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 in situ 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.