TiO₂ Nanotubes Supported PtO_x Nanoclusters with Enhanced Mass Activity for Electrocatalytic Hydrogen Evolution

Abstract

Developing proper supports to enhance Pt mass activity is crucial for the practical application of electrocatalytic hydrogen evolution reaction (HER). Herein, TiO2 nanotubes (TNTs) support is fabricated via anodizing Ti foil and loaded with PtOx nanoclusters using a facile photo‐deposition method. The formation of PtOx was confirmed by X‐ray photoelectron spectroscopy analysis. Interestingly, the TNTs supported PtOx (Ti/TNTs/PtOx) electrocatalyst showed superior activity towards HER than the benchmark Pt/C and TiO2 nanoparticles (TNPs) supported PtOx electrocatalysts. An overpotential of −30 mV was sufficient to deliver −10 mA cm−2 from the acidic medium. The electrocatalytic mass activity of Ti/TNTs/PtOx (i. e. 204 mA mg−1) is enhanced by 12 and 1.7‐fold in comparison with those of Pt/C and TNPs supported PtOx electrocatalysts, respectively. The superior activity of Ti/TNTs/PtOx is mainly due to its large electrochemical active surface area and the excellent electron mobility in TNTs support.

A highly efficient and stable platinum film deposited via a mixed metal-imidazole casting method as a benchmark cathode for electrocatalytic hydrogen evolution

“…For both Pt(w-MeIm) and Pt(w/o-MeIm) lms, the XPS peaks for Pt 4f 7/2 were deconvoluted into two distinct bands at 71.1 and 72.3 eV, being assigned for Pt 0 and Pt II valence states based on the literature. 18,42,43 The observations of Pt 0 in the XPS spectra were consistent with a facecentered cubic phase of crystalline Pt for both lms, as observed in the XRD data. Correspondingly, the Pt 4f 5/2 peaks were also deconvoluted into two bands at 74.4 and 75.6 eV assigned for Pt 0 and Pt II states, respectively.…”

“…The higher surface fraction of the Pt 0 state for the Pt(w-MeIm) lm is ascribable to its closely-compacted and wellinterconnected spherical particles. The partial surface oxidation of Pt 0 nanoparticles to Pt II O x is supported by the XPS spectra in the O 1s region for the Pt(w-MeIm) and Pt(w/o-MeIm) lms which exhibited two peaks at 531.6-531.7 and 533.2-533.3 eV, assigned to the surface adsorbed species (i.e., H 2 O and -OH) and Pt-O bonds, respectively 18,42,43 Although Pt materials are well-known to work as active electrocatalysts for the HER in a wide pH range, 44,45 here we mainly investigate the electrocatalytic HER under alkaline conditions because alkaline water electrolysis is expected to be a promising technology for future H 2 production. [46][47][48] The cyclic voltammograms (CV) of Pt(w-MeIm) and Pt(w/o-MeIm) lms on GC with the same G Pt (0.5 mmol cm À2 ) measured in 1.0 M KOH (pH 14.0) solution under Ar in the potential range À0.02-1.21 V vs. a reversible hydrogen electrode (RHE) are shown in Fig.…”

“…The partial surface oxidation of Pt 0 nanoparticles to Pt II O x is supported by the XPS spectra in the O 1s region for the Pt( w -MeIm) and Pt( w / o -MeIm) films which exhibited two peaks at 531.6–531.7 and 533.2–533.3 eV, assigned to the surface adsorbed species ( i.e. , H 2 O and –OH) and Pt–O bonds, respectively 18,42,43…”

“…The separation between the 4f 7/2 and 4f 5/2 for Pt 0 and the Pt II states is 3.3 eV, which agrees with the spin-orbit components of the Pt 4f corelevels. 18,42,43 The surface ratios of Pt 0 : Pt II states for the Pt(w-MeIm) and Pt(w/o-MeIm) lms were calculated to be 66.6 : 33.4 and 55.1 : 44.9 from the area ratio of the deconvoluted bands for the Pt 4f 7/2 peaks, respectively. This suggests that Pt 0 of the surface state is predominant rather than Pt II in both asprepared Pt(w-MeIm) and Pt(w/o-MeIm) lms; however, the fraction (66.6%) of the Pt 0 state for the Pt(w-MeIm) lm is higher than that (55.1%) for the Pt(w/o-MeIm) lm.…”

Characterization of electrocatalytic proton reduction and surface adsorption of platinum nanoparticles supported by a polymeric stabilizer on an ITO electrode

“…The XPS peak of Pt 4f 7/2 for citrate-Pt was deconvoluted into two distinct bands at 71.4 and 72.7 eV, being assigned to Pt 0 and Pt II valence states based on the literature. 30,31 Correspondingly, the Pt 4f 5/2 peak for citrate-Pt was also deconvoluted into two bands at 74.7 and 76.0 eV assigned to Pt 0 and Pt II states, respectively. This result suggests that the surface of Pt 0 nanoparticles is partially oxidized to Pt II O x .…”