Effect of the surfactant nature on the thermo-stability of surface modified SnO2 nanoparticles

Surface Functionalization of Metal Oxide Semiconductors with Catechol Ligands for Enhancing Their Photoactivity

“…[ 66–68,89 ] TGA is another technique used to investigate the surface adsorption of catechol ligands onto metal oxides, particularly looking at the changes in the stability of metal oxide–catechol ligand complexes over a wide range of temperatures. [ 22,69,90,91 ] Surface adsorption is also verified using UV–vis as catechol surface functionalization generally shows redshifting and an increase in the absorbance peak. This results in improved photoabsorption in the visible range and increased photocurrent density.…”

“…FTIR spectroscopy has been used to detect bidentate or monodentate binding between catechol‐type ligands and metal oxides. [ 22,33,62,87,88 ] In the FTIR spectra of catechol‐modified metal oxides, the development of C–O stretch and a decrease in –OH band intensity of the bonded catechol ligand is typically observed, which indicates deprotonation of the phenolic –OH groups, thereby providing support for the formation of bidentate‐type bonding. [ 66–68,89 ] TGA is another technique used to investigate the surface adsorption of catechol ligands onto metal oxides, particularly looking at the changes in the stability of metal oxide–catechol ligand complexes over a wide range of temperatures.…”

“…These parameters provide a toolbox for predicting adsorption/desorption, co‐adsorption and ligand exchange behavior, which can be used to identify the optimal metal oxide and ligand concentration when preparing substrates for various applications. [ 22,90,91 ] DFT calculations can be used to quantitatively assess the binding affinity of catechol ligands and model their absorption on various metal oxide surfaces, and to evaluate changes of their optical absorption spectra and vibrational properties. [ 62,71,94 ] DFT studies show that the surface modification of metal oxides with catechol‐type ligands lowers the bandgap of metal oxides.…”

“…[ 1,17,18 ] Similar to TiO 2 , ZnO is also limited by its wide bandgap and can have its photoabsorption enhanced by surface modification through catechol‐type ligands. [ 17,18 ] Catechol surface functionalization has also been explored for metal oxide semiconductors such as WO 3 , [ 21 ] SnO 2 , [ 22 ] Al 2 O 3 , [ 64 ] and BiOIO 3 . [ 19 ]…”

“…[ 1,17,18 ] Moreover, WO 3 , SnO 2, Al 2 O 3 , Fe 2 O 3 , and BiOIO 3 are seeing considerable interest in PEC applications. [ 19–23 ] To increase the effectiveness of semiconductor metal oxides photoelectrodes, researchers seek to use various photoabsorption amplification strategies including the coupling of metal oxides with plasmonic nanostructures, [ 24 ] bimetallic NPs, [ 25 ] graphene, [ 26 ] and quantum dots (QDs), [ 27 ] as well as dye sensitization [ 15 ] to create heterojunctions.…”