High Electrocatalytic Activity of Pt–Pd Binary Spherocrystals Chemically Assembled in Vertically Aligned TiO₂ Nanotubes

Abstract

To obtain noble metal catalysts with high efficiency, long-term stability, and poison resistance, Pt and Pd are assembled in highly ordered and vertically aligned TiO(2) nanotubes (NTs) by means of the pulsed-current deposition (PCD) method with assistance of ultrasonication (UC). Here, Pd serves as a dispersant which prevents agglomeration of Pt. Thus Pt-Pd binary catalysts are embed into TiO(2) NTs array under UC in sunken patterns of composite spherocrystals (Sps). Owing to this synthesis method and restriction by the NTs, the these catalysts show improved dispersion, more catalytically active sites, and higher surface area. This nanotubular metallic support material with good physical and chemical stability prevents catalyst loss and poisoning. Compared with monometallic Pt and Pd, the sunken-structured Pt-Pd spherocrystal catalyst exhibits better catalytic activity and poison resistance in electrocatalytic methanol oxidation because of its excellent dispersion. The catalytic current density is enhanced by about 15 and 310 times relative to monometallic Pt and Pd, respectively. The poison resistance of the Pt-Pd catalyst was 1.5 times higher than that of Pt and Pd, and they show high electrochemical stability with a stable current enduring for more than 2100 s. Thus, the TiO(2) NTs on a Ti substrate serve as an excellent support material for the loading and dispersion of noble metal catalysts.

Impact of Ultrasonic Waves in Direct Electrodeposition of Nanostructured AuPt Alloy Catalyst on Carbon Substrate: Structural Characterization and Its Superior Electrocatalytic Activity for Methanol Oxidation Reaction

“…From these CA experiments, the turnover number (TON) was also calculated to understand the difference in electrocatalytic activity and stability of electrocatalyst. From the steady-state current density, TON, expressed as molecules per site, is calculated from eq 5: 44 = × × i nF TON (6.02 10 )…”

Chiral Recognition and Enantioselective Photoelectrochemical Oxidation toward Amino Acids on Single-Crystalline ZnO

“…First, the TiO 2 NTs substrate was prepared by anodic oxidation on which the crystalline-seed-assisted hydrothermal method was adopted to construct SC ZnO according to the literature with certain modification. A 5 mM Zn(CH 3 COO) 2 ethanol solution was spin-coated on TiO 2 NTs several times, and then, a dense seed layer can be attained via 350 °C heat treatment.…”

Nanoparticles of Pt loaded on a vertically aligned TiO2 nanotube bed: synthesis and evaluation of electrocatalytic activity

“…Such vertically aligned nanotubes of Ti can be easily fabricated by simple electrochemical anodization of planar Ti. 34,35 Zhao et al 36 discussed in detail the role of vertically aligned TiNT as support material for electrocatalytic application. They reported that nanotubular metallic support provides favorable physicochemical stability and avoids catalyst loss and poisoning.…”

“…37 To synthesize Pt nanoparticle electrode with TiNT array support, several methods have been adopted. 36,38,39 The major drawback in most of the methods other than sputter coating is the aggregation of Pt particle resulting in reduced catalytic activity. 36,40 Wet impregnation is the most widely used method for synthesizing supported Pt catalyst.…”

“…36,38,39 The major drawback in most of the methods other than sputter coating is the aggregation of Pt particle resulting in reduced catalytic activity. 36,40 Wet impregnation is the most widely used method for synthesizing supported Pt catalyst. 41,42 Generally in an impregnation method, the support will be immersed in a solution containing precursor material, which, in subsequent steps will be dried to remove the imbibed solvent.…”