Cocrystallization Enabled Spatial Self-Confinement Approach to Synthesize Crystalline Porous Metal Oxide Nanosheets for Gas Sensing.

Crystalline metal oxide nanosheets show exceptional catalytic performance owing to the large surface-to-volume ratio and quantum confinement effect. However, it is still a challenge to develop a facile and general method to synthesize metal oxide nanosheets. Herein, we report a cocrystallization induced spatial self-confinement approach to synthesize metal oxide nanosheets. Taking the synthesis of SnO 2 as an example, the solvent evaporation from KCl and SnCl 2 solution induces the cocrystallization of KCl and K 2 SnCl 6 , and the obtained composite with encapsulated K 2 SnCl 6 can be in situ converted into SnO 2 nanosheets confined in KCl matrix, after water washing to remove KCl, porous SnO 2 nanosheets can be obtained. Notably, a series of metal oxide nanosheets can be obtained through this general and efficient green route. In particular, porous CeO 2 /SnO 2 nanosheets with improved surface O - species and abundant oxygen vacancies exhibit superior gas sensing performance to 3-hydroxy-2-butanone.