In situ photodeposition of ultra-small palladium particles on TiO2.

In situ and operando investigation of photocatalysts plays a fundamental role in understanding the processes of active phase formation and the mechanisms of catalytic reactions, which is crucial for the rational design of more efficient materials. Using a custom-made operando photocatalytic cell, an in situ procedure to follow the formation steps of Pd/TiO2 photocatalyst by synchrotron-based X-ray absorption spectroscopy (XAS) is proposed. The procedure resulted in the formation of ∼1 nm Pd particles with a much narrower size distribution and homogeneous spreading over TiO2 support compared with the samples generated in a conventional batch reactor. The combination of in situ XAS spectroscopy with high-angle annular dark-field scanning transmission electron microscopy demonstrated the formation of single-atom Pd(0) sites on TiO2 as the initial step of the photodeposition process. Palladium hydride particles were observed for all investigated samples upon exposure to formic acid solutions.

Designing functionalized nanodiamonds with hyaluronic acid-phospholipid conjugates for enhanced cancer cell targeting and fluorescence imaging capabilities.

Nanomedicine aims to develop smart approaches for treating cancer and other diseases to improve patient survival and quality of life. Novel nanoparticles as nanodiamonds (NDs) represent promising candidates to overcome current limitations. In this study, NDs were functionalized with a 200 kDa hyaluronic acid-phospholipid conjugate (HA/DMPE), enhancing the stability of the nanoparticles in water-based solutions and selectivity for cancer cells overexpressing specific HA cluster determinant 44 (CD44) receptors. These nanoparticles were characterized by diffuse reflectance Fourier-transform infrared spectroscopy, Raman spectroscopy, and photoluminescence spectroscopy, confirming the efficacy of the functionalization process. Scanning electron microscopy was employed to evaluate the size distribution of the dry particles, while dynamic light scattering and zeta potential measurements were utilized to evaluate ND behavior in a water-based medium. Furthermore, the ND biocompatibility and uptake mediated by CD44 receptors in three different models of human adenocarcinoma cells were assessed by performing cytofluorimetric assay and confocal microscopy. HA-functionalized nanodiamonds demonstrated the advantage of active targeting in the presence of cancer cells expressing CD44 on the surface, suggesting higher drug delivery to tumors over non-tumor tissues. Even CD44-poorly expressing cancers could be targeted by the NDs, thanks to their good passive diffusion within cancer cells.

Pt-TiO2 catalysts for glycerol photoreforming: comparison of anatase, brookite and rutile polymorphs.

We compared the H2 production from glycerol photoreforming for different TiO2 polymorphs, highlighting an increase of activity in the order Pt-rutile < Pt-P25 ≈ Pt-anatase < Pt-brookite with a different distribution of the reaction intermediates. We show that the highest ability to adsorb water and the different distribution of Pt active sites in brookite can positively influence its photoactivity.