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Optimizing one-dimensional TiO2 for photocatalytic hydrogen production from a water-ethanol mixture and other electron donors
摘要： This work is focused on synthesizing and employing one-dimensional (1D) titanium dioxide (TiO2) for hydrogen (H2) production. Based on using electron donors (EDs) (ethanol, methanol, formic acid and 1,2,3 propanetriol), the increased H2 production, when compared to P25 TiO2 nanoparticles, was due to the large specific surface area (SSA) and enhanced electron mobility of 1D TiO2. The impact of the 1D TiO2 synthesis reaction conditions (temperature, NaOH concentration and the TiO2 precursor concentration) on the photocatalytic H2 production rate was evaluated using a 3-factor 3-level Box Behnken design (BBD). The BBD model demonstrated that the temperature and the NaOH concentration significantly affected the 1D TiO2 phase structure, crystal size, SSA, bandgap and the photocatalytic H2 production rate. The phase structure and crystal size of 1D TiO2 were key factors affecting the H2 production rate. 1D TiO2 containing an anatase phase with a mean crystal size of 20.1±0.2 nm was synthesized at 126oC, 15 M NaOH and 49 g·L-1 TiO2. The maximum H2 production rate of 475±12 μmol·h-1 (quantum efficiency (ε) = 20.2±0.5%) for the 1D TiO2 sample was significantly enhanced when compared to commercial TiO2 P25. The H2 production rate for the optimized 1D TiO2 was significantly enhanced by decorating the structure with Pt and Au. Hydrothermal synthesized of 1D TiO2 provided an efficient and low cost method for producing H2 from ethanol, methanol, formic acid and 1,2,3 propanetriol.
关键词： hydrogen production,hydrothermal,1D titanium dioxide,TiO2-B,anatase,photocatalyst,quantum yield
更新于2025-09-23 15:23:52
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Atomic-thick TiO <sub/>2</sub> (B) nanosheets decorated with ultrafine Co <sub/>3</sub> O <sub/>4</sub> nanocrystals as a highly efficient catalyst for lithium-oxygen battery
摘要： Development of high efficient catalysts based on transition metal oxides (TMOs) is desirable, and remains a big challenge for lithium-oxygen (Li-O2) batteries. In the present work, atomic-thick TiO2(B) nanosheets decorated with ultrafine Co3O4 nanocrystals (Co3O4-TiO2(B)) was synthesized and utilized as cathode catalyst in Li-O2 batteries by designing a hybrid and inducing oxygen vacancies. The XPS characterization results suggested that the introduction of Co3O4 nanocrystals could induce numerous oxygen vacancies in the TiO2(B) nanosheets through Co doping in the hybrid catalyst. The subsequent electrochemical experiments indicated that the Li-O2 batteries with the prepared hybrid catalysts showed high specific capacity (11000 mAhg-1), and good cycling stability (200 cycles at a limited capacity of 1000mAhg-1) with low polarization (above 2.7V for discharge medium voltage and below 4.0V for charge medium voltage within 80 cycles). Furthermore, a possible working mechanism was proposed for a better understanding of the high performance of Co3O4-TiO2(B) catalysts for the Li-O2 batteries. This work also provided some new insights into designing efficient catalysts through interface engineering between 2D (two dimentional) TMOs and 0D (zero dimentional) TMOs for Li-O2 batteries or other catalysis related fields.
关键词： film-like Li2O2,oxygen vacancies,TiO2(B) nanosheets,Co3O4 nanocrystals,Li-O2 battery
更新于2025-09-23 15:21:21
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Surface plasma Ag-decorated single-crystalline TiO2?x(B) nanorod/defect-rich g-C3N4 nanosheet ternary superstructure 3D heterojunctions as enhanced visible-light-driven photocatalyst
摘要： Ag-TiO2-x(B)/g-C3N4 ternary heterojunctions photocatalysts are fabricated by hydrothermal-calcination, photo-deposition procedure, and followed by in-situ solid-state chemical reduction procedure. As-obtained photocatalysts are consisted with heterojunctions between 2D g-C3N4 sheets and 1D TiO2(B) single-crystalline nanorods. The band gap of Ag-TiO2-x(B)/g-C3N4 ternary heterojunctions photocatalysts is reduced to ~2.23 eV due to plasma Ag and surface engineering. Under visible light irradiation, it has an optimal photocatalytic property for the reduction of Cr6+ (95%) and degradation of NH4+ (93%). The apparent reaction rate constants (k) of ternary heterojunctions photocatalysts for NH4+ and Cr6+ are 25 and 12 folds higher than that of original TiO2(B). Furthermore, Ag-TiO2-x(B)/g-C3N4 also has excellent hydrogen production efficiency, which is up to 410 mmol h-1 g-1. This enhancement can be attributed to the unique heterojunction formed by 1D single-crystalline TiO2(B) nanorods and 2D g-C3N4 sheets, surface plasma resonance effect of plasma Ag nanoparticle, and surface engineering. A possible photocatalytic mechanism is also proposed by analysizing the XPS valence-band spectra and the Mott-Schottky.
关键词： Surface engineering,g-C3N4 sheet,Visible-light-driven photocatalysis,Single-crystalline TiO2(B) nanorod,Heterojunction
更新于2025-09-19 17:15:36
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Colour centre controlled formation of stable sub-nanometer transition metal clusters on TiO2 nanosheet for high efficient H2 production
摘要： The transition elements (Fe, Co, Ni) are important substitutes for noble metals as the co-catalysts in hydrogen evolution reaction. Enhancing the atom utilization efficiency is highly desirable, but preparation and preservation of the transition metal catalysts with the size downscaling to sub-nanometer are challenging. In this work, Fe, Co and Ni clusters with subnano size as co-catalysts are synthesized by controllable growth on 2D ultrathin TiO2(B) nanosheets for hydrogen evolution using a photo deposition method. The ultra-small Fe, Co, and Ni co-catalysts on the TiO2(B) nanosheets exhibit remarkably enhanced photo activities, compared to that with the best Pt loading. It is found that the oxygen bridge vacancies act as the colour centres locating at the position adjacent to the O1-Ti1 sites on the TiO2(B) (001) surface. The photo-colouration and photo-bleaching have significantly impact on the nucleation and growth of the metallic clusters. The high density and uniform dispersion of the sub-nano-sized transition metal clusters benefits for the photo reduction under light irradiation, as well as efficient carrier separation, leading to a great improvement of the photo activity.
关键词： TiO2(B),transition metal loading,photocatalysis,water splitting,sub-nanometer
更新于2025-09-19 17:13:59
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Hybrid 0D/2D Ni2P quantum dot loaded TiO2(B) nanosheet photothermal catalysts for enhanced hydrogen evolution
摘要： The development of low cost, stable, robust photocatalysts to convert solar energy into hydrogen energy is an important challenge. Here, we describe a simple solvothermal method to successfully fabricate a catalyst with a hybrid 0D/2D Ni2P quantum dot/TiO2(B) nanosheet architecture. HRTEM shows that Ni2P quantum dots about 5 nm in size were dispersed on ultrathin TiO2(B) nanosheets. The optimum photocatalytic H2 evolution rate with 10 wt% Ni2P/TiO2(B) (3.966 mmol g?1 h?1), which was 15 times higher than pure TiO2(B) nanosheets. Significantly, the new catalyst shows high stability and reusability in multiply cycled H2 production runs for a 30 h period. The H2 production rate can be considerably increased furthered by using synergistic photothermal H2 evolution (20.129 mmol g?1 h?1 at 90 °C).
关键词： TiO2(B) nanosheets,Photocatalytic H2 evolution,Ni2P quantum dots,0D/2D architecture,Synergistic photothermal catalysis
更新于2025-09-11 14:15:04
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Synthesis of TiO <sub/>2</sub> (B) and High-temperature Stable Anatase TiO <sub/>2</sub> Nanowires by Hydrothermal Method and Investigation of Photocatalytic Activity
摘要： In this study, TiO2 nanowires (TNWs) were synthesized through hydrothermal method and were characterized using X-Ray diffraction (XRD), transmission electron microscopy (TEM) and BET techniques. Monoclinic TiO2 (B) is the dominant phase of TNWs up to 600 ℃ which is completely transformed into a highly crystalline anatase phase at 800 ℃. The photocatalytic activity of TNWs, prepared at various calcination temperatures, was investigated in the removal of Rhodamine B (RhB) as an organic model pollutant. The results indicated that the photocatalytic activity of TNWs, prepared at 800 ℃ calcination temperature (TNWs-800), was better than that of other samples and even TiO2-P25 nanoparticles.
关键词： Anatase TiO2 nanowires,Photocatalytic activity,TiO2 (B),Hydrothermal method,High-temperature
更新于2025-09-10 09:29:36
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Assembly of surface-defect single-crystalline strontium titanate nanocubes acting as molecular bricks onto surface-defect single-crystalline titanium dioxide (B) nanorods for efficient visible-light-driven photocatalytic performance
摘要： Ti3+ self-doped single-crystalline SrTiO3(cid:1)x nanocubes acting as molecular bricks are successfully assembled onto Ti3+ self-doping single-crystalline TiO2(cid:1)x(B) nanorods through an effortless two-step hydrothermal process coupled with an in situ solid-state chemical reduction method. SrTiO3(cid:1)x nanocubes act as molecular bricks, which are uniformly assembled onto the surface of TiO2(cid:1)x(B) nanorods due to lattice matching. The band gap of the resultant SrTiO3(cid:1)x/TiO2(cid:1)x(B) sample is (cid:3)2.97 eV, which exhibits excellent photocatalytic performance for the reduction of Cr(VI) and hydrogen production under visible light. The apparent rate constant k value for the photocatalytic reaction of SrTiO3(cid:1)x/TiO2(cid:1)x(B) for Cr(VI) reduction is (cid:3)8 times higher than that of white TiO2(B). The photocatalytic hydrogen production rate for SrTiO3(cid:1)x/TiO2(cid:1)x(B) is (cid:3)160.2 lmol g(cid:1)1 h(cid:1)1, which is (cid:3)5 times higher than that of white TiO2(B). The enhanced photocatalytic activity can be considered to be caused by a synergetic effect of heterojunction formation and the introduction of Ti3+ self-doping, which can not only facilitate the separation of photogenerated charge carriers between TiO2(cid:1)x(B) and SrTiO3(cid:1)x, but also broaden the photoresponse from the UV to visible-light region.
关键词： Photocatalysis,Heterojunction,Ti3+ self-doping,TiO2(B),SrTiO3
更新于2025-09-10 09:29:36