Tailored fabrication of iridium nanoparticle-sensitized titanium oxynitride nanotubes for solar-driven water splitting: experimental insights on the photocatalytic–activity–defects relationship

Abstract

Uniform and vertically aligned nanotube arrays of titanium oxynitride functionalized with iridium nanoparticles (Ir/TiON-NTs) were fabricated for the solar driven-water splitting.

Tailoring the defects of sub-100 nm multipodal titanium nitride/oxynitride nanotubes for efficient water splitting performance

“…Thus, the annealing under ammonia led to the substitution of some O sites by N, in line with previous reports on N-doped TiO 2 . 28,33,42 That is obvious in the increment of N-content with increasing the nitridation rate. The estimated amount of N was about 1.9, and 3.1, and 4.5 % in TiON 2 NTs, TiON 4 NTs, and TiON 6 NTs, respectively, in line with the EDX.…”

“…The TiN peaks usually overlapped with the TiO 2 peaks that are in line with elsewhere reports. 33,42,45 However, the intensity of (020) (Figure 3b). and (220) peaks of TiN peak (Figure 3c) and their full width at the half maximum (FWHM) increased significantly with increasing the nitridation time as indicated by the dashed lines, due to the incorporation of N into the TiO 2 lattice structure results in the formation of crystal defects.…”

“…TiO 2 NTs w initially synthesized via the electrochemical anodization of titanium foils in the formamide-based electrolyte and then were annealed under ammonia gas for different times (Scheme 1). 42,43 The formamide, with its remarkable ability to control the electrolyte solution's viscosity and conductivity, prevents the current oscillation due to the "in-pore" local pH variation providing favorable conditions for tailoring the fabrication of ordered, aligned, and oriented thinwalled multipodal nanotubes. The solution pH was adjusted by adding 0.1 M acetic acid, and 1 wt % of PVP was used for structural stability.…”

“…Consequently, defect engineering in TiON-NTs and deciphering the defects-photocatalytic relationship can boost their charge carrier collection efficiency while preserving the crystallinity. 42 That can also pave the way towards integrating TiON-NTs into the cost-effective and efficient, practical solar-driven watersplitting devices.…”

Catalytic Methane Decomposition to Carbon Nanostructures and COx-Free Hydrogen: A Mini-Review

“…In addition, reducing greenhouse gases (GHG) in the atmosphere is of great importance in various industrial and environmental remediation applications [ 1 , 2 , 3 , 4 ]. Conventionally, hydrogen is produced through steam reforming of methane, auto thermal reforming of methane, water splitting, biomass, and coal gasification with varying levels of efficiency and productivity [ 5 , 6 , 7 ]. Unlike these methods, CMD possesses certain advantages, such as the production of relatively COxfree hydrogen, lower CO 2 emission, and feedstock [ 8 ].…”