Scalable Edge-Oriented Metallic Two-Dimensional Layered Cu₂Te Arrays for Electrocatalytic CO₂ Methanation.

Abstract

Copper-based nanomaterials are compelling for high-efficient, low-cost electrocatalytic CO₂ reduction reaction (CO₂RR) due to their exotic electronic and structural properties. However, controllable preparation of copper-based two-dimensional (2D) materials with abundant catalytically active sites, that guarantee high CO₂RR performance, remains challenging, especially on a large scale. Here, an <i>in situ</i> vertical growth of scalable metallic 2D Cu₂Te nanosheet arrays on commercial copper foils is demonstrated for efficient CO₂-to-CH₄ electrocatalysis. The edge-oriented growth of Cu₂Te nanosheets with tunable sizes and thicknesses is facilely attained by a two-step process of chemical etching and chemical vapor deposition. These active sites abounding on highly exposed edges of Cu₂Te nanosheets greatly promote the electroreduction of CO₂ into CH₄ at a potential as low as -0.4 V (versus the reversible hydrogen electrode), while suppressing hydrogen evolution reaction. When a flow cell is employed to accelerate the mass transfer, the faradaic efficiency reaches ∼63% at an applied current density of 300 mA cm^-2. These findings will provide great possibilities for developing scalable, energy-efficient Cu-based CO₂RR electrocatalysts.