Nanoscale
·
2025
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IF 5.1
Bo Li,Lipan Luo,Yujia Liu,Xiaohan Zhou,Yuyu Zhang,Lishuai Song,Nan Liu,Qing Tang,Zequan Li
Pt/TiO2 photocatalysts were synthesized using incipient wetness impregnation followed by oxidative and/or reductive thermal treatments. The loading dimensions of Pt elements on the TiO2 surface (PtP, PtSA, and PtC) were controlled by varying the impregnated solution. Experimental results demonstrate that PtC with intermediate size exhibits the highest photolysis rate under 300W xenon lamp irradiation, achieving a hydrogen yield of 11.42 mmol g^-1 h^-1 and an apparent quantum yield of 40.65%. Similarly, Ru/TiO2 and Ir/TiO2 photocatalysts prepared under the same conditions exhibited the same pattern. Photoelectrochemical tests reveal that PtC/TiO2 has the narrowest band gap, the highest interfacial charge transfer capacity, and the greatest carrier separation efficiency. DFT calculations indicate that PtC/TiO2 has the most suitable d-band center, resulting in a close-to-zero ΔGH* value of 0.05 eV. This optimal value significantly balances the adsorption and desorption of hydrogen intermediates (H*) during the photocatalytic hydrogen evolution (PHE) reaction. This study provides new insights into the preparation of precious metal-loaded photocatalysts.
研究领域:
材料科学
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能源化学
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产品关联
DOI
PubMed
高影响因子
Catalysis Science & Technology
·
2020
·Vol. 10
·期 15
·5048-5059
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IF 5.721
Yao-Yao Wang,Zheng Tang,Xue-Yang Ji,Song Wang,Zi-Shuo Yao,Jun Tao
Pt nanoparticles (NPs) can enhance the photocatalytic performance of metal–organic frameworks (MOFs) for hydrogen evolution. However, Pt atoms in the core of Pt NPs cannot be utilized for the hydrogen evolution reaction (HER) and the agglomeration of Pt NPs also reduces the enhancement effect. In this paper, we propose a simple and kinetically modulated post-synthetic strategy to encapsulate low-coordinated and monodispersed Pt clusters (PCs) with a mean size of 1.6 nm into the inner space of NH2-UiO-66 (U6N). The X-ray absorption spectroscopy (XAS) data indicate that the PCs with low coordination numbers and short Pt–Pt bonds possess more unoccupied d orbitals, which enhance the interactions between PCs and the MOF. Consequently, such enhanced interactions result in the acceleration of electron–hole separation that is beneficial to the HER activity of U6N, as confirmed by ultrafast transient absorption spectra. This MOF with encapsulated PCs shows a H2 production efficiency of 36.83 mmol h−1 g−1 and turnover number of 598 h−1 under visible light with photosensitizer erythrosin B and sacrificial agent triethanolamine. The results suggest that such PCs can efficiently boost the photocatalytic HER of U6N, and our strategy may provide a new avenue for fabricating MOFs with excellent catalytic properties.
研究领域:
材料科学
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化学
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产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
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2024
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IF 7.4
Shuang Liu,Nan Zhao,Liyuan Zheng,Richard I. Foster,Wonseok Yang,Zhe Wang,Yuexiang Lu
Photocatalysis has been regarded as one of the effective methods of removing U(VI) from radioactive wastewater in recent years, due to the benefits of being environmentally friendly and efficient. In this work, a Pt cluster modified carbon nitride photocatalyst (Pt-CN) was synthesized in zinc chloride molten salt. The photocatalysts were characterized by XRD, IR, XPS, UV–vis, PL and EIS. The result demonstrated that the doping of Pt makes Pt-CN show higher electronic conductivity and better charge separation and migration, leading to an enhanced photocatalytic activity and faster kinetics compared with bulk graphitic carbon nitride (g-C 3 N 4 ). Moreover, for uranium contained solution photocatalytic treatment, Pt-CN reached 94.6 % removal efficiency after 300 min of illumination with Xe light, and the kinetics improved by a factor of three compared to that of g-C 3 N 4 . Furthermore, the good reusability and photostability of the Pt-CN was confirmed as the removal efficiency remained at 83.7 % even after being recycled and reused five times. The photocatalytic reaction product was characterized as (UO 2 )O 2 ·2 H 2 O, and the mechanism was deduced as uranium species reacting with H 2 O 2 generated by light illumination in an open system. This molten salt one-step synthesis and Pt doping method and the performance of U(VI) extraction in air showed a promising potential for the application of Pt-CN for U(VI) extraction and removal from water.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
Journal of Cleaner Production
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2022
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IF 11.072
Feng Long,Xincheng Cao,Peng Liu,Xia Jiang,Jianchun Jiang,Xiaolei Zhang,Junming Xu
Efficient deoxygenation for the bio-derived fatty acid is paramount to producing diesel-like alkane and usually requires harsh reaction conditions. Here, we reported an efficient conversion system for the photocatalytic conversion of fatty acid over Pt/TiO 2 catalysts and acid conversion higher than 99.0% (yield nearly 84.5%) under the mild conditions 30 °C, 0.1 MPa H 2, and 365 nm light. X-ray photoelectron spectroscopy (XPS) and Density Functional Theory (DFT) calculations suggest that the oxygen vacancies TiO 2 can achieve the charge transfer from TiO 2 support to Pt clusters. The electron-rich Pt cluster can promote hydrogen spillover to form a hydrogen-rich surface. Thus, it leads to the photo-decarboxylation C n-1 alkyl radical being amenable to proton hydrogenation to produce C n-1 alkane. Detailed characterization demonstrates that 0.50 wt% Pt/TiO 2 has superior photocatalytic performance. Introducing the Pt atoms can promote the formation the oxygen vacancies and reverse charge transfer, which determines the acid adsorption and conversion mechanism.
研究领域:
化学工程
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材料科学
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能源科学
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DOI
高影响因子
ACS Catalysis
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2022
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IF 13.7
Jinqiu Guo,Mi Peng,Zhimin Jia,Chengyu Li,Hongyang Liu,Hongbo Zhang,Ding Ma
C–H bond activation is very important in upgrading of alkanes or aromatics into value-added products, such as alkenes or even oxygenates, etc., during natural gas utilization and hydrogen transportation via chemical strategies. Because of the low polarization ability and high bond energies of the C–H bonds within the hydrocarbons, the selective C–H bond activation suffers from low efficiency for a long time and requests systematic work on understanding the reaction mechanisms, in which the kinetic studies are highly desired and not well understood in a comprehensive manner. Herein, a universal kinetic model has been established to explain the entire reaction process of C–H bond activation for cyclohexane dehydrogenation (CDH) over various structures of Pt (cluster: Ptn and particle: Ptp) decorated nanodiamond@graphene (Ptx/ND@G) nanocomposite with specific emphasis on the elementary steps, the rate-determining step(s) (RDS), and the most abundant surface intermediates (MASIs). With the combination of kinetic and thermodynamic measurements, it was found that cyclohexane dehydrogenation shows different reaction mechanisms over Ptn catalysts, compared to Ptp catalysts. And C6H12 dehydrogenation rates showed nearly first-order (Ptn: rDH ∼ [C6H12]∼0.6; Ptp: rDH ∼ [C6H12]∼1.0) dependence on the C6H12, while the orders of H2 are obviously different over the two catalysts, in which the addition of H2 shows negligible effect (nearly zero-order) once a trace amount of H2 is introduced, and then obviously promotes (nearly second-order) dehydrogenation over Ptn (Ptn: rDH ∼ [H2]∼0–2), while the dehydrogenation rate over Ptp is prominently inhibited by adding H2 to the catalytic system under similar reaction conditions (Ptp: rDH ∼ [H2]∼ –1.0–0), thus indicating that Ptn and Ptp catalysts have diverse MASIs, which is further supported by the developed universal kinetic model of dehydrogenation. That perfectly explains the relationship between the dehydrogenation events and the coverage of surface hydrogen species. The predicted reaction process following a Langmuir–Hinshelwood model that matches the experimental configurations very well, suggesting that the first C–H bond rupture of C6H12 is probably the RDS for both Ptn and Ptp catalysts, while the MASIs varied from C6H10* to H* explained the diversities of the H2 dependencies between Ptn and Ptp catalysts systematically. This kinetic case study as well as the established universal model could be easily extended to some other systems related to C–H bond rupture and attracts the attention on exploring the correlations between nanostructure and the reaction performance.
研究领域:
催化化学
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材料科学
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反应动力学
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产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2021
·Vol. 11
·期 15
·5250-5259
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IF 6.119
Zhiyang Zhang,Wenlong Xu,Xiaomei Ye,Yonglan Xi,Cunpu Qiu,Liping Ding,Gui Liu,Qingbo Xiao
Enclosing metal clusters in zeolites can enhance their catalytic performance due to the complex effects of the zeolitic environment. However, for the first time, herein, we report the significant passivation effects of the surrounding zeolitic framework on the d-band center and catalytic performance of enclosed Pt clusters. For the dehydrogenation of propane to propylene, the Pt/NaX catalyst with Pt clusters on the exterior of X-zeolite showed a ∼1100% enhancement in TOF and largely improved selectivity for propylene compared with the corresponding Pt@NaX catalyst, in which the Pt clusters were stuck to the inside of X-zeolite. Moreover, less coke deposition and high stability were detected in Pt/NaX after the reaction for 18 h. Combining the detailed experiments and DFT calculations, it was revealed that the significant passivation effect is mainly attributed to the surrounding zeolitic framework for the enclosed Pt clusters, which decreases the d-band center of the Pt clusters and weakens the activation of propane, preventing the desorption of propylene with a reduction in propylene selectivity and increase in coke deposition. Thus, the present investigation reveals that enclosing metal clusters in zeolites may not be beneficial for some specific catalytic reactions, deepening the understanding for this type of catalyst of metal clusters enclosed in zeolites.
研究领域:
催化
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化学工程
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材料科学
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物理化学
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产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
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2023
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IF 6.7
Yingzhang Shi,Taikang Wu,Zhiwen Wang,Cheng Liu,Jinhong Bi,Ling Wu
Optimizing the electronic structure of the surface active sites and introducing functional sites for a photocatalyst are effective strategies to achieve the photocatalytic selective hydrogenation of biomass. Herein, Pt clusters/bimetallic NiMg-MOF-74 (MNM) ultrathin nanosheets were constructed for the photocatalytic precise hydrogenation of furfural (FUR) to furfuryl alcohol (FAL). A representative sample (Pt/MNM-0.25) shows 99.9% conversion of FUR and 99.9% selectivity of FAL. The electron density of surface coordinatively unsaturated Ni II atoms in MNM is decreased after the doping of Mg. In situ ATR-IR indicated that the optimized surface Ni II sites induced a more effective coordination activation of FUR molecules via the Ni-η 1 -(O)-furfural coordination. Electrochemical measurements and in situ EPR results reveal that Pt clusters are the functional surface sites for transferring the photogenerated electrons and dissociating H 2 . The synergistic effect of surface optimized Ni II sites and Pt clusters is emphasized. This work successfully achieves the high-efficiency precise hydrogenation of FUR to FAL via designing surface functionalized Pt clusters/bimetallic MOF ultrathin nanosheets.
研究领域:
催化
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材料科学
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化学工程
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光化学
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产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Yangfei Fang,Kaijie Liu,Xin Shen,Daying Zheng,Xiaohui Chen,Bin Hu,Huaiyuan Wang,Mengyao Bian,Liwei Sun,Haijiao Xie,Yibo Zhang,Xiangguang Yang
Developing highly active catalysts for hydrocarbon combustion at low temperatures is paramount but yet challenging. The crystal form of carrier and the dispersion degree of active species have great influence on propane combustion catalysts, but its internal mechanism is still unclear. In this study, the amorphous atomic-layer Pt clusters (AL) and Pt single atoms (SA) on TiO 2 with various crystal phases were prepared and used as propane combustion catalysts, where the as-synthesized Pt/a-TiO 2 catalyst with atomic-layer Pt clusters exhibited better catalytic performance. The Pt/a-TiO 2 -AL could achieve a 90 % propane conversion (T 90 ) at 230 °C, with the highest reaction rate (39.57 × 10 −7 mol g −1 s −1 ) and TOF value (7.72 × 10 −2 s −1 ) at 240 °C. Kinetic studies showed that oxygen had a lower inhibitory effect on Pt/a-TiO 2 -AL compared to that on the Pt/p-TiO 2 -AL and Pt/r-TiO 2 -AL catalysts; simultaneously, the Pt/a-TiO 2 -AL catalyst presented lower apparent activation energy compared with Pt/a-TiO 2 -SA. DFT results showed that atomic-layer Pt clusters on TiO 2 had the lower formation energy of oxygen vacancy than Pt single atoms due to the synergistic effect between adjacent exposed Pt atoms in the fully exposed atomic-layer Pt clusters, which had a higher activation capacity for oxygen and thus accelerated propane combustion through the ignition effect (rapid activation of oxygen and rapid combustion of propane). Our primary results provide a promising approach for the creation of high-efficiency Pt-based catalysts, specifically tailored for the catalytic combustion of volatile organic compounds (VOCs).
研究领域:
催化
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化学工程
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材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）