Efficient Lead Removal by Assembly of Bio-Derived Ellagate Framework, Which Enables Electrocatalytic Reduction of CO₂...

Lead (Pb) poisoning and CO₂-induced global warming represent two exemplary environmental and energy issues threatening humanity. Various biomass-derived materials are reported to take up Pb and convert CO₂ electrochemically into low-valent carbon species, but these works address the problems separately rather than settle the issues simultaneously. In this work, cheap, natural ellagic acid (EA) extracted from common plants is adopted to assemble a stable metal-organic framework (MOF), EA-Pb, by effective capture of Pb²⁺ ions in an aqueous medium (removal rate close to 99%). EA-Pb represents the first structurally well-defined Pb-based MOF showing selective electrocatalytic CO₂-to-HCOO^- conversion with Faradaic efficiency (FE) of 95.37% at -1.08 V versus RHE. The catalytic mechanism is studied by ¹³CO₂ labeling, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and theoretical calculation. The use of EA-Pb as an electrocatalyst for CO₂ reduction represents a 2-in-1 solution of converting detrimental wastes (Pb²⁺) as well as natural resources (EA) into wealth (electrocatalytic EA-Pb) for addressing the global warming issue.