@article{huang_shi_wang_2019, title={Optical Properties and Photocatalytic Applications of Two-Dimensional Janus Group-III Monochalcogenides}, volume={123}, ISSN={["1932-7455"]}, DOI={10.1021/acs.jpcc.8b12450}, abstractNote={Photocatalytic water splitting has received much attention for the production of renewable hydrogen from water, and two-dimensional (2D) materials show great potential for use as efficient photocatalysts. In this paper, the stabilities and electronic and optical properties of Janus group-III monochalcogenide M2XY (M = Ga and In and X/Y = S, Se, and Te) monolayers were investigated using first-principles calculations. The band gaps of the Janus M2XY monolayers are in the range of 1.54–2.98 eV, which satisfies the minimum band gap requirement of photocatalysts for overall water splitting. Indirect-to-direct band gap transitions occur in the M2XTe (M = Ga and In and X = S and Se) monolayers. These transitions were induced by the valence band maximum at the Γ point, being composed of the px and py orbitals of the M and Y atoms in M2XTe instead of the pz orbitals of the M and X atoms in the MX and other M2XY monolayers. The Janus M2XY monolayers have a considerable optical absorption coefficient (∼3 × 104/cm) in the visible light region and an even larger absorption coefficient (∼105/cm) in the near ultraviolet region. This study not only highlights the efficient photocatalytic performance of the 2D MX and M2XY monolayers but also provides an approach for tuning the band structures of 2D photocatalysts by forming Janus structures.}, number={18}, journal={JOURNAL OF PHYSICAL CHEMISTRY C}, author={Huang, Aijian and Shi, Wenwu and Wang, Zhiguo}, year={2019}, month={May}, pages={11388–11396} }
 @article{shi_li_wang_2019, title={Triggering Catalytic Active Sites for Hydrogen Evolution Reaction by Intrinsic Defects in Janus Monolayer MoSSe}, volume={123}, ISSN={["1932-7447"]}, DOI={10.1021/acs.jpcc.9b01485}, abstractNote={Janus transition-metal dichalcogenides have been predicted to be promising candidates for hydrogen evolution reaction (HER) due to their inherent structural asymmetry. However, the effect of intrinsic defects, including vacancies, antisites, and grain boundaries, on their catalytic activity is still unknown. MoSSe provides an ideal platform for studying such defects, since theoretical calculation has indicated that the formation energies of point defects and grain boundaries on MoSSe were lower than that of pristine MoS2 monolayer. In this work, density functional theory is utilized to study all of the possible intrinsic defects on the MoSSe monolayer for HER. The MoSSe monolayer with 4|4, 4|8a, 5|7b, 8|10a GBs, vacancies (VS, VSe, VSSe, VMo, VMoS3), and antisite defects (MoSSe, SeMo, SMo) shows enhanced HER performance. The adsorption behavior of hydrogen on defects were explained by using a "states-filling" model. The adsorption energy of hydrogen during catalysis changes linearly with the work required to fill unoccupied electronic states within the catalysts. This work could provide a more comprehensive understanding of all of the possible active sites of Janus transition-metal dichalcogenides for HER.}, number={19}, journal={JOURNAL OF PHYSICAL CHEMISTRY C}, author={Shi, Wenwu and Li, Guoqing and Wang, Zhiguo}, year={2019}, month={May}, pages={12261–12267} }