The Bismuth Architecture Assembled by Nanotubes Used as Highly Efficient Electrocatalyst for CO2 Reduction to Formate

Abstract Electrochemical conversion of CO2 into valuable chemical fuels is a promising technology for addressing climate change and energy issues, but the progress of it has been hampered by the lack of selective and stable electrocatalysts. In this work, metallic bismuth (Bi) architecture electrocatalyst was synthesized by in situ electrochemical reduction of two-dimensional (2D) bismuth oxyiodide (BiOI) architecture, which was composed by one-dimensional (1D) BiOI nanotubes using structural assembly method. Owning to the enhanced active sites from this unique morphology, this Bi electrocatalyst exhibited high activity, excellent selectivity (Formate Faradaic efficiency is 97.1% with a partial current density of 31.1 mA cm−2 at an overpotential of only 790 mV), and excellent durability (65 h at a current density of 10 mA cm−2) for CO2 reduction reaction (CO2RR). For deeply understanding the factors governing the activity of this Bi catalyst, density functional theory (DFT) computations are employed, and the OCHO* intermediate preferentially adsorbs on the edge sites. When the rich edges sites were covered by oleylamine molecules, this step was impeded, and formate production obviously decreased. This work shows the importance of metallic Bi with unique nanostructure for catalyzing CO2RR towards formate with high efficiency and selectivity.