Formation of two-dimensional structures by tuning the driving force of chemical reactions: An interpretation of kinetic control

Au2Sx/CdS Nanorods by Cation Exchange: Mechanistic Insights into the Competition Between Cation‐Exchange and Metal Ion Reduction

“…According to calculations, the formation of Au 2 S 3 is thermodynamically more favorable than the formation of Au 2 S. To compare this with the competing reaction of metal ion reduction, we also evaluated the free energy change for the formation of Au with water acting as the reducing agent in the medium by a method reported in literature. [33][34][35] We note that this free energy change is negative indicating that water can indeed reduce Au salt to metal at room temperature. However, our control experiments indicate that there could be signifi cant kinetic barriers and thus higher temperatures and/or a lowering of nucleation barrier by lowering the interfacial energy for heterogeneous nucleation may be needed for the formation of Au [ 36 ] (also see Supporting Information).…”

Mechanistic Aspects of Shape Selection and Symmetry Breaking during Nanostructure Growth by Wet Chemical Methods

“…The details of the calculations are available in previous publications. 45,50 The critical driving forces for respective metals with water as the reducing agent are given in Table 3.…”

“…More recently, there has been enormous interest in controlling the shape of the materials at the nanoscale owing to the intriguing shape-dependent properties exhibited by nanostructures, and it has become a topic of fundamental importance in solid-state sciences. 8,20,25,[41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60] For instance, the interaction of electromagnetic radiation with spherical nanoparticles of Au and Ag leads to only one type of polarization and hence shows up as a single peak in UV-visible spectra, whereas anisotropic shapes such as rods, wires, and prisms of Au and Ag show more than one resonance in the UV/near-IR region. 9,10,42,43,60, 61 The number of resonances depends on the number of ways in which the electron density can be polarized and is determined by the shape of the nanoparticles.…”

ZnO–Au nanohybrids by rapid microwave-assisted synthesis for CO oxidation

“…S1a Our earlier reports showed that Au 3+ can be reduced by water under suitable conditions and detailed calculations using the Nernst equation and chemical free energies are explained in our previous studies. 14,15 In this study, we investigate the thermodynamic and the kinetic aspects of reduction of Au salt by water with and without the presence of faceted ZnO nanorods as a heterogeneous nucleation site. Fig.…”