Eectronic Regulation of Ni Single Atom by Confined Ni Nanoparticles for Energy-Efficient CO2 Electroreduction

The electronic modulation of atomic dispersed active sites is promising to boost the catalytic activity, which is however remains a challenge. Here we show a cooperative Ni single-atom on nanoparticle catalyst (NiSA/NP) via direct solid-state pyrolysis, where Ni nanoparticles donate electrons to Ni(i)-N-C sites via carbon nanotubes network, achieving a high CO current density of 346 mA cm-2 at -0.5 V vs RHE in an alkaline flow cell. When coupled with a NiFe-based oxygen evolution anode into a zero-gap membrane electrolyzer, it delivers an industrial-relevant CO current density of 310 mA cm-2 at a low cell voltage of -2.3 V, corresponding to an overall energy efficiency of 57%. The superior CO2 electroreduction performance is attributed to the enhanced adsorption of key intermediate COOH* on electron-rich Ni single atom, together with the dense active sites.