Abstract: The present invention relates to an ambient ion based method of making free-standing 2D metal sheets made of bare NPs, at the air-liquid interface. An electro-hydrodynamic flow field was generated by electrospray deposition on the liquid surface, which in turn assisted the assembly of the NPs. The NP-NSs were made under ambient conditions at room temperature from metal salt precursors. The sheets can be made of different elements such as Pd, Au, and Ag. Synthesized 2D NP-NSs were used as efficient and reusable heterogeneous catalysts for C—C bond formation reactions. These thin metal sheets may also be used as catalysts, sensors, gas adsorbing media, electrodes for electrochemical reactions, etc.