CO2-Assisted Synthesis of Amorphous and Crystal PdCu Nanodots for Enhanced Photothermal and Catalytic Application

Abstract

Metallic nanomaterials with an amorphous structure and unique properties have received increasing attention. However, the formation of the amorphous structure is strictly limited by the preparation method, and at the same time, the control of the proportion of amorphous regions is difficult to realize. Here, for the first time, we report that PdCu nanodots with an amorphous or crystal structure can be successfully modulated with the assistance of supercritical carbon dioxide (SC CO2), including their thickness, crystallinity, and valence state. In addition, the corresponding applications of the as-prepared PdCu nanodots are also demonstrated; amorphous PdCu nanodots can realize efficient photothermal conversion, while crystal PdCu nanodots can help realize excellent electrocatalytic activity for formic acid oxidation. The mass activity is 1502.6 mA/mgPd, which is 3.7 times higher than that of the commercial Pd/C catalyst. More importantly, this study sheds light on the amorphization mechanism of a pure metal material system in SC CO2 and provides inspiration for preparing more amorphous nanomaterials with fascinating structures and properties.