Coupling Interfacial Redox‐Reactions with In Situ Proton Generation for the Photoelectrochemical Separation of Rare‐Earth Elements
Year: 2025
Type: article
Abstract: A dual‐function photoelectrochemical (PEC) separation system is demonstrated for rare‐earth element (REE) recovery. The sustainable release of the captured REEs is promoted through the synergistic integration of a redox‐reaction for electrostatic repulsion, and in situ proton generation for ion‐exchange, all driven by photoelectrochemistry. The platform consists of a redox‐copolymer, poly(ferrocenylpropyl methacrylamide‐ co ‐methacrylic acid) (P(FPMAm‐ co ‐MAA)) (PFM), conjugated with carbon nanotubes (CNTs) and coated onto titanium dioxide nanorods (TNRs). The (PFM‐CNT)/TNR spontaneously adsorbs up to 214.2 mg of Yttrium/g PFM by ion‐exchange, and demonstrates broad applicability for other REEs. The adsorbed REEs are released through the PEC oxidation of ferrocene (Fc) to ferrocenium (Fc + ), and the simultaneous PEC water splitting reactions at the TNRs that protonate the carboxylate binding groups. This dual photoelectrochemically‐driven mechanism for REE release is investigated by in situ pH measurements, as well as vibrational and X‐ray photoelectron spectroscopy. Through PEC approaches, a 68.8% reduction in energy consumption during REE recovery has been achieved compared to purely electrochemical systems, with a regeneration efficiency close to 100%. For NdFeB magnets from waste hard disk drives, Nd and Dy recovery efficiencies of 59.2 and 61.1% are achieved. The dual‐functionality of these copolymer PEC systems offers a sustainable platform for modulating critical element recovery.
Source: Advanced Functional Materials
Authors: Ki‐Hyun Cho, Wangsuk Oh, Melanie J. Fournier, Xiao Su
Institution: University of Illinois Urbana-Champaign
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $5,790
Funders: National Science Foundation, U.S. Department of Energy, Northwestern University, University of Illinois at Urbana-Champaign, Office of Science, Materials Research Science and Engineering Center, Harvard University, Division of Materials Research, Division of Electrical, Communications and Cyber Systems, Basic Energy Sciences
Awards: NNCI: Soft Hybrid Nanotechnology Experimental (SHyNE) Resource, G218438098, G2233802770, G2343375527, CONTINUOUS REDOX-MEDIATED ELECTROCHEMICAL LIQUID-LIQUID EXTRACTION FOR CRITICAL ELEMENT RECOVERY, G3010471893, G3203750490, Northwestern University Materials Research Science and Engineering Center, G4958141111, G6540817556
OpenAlex ID: W4410519096