Site-Selective Loading of Single-Atom Pt on TiO₂ for Photocatalytic Oxidation and Reductive Hydrodefluorination

Abstract

Separating the redox sites of photocatalysts is one of most promising strategies to promote an efficient photoinduced charge transfer of semiconductor photocatalysis. Herein, we present a site-selective loading of single-atom Pt (Pt1) on facet-engineered TiO2 to achieve decomposition of recalcitrant halogenated water pollutants, including perfluorooctanoic acid (PFOA). Positively charged Pt1 are atomically dispersed catalytic sites that are selectively loaded onto the reductive sites of tailored TiO2 to attract the photoinduced electrons efficiently. This enhances the number of holes, and consequently hydroxyl radicals, remaining on the sites of facet-engineered TiO2, confirmed by the enhancement of degradation of sulfamethoxazole and 2,4-dichlorophenoxyacetic acid. While Pt nanoparticle cocatalysts consume photoinduced electrons for the reduction of oxygen molecules, site-specifically loaded Pt1 produce surface hydrogen atoms and enhance hydrogen spillover onto the TiO2 surface, to achieve efficient hydrodefluorination of PFOA via the cleavage of the C–F bond with the Ti–H bond. The site-selective loading of Pt1 on facet-engineered TiO2 serves as a versatile platform that harnesses both reductive and oxidative degradation of emerging aqueous pollutants.

Light-Induced Advanced Oxidation Processes as PFAS Remediation Methods: A Review

“…With the highest work function, Pt can attract more electrons from TiO 2 to form a strong Schottky barrier at the interface, which improves h + /e − separation during irradiation. Weon et al [67] successfully loaded Pt nanoparticles on the reductive sites of the TiO 2 facet to precisely capture photoinduced electrons (Figure 2b). This charge separation led to an increase in the number of holes on TiO 2 sites which participate in PFOA degradation.…”

“…Figure 2. PFOA degradation using (a) TiO 2 quantum dots supported on sulfonated graphene nanosheets (reprinted from[64], copyright (2020) with permission from Elsevier) and (b) single Pt atoms loaded on the reductive sites of the TiO 2 facet (reprinted from[67], copyright (2021) with permission from ACS Publications).…”

Elucidating the Role of Single-Atom Pd for Electrocatalytic Hydrodechlorination

“…The second step involved the photoreduction of the Pd precursor by photogenerated electrons under 254 nm UVC irradiation, similar to our previous work. 23,41,44 This facile process yielded Pd 1 /rGO with a Pd loading amount of 0.96 wt % according to ICP−MS results (i.e., Pd/C atomic ratio = 1/830. See Text S2 for calculations).…”

Single-Atom (Iron-Based) Catalysts: Synthesis and Applications

“…The atomically dispersed nature of SACs allows the utilization of almost 100% of its activity, which bodes well for newer opportunities in several applications. Apart from carbon as a support material, several other porous metal oxides including 2D nanomaterials have been successfully utilized for the preparation of SACs. ,− …”