Au-coated Fe3O4@SiO2 core-shell particles with photothermal activity

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

“…For example, Aucoated Fe 3 O 4 @SiO 2 core−shell catalysts showed higher catalytic activity under NIR irradiation than Au-coated Fe 3 O 4 without shell. 18,19 In addition, core−shell TiO 2 NPs 22 and hollow cubic CuS@spiky Au core−shell particles showed high performance as photothermal agents. 23 Core materials acted as vehicles for supporting the shell materials, which mainly contributed as catalytic sites with strong absorption of NIR by their LSPR phenomena.…”

“…After thermal equilibrium, which occurred after 20 min, the NIR laser was turned off and the solution was cooled for 10 min. Based on the cooling curve in Figure , the photothermal conversion efficiency was calculated as follows , where η, h , and A are the photothermal conversion efficiency, heat transfer coefficient, and surface area of the sample, respectively; T max and T Surr are the temperature at and around the thermal equilibrium state, respectively; I is the laser power; and A wavelength is the absorbance of the sample at a wavelength of 808 nm. Owing to the unprecise information on the surface area, hA was determined from the dimensionless driving force temperature (θ) and time constant (τ s ), which are defined as follows where T , m i , and C p , i are the solution temperature, mass, and heat capacity, respectively.…”

“…The surface temperature of the p­(NIPAM-AA)@HAuNPs was increased by the photothermal effect under NIR irradiation, but the reactor temperature was not increased. The reactor configuration and temperature change were determined in a previous study . The photothermal-mediated catalytic activities were induced on samples with photothermal conversion efficiency above 50% and were monitored with a UV–vis spectrometer.…”

“…To enhance the photothermal effect, the structure of the AuNPs was changed to a hollow form by galvanic replacement reaction of AgNPs with a gold precursor. In previous studies, HAuNPs showed higher absorption in the NIR region than spherical AuNPs. , The reaction rate and photothermal conversion efficiency of the reduction of 4-NP by the as-made catalysts, p­(NIPAM-AA)@HAuNPs, was tested with different numbers of HAuNPs loaded onto the p­(NIPAM-AA) and with and without NIR irradiation. To confirm the photothermally localized heating effect by the HAuNPs in the reaction, a control experiment was also conducted whereby the temperature of the solution itself was increased.…”

Rare‐Earth Doped Iron Oxide Nanostructures for Cancer Theranostics: Magnetic Hyperthermia and Magnetic Resonance Imaging

“…[3,4,6] In addition, the magnetic properties of superparamagnetic nanoparticles depend on nanoparticle crystallite size, shape, and geometry. Therefore, researchers turned their attention on the fabrication of pure Fe 3 O 4 (magnetite) with tunable sizes and shapes, and its derivatives starting from core-shell geometries, [10][11][12][13][14][15][16][17][18][19] nanocomposites [20][21][22][23][24][25][26][27][28] to doped systems [29][30][31][32][33][34][35] having interesting magnetic, dielectric and chemical properties and applied them for advanced technological and biomedical applications. For example, bulk magnetite exhibits a saturation magnetization (M S ) of about 92 emu g -1 .…”