Browsing by Author "Brink, F"

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    Highly efficient visible light catalysts driven by Ti3+-VO-2Ti4+-N3− defect clusters
    (Wiley, 2018-10-13) Sun, QB; Zhang, SY; Cortie, DL; Langley, J; Cox, N; Frankcombe, TJ; Gao, J; Chen, H; Withers, RL; Kremer, F; Yu, DH; Brink, F; Shi, WS; Liu, Y
    Local defect structures play significant roles on material properties, but they are seriously neglected in the design, synthesis, and development of highly efficient TiO2-based visible light catalysts (VLCs). Here, we take anatase TiO2 nanocrystals that contain (Ti3+, N3−) ions and have the complicated chemical formula of (Ti1-x4+Tix3+)(O2-2-y-zNy3-□z) as an example, and point out that the formation of Ti3+-VO-2Ti4+-N3− local defect clusters is a key missing step for significantly enhancing VLC properties of host TiO2 nanocrystals. Experimental and theoretical investigations also demonstrate the emergent behaviors of these intentionally introduced defect clusters for developing highly efficient VLCs. This research thus not only provides highly efficient visible light catalysts for various practical applications but also addresses the significance of local defect structures on modifying material properties. © 2019 Wiley-VCH Verlag GmbH & Co.
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    Highly efficient visible light catalysts driven by Ti3+‐VO‐2Ti4+‐N3− defect clusters
    (Wiley, 2018-10-13) Sun, QB; Zhang, SY; Cortie, DL; Langley, J; Cox, N; Frankcombe, TJ; Gao, J; Chen, H; Withers, RL; Kremer, F; Yu, DH; Brink, F; Shi, WS; Liu, Y
    Local defect structures play significant roles on material properties, but they are seriously neglected in the design, synthesis, and development of highly efficient TiO2‐based visible light catalysts (VLCs). Here, we take anatase TiO2 nanocrystals that contain (Ti3+, N3−) ions and have the complicated chemical formula of ()(□z) as an example, and point out that the formation of Ti3+‐VO‐2Ti4+‐N3− local defect clusters is a key missing step for significantly enhancing VLC properties of host TiO2 nanocrystals. Experimental and theoretical investigations also demonstrate the emergent behaviors of these intentionally introduced defect clusters for developing highly efficient VLCs. This research thus not only provides highly efficient visible light catalysts for various practical applications but also addresses the significance of local defect structures on modifying material properties. © 1999-2024 John Wiley & Sons, Inc or related companies.
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    Predicted CO2 water rock reactions in naturally altered CO2 storage reservoir sandstones, with interbedded cemented and coaly mudstone seals
    (Elsevier, 2022-03-15) Pearce, JK; Dawson, GW; Golding, SD; Southam, G; Paterson, DJ; Brink, F; Underschultz, JR
    Geological storage of CO2 captured from industrial processes such as coal combustion or from direct air capture is part of the transition to low emissions. The Jurassic Precipice Sandstone of the southern Surat Basin, Queensland, Australia, is undergoing feasibility studies for industrial scale CO2 geological storage, however regional data has so far been lacking. Precipice Sandstone reservoir drill core samples from the Southwood 1 and Tipton 153 wells in the southern Surat Basin include favourably quartz rich sandstone regions with quartz grain fracturing. A mudstone layer is also present in the reservoir. The overlying lower section of the Evergreen Formation seals consist of clay rich sandstones, interbedded mudstones, coal layers, Fe-Mg-Mn siderite, and Mg-calcite cemented sandstones. K-feldspars are weathered creating localised secondary porosity and pore filling kaolinite and illite. Layers of coal, pore filling cements, and framework grain compaction introduce vertical heterogeneity. Heavy minerals including pyrite, mixed composition sulphides, and barite are associated with disseminated coals in mudstones. Precipice Sandstone mercury intrusion porosities (MIP) ranged from 9 to 22% with favourably low reservoir injection threshold pressures, and the QEMSCAN measured open porosity between 2 and 22%. Evergreen Formation seal porosities were 7.5 to 16% by MIP or 1 to 19% by QEMSCAN, with the smallest pore throat distribution associated with the low permeability coal rich mudstone. Synchrotron XFM shows Rb mainly hosted in K-feldspars and muscovite, with metals including Mn mainly hosted in siderite. Zn and As are present in sulphides; and calcite and apatite cements mainly hosted Sr. Twenty kinetic geochemical CO2-water-rock models were run for 30 and 1000 years with Geochemist Workbench, with calcite and siderite initially dissolving. In the Precipice Sandstone reservoir variable alteration of carbonates, feldspars and chlorite to kaolinite, silica, siderite and smectite were predicted with the pH remaining below 5.5. CO2 was mineral trapped through alteration of chlorite to siderite in three of the four cases, with −0.02 to 1.43 kg/m3 CO2 trapped after 1000 years. In the calcite and siderite cemented Evergreen Formation seal, plagioclase conversion to ankerite trapped the most CO2 with 2.6 kg/m3 trapped after 1000 years. The Precipice Sandstone in both wells appears to be generally suitable as a storage reservoir, with mineral trapping predicted to mainly occur in the overlying lower Evergreen Formation and in interbedded mudstones. Heterogeneity in interbedded sandstone, mudstone, and coal layers are likely to act as baffles to CO2 and encourage mineral trapping. Quartz grain fractures may influence preferential migration pathways in the reservoir but this would need future experimental investigation. Experimental CO2 water rock reactions to understand porosity and permeability changes were out of scope here but are recommended in future validation, along with investigating the potential for CO2 adsorption trapping in coal and mudstone layers. © 2022 Elsevier B.V. All rights reserved.