Flooding-tolerant C2-selective CO2 reduction electrode based on hydrophobic Cu-W tandem electrocatalyst

CO2 conversion to value-added mono/multicarbon products is an appealing area of research to achieve negative CO2 emissions while exploiting CO2 as a C-based feedstock. The CO2 reduction reaction (CO2RR) powered by renewable electricity provides a way to effectively utilize CO2.

Gas diffusion electrode (GDE)-based CO2RR reactors significantly increase current density to commercially relevant levels due to thinner mass transport layers that overcome the aqueous systems diffusion constraint.

Nevertheless, it is still challenging to achieve highly stable GDE, especially in high current density operation, owing to electrolyte flooding as a consequence of hydrophobicity decline. So, the GDE is the primary driver of CO2RRs viability, but improving its performance is paramount.

What sets this proposal apart from previous researches is that we seek to demonstrate a compelling way to reinforce the structure of Cu-based GDEs via the formation of bimetallic structures pursuing tandem effect without using precious metals, which enhances the selectivity toward C2 products.

An improvement in the performance and C2 selectivity is envisaged thanks to the formation of noble metal-free Cu-W heterostructures for the first time, giving rise to heteroatomic reaction sites between oxophilic W and Cu atoms to reduce the bonding energy of adsorbed CO. At the same time, flooding is minimized by the obtained hydrophobic surface topology.

The surface topology endows high surface area with adequate hydrophobicity to the GDE to establish an electrode/electrolyte interface, which not only traps more CO2 along the hierarchical Cu-W surface as tandem active sites, but also efficiently prevents electrolyte flooding even at high rates.

FOTOCER's achievements will lead to advancements in cutting-edge industrial CO2 to useful C2+ products, which are essential in achieving the EU's environmental targets at an affordable scale-up cost.