Photo-induced acceleration of chemical reactions by spherical mono- and bimetallic nanoparticles

Abstract

The paper considers the problem of choosing the composition, structure, and size of spherical catalyst nanoparticles for carrying out plasmon-induced polymerization reactions. The concept of reducing the activation energy of the reaction in the presence of a catalyst and, accordingly, increasing the rate of a chemical reaction during heating due to the excitation of surface plasmon resonance is presented. Using the Drude model for the dielectric function, relationships were obtained for the frequency dependences of such characteristics as the real and imaginary parts of the polarizability, heating and the rate of chemical reactions when monometallic and bimetallic nanoparticles are used as catalysts, as well as the amplification of fields in their vicinity. The concepts developed in this work take into account the classical size dependence of the effective electron relaxation rate in monometallic and bimetallic nanoparticles under the assumption of diffuse scattering of electrons. Changes in the positions of the maxima of the imaginary part of the polarizability, heating, and reaction rate are analyzed with a change in the radii of monometallic and bimetallic nanoparticles. It is shown that the maxima of the dependences under study correspond to dipole surface plasmon resonances, and their number depends on the particle morphology. Changes in the amplification of electric fields in the vicinity of nanoparticles of different morphology have been studied. It has been found that the enhancement of the fields in all considered cases is maximum on the surface of the nanoparticle and decreases with distance from it. Practical recommendations are formulated regarding the size, composition and structure of nanoparticles for plasmon catalysis, which provide the highest rates of chemical reactions. Thus, all obtained frequency dependences have one maximum for monometallic and two maxima for bimetallic nanoparticles.