Catalytic activation of liquid gallium by discretely dispersed copper atoms

• Gallium based alloys containing copper can be used for reduction reactions. • Experimental and theoretical approach confirmed that the copper atoms activate the surrounding gallium atoms, providing evidence for a previously proposed reaction mechanism underpinning liquid metal-based catalysis. • Transition metals can activate and catalyse the oxidation of a liquid metal solvent. Despite the rising use of liquid metal alloys in catalytic applications, the nature of synergistic effects between constituent metals which are central to achieving enhanced reactivity, remains unclear. Herein, we report the synthesis of liquid metal alloys consisting of discretely dispersed Cu in the eutectic gallium-indium alloy EGaIn and investigate the role Cu plays in the activation of Ga. The performance of Cu-based liquid metal alloys was assessed for the synthesis of solketal and in situ hydrogen generation applications. Molecular dynamics simulations combined with experimental investigation indicated that the activation of Ga atoms by adjacent Cu atoms is responsible for the observed enhanced activity of the Cu-EGaIn alloy. This research clarifies the role dissolved metallic species play in liquid metal catalysis and also highlights opportunities for the use of liquid metals as reducing agents in organic synthesis and in situ hydrogen generation applications.