APPLIED CATALYSIS B-ENVIRONMENTAL
·
2021
·
IF 19.503
Kaiyi Su,Yehong Wang,Chaofeng Zhang,Zhuyan Gao,Jianyu Han,Feng Wang
Herein, we reported the tuning of dominant products in the photocatalytic hydrogen transfer reaction over Pt/Nb 2 O 5 photocatalysts, using a support-induced modification strategy. In the photocatalytic conversion of phenylacetylene with ethanol as a probe reaction, the dominant product was styrene over Pt/2D Nb 2 O 5 nanoplates; in contrast, H 2 was the main product over the Pt/bulk Nb 2 O 5 . Compared to the metallic Pt species over bulk Nb 2 O 5 , the positively charged Pt (Pt δ+ ) species over 2D Nb 2 O 5 nanoplates contributed to the reduction of phenylacetylene, which was revealed by CO adsorbed Fourier transform infrared spectra. Furthermore, the present Pt δ+ species were due to the formation of Pt δ+ –O–Nb structure via oxygen transfer of 2D Nb 2 O 5 nanoplates, which was verified by the results of X-ray photoelectron spectra and H 2 temperature-programmed reduction. This work sheds light on the design and application of Nb-based catalysts in the transfer hydrogenation of organics in photocatalysis.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
RENEWABLE ENERGY
·
2022
·
IF 8.634
Siteng Rong,Hongzi Tan,Zhaobin Pang,Zhiyuan Zong,Rongrong Zhao,Zhihe Li,Zhe-Ning Chen,Ning-Ning Zhang,Weiming Yi,Hongyou Cui
Lignin could be depolymerized into large amount of phenolic compounds via fast pyrolysis . The upgrade of phenolic compounds via hydrodeoxygenation (HDO) involves multiple reaction pathways. It is challenging to selectively remove the oxygen-containing groups while keeping the aromatic rings intact. In this work, hierarchical Nb 2 O 5 (H–Nb 2 O 5 ) microspheres with abundant oxygen vacancies were synthesized to anchor the Pd clusters, which is featured with strong metal-support interaction via the electron transfer between Pd species and Nb species. For phenol HDO reaction, the oxygen vacancies were prone to interact with the phenolic hydroxy groups, resulting in phenol molecule adsorbed in a “nonplanar” manner, greatly weakening the C Ar -O bonds and averting the ring hydrogenation. Besides, the activated hydrogen atoms on Pd clusters could migrate to the vicinity of oxygen vacancies via spillover, promoting the cleavage of C Ar -O bond to obtain benzene. Current work provides a deep insight into the synergetic catalytic mechanism of Pd/H–Nb 2 O 5 catalyst for phenol HDO reaction, and also sheds light on the design and synthesis of high-efficient catalysts in other heterogeneous catalysis fields.
研究领域:
催化化学
·
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
·
2020
·Vol. 45
·期 2
·3129-3141
·
IF 3.741
Xuelian Zhang,Ke Wang,Xin Zhang,Jianjiang Hu,Mingxia Gao,Hongge Pan,Yongfeng Liu
Summary High operation temperatures and slow reaction kinetics are major obstacles to use MgH 2 as a solid hydrogen store. We report here the synthesis of Nb 2 O 5 hollow spheres (o-Nb 2 O 5 ) with wall thickness of approximately 50 nm and mossy surfaces using a facile hydrothermal and calcination process, which showed high activity in catalysis of MgH 2 for hydrogen storage. The dehydrogenation onset temperature of MgH 2 was decreased to 195°C with 7 wt% of o-Nb 2 O 5 . More than 5.5 wt% H 2 can be desorbed at 300°C within 5 minutes. Hydrogen re-absorption starts even at 25°C and reaches 5.6 wt% within 5 minutes at 200°C. Practical hydrogen capacity stabilizes at 5.8 wt% after 10 cycles of hydrogen uptake/release. The o-Nb 2 O 5 was found to be reduced in situ by MgH 2 to low-valence Nb species during the initial dehydrogenation process, which functions as an active catalyst and leads to the enhanced dehydrogenation kinetics.
研究领域:
材料科学
·
催化
·
能源存储
✓ 已验证
DOI
高影响因子
ChemNanoMat
·
2023
·Vol. 10
·期 3
·e202300479
·
IF 3.8
Zijian Wang,Mengdie Li,Mingjiao Xiao,Yanze Wei,Ranbo Yu,Zumin Wang
Graphical Tiny NiP nanoparticles dispersed was used as an inexpensive, stable, and active cocatalysts on ultrathin Nb 2 O 5 nanosheets to replace the noble metal Pt. Owing to the extended light harvesting, enhanced carrier separation, and improved surface reaction, the NiP/Nb 2 O 5 exhibits even higher activity and selectivity towards CO 2 photocatalytic reduction. And the roles and function mechanisms of the cocatalyst were studied. Photocatalytic CO 2 reduction holds great promise to solve energy shortage and global warming. Nb 2 O 5 has demonstrated superiority in CO 2 activation and selectivity regulation, but suffers from poor light absorption ability and fast carrier recombination. To tackle these problems, we designed and synthesized ultrathin Nb 2 O 5 nanosheets which were decorated with tiny NiP nanoparticles as cocatalyst. In this way, light absorption range broadened, carrier migration distance reduced, charge transfer resistance decreased, and surface reaction kinetics promoted. Consequently, the as-prepared NiP/Nb 2 O 5 showed notably enhanced activity (148.7 μmol ⋅ g −1 ) and selectivity (82.1 %) towards CO, as well as remarkable stability. This work paves the way for cheap and earth abundant alternatives as cocatalysts and deepens the understanding of their functions in CO 2 photoreduction.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2021
·
IF 3.764
Yu Ling,Xiao Chen,Hongkai Tong,Weixiang Guan,Ping Chen,Zhaohui Huang,Changhai Liang
Propylene dimerization is an attractive way to branch out the bulk chemicals to high-value-added fine chemicals. Based on the coordinatively unsaturated surface sites of nickel and solid acid sites for boosting highly selective dimerization of propylene, a series of NiSO4/Nb2O5 catalysts were synthesized by tuning the synergistic effect through adjusting the calcination temperatures. Under the conditions of 70 °C, 2.5 MPa, and LHSV = 3 h–1 in a fixed-bed reactor, the NiSO4/Nb2O5-400 catalyst exhibits the highest propylene conversion of ca. 89% with 75% selectivity to C6 products (mainly including 4-methyl-2-pentene and 3-hexene). A possible Cossee–Arlman pathway has been proposed for the dimerization of propylene. In the long-term stability testing, an induction period has been observed, which may be attributed to the coordination of propylene molecules to unsaturated Ni2+ cations generating some active nickel species. Subsequently, the NiSO4/Nb2O5-400 catalyst presents a stability up to 30 h. The interesting results inspired us to modulate the interaction of metal (salt) and acid sites to strengthen the selective dimerization of low-carbon olefins.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
GREEN CHEMISTRY
·
2017
·Vol. 19
·期 21
·5103-5113
·
IF 9.125
Ying Duan,Min Zheng,Dongmi Li,Dongsheng Deng,Lu-Fang Ma,Yanliang Yang
The catalytic conversion of HMF to 2-hydroxy-3-methyl-2-cyclopenten-1-one (MCP), which is a valuable edible essence that has traditionally been obtained from adipic acid, was achieved with an isolated yield of 58%. This procedure comprised two steps: the hydrogenation of 5-hydroxymethylfurfural (HMF) to 1-hydroxy-2,5-hexanedione (HHD) in water on Pd/Nb2O5 catalysts and then the isomerization of HHD to MCP in the presence of a base. The Nb2O5 supports, which were acidic, were characterized by FTIR, XRD and NH3-TPD. The supported Pd/Nb2O5 catalysts, in which Pd was highly dispersed, were synthesized employing cyclohexene as a reductant and were characterized by XRD, TEM, ICP-AES, XPS, EDX and CO pulse chemisorption. The high conversion of HMF was attributed to the high dispersion of Pd, and the acidity of the supports led to high selectivity for HHD. The conversion of HHD to MCP was an intramolecular aldol condensation reaction, and the protonic solvent favored this reaction. Ca–Al was proved to be an effective solid base for the conversion of HHD to MCP in water.
研究领域:
化学工程
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 99
·96809-96815
·
IF 3.289
Hualei Zhang,Qianying Lin,Shangbo Ning,Yangen Zhou,Huaxiang Lin,Jinlin Long,Zizhong Zhang,Xuxu Wang
Mesoporous Pt–Nb2O5 photocatalysts with high photocatalytic hydrogen production activity were synthesized by a one-step method. The mesoporous structure of the as-made samples was characterized by X-ray diffraction, N2 adsorption–desorption isotherms and transmission electron microscopy. Pt–Nb2O5 exhibited higher hydrogen production activity than pure Nb2O5 and 0.8-Pt–D–M–Nb exhibited the best photocatalytic activity. In addition, Pt–Nb2O5 synthesized by a one-step method exhibited higher photocatalytic hydrogen production activity than that prepared by an incipient wetness impregnation method; 0.8-Pt–D–M–Nb exhibits a H2 evolution rate of 9.79 mmol h−1 g−1, while 0.8-Pt–I–M–Nb2O5 exhibits a H2 evolution rate of 7.73 mmol h−1 g−1. The enhanced photocatalytic activity of Pt–Nb2O5 was predominantly attributed to the efficient separation of photoinduced electrons and holes.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Moke Zhou,Hetuo Chen,Guohong Zhou,Yi He,Shuren Zhang,Bin Tang
Four control experiments (S1: Y 3 Al 5 O 12 , S2: Y 3 Al 5 O 12 +1 wt%Nb 2 O 5 , S3: Y 3 Al 4.955 Nb 0.045 O 12 , S4: Y 2.955 Al 5 Nb 0.045 O 12 ) were designed to investigate the co-effects of Nb 2 O 5 and non-stoichiometry on the microwave dielectric properties of Y 3 Al 5 O 12 . The beneficial results of Nb 2 O 5 doping are demonstrated based on X-ray patterns, electron diffraction information, Rietveld refinement , and micromorphological characterization. Differences in dielectric properties were explored using lattice defects, ion polarizability, bond valence, and Raman spectroscopy . In contrast, the Y-deficient sample (S4) possesses the best dielectric properties ( ε r ∼ 10.37, Q × f ∼ 161,724 GHz and τ f ∼ -33.8 ppm/°C).
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
Biomass Conversion and Biorefinery
·
2022
·
IF 4.05
Wang Jiacheng,Li Xingyong,Wu Yankun,Duan Jinyi,Zhuang Nihong,Wang Dechao,Zhang Zhaoxia,Ye Yueyuan,Li Shuirong,Zheng Zhifeng
The wide-scale application in the bio-fuel area of fatty acid methyl esters (FAME) has been limited because of its high oxygen content, awful low temperature flowability, and low heating value. In this work, the hydrodeoxygenation (HDO) of methyl palmitate as fatty acid methyl ester model compounds for long-chain alkane via Nb 2 O 5 modified NiAl 2 O 4 catalysts was investigated. The effect of Nb/Ni atomic ratio (0.05:0.30), reaction temperature (260–340 ℃), time (2–10 h), and H 2 pressure (1–5 MPa) on the production of long-chain alkane is exhaustively researched. The results show that the products are mainly pentadecane with a few other alkane hydrocarbons and nickel metal was the main active site. Besides, the added promoter Nb promoted the dispersion of active metal Nickel, increased the acidity, and thus substantially enhanced the HDO activity of methyl palmitate. In response to the best conditions (0.3 g catalyst, 3 g methyl palmitate), the methyl palmitate conversion and pentadecane selectivity over Nb 2 O 5 -NiAl 2 O 4 with 0.20 Nb/Ni atomic ratio reached 91.14% and 80.07%, respectively. However, the methyl palmitate conversion and pentadecane selectivity over pure NiAl 2 O 4 catalyst were only 62.53% and 74.67%, respectively. Therefore, Nb 2 O 5 -NiAl 2 O 4 catalysts exhibit remarkable catalytic ability for HDO of methyl palmitate to alkanes. The low cost, easy preparation, high catalytic performance, and recycling stability of Nb 2 O 5 -NiAl 2 O 4 catalyst demonstrate that catalyst Nb 2 O 5 -NiAl 2 O 4 is a promising effective and efficient catalyst for producing long-chain alkane from methyl palmitate. Graphical abstract
研究领域:
催化化学
·
可再生燃料化学
✓ 已验证
产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 41
·14532-14536
·
IF 4.39
Yang Zhang,Yakun Tang,Lang Liu,Yue Zhang,Zhiguo Li
A T-Nb2O5/CNT nanohybrid with short transmission paths, many active sites, and favorable mechanical flexibility can achieve the fast transportation of ions/electrons. The obtained nanohybrid with continuous conductive networks exhibited better lithium storage performance than sodium storage performance, due to lower resistance to the diffusion of Li+ ions crossing the carbon matrix.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Haonan Zhu,Fangyuan Wang,Yingying Cao,Yuhai Yang,Siyu Yang,Zipeng Zou,Fengjie Hu,Feng Chen,Jianping Qiu,Shuang Song
Nb 2 O 5 based photocatalysts have garnered significant attention in the field of antibiotic photodegradation due to their potential. Enhancing the efficiency of carrier separation efficiency still remains a crucial factor for optimizing photocatalytic performance. Herein, a Nb 2 O 5 /Co 3 O 4 p–n heterojunction photocatalyst was synthesized by a straightforward one-step hydrothermal method. The Nb 2 O 5 /Co 3 O 4 composites effectively utilized visible light to catalytically degrade norfloxacin, achieving 89.2% degradation in 90 min. This performance was 2.68 and 7.42-fold greater than pure Nb 2 O 5 and Co 3 O 4 , respectively. Furthermore, this composite maintained its high activity through five cycles of photocatalysis. The exceptional performance was creditable to the establishment of p-n heterojunction structure between Nb 2 O 5 and Co 3 O 4 , which effectively inhibited the electron-hole recombination and distinctly broadens the visible light adsorption region. •O 2 − and h + were confirmed as the critical active species in this process. The primary degradation pathways for norfloxacin were decarboxylation and ring-opening. This study introduced an innovative method for developing and fabricating flower-like Nb 2 O 5 -based heterojunctions for enhancing photocatalytic efficiency. This approach held significant promise for the effective treatment of antibiotic-contaminated wastewater through photocatalysis.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Nano-Micro Letters
·
2023
·Vol. 15
·期 1
·1-16
·
IF 26.6
Su Zhe,Yi Shan,Zhang Wanyu,Xu Xiaxi,Zhang Yayun,Zhou Shenghu,Niu Bo,Long Donghui
The integration of nano-semiconductors into electromagnetic wave absorption materials is a highly desirable strategy for intensifying dielectric polarization loss; achieving high-attenuation microwave absorption and realizing in-depth comprehension of dielectric loss mechanisms remain challenges. Herein, ultrafine oxygen vacancy-rich Nb 2 O 5 semiconductors are confined in carbon nanosheets (ov-Nb 2 O 5 /CNS) to boost dielectric polarization and achieve high attenuation. The polarization relaxation, electromagnetic response, and impedance matching of the ov-Nb 2 O 5 /CNS are significantly facilitated by the Nb 2 O 5 semiconductors with rich oxygen vacancies, which consequently realizes an extremely high attenuation performance of − 80.8 dB (> 99.999999% wave absorption) at 2.76 mm. As a dielectric polarization center, abundant Nb 2 O 5 –carbon heterointerfaces can intensify interfacial polarization loss to strengthen dielectric polarization, and the presence of oxygen vacancies endows Nb 2 O 5 semiconductors with abundant charge separation sites to reinforce electric dipole polarization. Moreover, the three-dimensional reconstruction of the absorber using microcomputer tomography technology provides insight into the intensification of the unique lamellar morphology regarding multiple reflection and scattering dissipation characteristics. Additionally, ov-Nb 2 O 5 /CNS demonstrates excellent application potential by curing into a microwave-absorbing, machinable, and heat-dissipating plate. This work provides insight into the dielectric polarization loss mechanisms of nano-semiconductor/carbon composites and inspires the design of high-performance microwave absorption materials.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）