Aggregation-Induced Fast Crystal Growth of SnO₂ Nanocrystals

Abstract

In this paper, we report an ultrafast growth of SnO(2) nanocrystals directly from ~4 to ~350 nm in a hydrothermal process (250 °C, time >180 h). The crystal growth system is characterized by "either small or large" particle size; that is, only two differently sized SnO(2) particles, either several nanometers or ~350 nm, coexist. During the fast growth process, SnO(2) nanoparticles assembled to form densely aggregated aggregates that can quickly transform to big (bulk-like) crystals. The kinetic analysis, for the first time, point outs that the fast growth reaction (from nanocrystal aggregates to bulk-like crystals) follows a first-order reaction law with a very large kinetic pre-exponent factor (1.53 × 10(27) h(-1)), which is in line with our proposed aggregation-induced fast crystal growth mechanism. Small-angle X-ray scattering (SAXS) study of the aggregates supports that the onset of the fast growth is closely related to an increase in the aggregation degree of the aggregates. Moreover, disintegrating the aggregation state via introduction of other particles (Al(2)O(3)) into the system prohibited the fast growth. The finding in this work provides new threads for syntheses of novel nanomaterials that may possess properties not readily obtained via conventional crystal growth routes.

Gold nanorings synthesized via a stress-driven collapse and etching mechanism

“…In fact, similar to our observations, a NP fusion or Ostwald ripening process has been proposed to play an important role in 'aggregation-induced fast crystal growth'. [39][40][41] The aggregated NPs may fuse others across a mismatched interface. Grain boundaries then migrate toward the adjacent particle, leading to the growth of one orientation at the expense of the other, which is quickly consumed.…”

Metal oxide mesocrystals with tailored structures and properties for energy conversion and storage applications

“…This definition has been developed in recent years, where MCs are defined entirely according to their structures rather than their formation mechanism. 12 In this decade, a variety of MCs of metal oxides (for example, TiO 2 , [13][14][15][16][17][18][19][20][21][22][23] ZnO, [24][25][26][27][28][29][30][31][32][33][34] hematite (a-Fe 2 O 3 ), [35][36][37][38][39][40] maghemite (g-Fe 2 O 3 ), 41 Co 3 O 4 , 42 SnO, [43][44][45] Ag 2 O, 46 CuO [47][48][49] ), metal chalcogenides (for example, ZnS, 50,51 PbS, 52 PbSe 53,54 ), metals (for example, Au, 55 Ag, 56,57 Cu, 58 Pt, 59,60 Pd 61 ), organic compounds (for example, DL-alanine, 62,63…”

Rational design of SnO2 aggregation nanostructure with uniform pores and its supercapacitor application

“…Compared with previous work reported [23], our strategy differs mainly in three aspects: (1) SnCl 4 and ammonia solutions were directly isolated by a beaker, which can effectively control the nucleation rate of SnO 2 and benefit crystal growth orderly follow the Oriented Attachment (OA) mechanism [27,28] to form aggregated structure at the vapour-liquid interface, because the overflowed ammonia gas (NH 3 ) from the ammonia solution by heating was firstly absorbed on the surface of the SnCl 4 solution; (2) the mixed solvent of EG and water with different ratios facilely achieved regulating the (3) the introduction of F -plays a key role to obtain a uniform porous distribution of these aggregation nanostructures, which may result from the coordination between F -and Sn 4? to further orderly adjust the hydrolysis rate of Sn 4?…”

“…Over the past two decades, different morphologies of SnO 2 nanostructures have been synthesized, such as 0D nanoparticles [1,7]; 1D nanowires [20], nanorods [21], nanotubes [22], and nanobelts [6]; and 2D nanosheets [2]. However, the 3D aggregated nanostructures have rarely been reported [23], because previous kinetic studies indicate that SnO 2 particles typically grow very slowly, limiting the crystals to only a few nanometers and with bad interconnected aggregation [24][25][26]. For instance, Zhuang et al [24] demonstrated that nano-SnO 2 treated hydrothermally could only stabilized at a small particle size for a long time (4.2 nm, 250°C, 180 h).…”

“…For instance, Zhuang et al [24] demonstrated that nano-SnO 2 treated hydrothermally could only stabilized at a small particle size for a long time (4.2 nm, 250°C, 180 h). They subsequently found an aggregation-induced growth of bulk-SnO 2 crystal with the size of *500 nm when coarsening in water at 250°C for 470 h [23]. Therefore, the synthetic techniques for preparing SnO 2 aggregation structures still face challenges.…”