El objetivo de esta línea de investigación es la modificación química de los CNTs orientada a la obtención de materiales para determinados usos tecnológicos. La investigación en nanoquímica está estructurada en las líneas de investigación siguientes:
- Puesta a punto de procedimientos de purificación de nanotubos
- Tratamientos de activación para aumentar la porosidad
- Funcionalización covalente orgánica
- Funcionalización con metales
Graphene oxide (GO) and related materials are widely reported to enhance the photocatalytic activity of zinc oxide. However, the origin of the observed performance improvements remains elusive and studies contributing to a deeper understanding of this critical issue are largely missing. In this work, we have prepared a set of benchmark ZnO-GO hybrid materials in order to systematically put under closer scrutiny the influence of the surface chemistry of GO on the photocatalytic degradation of methylene blue. The set of ZnO-GO hybrids has been synthesized in an ultrasonication process involving ZnO nanoparticles obtained in a microwave synthesis process and GO with three distinct oxidation degrees, employed in three different loading fractions. Structural and physical-chemical characterization by XRD, FTIR, Raman, UV–vis, photoluminescence and spectroscopy and XPS, consistently demonstrate the importance of the surface chemistry of GO for establishing photo-induced charge-transfer interface interactions with ZnO, facilitating the enhancement of the catalytic activity of the ZnO-GO catalyst. Optimized interface interactions thus enabled the design of a ZnO-GO catalyst exhibiting a conversion rate of 80% obtained in a time of 70 min and at a catalyst concentration of only 0.045 mg/mL.
A versatile room-temperature method for the preparation of customized fluorescent non-conjugated polymer dots
We present a general procedure for the synthesis and in situ functionalization of highly fluorescent non-conjugated polymer dots, by exploiting the room-temperature carbodiimide-mediated condensation between citric acid and amines. The versatility of this method is proved by the preparation and characterization of a broad set of fluorescent nanoparticles with customized polymer structures and functional groups.
The effect of doping on the electronic properties in bulk single-walled carbon nanotube (SWCNT) samples is studied for the first time using a new in situ Raman spectroelectrochemical method, and further verified by DFT calculations and photoresponse. We use p-/n-doped SWCNTs prepared by diazonium reactions as a versatile chemical strategy to control the SWCNT behavior. The measured and calculated data testify an acceptor effect of 4-aminobenzenesulfonic acid (p-doping), and a donor effect (n-doping) in the case of benzyl alcohol. In addition, pristine and covalently functionalized SWCNTs were used for the preparation of photoactive film electrodes. The photocathodic current in the photoelectrochemical cell is consistently modulated by the doping group. These results validate the in situ Raman spectroelectrochemistry as a unique tool box for predicting the electronic properties of functionalized SWCNTs …
Interfacing transition metal dichalcogenides with carbon nan-odots for managing photoinduced energy and charge-transfer processes
Exfoliated semiconducting MoS2 and WS2 were covalently functionalized with 1,2-dithiolane-modified carbon nanodots (CNDs). The newly synthesized CND-MoS2 and CND-WS2 hybrids were characterized by spectroscopic, thermal and elec-tron microscopy imaging methods. Based on electronic absorption and fluorescence emission spectroscopy, modulation of the optoelectronic properties of TMDs by interfacing with CNDs was accomplished. Electrochemical studies revealed facile oxidation of MoS2 over WS2 in the examined hybrids, suggesting it to be better electron donor. Excited state events, inves-tigated by femtosecond transient absorption spectroscopic studies, revealed ultrafast energy transfer from photoexcited CNDs to both MoS2 and WS2. Interestingly, upon MoS2 photoexcitation charge transfer from an exciton dissociation path of MoS2 to CNDs, within CND-MoS2, was observed. However, such …