Dealloying-Derived Nanoporous Bismuth for Selective CO2 Electroreduction to Formate

Electrochemical CO2 reduction (CO2ER) to formate is an attractive approach for CO2 utilization. Here, we report a nanoporous bismuth (np-Bi) catalyst fabricated by chemically dealloying a rapidly solidified Mg92Bi8 alloy for CO2ER. The np-Bi catalyst exhibits a three-dimensional interconnected ligament-channel network structure, which can efficiently convert CO2 to formate with a selectivity of ≤94% and an activity of 62 mA cm–2 in a wide potential range. Remarkably, the np-Bi catalyst delivers an industry-level current density of ∼500 mA cm–2 for formate production at a low overpotential of 420 mV in the flow cell. The outstanding CO2ER performance can be attributed to the enlarged surface area with abundant accessible active sites and highly curved surfaces with enhanced intrinsic activity. This work highlights the structural synergies for enhancing CO2ER.