Lignin-derived bimetallic platinum group metal-free oxygen reduction reaction electrocatalysts for acid and alkaline fuel cells

• Published in: Journal of power sources Vol. 556; p. 232416
• Main Authors: Muhyuddin, Mohsin, Friedman, Ariel, Poli, Federico, Petri, Elisabetta, Honig, Hilah, Basile, Francesco, Fasolini, Andrea, Lorenzi, Roberto, Berretti, Enrico, Bellini, Marco, Lavacchi, Alessandro, Elbaz, Lior, Santoro, Carlo, Soavi, Francesca
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2023
• Subjects: Anion exchange membrane fuel cell; Lignin-derived char; Oxygen reduction reaction; Platinum group metal-free; Proton exchange membrane fuel cell; Anion exchange membrane fuel cell; Proton exchange membrane fuel cell; Lignin-derived char; Platinum group metal-free; Oxygen reduction reaction
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2022.232416

Metal-nitrogen-carbons (M-N-Cs) as a reliable substitution for platinum-group-metals (PGMs) for oxygen reduction reaction (ORR) are emerging candidates to rationalize the technology of fuel cells. The development of M-N-Cs can further be economized by consuming waste biomass as an inexpensive carbon source for the electrocatalyst support. Herein, we report the simple fabrication and in-depth characterization of electrocatalysts using lignin-derived activated char. The activated char (LAC) was functionalized with metal phthalocyanine (FePc and MnPc) via atmosphere-controlled pyrolysis to produce monometallic M-N-Cs (L_Mn and L_Fe) and bimetallic M1-M2-N-Cs (L_FeMn) electrocatalysts. Raman spectroscopy and transmission electron microscopy (TEM) revealed a defect-rich architecture. XPS confirmed the coexistence of various nitrogen-containing active moieties. L_Fe and L_FeMn demonstrated appreciable ORR in both acidic and alkaline conditions whereas L_FeMn helped in restricting the peroxide yield, particularly in alkaline media. L_Fe and L_FeMn demonstrated remarkable onset potential (Eonset) of ∼0.942 V (vs RHE) with an E1/2 of 0.874 V (vs RHE) in 0.1 M KOH. In acid, L_FeMn had an Eonset of 0.817 V (vs RHE) and an E1/2 of ∼0.76 V (vs RHE). Finally, the L_FeMn as a cathode electrocatalyst was integrated and tested in PEMFC and AEMFC. AEMFC demonstrated optimistic performance with a peak power density of 261 mW cm−2 at the current density of ∼577 mA cm−2. •Waste lignin was valorized through pyrolysis and high surface area char was synthesized.•The biochar was functionalized by Fe-, Mn- and Fe–Mn phthalocyanine.•Fe- and FeMn- catalysts showed superior ORR compared to Mn-catalyst.•Integration of PGM-free FeMn-catalyst in PEMFC reached a Pmax of ∼72 mW cm−2.•Integration of PGM-free FeMn-catalyst in AEMFC reached a Pmax of ∼261 mW cm−2.