Facile synthesis of platinum-copper aerogels for the oxygen reduction reaction

Abstract

Although carbon-supported platinum (Pt/C) has been generally used as a catalyst for the oxygen reduction reaction (ORR) in fuel cells, its practical application is limited by the corrosion reaction of the carbon support. Therefore, it is essential to develop new self-supported catalysts for the ORR. Noble metal aerogels represent highly promising self-supported catalysts with large specific surface area and excellent electrocatalytic activity. Classic sol-gel processes for aerogel synthesis usually take days due to the slow gelation kinetics. Here, we report a straightforward strategy to synthesize platinum-copper (PtCu) aerogels by reducing the metal salt solution with an excess of sodium borohydride at room temperature. The PtCu aerogels are formed in a relatively short time of 1 h through a rapid nucleation mechanism. The obtained PtCu aerogels have a highly porous structure with an appreciable topological surface area of 33.0 m²/g and mainly exposed (111) facets, which are favorable for the ORR. Consequently, the PtCu aerogels exhibit excellent ORR activity with a mass activity of 369.4 mA/mg_Pt and a specific activity of 0.847 mA/cm², which are 2.6 and 3.3 times greater than those of Pt/C, respectively. The PtCu aerogels show remarkable ORR catalysis among all the noble metal aerogels that have been reported. The porous morphology and outstanding electrocatalytic activities of the PtCu aerogels illustrate their promising applications in fuel cells.

Keywords

Noble metal aerogels / platinum-copper alloy / rapid nucleation / electrocatalysis / oxygen reduction reaction

References

[1] Nørskov JK,Logadottir A.Origin of the overpotential for oxygen reduction at a fuel-cell cathode.J Phys Chem B2004;108:17886-92

[2] Yu Y,Wang C.High-entropy alloy nanoparticles as a promising electrocatalyst to enhance activity and durability for oxygen reduction.Nano Res2022;15:7868-76

[3] Lu R,Zhang C.Establishing a theoretical insight for penta-coordinated iron-nitrogen-carbon catalysts toward oxygen reaction.Nano Res2022;15:6067-75

[4] Jang I,Jang J,Yoo SJ.Improved platinum-nickel nanoparticles with dopamine-derived carbon shells for proton exchange membrane fuel cells.Intl J of Energy Res2022;46:13602-12

[5] Sohn Y,Kim P.Dealloyed PtCu catalyst as an efficient electrocatalyst in oxygen reduction reaction.Curr Appl Phys2015;15:993-9

[6] Wu D,Dai C.Enhanced oxygen reduction activity of PtCu nanoparticles by morphology tuning and transition-metal doping.Int J Hydrog Energy2020;45:4427-34

[7] Garcia-cardona J,Alcaide F,Centellas F.Electrochemical performance of carbon-supported Pt(Cu) electrocatalysts for low-temperature fuel cells.Int J Hydrog Energy2020;45:20582-93

[8] Pavlets A,Tabachkova NY.A novel strategy for the synthesis of Pt–Cu uneven nanoparticles as an efficient electrocatalyst toward oxygen reduction.Int J Hydrog Energy2021;46:5355-68

[9] Strasser P,Anniyev T.Lattice-strain control of the activity in dealloyed core-shell fuel cell catalysts.Nat Chem2010;2:454-60

[10] Stephens IE,Perez-Alonso FJ.Tuning the activity of Pt(111) for oxygen electroreduction by subsurface alloying.J Am Chem Soc2011;133:5485-91

[11] Zhao J,Chan SH.Carbon corrosion mechanism and mitigation strategies in a proton exchange membrane fuel cell (PEMFC): a review.J Power Sources2021;488:229434

[12] Bigall NC,Vogel M.Hydrogels and aerogels from noble metal nanoparticles.Angew Chem Int Ed Engl2009;48:9731-4

[13] Wen D,Borchardt L.Controlling the growth of palladium aerogels with high-performance toward bioelectrocatalytic oxidation of glucose.J Am Chem Soc2014;136:2727-30

[14] Du R,Hübner R.Specific ion effects directed noble metal aerogels: versatile manipulation for electrocatalysis and beyond.Sci Adv2019;5:eaaw4590 PMCID:PMC6534393

[15] Ranmohotti KGS,Arachchige IU.Salt-mediated self-assembly of metal nanoshells into monolithic aerogel frameworks.Chem Mater2013;25:3528-34

[16] Gao X,Luong TT,Arachchige IU.Oxidation-induced self-assembly of Ag nanoshells into transparent and opaque Ag hydrogels and aerogels.J Am Chem Soc2014;136:7993-8002

[17] Gao X,Nahar L,Arachchige IU.Direct cross-linking of Au/Ag Alloy nanoparticles into monolithic aerogels for application in surface-enhanced raman scattering.ACS Appl Mater Interfaces2016;8:13076-85

[18] Nahar L,Esteves RJA.Shape controlled synthesis of Au/Ag/Pd nanoalloys and their oxidation-induced self-assembly into electrocatalytically active aerogel monoliths.Chem Mater2017;29:7704-15

[19] Naskar S,Deutsch J.Porous aerogels from shape-controlled metal nanoparticles directly from nonpolar colloidal solution.Chem Mater2017;29:9208-17

[20] Wen D,Haubold D.Gold aerogels: three-dimensional assembly of nanoparticles and their use as electrocatalytic interfaces.ACS Nano2016;10:2559-67 PMCID:PMC4768295

[21] Wen D,Herrmann AK.Simple and sensitive colorimetric detection of dopamine based on assembly of cyclodextrin-modified Au nanoparticles.Small2016;12:2439-42

[22] Zhu C,Fu S.Efficient synthesis of MCu (M = Pd, Pt, and Au) aerogels with accelerated gelation kinetics and their high electrocatalytic activity.Adv Mater2016;28:8779-83

[23] Du R,Fan X.Disturbance-promoted unconventional and rapid fabrication of self-healable noble metal gels for (photo-)electrocatalysis.Matter2020;2:908-20 PMCID:PMC7115346

[24] Liu W,Geiger D.High-performance electrocatalysis on palladium aerogels.Angew Chem Int Ed Engl2012;51:5743-7

[25] Henning S,Kühn L.Unsupported Pt-Ni aerogels with enhanced high current performance and durability in fuel cell cathodes.Angew Chem Int Ed Engl2017;56:10707-10

[26] Liu W,Borchardt L.Bimetallic aerogels: high-performance electrocatalysts for the oxygen reduction reaction.Angew Chem Int Ed Engl2013;52:9849-52

[27] Shi Q,Du D.Kinetically controlled synthesis of AuPt bi-metallic aerogels and their enhanced electrocatalytic performances.J Mater Chem A2017;5:19626-31

[28] Shi Q,Zhong H.Nanovoid incorporated Ir x Cu metallic aerogels for oxygen evolution reaction catalysis.ACS Energy Lett2018;3:2038-44

[29] Wang H,Luo X.Ternary PtRuCu aerogels for enhanced methanol electrooxidation.Nanoscale2019;11:10575-80

[30] Shi Q,Tian M.Ultrafine Pd ensembles anchored-Au₂Cu aerogels boost ethanol electrooxidation.Nano Energy2018;53:206-12

[31] Zhu C,Fu S.Core-shell PdPb@Pd aerogels with multiply-twinned intermetallic nanostructures: facile synthesis with accelerated gelation kinetics and their enhanced electrocatalytic properties.J Mater Chem A2018;6:7517-21

[32] Burpo FJ,Morris LA,Ryu MY.Direct solution-based reduction synthesis of Au, Pd, and Pt aerogels.J Mater Res2017;32:4153-65 PMCID:PMC6101767

[33] Yazdan-abad M, Noroozifar M, Modaresi Alam AR, Saravani H. Palladium aerogel as a high-performance electrocatalyst for ethanol electro-oxidation in alkaline media.J Mater Chem A2017;5:10244-9

[34] Yazdan-abad M, Noroozifar M, Douk AS, Modarresi-alam AR, Saravani H. Shape engineering of palladium aerogels assembled by nanosheets to achieve a high performance electrocatalyst.Appl Catal B2019;250:242-9

[35] Douk A, Saravani H, Noroozifar M. Three-dimensional assembly of building blocks for the fabrication of Pd aerogel as a high performance electrocatalyst toward ethanol oxidation.Electrochim Acta2018;275:182-91

[36] Kondo S,Maki N.Active sites for the oxygen reduction reaction on the low and high index planes of palladium.J Phys Chem C2009;113:12625-8