Hierarchical TiO2:Cu2O nanostructures for gas/vapor sensing and CO2 sequestration

We investigate the effect of high-surface-area self-assembled TiO2:Cu2O nanostructures for CO2¬ and relative humidity (RH) gravimetric detection using polyethylenimine (PEI), 1-ethyl-3-methylimidazolium (EMIM), and polyacrylamide (PAAm). Introduction of hierarchical TiO2:Cu2O nanostructures on the surface of quartz crystal microbalance (QCM) sensors is found to significantly improve sensitivity to CO2 and to H2O vapor. The response of EMIM to CO2 increases 5-fold for 100 nm thick TiO2:Cu2O as compared to gold. At ambient CO2 concentrations the hierarchical assembly operates as a sensor with excellent reversibility, while at higher pressures the CO2 desorption rate decreases, suggesting possible application for CO2 sequestration under those conditions. The gravimetric response of PEI to CO2 increases by a factor of 3 upon introduction of a 50 nm TiO2:Cu2O layer. The PAAm gravimetric response to water vapor also increases by a factor of 3 and displays improved reversibility with the addition of 50 nm TiO2:C...