Abstract
Background: The hydrogen evolution reaction is a crucial step in electrochemical water splitting to generate molecular hydrogen with high purity, but it usually suffers from a sluggish reaction kinetics in alkaline media because of additional water dissociation and/or improper adsorption energy of reactive hydrogen intermediates. It is desirable to design highly active and robust nonprecious electrocatalysts as alternatives to state-of-the-art commercially available Pt/C catalysts for large-scale hydrogen production via water-alkali electrolysis.
Methods: We developed monolithic nanoporous hybrid electrodes composed of electroactive Mo@MoOx nanoparticles, which are seamlessly integrated on hierarchical nanoporous Cu scaffold (Cu/Mo@MoOx) by making use of a spontaneous phase separation of Mo nanoparticles and subsequently, self-grown MoOx in chemical dealloying.
Results: Owing to the unique monolithic electrode architecture, in which the constituent Mo@MoOx nanoparticles work as electroactive sites and the hierarchical nanoporous Cu skeleton serves as fast electron-transfer and mass-transport pathways, the monolithic nanoporous Cu/Mo@MoOx hybrid electrode exhibits superior electrocatalysis in 1 M KOH, with a low Tafel slope of 66 mV dec−1 and outstanding stability. It only takes them ~185 mV overpotential to reach −400 mA cm−2, ~150 mV lower than that of nanoporous Cu supported Pt/C.
Conclusion: The outstanding electrochemical performance and excellent structural stability make nanoporous Cu/Mo@MoOx electrodes attractive alternatives to Pt/C catalysts in alkaline-based devices.
Keywords: Nanoporous metals, hybrid materials, hydrogen evolution reaction, electrocatalysts, metal oxides, dealloying.
Graphical Abstract
[http://dx.doi.org/10.1038/35104599] [PMID: 11713539]
[http://dx.doi.org/10.1038/nmat4834] [PMID: 27994253]
[http://dx.doi.org/10.1126/science.aad4998] [PMID: 28082532]
[http://dx.doi.org/10.1021/cr100290v] [PMID: 21375330]
[http://dx.doi.org/10.1126/science.1103197] [PMID: 15310892]
[http://dx.doi.org/10.1038/s41560-019-0407-1]
[http://dx.doi.org/10.1039/C4CS00470A] [PMID: 25672249]
[http://dx.doi.org/10.1038/nmat4738] [PMID: 27994237]
[http://dx.doi.org/10.1039/C4CS00448E] [PMID: 25886650]
[http://dx.doi.org/10.1038/nnano.2016.304] [PMID: 28192390]
[http://dx.doi.org/10.1126/sciadv.1501602] [PMID: 27034988]
[http://dx.doi.org/10.1021/jacs.8b04006] [PMID: 29792321]
[http://dx.doi.org/10.1021/jacs.6b09351] [PMID: 27775881]
[http://dx.doi.org/10.1002/anie.201710556] [PMID: 29194903]
[http://dx.doi.org/10.1002/advs.201700464] [PMID: 29610722]
[http://dx.doi.org/10.1039/c3ee00045a]
[http://dx.doi.org/10.1016/j.nanoen.2016.04.017]
[http://dx.doi.org/10.1016/S0013-4686(02)00329-8]
[http://dx.doi.org/10.1002/cphc.200500646] [PMID: 16607662]
[http://dx.doi.org/10.1021/acsenergylett.9b00845]
[http://dx.doi.org/10.1039/C4EE01760A]
[http://dx.doi.org/10.1038/ncomms5695] [PMID: 25146255]
[http://dx.doi.org/10.1021/ja5127165] [PMID: 25658518]
[http://dx.doi.org/10.1002/adma.201506314] [PMID: 26996884]
[http://dx.doi.org/10.1021/acscatal.8b02904]
[http://dx.doi.org/10.1021/jacs.5b11986] [PMID: 26777119]
[http://dx.doi.org/10.1002/anie.201602237] [PMID: 27100374]
[http://dx.doi.org/10.1002/adfm.201603674]
[http://dx.doi.org/10.1002/adma.201602697] [PMID: 27717140]
[http://dx.doi.org/10.1002/adma.201704156]
[http://dx.doi.org/10.1002/aenm.201600221]
[http://dx.doi.org/10.1002/adma.201605502]
[http://dx.doi.org/10.1021/acscatal.8b04291]
[http://dx.doi.org/10.1002/adfm.201600915]
[http://dx.doi.org/10.1021/acscatal.8b01794]
[http://dx.doi.org/10.1016/S0022-0728(72)80485-6]
[http://dx.doi.org/10.1021/acscatal.8b00949]
[http://dx.doi.org/10.1038/ncomms7512] [PMID: 25758159]
[http://dx.doi.org/10.1002/adma.201403808] [PMID: 25363090]
[http://dx.doi.org/10.1038/ncomms3169] [PMID: 23851924]
[http://dx.doi.org/10.1007/s10973-019-08977-0]
[http://dx.doi.org/10.1007/s10973-019-08694-8]
[http://dx.doi.org/10.1108/MMMS-02-2018-0023]
[http://dx.doi.org/10.1038/s41598-020-63708-y] [PMID: 32317721]
[http://dx.doi.org/10.1615/ComputThermalScien.2020027016]
[http://dx.doi.org/10.1146/annurev-matsci-070115-031739]
[http://dx.doi.org/10.1002/adfm.201401868]
[http://dx.doi.org/10.1002/adma.200702700]
[http://dx.doi.org/10.1038/s41467-020-16769-6] [PMID: 32522988]
[http://dx.doi.org/10.34133/2020/2987234] [PMID: 32161925]
[http://dx.doi.org/10.1016/j.apcatb.2017.01.074]
[http://dx.doi.org/10.1021/j100126a024]
[http://dx.doi.org/10.1038/s41929-018-0200-8]
[http://dx.doi.org/10.1021/acsenergylett.9b00091]