JOURNAL OF CATALYSIS
·
2026
·
IF 6
Mufan Niu,Qiyu Sun,Chongbin Wei,Fubin Peng,Xiaohe Huang,Han Yang,Ying Cui,Shenyong Ren,Chunming Xu,Baojian Shen
To elucidate the active sites and reaction mechanism of CrO x /ZrO 2 catalysts in CO 2 -assisted oxidative dehydrogenation (CO 2 -ODH) of ethane, a combination of multiple characterization techniques, DFT calculations, and in situ FTIR spectroscopy was employed. Results reveal the coexistence of isolated and polymeric Cr 6+ species on the catalyst surface, with catalytic activity exhibiting a strong positive correlation with the content of polymeric Cr 6+ , confirming its role as the key active component. Further investigation uncovers a distinct and strong electronic interaction between CrO x and ZrO 2 that facilitates the formation and stabilization of polymeric Cr 6+ . This interaction is absent in CrO x /CeO 2 and CrO x /TiO 2 systems, offering a theoretical rationale for the rational design of catalyst supports. Mechanistically, CO 2 plays a dual role: it participates in both ethane ODH and the RWGS reaction, and reoxidizes coordinatively unsaturated Cr 3+ to Cr 6+ , thereby enhancing reaction stability. This work elucidates the CO 2 -ODH pathway and the regulatory role of CO 2 , offering new insights into the design of active sites in CrO x -based catalysts. However, pronounced catalyst deactivation currently limits industrial application, highlighting the need for future efforts to focus on improving catalyst stability.
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高影响因子
ENERGY & FUELS
·
2026
·Vol. 40
·期 35
·19600-19613
·
IF 6
Dai Xinrui,Lin Min,Wang Hua,Zhu Xing
High-loading chromium oxide catalysts are attractive
for the dehydrogenation
of ethylbenzene (EB) to styrene (ST), but the migration, aggregation,
and irreversible restructuring of Cr species during high-temperature
calcination and reaction often reduce active-site accessibility and
accelerate catalyst deactivation. Herein, we report a reverse double-solvent
strategy to construct a shape-preserving mesoporous SiO 2 framework within a Cr-MOF precursor, yielding a Cr@Si-6 catalyst
in which Cr 3+ -rich nanoscale Cr 2 O 3 domains and highly dispersed chromate-like Cr 6+ species
are stabilized within a silica cage-like network. This architecture
integrates three complementary structural features: the homogeneous
Cr distribution inherited from the MOF precursor, physical confinement
by the mesoporous SiO 2 framework, and chemical anchoring
with electronic regulation through Cr–O–Si interfacial
linkages, thereby reconciling high Cr loading with high dispersion.
Structural and spectroscopic characterizations show that the SiO 2 skeleton suppresses long-range Cr migration, aggregation,
and the development of bulk-like Cr 2 O 3 domains,
while Cr–O–Si interfacial coupling regulates the local
coordination and electronic environment of the Cr species and strengthens
their resistance to reduction-induced restructuring. In the chemical
looping oxidative dehydrogenation of ethylbenzene (EB-CL-ODH), lattice
oxygen participates in EB conversion during the reduction step, followed
by regeneration of the reduced catalyst in a separate O 2 oxidation step. Cr@Si-6 achieves 80% EB conversion, 91% ST selectivity,
and 73% ST yield at the moderate temperature of 450 ° C, outperforming
directly calcined Cr-MOF-600 and conventional Cr/SiO 2 ,
while maintaining an ST selectivity above 90% with no obvious decay
in EB conversion over 40 redox cycles. Postreaction XRD, Raman, TG/DTG,
GC–MS/TIC, and SEM/EDS analyses further show that the confined
Cr 2 O 3 /SiO 2 architecture is largely
preserved and that reaction-induced carbonaceous and heavy organic
deposits can be substantially removed through oxidative regeneration.
This work demonstrates that integrating MOF-derived Cr distribution,
mesoporous silica confinement, and Cr–O–Si interfacial
regulation provides an effective strategy for constructing high-loading,
highly dispersed, and regenerable Cr-based oxygen carriers for moderate-temperature
EB-CL-ODH.
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高影响因子
APPLIED SURFACE SCIENCE
·
2014
·
IF 2.538
Fei Ma,Shu Chen,Yanhua Li,Hang Zhou,Aixin Xu,Weimin Lu
Propane oxidative dehydrogenation was investigated on nano-MgO supported Cr catalysts. Cr-5.0 wt.% sample exhibited the best catalytic performance with a propylene selectivity of 84.1% and propane conversion of 10.8% at 450 °C. Cr 5 O 12 and MgCrO 4 were proved to be formed, and they could be consecutively reduced as shown by temperature programmed reduction results. The impacts of different Cr phases on propane reaction pathway were also investigated. Fourier transform infrared spectroscopy reflects that Cr 5 O 12 is favorable for the propane dehydrogenation process, while MgCrO 4 would activate propane but lead to the CO x outcome.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2026
·
IF 3.1
Shiyang Wang,Lijia Ding,Ruotong Chen,Yang Yang,Jianhao Guo,Xiaofeng Xue,Ning Zhao,Yibin Zhan,Tiedong Xie,Boping Liu,Yulong Jin
Trimetallic catalysis provides a potential route for the one-pot production of multimodal PE with balanced mechanical and processing properties. Herein, a series of CrO x /VO x /CpCr/SiO 2 trimetallic catalysts are constructed by grafting CrCp 2 onto a CrO x /VO x /SiO 2 with tunable CrCp 2 loadings and benchmarked against mono- and bimetallic catalysts. FT-IR spectroscopy confirmed successful CrCp 2 immobilization, and the catalyst containing 0.25 wt% CrCp 2 exhibited the highest productivity. Owing to the distinct H 2 sensitivities of the three active sites, both molecular weight (MW) and molecular weight distribution (MWD) can be efficiently regulated through CrCp 2 loading and H 2 partial pressure, enabling the synthesis of tri- or broad-modal PE in a single reactor. Compared with unimodal PE of comparable MW, the trimodal PE exhibited lower melt viscosity and an improved stiffness-toughness balance.
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高影响因子
EUROPEAN POLYMER JOURNAL
·
2025
·
IF 6.3
Shiyang Wang,Liting Wei,Xinglong Zhao,Lantian Li,Yuxin Gao,Shuang Chen,Yang Yang,Boping Liu,Yulong Jin
A series of mono-, bi- and tri-metallic catalysts including Ind 2 ZrCl 2 /silica, CrO x /VO x /silica and CrO x /VO x /Ind 2 ZrCl 2 /silica were synthesized for C 2 H 4 polymerization in this work. The results show that conventional cocatalyst TiBA could hardly activate Ind 2 ZrCl 2 /silica. However, under the assistance of the surface species over CrO x /VO x /silica, traces of TiBA (Al/metal ＜15, molar ratio) endowed the Zr species with moderate activity. The combined results of XPS, FTIR-pyridine-adsorption and DRS Uv–vis show that the Lewis acidic Cr and V sites could interact with Ind 2 ZrCl 2 and improve the electronic deficiency of Zr center, which is possible to promote zirconocene activation, though direct Si-O-Zr linkage was non-negligible, and redox between Cr(VI)/V(V) and zirconocene existed. The Zr species were responsible for ultra-high molecular weight polyethylene (UHMWPE) synthesis, and the relative content of UHMWPE fractions could be controllably regulated by polymerization temperature, partial pressure of hydrogen and the loading amount of Zr. Generally, these tri-metallic catalysts CrO x /VO x /Ind 2 ZrCl 2 /silica could synthesize trimodal HDPE/UHMWPE in-reactor blends with very broad molecular weight distribution. Meanwhile, owing to the excellent copolymerization ability of zirconcene, preferential distribution of the short chain branches along the ultra-high molecular weight (MW) chains for C 2 H 4 /1-hexene trimodal copolymers was achieved. The rheological results show that the fractions with extreme MW difference in the trimodal polyethylene (PE) exhibited excellent miscibility, and its superiority in processing and mechanical properties over the monomodal PE with similar MW was verified by rheological, tensile and impact tests.
研究领域:
材料科学
·
高分子化学
·
催化化学
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 39
·18744-18750
·
IF 3.925
Dawang Chu,Hui Zhou,Zhicheng Luo
Selective conversion of glycerol to lactic acid requires the synergistic activation of C–H, C–O, and O–H. Herein, we report an inexpensive Fe–Cr/TiO2 catalyst that achieves lactic acid formation with a high selectivity of 60.5%. By changing the Fe/Cr ratios and reduction temperatures, the structures of Vő and Vő-OH were altered, which determined the overall oxidation–dehydration–isomerization process. The in situ ATR-IR experiments confirmed the activation of glycerol by adsorbing the primary −OH, and a series of control experiments verified that Fe was responsible for the cleavage of C–H and O–H, while CrOx catalyzed the activation of C–O and C–H. This work designs a hydrothermal catalyst with multifunctional ability, which may guide the rational catalyst design for the selective oxidation of glycerol to lactic acid.
研究领域:
催化化学
·
材料科学
·
绿色化学
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高影响因子
Catalysis Science & Technology
·
2026
·
IF 4.2
Jianyi Liu,Jialei Liu,Yang Yang,Jianhao Guo,Xiaofeng Xue,Ning Zhao,Yibin Zhan,Tiedong Xie,Boping Liu,Yulong Jin
Support modification is a simple but effective method to promote olefin polymerization catalysts, which is often correlated with enhanced acidity. Here, following this rule, the bimetallic catalyst CrOx/VOx/silica for UHMWPE/HDPE in-reactor blends was modified by alumina, sulfate, and alumina/sulfate. All modified catalysts were promoted notably, with ethylene polymerization activities about twice that of the unmodified one. Similarly, NH3-TPD and FTIR-pyridine confirmed their enhanced acidity. Theoretical studies emphasized the importance of Lewis acidic Al³⁺ site, which induced geometric and electronic rearrangement of the active site, thus reducing steric hindrance and improving LUMO reactivity. Sulfation further strengthened Al³⁺ acidity, exacerbating rearrangement and lowering the insertion barrier. Contrary to expectations, the alumina/sulfate-modified catalyst—with much stronger Brønsted and Lewis acidity—was only moderately promoted. XPS, DRS UV-vis, elemental analysis, and DFT results indicate that, while modification improves metal center electron deficiency and facilitates ethylene insertion, stronger acidity also weakens the anchoring of Cr(VI) and V(V) active precursors and promotes inactive Cr(III) and V(III) species. This effect was more pronounced for the superacidic alumina/sulfate modifier, partially counteracting its promotional effect.
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JOURNAL OF MEMBRANE SCIENCE
·
2024
·
IF 8.4
Zhixu Gan,Nikita Dewangan,Zhigang Wang,Shaomin Liu,Xiaoyao Tan,Sibudjing Kawi
The synthesis of SAPO-34 hollow fiber membranes employs the ball-milling assistant method to enhance membrane yield and quality. These membranes are then combined with CrO x /Al 2 O 3 catalyst to create a packed bed membrane reactor (PBMR) for propane dehydrogenation (PDH). The study investigates the impact of operating temperatures, weight hourly space velocities (WHSV), and sweep gas flow rates on the SAPO-34 zeolite membrane reactor's performance, comparing it to a traditional packed bed reactor (PBR). The removal of hydrogen from the reaction side significantly improves propane conversion, surpassing thermodynamic equilibrium. In PBMR, propylene selectivity slightly exceeds that in PBR, influenced by side reactions like hydrogenolysis and cracking after hydrogen removal. Furthermore, the SAPO-34 zeolite membrane reactor undergoes a prolonged stability test with frequent regeneration using pure propane as feedstock to simulate industrial conditions. It exhibits consistent performance over 120 regeneration cycles within 240 h, maintaining similar H 2 permeability and H 2 /C 3 H 8 selectivity as the fresh membrane post long-term testing.
研究领域:
化学工程
·
材料科学
·
催化
·
膜技术
·
反应工程
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