Figure 40.

(A) Illustration of a continuous-flow system used for removing precious metal ions. (B) Comparison of the capabilities of the pristine, amino-TiO₂, and thiol-TiO₂ nanofiber-based mats for scavenging Pt⁴⁺, Rh³⁺, and Pd²⁺ ions. (C) TEM images of a TiO₂ nanofiber decorated with Pd nanoparticles (indicated by arrows in the inset), which were formed by reducing the scavenged Pd²⁺ ions with NaBH₄. The scale bar in the inset is 10 nm. (D) Chromatography−mass spectrometry chromatogram taken from the first 0.5 mL of the product solution of a Suzuki coupling reaction. The four peaks can be assigned as follows: (1) phenylboronic acid, (2) biphenyl, (3) 4′-iodoacetophenone, and (4) 4-acetylbiphenyl. In addition to the reactants (1 and 3) and product (4), a small amount of biphenyl (2) was observed as a byproduct, corresponding to a selectivity of 99.2%. Reprinted with permission from ref 503. Copyright 2016 Wiley-VCH.