Topotactic Growth of Edge-Terminated MoS₂ from MoO₂ Nanocrystals

TY - JOUR

T1 - Topotactic Growth of Edge-Terminated MoS2 from MoO2 Nanocrystals

AU - Dahl-Petersen, Christian

AU - Šarić, Manuel

AU - Brorson, Michael

AU - Moses, Poul Georg

AU - Rossmeisl, Jan

AU - Lauritsen, Jeppe Vang

AU - Helveg, Stig

PY - 2018/6/26

Y1 - 2018/6/26

N2 - Layered transition metal dichalcogenides have distinct physicochemical properties at their edge-terminations. The production of an abundant density of edge structures is, however, impeded by the excess surface energy of edges compared to basal planes and would benefit from insight into the atomic growth mechanisms. Here, we show that edge-terminated MoS2 nanostructures can form during sulfidation of MoO2 nanocrystals by using in situ transmission electron microscopy (TEM). Time-resolved TEM image series reveal that the MoO2 surface can sulfide by inward progression of MoO2(202):MoS2(002) interfaces, resulting in upright-oriented and edge-exposing MoS2 sheets. This topotactic growth is rationalized in the interplay with density functional theory calculations by successive O-S exchange and Mo sublattice restructuring steps. The analysis shows that formation of edge-terminated MoS2 is energetically favorable at MoO2(110) surfaces and provides a necessary requirement for the propensity of a specific MoO2 surface termination to form edge-terminated MoS2. Thus, the present findings should benefit the rational development of transition metal dichalcogenide nanomaterials with abundant edge terminations.

AB - Layered transition metal dichalcogenides have distinct physicochemical properties at their edge-terminations. The production of an abundant density of edge structures is, however, impeded by the excess surface energy of edges compared to basal planes and would benefit from insight into the atomic growth mechanisms. Here, we show that edge-terminated MoS2 nanostructures can form during sulfidation of MoO2 nanocrystals by using in situ transmission electron microscopy (TEM). Time-resolved TEM image series reveal that the MoO2 surface can sulfide by inward progression of MoO2(202):MoS2(002) interfaces, resulting in upright-oriented and edge-exposing MoS2 sheets. This topotactic growth is rationalized in the interplay with density functional theory calculations by successive O-S exchange and Mo sublattice restructuring steps. The analysis shows that formation of edge-terminated MoS2 is energetically favorable at MoO2(110) surfaces and provides a necessary requirement for the propensity of a specific MoO2 surface termination to form edge-terminated MoS2. Thus, the present findings should benefit the rational development of transition metal dichalcogenide nanomaterials with abundant edge terminations.

KW - density functional theory

KW - edge termination

KW - growth mechanism

KW - in situ transmission electron microscopy

KW - MoS

KW - topotaxy

U2 - 10.1021/acsnano.8b00125

DO - 10.1021/acsnano.8b00125

M3 - Journal article

C2 - 29767949

AN - SCOPUS:85047398940

SN - 1936-0851

VL - 12

SP - 5351

EP - 5358

JO - ACS Nano

JF - ACS Nano

IS - 6

ER -