Plasma-Induced Heating Effects on Platinum Nanoparticle Size During Sputter Deposition Synthesis in Polymer and Ionic Liquid Substrates

Nanoparticle catalyst materials are becoming ever more important in a sustainable future. Specifically, platinum (Pt) nanoparticles have relevance in catalysis, in particular, fuel cell technologies. Sputter deposition into liquid substrates has been shown to produce nanoparticles without the presence of air and other contaminants and the need for precursors. Here, we produce Pt nanoparticles in three imidazolium-based ionic liquids and PEG 600. All Pt nanoparticles are crystalline and around 2 nm in diameter. We show that while temperature has an effect on particle size for Pt, it is not as great as for other materials. Sputtering power, time, and postheat treatment all show slight influence on the particle size, indicating the importance of temperature during sputtering. The temperature of the liquid substrate is measured and reaches over 150 degrees C during deposition which is found to increase the particle size by less than 20%, which is small compared to the effect of temperature on Au nanoparticles presented in the literature. High temperatures during Pt sputtering are beneficial for increasing Pt nanoparticle size beyond 2 nm. Better temperature control would allow for more control over the particle size in the future.

Automated summary

Nanoparticle catalyst materials, particularly Pt nanoparticles, play a crucial role in sustainable development, especially in catalysis and fuel cell technologies. Temperature has an effect on the size of Pt nanoparticles, but it is not as significant as for other materials. Control over sputtering power, time, and postheat treatment can slightly influence particle size, highlighting the importance of temperature during sputtering. Increasing the temperature of the liquid substrate during sputtering can lead to a small increase in particle size, with high temperatures beneficial for achieving Pt nanoparticles larger than 2 nm.