Shaping hollow spherical assemblies for enhanced Cu0/Cu+interface to boost C2+selectivity in CO2electroreduction

The creation of Cu0/Cu+interface over Cu-based catalysts is known to facilitate the production of multi-carbon (C2+) products during CO2reduction reaction (CO2RR). However, the Cu+moieties exhibit high susceptibility towards reduction into Cu0at a high current density. Thus, a comprehensive understanding and rational shaping strategy for the construction and stabilization of Cu0/Cu+interface in Cu-based catalysts is imperative. Herein, we proposed a controllable “nanoparticle assembly” strategy to obtain hollow spherical assemblies (HSA) composed of numerous Cu2O nanoparticles (HSA-Cu2O). The HSA-Cu2O catalysts significantly enhance the selectivity of C2+products, resulting in an impressive overall Faraday efficiency (FE) of 79.2% ± 0.7% at a partial current density of 317.1 mA cm−2. The HSA-Cu2O catalysts undergo in-situelectrochemically reconstruction during CO2RR, achieving Cu0/Cu+interfacial sites with a high density. The Auger electron spectra, in-situRaman, and morphological evolution studies have confirmed that the combination of the Cu0/Cu+interface and hollow sphere architecture facilitated the concentration of *CO intermediates, thereby promoting C–C dimerization to boost C2+selectivity in CO2RR.