Enhanced Water Photolysis with Pt Metal Nanoparticles on Single Crystal TiO₂ Surfaces

Abstract

Two novel deposition methods were used to synthesize Pt-TiO(2) composite photoelectrodes: a tilt-target room temperature sputtering method and aerosol-chemical vapor deposition (ACVD). Pt nanoparticles (NPs) were sequentially deposited by the tilt-target room temperature sputtering method onto the as-synthesized nanostructured columnar TiO(2) films by ACVD. By varying the sputtering time of Pt deposition, the size of deposited Pt NPs on the TiO(2) film could be precisely controlled. The as-synthesized composite photoelectrodes with different sizes of Pt NPs were characterized by various methods, such as SEM, EDS, TEM, XRD, and UV-vis. The photocurrent measurements revealed that the modification of the TiO(2) surface with Pt NPs improved the photoelectrochemical properties of electrodes. Performance of the Pt-TiO(2) composite photoelectrodes with sparsely deposited 1.15 nm Pt NPs was compared to the pristine TiO(2) photoelectrode with higher saturated photocurrents (7.92 mA/cm(2) to 9.49 mA/cm(2)), enhanced photoconversion efficiency (16.2% to 21.2%), and increased fill factor (0.66 to 0.70). For larger size Pt NPs of 3.45 nm, the composite photoelectrode produced a lower photocurrent and reduced conversion efficiency compared to the pristine TiO(2) electrode. However, the surface modification by Pt NPs helped the composite electrode maintain higher fill factor values.

Exceptional performance of bimetallic Pt1Cu3/TiO2 nanocatalysts for oxidation of gluconic acid and glucose with O2 to glucaric acid

“…S6). This implies that plasmon absorption on the Pt/TiO 2 catalyst surface is nonsignificant [36]. The onset of bimetallic PtCu catalyst samples is, however, found to be very different.…”

“…Since the metal loading is only $1 wt.% in the catalyst samples, the characteristic absorption of the TiO 2 support ($300 nm wavelength [35]) is dominant in all UV-vis spectra (Fig. 2 insets), but the shift of absorption peaks indicates plasmon characteristics of metal nanoparticles on the surface of TiO 2 [36]. The onset of UV-vis absorption for Pt (black curve) is around 305-310 nm, which is similar to the value observed for Cu/TiO 2 and TiO 2 support (300-310 nm, in Fig.…”

Uses of Physical Vapor Deposition Processes in Photoelectrochemical Water Splitting Systems

“…Pt NPs were formed by sputtering Pt targets over TiO 2 nanorods [53] (NRs) and 1D columnar TiO 2 nanostructures [52]. Both works have shown that the deposition of Pt for 20 s has generated the most effective photoelectrodes.…”

Fabrication of Titanium Dioxide Nanotube Array as a Photocathode for Hydrogen Evolution

“…The unique properties of TiO 2 nanotube array (TNTA) with large surface area and tunable morphology has been used as the active materials for dye sensitized solar cells (11), antibacterial agents (12), hydrogen sensing (13), photocatalyst (14)(15)(16), and photoelectrochemical water photolysis (17,18). In addition, the fabrication of TNTAs using electrochemical processes have been demonstrated to be an effective photoelectrode for photoelectrochemical water splitting with markedly improved efficiency (19). The nanotube structure creates a higher surface area compared with other materials, leading to the increase in efficient absorption by scattering the path length of incident photons (20).…”

“…The transition metal modified TiO 2 nanotube arrays have been demonstrated to significantly enhance photoelectrochemical activity of hydrogen generation (19,23). Usually metals with Fermi level lower than that of TiO 2 can rapidly transfer photoexcited electrons from TiO 2 to metal particles, and, therefore, reduce the possibility of electron-hole recombination and lead to efficient charge separation (23).…”