Fig. 17.

Intrinsic 1D and 2D defects in 2D TMDCs during the synthesis. a HRTEM-ADF images of 2D MoS₂ including line defects at a mirror twin grain boundary (top). Below is the zoomed-in image shows a periodic line of 8–4–4 ring defects along the grain boundary, including an atomistic model on the right. Adapted with permission from Ref. [147]. Copyright 2019, ACS Publications. b Mesoporous (holey) 1T-MoS₂ nanosheet with two-dimensional defects many edge sites synthesised with severe desulphurisation reaction condition between lithium and MoS₂. Adapted with permission from Ref. [148]. Copyright 2015, ACS Publications. c HRTEM images of engineered sulphur deficient MoS₂ show dislocations and distortions of lattice planes decreases (left to right) from reaction precursor Mo/S ratios of 4:2 (D_H), 4:4 (D_M) and 4:8 (D_L). Adapted with permission from Ref. [149]. Copyright 2019, Nature Publishing Group. d HRTEM micrograph of defect-rich structure of MoS₂ and active edge sites generated by varying precursors during the synthesis process. Adapted with permission from Ref. [150]. Copyright 2013, Wiley