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Metal oxide pseudocapacitors are limited by low electrical and ionic conductivities. The present work integrates defect engineering and architectural design to exhibit, for the first time, intercalation pseudocapacitance in CeO2–x. An engineered chronoamperometric electrochemical deposition is used to synthesize 2D CeO2–x nanoflakes as thin as ~12 nm. Through simultaneous regulation of intrinsic and extrinsic defect concentrations, charge transfer and charge–discharge kinetics with redox and intercalation capacitances together are optimized, where reduction increases the gravimetric capacitance by 77% to 583 F g–1, exceeding the theoretical capacitance (562 F g–1). Mo ion implantation and reduction processes increase the specific capacitance by 133%, while the capacitance retention increases from 89 to 95%. The role of ion-implanted Mo6+ is critical through its interstitial solid solubility, which is not to alter the energy band diagram but to facilitate the generation of electrons and to establish the midgap states for color centers, which facilitate electron transfer across the band gap, thus enhancing n-type semiconductivity. Critically, density functional theory simulations reveal, for the first time, that the reduction causes the formation of ordered oxygen vacancies that provide an atomic channel for ion intercalation. These channels enable intercalation pseudocapacitance but also increase electrical and ionic conductivities. In addition, the associated increased active site density enhances the redox such that the 10% of the Ce3+ available for redox (surface only) increases to 35% by oxygen vacancy channels. These findings are critical for any oxide system used for energy storage systems, as they offer both architectural design and structural engineering of materials to maximize the capacitance performance by achieving accumulative surface redox and intercalation-based redox reactions during the charge/discharge process., Peer Reviewed, Postprint (published version)

Porous titania networks containing gold nanoparticles have been synthesized and tested in photocatalytic applications. The porous structure was controlled using a templating technique, while a range of gold concentrations and a variety of routes were investigated to incorporate the gold nanoparticles. The influence of these parameters on the final structure (surface area and pore size), the gold crystal size, distribution, and content, and the photocatalytic activity of the porous materials were investigated. UV-vis diffuse reflectance spectra of the Au/TiO2 materials showed strong absorbance at approximately 580 nm, indicating the successful incorporation of the gold species. X-ray diffraction analysis ascertained that the titania materials were crystalline (anatase phase) with gold peaks observed only when the gold content was greater than 0.25 wt %. Gold distribution and content in the materials were measured using secondary ion mass spectrometry and inductively coupled plasma mass spectrometry. From transmission electron microscopy analysis, the gold particle size and distribution varied with both the material preparation method and the concentration of gold used in the synthesis. Photocatalytic activity was dependent on the gold particle size and gold quantity. The highest photocatalytic activity under UV light irradiation as monitored by the photodecomposition of methylene blue was obtained for the Au/TiO2 sample containing 2.0 wt % gold prepared by the deposition of gold onto prefabricated porous TiO2.

Porous titania networks containing gold nanoparticles have been synthesized and tested in photocatalytic applications. The porous structure was controlled using a templating technique, while a range of gold concentrations and a variety of routes were investigated to incorporate the gold nanoparticles. The influence of these parameters on the final structure (surface area and pore size), the gold crystal size, distribution, and content, and the photocatalytic activity of the porous materials were investigated. UV-vis diffuse reflectance spectra of the Au/TiO2 materials showed strong absorbance at approximately 580 nm, indicating the successful incorporation of the gold species. X-ray diffraction analysis ascertained that the titania materials were crystalline (anatase phase) with gold peaks observed only when the gold content was greater than 0.25 wt %. Gold distribution and content in the materials were measured using secondary ion mass spectrometry and inductively coupled plasma mass spectrometry. From transmission electron microscopy analysis, the gold particle size and distribution varied with both the material preparation method and the concentration of gold used in the synthesis. Photocatalytic activity was dependent on the gold particle size and gold quantity. The highest photocatalytic activity under UV light irradiation as monitored by the photodecomposition of methylene blue was obtained for the Au/TiO2 sample containing 2.0 wt % gold prepared by the deposition of gold onto prefabricated porous TiO2.

Porous titania networks containing gold nanoparticles have been synthesized and tested in photocatalytic applications. The porous structure was controlled using a templating technique, while a range of gold concentrations and a variety of routes were investigated to incorporate the gold nanoparticles. The influence of these parameters on the final structure (surface area and pore size), the gold crystal size, distribution, and content, and the photocatalytic activity of the porous materials were investigated. UV-vis diffuse reflectance spectra of the Au/TiO2 materials showed strong absorbance at approximately 580 nm, indicating the successful incorporation of the gold species. X-ray diffraction analysis ascertained that the titania materials were crystalline (anatase phase) with gold peaks observed only when the gold content was greater than 0.25 wt %. Gold distribution and content in the materials were measured using secondary ion mass spectrometry and inductively coupled plasma mass spectrometry. From transmission electron microscopy analysis, the gold particle size and distribution varied with both the material preparation method and the concentration of gold used in the synthesis. Photocatalytic activity was dependent on the gold particle size and gold quantity. The highest photocatalytic activity under UV light irradiation as monitored by the photodecomposition of methylene blue was obtained for the Au/TiO2 sample containing 2.0 wt % gold prepared by the deposition of gold onto prefabricated porous TiO2.

Porous titania networks containing gold nanoparticles have been synthesized and tested in photocatalytic applications. The porous structure was controlled using a templating technique, while a range of gold concentrations and a variety of routes were investigated to incorporate the gold nanoparticles. The influence of these parameters on the final structure (surface area and pore size), the gold crystal size, distribution, and content, and the photocatalytic activity of the porous materials were investigated. UV-vis diffuse reflectance spectra of the Au/TiO2 materials showed strong absorbance at approximately 580 nm, indicating the successful incorporation of the gold species. X-ray diffraction analysis ascertained that the titania materials were crystalline (anatase phase) with gold peaks observed only when the gold content was greater than 0.25 wt %. Gold distribution and content in the materials were measured using secondary ion mass spectrometry and inductively coupled plasma mass spectrometry. From transmission electron microscopy analysis, the gold particle size and distribution varied with both the material preparation method and the concentration of gold used in the synthesis. Photocatalytic activity was dependent on the gold particle size and gold quantity. The highest photocatalytic activity under UV light irradiation as monitored by the photodecomposition of methylene blue was obtained for the Au/TiO2 sample containing 2.0 wt % gold prepared by the deposition of gold onto prefabricated porous TiO2.