Laser Irradiation Induced Melting and Reduction Reaction for the formation of Pt-based Bimetallic Alloy Particles in Liquids

Laser melting in liquids (LML) is one of the most effective methods to prepare bimetallic alloys, the formation process of which is always research focus but still ambiguous. In this paper, we prepared two types of Pt-based bimetallic alloys by LML, including Pt-Au alloys and Pt-iron group metal (iM = Fe/Co/Ni) alloys, and investigated the corresponding mechanisms of alloying process. Detailed component and structural characterizations indicate that laser irradiation induced a quite rapid formation process (not exceed 10 s) of Pt-Au alloy nanospheres, and the crystalline structures of Pt-Au alloys is determined by the monometallic constituents with higher content. For Pt-iM alloys, we show direct evidences to support that FeOx/CoOx/NiOx colloids can be reduced to elementary Fe/Co/Ni particles by ethanol molecules during laser irradiation, which then react with Pt colloids to form Pt-iM sub-microspheres. These results manifest that LML provide an optional route to prepare Pt-based bimetallic alloy particles with tunable size, components, crystalline phase, which should have promising applications in biological and catalysis studies.