Bamboo-like amorphous Ni(OH)2 nanotubes wrapped Cu nanoparticles with a confined geometry for CO2 electroreduction to ethane in a flow cell

It has made significant progress in catalyst and reactor design for commercial current densities in CO₂ electroreduction (CO₂ER). However, these catalyst systems have rarely been applied for a C₂ gas product of ethane due to its commonly inferior selectivity relative to other C₁ and C₂ products. Herein, bamboo-like amorphous Ni(OH)₂ nanotubes wrapped Cu nanoparticles composite (Cu NPs@a-Ni(OH)₂ NTs) is constructed for selective CO₂ER to ethane in a flow cell. The unique Cu NPs@a-Ni(OH)₂ NTs structure provides a confined geometry to improve the adsorption of the reactive species. The interface of Cu NPs and a-Ni(OH)₂ NTs is stabilized by generating some NiOH species. The produced Cu@NiOH interface enhances the activation of CO₂ to *C*OOH and strengthens the adsorption of *CO_L on Cu site for more *COH formation and its dimerization for final ethane production. Meanwhile, amorphous Ni(OH)₂ nanotubes promote water dissociation for the hydrogenation of carbonous intermediates, contributing to ethane production. The synthesized Cu NPs@a-Ni(OH)₂ NTs can reach a Faradaic efficiency of 48.3% and a partial current density of −226.7 mA cm⁻² for ethane at −0.7 V in a flow cell, with a remarkable stability for 24 h. This work provides a rational strategy to engineer Cu-based composite for selective CO₂ER to ethane in a flow cell.