# Cu─O─Al Interfacial Engineering on Cu Nanowires for Durable CO2 Electroreduction Into Multi‐Carbon Products

## TL;DR

This paper introduces a new catalyst design that improves CO2 electroreduction into multi-carbon products while maintaining long-term stability.

## Contribution

A Cu nanowire/AlOx core-shell catalyst is developed to enhance CO2 electroreduction selectivity and durability through interfacial engineering.

## Key findings

- The Cu─O─Al interface stabilizes Cu+ species and promotes C─C coupling for efficient C2+ production.
- The catalyst achieves a C2+ Faradaic efficiency of 69.6% at 600 mA cm−2 with stability over 64 hours.
- AlOx shell crystallinity tuning affects product distribution via *OH adsorption at the interface.

## Abstract

The balance between high selectivity and long‐term stability for multi‐carbon (C2+) production remains a critical challenge in CO2 electrocatalysis due to competing reaction pathways and catalyst reconstruction under operating conditions. In this study, a core‐shell heterostructure is synthesized by encapsulating copper nanowires (Cu NWs) with an aluminum oxide (AlOx) shell. Acting as a Lewis acid, the AlOx shell promotes charge redistribution to stabilize Cu+ species at the Cu─O─Al interface while creating an alkaline local microenvironment via *OH adsorption. These effects not only stabilize the catalyst structure but also preserve an optimal *CO intermediate coverage for efficient C─C coupling, as evidenced by in situ Raman spectroscopy and density functional theory (DFT) calculations. As a result, the system achieves a remarkable C2+ Faradaic efficiency (FE) of 69.6% at 600 mA cm−2 in a flow‐cell configuration. The stability tests further reveal a sustained FEC2+ above 50% over 64 h of continuous operation at 300 mA cm−2. Tuning of the AlOx shell crystallinity alters product distribution owing to different *OH adsorption capacities at the Cu─O─Al interface. These findings highlight the promise of AlOx encapsulation as a versatile strategy to simultaneously enhance selectivity and durability of Cu‐based catalysts in the electrochemical CO2 reduction reaction (eCO2RR).

A Cu nanowire/AlOx core‐shell catalyst is reported for CO2 electroreduction. Acting as a Lewis acid, the AlOx shell not only stabilizes Cu+ species at the Cu─O─Al interface but also creates an alkaline local microenvironment via *OH adsorption. This dual functionality stabilizes the catalyst structure while promoting the C─C coupling process, resulting in efficient and durable multicarbon production.