Photochemical Oxidative Growth of Iridium Oxide Nanoparticles on CdSe@CdS Nanorods

Abstract

We demonstrate a procedure for the photochemical oxidative growth of iridium oxide catalysts on the surface of seeded cadmium selenidecadmium sulfide (CdSe@CdS) nanorod photocatalysts. Seeded rods are grown using a colloidal hot-injection method and then moved to an aqueous medium by ligand exchange. CdSe@CdS nanorods, an iridium precursor and other salts are mixed and illuminated. The deposition process is initiated by absorption of photons by the semiconductor particle, which results with formation of charge carriers that are used to promote redox reactions. To insure photochemical oxidative growth we used an electron scavenger. The photogenerated holes oxidize the iridium precursor, apparently in a mediated oxidative pathway. This results in the growth of high quality crystalline iridium oxide particles, ranging from 0.5 nm to about 3 nm, along the surface of the rod. Iridium oxide grown on CdSe@CdS heterostructures was studied by a variety of characterization methods, in order to evaluate its characteristics and quality. We explored means for control over particle size, crystallinity, deposition location on the CdS rod, and composition. Illumination time and excitation wavelength were found to be key parameters for such control. The influence of different growth conditions and the characterization of these heterostructures are described alongside a detailed description of their synthesis. Of significance is the fact that the addition of iridium oxide afforded the rods astounding photochemical stability under prolonged illumination in pure water (alleviating the requirement for hole scavengers). Video LinkThe video component of this article can be found at

Molecular Metallocorrole–Nanorod Photocatalytic System for Sustainable Hydrogen Production

“…Given the demanding set of requirements for proper selection of a semiconductor system that can support visible light water splitting (e.g., suitable bandgap and electron affinity), and the fact that CdS is among the few materials that meet these strict requirements, addressing CdS stability is of outmost importance. The addition of a second co-catalyst such as IrO 2 [7,8] or Ru [9] that can scavenge the holes from the semiconductor and mediate their transfer to water was shown to afford CdS-based structures the desired photochemical stability. Yet these co-catalysts did not support a sustainable oxidation process.…”

Highly Polarized Fluorescent Film Based on Aligned Quantum Rods by Contact Ink-Jet Printing Method

“…Fluorescent semiconductor quantum rods (QRs) are brought into focus and applied in many photoelectric devices including liquid crystal (LC) display backlights [1], [2]- [4], LC cells [4]- [6], light emitting diodes (LEDs) [7]- [9], microcavities and lasers [10]- [14], solar cells [15]- [17], luminescent solar concentrators (LSC) [18]- [20], and other applications including photocatalytic hydrogen generation [21]- [23] and bioimaging [24]- [27]. Because there are a lot of outstanding properties of QRs covering tunable emission, polarized emission, narrow full width at half maximum (FWHM), and large quasi-Stokes shift [20], [28], [29].…”