SCHEDULED MAINTENANCE
Synthesis of S-doped AuPbPt alloy nanowire-networks as superior catalysts towards the ORR and HER†
c
and
Haibing
Xia
*a
Abstract
In this work, S-doped AuPbPt alloy nanowire-networks (NWNs) are synthesized by conformal growth of Pt onto S-doped AuPb NWNs as templates, which are obtained by NaBH4 reduction of an extended network of 2 nm Au nanoclusters resulting from Pb2+ ion-directed self-assembly. The contents of Pb and S in the S-doped AuPb NWNs are optimized in order to create the appropriate content of PtS in the resulting S-doped AuPbPt alloy NWNs because Pb in both AuPb3 and PbS is involved with the formation of PtS and PbPtx during the conversion of S-doped AuPb NWNs to S-doped AuPbPt alloy NWNs. Moreover, the formation of an optimal content of PtS in the resulting S-doped AuPbPt alloy NWNs remarkably downshifts the d-band center of Pt, on the basis of results from X-ray Photoelectron Spectroscopy (XPS) characterization and density functional theory (DFT) calculations, and then improves the resistance of active Pt sites against oxidation and in turn renders the Pt surfaces more catalytically active for the ORR and more structurally stable. Furthermore, the as-prepared S-doped AuPbPt alloy NWNs indeed exhibit excellent electrocatalytic activity towards both the ORR (e.g., Eonset = 1.047 V and E1/2 = 0.921 V) and HER (Eonset = −2 mV and overpotential of 12 mV at 10 mA cm−2) in acidic media with excellent durability because of the presence of an optimal amount of PtS, based on the results of control experiments and DFT calculations.
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