Dealloying-Derived Nanoporous Bismuth for Selective CO 2 Electroreduction to Formate.

Electrochemical CO 2 reduction (CO 2 ER) to formate is an attractive approach for CO 2 utilization. Here, we report a nanoporous bismuth (np-Bi) catalyst fabricated by chemically dealloying a rapidly solidified Mg 92 Bi 8 alloy for CO 2 ER. The np-Bi catalyst exhibits a three-dimensional interconnected ligament-channel network structure, which can efficiently convert CO 2 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 CO 2 ER 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 CO 2 ER.