Photothermal-Mediated Catalytic Reduction of 4-Nitrophenol Using Poly(N-isopropylacrylamide-acrylamide) and Hollow Gold Nanoparticles

Abstract

Hollow gold nanoparticles (HAuNPs) have received significant attention for photothermal applications owing to their strong absorbance in the near-field region, resulting in high photothermal conversion efficiency. Localized surface plasmon resonance (LSPR)-mediated heating, which is a non-radiative property of AuNPs, has been shown to enhance photothermalmediated catalytic reactions. In addition, the modification of the structure and interparticle distance of plasmonic NPs induce the surface plasmon resonance-coupling effect. In this study, we prepared the core-satellite structure used in the photothermalmediated catalytic reduction of 4-nitrophenol with poly(Nisopropylacrylamide-acrylamide) [p(NIPAM-AA)] and HAuNPs. The amount of satellite HAuNPs (80 ppm) on 10 μL of 0.18 M p(NIPAM-AA) core varied from 6 to 12 mL. As-made p(NIPAM-AA)@HAuNP-8 sample reached a photothermal conversion efficiency of 56.9% and showed a high photothermal-mediated catalytic reduction rate. The reaction rate was enhanced from 0.162 to 0.354 min −1 by near-infrared irradiation, resulting in the effective photothermal effect of satellite HAuNPs and the enhanced LSPR-coupling between neighboring HAuNPs through the shrinkage of the p(NIPAM-AA) core. The results showed that the localized heating of p(NIPAM-AA)@HAuNP-8s effectively enhances the catalytic activity through the photothermal effect without the need to heat the entire solution with additional heating.

Photothermal Oxidation of Cinnamyl Alcohol with Hydrogen Peroxide Catalyzed by Gold Nanoparticle/Antimony‐Doped Tin Oxide Nanocrystals

“…Further, the surface temperature of the Au/ATO NC catalyst under the NIR irradiation was estimated to be 325 K by substituting the k NIR2 value into the equation. The temperature is higher than the initial temperature of the reaction solution (296 K) or the increment of temperature Δ T =29 K. Although it is impossible to simply compare the Δ T with the other systems as the light irradiation conditions are different, the Δ T in this system is comparable with those under NIR‐laser irradiation ( λ ex =808 nm, 1.3–4.0 W cm −2 ) [21–23] …”

“…The temperature is higher than the initial temperature of the reaction solution (296 K) or the increment of temperature ΔT = 29 K. Although it is impossible to simply compare the ΔT with the other systems as the light irradiation conditions are different, the ΔT in this system is comparable with those under NIR-laser irradiation (λ ex = 808 nm, 1.3-4.0 W cm À 2 ). [21][22][23] The light intensity integrated from 660 nm to 780 nm was measured to be 6.54 mW cm À 2 , which is approximately half of the sunlight intensity in the wavelength region (Figure S3). Importantly, the photothermal effect of the ATO NC support induces the significant enhancement of the catalytic activity of…”

“…Consequently, taking advantage of this photothermal effect can rise the local temperature near the catalytically active sites of Au/MOs to boost the activity. The research on the group VIII NP-based photothermal catalysts is rapid in progress, [20] but to our knowledge, the studies on the photothermal catalysis of the AuNP-based catalysts have only been limited to Suzuki coupling reactions by unsupported Au nanorods decorated with TiO x film and Pd NPs, [21] and 4nitorophenol reduction by NaBH 4 over unsupported branched Au nanostructures [22] and over Au/polymer [23] under near infrared (NIR)-laser irradiation (excitation wavelength, λ ex = 808 nm). On the contrary, antimony-doped tin oxide nanocrystal (ATO NC) also possesses the absorption in the near infrared (NIR)-IR region due to the low density of free electrons [24] in addition to the splendid physicochemical stability.…”

Antimony-Doped Tin Oxide Catalysts for Green and Sustainable Chemistry

“…The surface temperature of the SnO 2 :Sb NC catalyst under the irradiation was estimated to be 315 K by substituting the first-order rate constant under irradiation ( k p ) into the equation. The temperature is higher than the initial temperature of the reaction solution (300 K) or the increment of temperature Δ T = 22 K, which is comparable with those under NIR-laser irradiation (λ ex = 808 nm, 1.3–4.0 W cm –2 ). − Further, the adsorption properties of benzylamine and benzaldehyde on the photocatalysts were examined at 25 and 45 °C. The temperature effect on the adsorption of benzylamine is small in every system (Figure c) probably because of the strong acid–base interaction between the solids and benzylamine.…”

Chiroptical and colorimetric switches based on helical polymer-metal nanocomposites preparedviaredox metal translocation of helical polymer metal complexes

“…In recent decades, metallic nanoparticles (MNPs) have attracted the attention of the scientific community due to their multiple applications in fields such as sensing, 1 theranostics, 2,3 and catalysis, 4,5 among others. Most of these applications are related to the presence of localized surface plasmon resonance (LSPR) characteristics in these types of materials.…”