Colloidal Synthesis Enables Indium Solubility Modulation in Liquid Gallium Nanoparticles for Temperature-dependent Generation of CO2 Electrocatalytic Active Sites

Bulk liquid metals (LMs) are unique stimuli-responsive dynamic materials which are appealing across different fields of science and technology, including catalysis. However, their low surface-to-volume ratio, limited atomic-scale design and required ad-hoc reactor engineering limit their exploitation. Colloidal LM nanoparticles (NPs) can address all these shortcomings; however, their synthetic chemistry is challenging and less advanced compared to other materials. Here, we advance the synthetic knowledge on LM NPs and propose a colloidal approach for the synthesis of monodispersed In-Ga NPs with tunable indium content via a balanced precursor reactivity strategy. The synthesis generates temperature- and voltage- responsive supercooled metastable NPs, which we leverage for CO2 electroreduction. The metastable NPs show a unique temperature-dependent modulation of active sites, which results into increasing formate production with temperature. This behavior opposes the temperature deactivation reported so far for solid CO2RR catalysts towards the same product.