Disordered Cu Sites in Amorphous Cu2Te Nanosheets Promote Electrocatalytic Acetylene Semi-hydrogenation.

Electrocatalytic acetylene semi-hydrogenation offers a sustainable and energy-efficient alternative to conventional thermocatalytic methods, yet remains challenged by competing side reactions, including hydrogen evolution, over-hydrogenation, and carbon-carbon coupling. Here, the transformation of 2D van der Waals crystalline Cu2Te nanosheets (c-Cu2Te NSs) into oxygen-doped amorphous analogues (a-Cu2Te NSs) via controlled air calcination is reported. The resulting a-Cu2Te NSs feature a disordered Cu coordination network and deliver an ethylene Faradaic efficiency of 91.7% at a high partial current density of 550 mA cm-2, along with excellent stability, outperforming both c-Cu2Te NSs and state-of-the-art catalysts. Mechanism investigations reveal that structural amorphization drives the redistribution of interlayer Cu atoms and alters key electronic properties, including the density of states and the Cu d-band center, through Cu 3d-O 2p orbital hybridization. These effects increase the density of accessible Cu active sites, optimize adsorption energetics, accelerate interfacial water dissociation, and promote hydrogen accumulation, thereby effectively suppressing undesirable side reactions. This work highlights amorphous engineering as a powerful strategy for designing high-performance electrocatalysts.