In situ encapsulated and well dispersed Co3O4 nanoparticles as efficient and stable electrocatalysts for high-performance CO2 reduction

Abstract

The development of appropriate catalysts with relatively low cost, good selectivity and excellent stability is one of the major issues in electrochemical reduction of CO₂. In this work, an efficient electrocatalyst was fabricated via ultra-small Co₃O₄ nanoparticles encapsulated within the tip of carbon nanotubes, denoted as Co/CNTs. Benefiting from the synergistic effects of highly active Co₃O₄ nanoparticles and well-graphitized carbon nanotubes, Co/CNTs exhibited remarkable performance in CO₂ electroreduction. In a conventional H-type cell, CO with a 90% faradaic efficiency and 20.6 mA cm⁻² partial current density was obtained at only −0.7 V_RHE cathode potential with 40 hour stability. Upon switching to a gas-diffusion device, the CO partial current density could reach as high as 232.6 mA cm⁻² with >80% faradaic efficiency, which might be even comparable to that of state-of-the-art CO₂ electrocatalysts. Our work could also provide a new strategy for developing non-noble metal catalysts for CO₂ electroreduction.