Hierarchical TiO₂:Cu₂O Nanostructures for Gas/Vapor Sensing and CO₂ Sequestration

Abstract

We investigate the effect of high-surface-area self-assembled TiO 2 :Cu 2 O nanostructures for CO 2 and relative humidity gravimetric detection using polyethylenimine (PEI), 1-ethyl-3methylimidazolium (EMIM), and polyacrylamide (PAAm). Introduction of hierarchical TiO 2 :Cu 2 O nanostructures on the surface of quartz crystal microbalance sensors is found to significantly improve sensitivity to CO 2 and to H 2 O vapor. The response of EMIM to CO 2 increases fivefold for 100 nmthick TiO 2 :Cu 2 O as compared to gold. At ambient CO 2 concentrations, the hierarchical assembly operates as a sensor with excellent reversibility, while at higher pressures, the CO 2 desorption rate decreases, suggesting possible application for CO 2 sequestration under these conditions. The gravimetric response of PEI to CO 2 increases by a factor of 3 upon introduction of a 50 nm TiO 2 :Cu 2 O 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 TiO 2 :Cu 2 O structures. We found that TiO 2 :Cu 2 O can be used to lower the detection limits for CO 2 sensing with EMIM and PEI and lower the detection limits for H 2 O sensing with PAAm by over a factor of 2. Coarse-grained and all-atom molecular dynamics simulations indicate the dissociative character of ionic liquid assembly on TiO 2 :Cu 2 O interfaces and different distributions of CO 2 and H 2 O molecules on bare and ionic liquid-coated surfaces, confirming experimental observations. Overall, our results show high potential of hierarchical assemblies of TiO 2 :Cu 2 O/room temperature ionic liquid and polymer films for sensors and CO 2 sequestration.

Nanoscale Ion Transport Enhances Conductivity in Solid Polymer-Ceramic Lithium Electrolytes

“…The cross interactions are modeled with LJ and Coulomb potentials for charged atoms. 50 Initial System Setup. A single PEO molecule was built with Moltemplate and an energy minimization on the single PEO molecule was performed.…”

“…For the Li + salt, optimized potential for simulation all atom (OPLS-AA) force-field , was used. The cross interactions are modeled with LJ and Coulomb potentials for charged atoms …”

Titanium-based photocatalytic coatings for bacterial disinfection: The shift from suspended powders to catalytic interfaces

“…Later, the development of nanostructured tailored materials for water remediation has been growing during the last three decades [18]. Many nano-architectures have been reported to degrade organic pollutants [19,20], disinfect bacteria [21], inhibit viruses' growth [22] and remove malodors [23,24]. The reported nano-designs range from suspended nanoparticles, nanotubes, nano-spheres, nano-flocks, nanowires amongst others.…”

Simultaneous Tuning Band Gaps of Cu2O and TiO2 to Form S‐Scheme Hetero‐Photocatalyst

“…[17][18][19][20] Among those HCs, Cu 2 O/TiO 2 heterostructure has been used for photoreduction of CO 2 , [21] water splitting, [22] and so on. [23,24] However, the formed band structure is often a type I structure due to using bulk values, not fully benefitting for charge separation, high redox reaction and visible light absorption.…”