of illuminated Eb polarized photons is also approximately 12 times faster than that of the illuminated Eb polarized light in a 25 μM MNB solution. The enhanced photocatalytic behavior of ReS2 along the DC also shows a peak photoreponse of ∼25 μV detected in the polarized photovoltaic spectrum of the 0.5 μM MNB dye-sensitized solar cell positioned at ∼1.99 eV. The formation of a nano-DC and a one-layer trigonal crystalline phase is beneficial for the versatile energy applications of ReS2.