Crystallization\nof 2D TiO<sub>2</sub> Nanosheets via\nOriented Attachment of 1D Coordination Polymer

Demystifying the molecular mechanism of growth is vital\nfor the\nrational design, synthesis, and optimization of functional nanomaterials.\nDespite the promising perspectives and extensive efforts, the growth\nmechanism of atomically thin TiO<sub>2</sub>(B) nanosheets remains\nunclear, hence it is difficult to tune their band and surface structures.\nHerein, we report an oriented attachment-based crystallization mechanism\nof TiO<sub>2</sub>(B) nanosheets from a 1D titanium glycolate coordination\npolymer through hydrolysis and condensation. With time-tracking experiments,\nthis 1D coordination polymer is found to be an intermediate in the\nsynthesis of TiO<sub>2</sub>(B) nanosheets by using Ti alkoxides and\nchlorides as precursors, suggesting the universality of the 1D-to-2D\ngrowth mechanism. Such a side-to-side attachment pathway bridges the\nclassical and nonclassical interpretations of crystallization, and\nmeanwhile hints at the possibility of other 1D complexes as potential\nprecursors for 2D materials.