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

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 photothermal-mediated 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 photothermal-mediated catalytic reduction of 4-nitrophenol with poly(N-isopropylacrylamide-acrylamide) [p(NIPAM-AA)] and HAuNPs. The amount of satellite HAuNPs (80 ppm) on 10 mu L 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.

Automated summary

The study investigated the use of core-satellite structures in photothermal-mediated catalytic reactions, enhancing the photothermal effect by adjusting the structure and spacing of HAuNPs. The results demonstrated that localized heating effectively increased catalytic activity without the need to heat the entire solution additionally.