Assayehegn Elias, Solaiappan Ananthakumar, Gidey Abraha Tadese, Gebreegziabher Gebremedhin Gebremariam, Gebretsadik Tesfamariam Teklu, Chebude Yonas, Alemayehu Esayas
Materials Science and Technology Division National Institute for Interdisciplinary Science and Technology (NIIST-CSIR) Thiruvananthapuram 695019 India.
National Centre for Catalysis Research and Department of Chemistry Indian Institute of Technology-Madras Chennai 600036 India.
Glob Chall. 2024 Sep 19;8(10):2400174. doi: 10.1002/gch2.202400174. eCollection 2024 Oct.
Visible-light active anatase/brookite/rutile (A/B/R) ternary N-doped titania (N/TiO) crystals are successfully prepared by a facile sol-gel method using titanium butoxide and benign N-dopant source, guanidinium chloride. Systematically varying the aging time (1, 4, 8, and 12 d), its influence on physicochemical properties of as-obtained spherical heterojunction nanomaterials is studied. Detailed characterizations confirm that a substantial amount of anatase (88% to 50%) is transformed to rutile (2% to 38%) via intermediate brookite phase (9% to 25%) as the function of aging time; not only the A/B/R phase content of the samples is tuned by sol-gel aging time of the precursors solution but also their optical-response and methylene blue photocatalytic properties are profoundly dictated. Notably under visible-light irradiation, the photostable rutile rich mesoporous A/B/R triphasic N/TiO (50% A, 12% B, 38% R) aged for 12 d demonstrates higher degradation activity (97%) with a faster degradation rate (0.033 min) than both lesser aged N/TiO and undoped titania. This enhancement is attributed to the synergistic effect of interstitial-N-doping and optimal A/B/R interfacial charge transfer that leads to higher light absorption, lower bandgap energy and well-separated charge carriers. The current work provides a new perspective for designing highly active visible-light heterostructure nanomaterials with controllable phase composition.
采用丁醇钛和良性氮掺杂源氯化铵，通过简便的溶胶-凝胶法成功制备了可见光活性锐钛矿/板钛矿/金红石（A/B/R）三元氮掺杂二氧化钛（N/TiO）晶体。系统地改变老化时间（1、4、8和12天），研究其对所得球形异质结纳米材料物理化学性质的影响。详细表征证实，随着老化时间的变化，大量锐钛矿（88%至50%）通过中间相板钛矿相（9%至25%）转变为金红石（2%至38%）；不仅样品的A/B/R相含量可通过前驱体溶液的溶胶-凝胶老化时间进行调节，而且它们的光学响应和亚甲基蓝光催化性能也受到深刻影响。值得注意的是，在可见光照射下，经过12天老化的光稳定富金红石介孔A/B/R三相N/TiO（50%A、12%B、38%R）表现出比老化程度较低的N/TiO和未掺杂二氧化钛更高的降解活性（97%）和更快的降解速率（0.033分钟）。这种增强归因于间隙氮掺杂和最佳A/B/R界面电荷转移的协同效应，导致更高的光吸收、更低的带隙能量和良好分离的电荷载流子。目前的工作为设计具有可控相组成的高活性可见光异质结构纳米材料提供了新的视角。
