Search

TiO 2 nanotube membranes (TNM) were synthesized, separated (by electrochemical anodization) and modified with Pt-Ru electrocatalyst to assess their photoelectrocatalytic activity towards methanol (MeOH) oxidation. The feasibility of use of these composite materials was evaluated in different supports to observe the development of the electrochemical responses as a function of the nature of the electrical collecting substrate. The results suggested that, while the Pt-Ru decorated TMN present photoelectrocatalytic activity, the electrical contact in the back might be the limiting step in current collection. Such findings were demonstrated by performing scanning electrochemical microscopy SECM over the surface of the TNMs, where methanol was oxidized in the microelectrode tip of the SECM. This approach corroborated the suitability of TNMs to be modified with an electrocatalyst and its application in current technology such as microfluidic fuel cells. [ABSTRACT FROM AUTHOR]

Anodic photo-electrocatalysts comprising anodically grown TiO 2 nanotubes (TiO 2 -NT) with an average inner diameter of 70 nm and lengths of 7, 15 and 30 μm with nanoparticulate electrodeposited Ni species (namely NiO, Ni(OH) 2 ) were synthesized and evaluated for its use as anode for direct methanol fuel cell. The Ni deposit with an average diameter of 200 nm was obtained by cyclic voltammetry from a modified acid Watts bath. Morphology, composition, crystallinity and optical properties were investigated by SEM, EDS, XRD, Raman and diffuse reflectance spectroscopy. UV–vis irradiation coming from a Xe lamp on the anodes increased the current density by 24% in half-cell configuration. Finally, a microfluidic fuel cell was assembled and tested using methanol as fuel reached an OCP of 0.7 V. This finding suggests that such composite materials are promising alternatives for the development of a new generation of hybrid-microfluidic devices. [ABSTRACT FROM AUTHOR]

In this study, C 3 N 4 was prepared using the polycondensation method, and TiO 2 (ansate/Brookite) was synthesized using the solvothermal method. These materials were subsequently utilized to prepare C 3 N 4 /TiO 2 heterojunction materials via the photoanchoring method, with the aim of improving photocatalytic hydrogen production. The physical, chemical, and optical properties of the composites were investigated to verify the formation of heterojunctions, as well as to assess the impact of varying levels of C 3 N 4 content (1%, 5%, and 10%) in the C 3 N 4 /TiO 2 composite on hydrogen production. Notably, the composite with 5% C 3 N 4 demonstrated superior photocatalytic hydrogen production (approximately 692 μmol h-1 g-1), and the underlying reasons were elucidated using photoelectrochemical characterization. To establish the band alignment of C 3 N 4 and TiO 2 before and after contact, a comprehensive array of techniques was employed, encompassing Kelvin force microscopy to acquire work functions, UV–Vis spectral analysis to ascertain band gaps, XPS valence spectra to identify the Valence Band Maxima, and the Kraut method to calculate Band Offsets. These analyses revealed that the formation of the heterojunction is staggered in nature. Finally, utilization of ESR analysis has conclusively verified that the charge transfer mechanism inherent in the C 3 N 4 /TiO 2 heterojunction adheres to the Z-scheme. [ABSTRACT FROM AUTHOR]