Ultrathin Vein‐Like Iridium–Tin Nanowires with Abundant Oxidized Tin as High‐Performance Ethanol Oxidation Electrocatalysts

Abstract

Iridium (Ir) holds great promise for ethanol oxidation reaction (EOR), while its practical applications suffer from the limited shape-controlled synthesis due to its low-energy barrier for nucleation. To overcome this limitation, the preparation of a new class of ultrathin vein-like Ir-tin nanowires (IrSn NWs) with abundant oxidized Sn is reported. By tuning the ratio of Ir to Sn, the optimized Ir Sn /C exhibits the highest mass density of 95.6 mA mg Ir for EOR at low potential (0.04 V), which is 4.1-fold and 20-fold higher than that of Ir/C and the commercial Pt/C, respectively. It also exhibits the smallest Tafel slope of 153 mV dec and superior stability after 2 h chronoamperometric measurement. Electrochemical measurements and X-ray photoelectron spectra results confirm that the abundant oxidized Sn promotes a complete oxidization of ethanol into CO at low potential. This work highlights the importance of non-noble metal on enhancing the EOR performance.

Atomic Iridium Incorporated in Cobalt Hydroxide for Efficient Oxygen Evolution Catalysis in Neutral Electrolyte

“…In order to identify the surface chemical composition and valence state information of the self‐assembled CoIr‐ x hierarchical structures, X‐ray photoelectron spectroscopy (XPS) was conducted. The high‐resolution Ir 4f XPS spectrum of CoIr‐ x can be splitted into four peaks at 60.9, 62.4, 63.8, and 65.5 eV, corresponding to the binding energies of Ir 0 4f 7/2 , Ir 4+ 4f 7/2 , Ir 0 4f 5/2 , and Ir 4+ 4f 5/2 , respectively ( Figure a), indicating that Ir 0 and Ir 4+ are coexistence in CoIr‐ x which will be further explored in the following section. The high‐resolution Co 2p XPS spectrum of CoIr‐ x exhibits two main peaks located at the binding energies around 781 and 797 eV with two shakeup satellite peaks corresponding to the characteristic peaks of Co 2p 3/2 and Co 2p 1/2 orbit levels (Figure b), respectively, in good agreement with the state of Co in α‐Co(OH) 2 .…”

Platinum Group Nanowires for Efficient Electrocatalysis

“…For Pd‐based nanowires, Pd–Ag, Pd–Au, and Pd–Ni alloy nanowires have been successfully prepared . There are only a few reports on Ir‐based nanowires . For example, Ir–Sn nanowires were successfully prepared by Zhu et al, using iridium(III) chloride hydrate (IrCl 3 ) and tin(II) acetate (Sn(Ac) 2 ) as metal precursors, citric acid (CA) as the reducing agent, PVP as the reducing agent, and EG as the solvent and reducing agent …”

Nanocatalysts for Electrocatalytic Oxidation of Ethanol

“…[202] Most recently,Z hang et al reportedt he construction of ternary Pt 3 RhM (M = Fe, Co, Ni, Cu;G a, In, Sn, Pb) nanoalloys with similar spherical geometries and comparable crystallite sizes of about 8.5 nm through introducing late 3d transition metalsa nd maingroup (IIIA and IVA) metalsinaone-potsolvothermal method, andi nvestigated the intrinsic composition and electronic effects in the nanoalloys for achieving good catalytic properties for ethanol oxidation by combining experiments with DFT computations. [167] RhSn microwave-assistedcoreduction combination of bifunctional mechanism, electronic modification, and CÀCb ond splitting 2015 [168] [a] fcc = face-centered cubic. Specifically,t he ternary Pt 3 RhSn nanoalloys supported on Vulcan XC-72 carbon substrates exhibited 67-and 7-fold increases in specific activity and mass activity,r espectively,a t 0.45 V( vs. RHE) for ethanol oxidation in acidic conditions, compared with that of ac ommercial Pt/C catalyst ( Figure 6).…”

“…In addition, they also showed that the CO 2 selectivity was linearly correlated with the sum of the binding energies of oxygen and H 2 O( E O + E H 2 O ), closely matching the experimental observations for typical catalysts. [167] RhSn microwave-assistedcoreduction combination of bifunctional mechanism, electronic modification, and CÀCb ond splitting 2015 [168] [a] fcc = face-centered cubic.…”