Fundamental Research
·
2024
·
IF 5.7
Haoyang Fu,Qingze Chen,Benzhi Min,Shuzhou Li,Xiaodong Chen,Lan Ling
Probing the molecular-level redox behavior and mechanism of oxides is essential to developing innovative applications in different fields such as catalysis, but remains a challenge for the scientific community. Using in-situ transmission electron microscopy, here we provide an overall reduction view of single-crystalline α-Fe 2 O 3 with different characteristics from the conventional wisdom of oxide reduction. Specifically, the formation of epitaxial nanoislands with concomitant oscillatory phase transitions (α-Fe 2 O 3 →defective γ-Fe 2 O 3 →α-Fe 2 O 3 ) at the subsurface is observed during reduction. The dynamic equilibrium of lattice oxygen at the surface and the limited oxygen replenishment from the deep layer drive the α-Fe 2 O 3 →defective γ-Fe 2 O 3 transformation in the subsurface, while the polymorphic transition (defective γ-Fe 2 O 3 →α-Fe 2 O 3 ) spontaneously occurs under heating conditions. Such oscillatory phase transition is accompanied by the release of asymmetric stress, inducing the extension of epitaxial nanoislands. Our work highlights the complexity of reduction by providing an integral picture of oxide reduction, which contributes to the understanding of the site evolution of oxide-based catalysts in their working state.
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
Soft Matter
·
2021
·Vol. 18
·期 2
·382-389
·
IF 3.679
Shizhen Zhao,Hongkun Yang,Dong Wang,Thomas P. Russell
A simple and efficient strategy to modify epoxy dynamic polymer networks (DPNs) is presented. The introduction of the flexible epoxidized form of naturally occurring soybean oil (ESO) into epoxy DPNs markedly improves their mechanical properties, stress relaxation rate and malleability. Specifically, at 7.5 wt% ESO loading, the elongation at break of the as-produced epoxy-ESO DPNs was increased from 10% to 108%, the stress relaxation time decreased from 6100 s to 2570 s at 120 °C, and the reprocessing temperature was reduced by 26 °C, which is advantageous for expanding the scope of applications of these materials, especially for reducing the energy consumption during reprocessing. At this composition, the epoxy-ESO DPNs also showed excellent self-healing, welding and chemical degradation properties. This work provides a novel pathway to fabricate epoxy-based DPNs with high performance in an energy-conserving manner.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2024
·
IF 8.2
Zhenzhen Jia,Qiuxin Liu,Jiatang Hu,Shiyu Li,Hujunjie Chen
Water hypoxia and metal pollution are commonly co-existed in urbanized estuaries. This study focuses on the effect of an extended dissolved oxygen (DO) full-life dynamics (86 days) on metal behavior across the sediment-water interface through laboratory microcosms from two typical zones in Pearl River Estuary. Combining our time-series results of concentrations and fluxes, it showed that Co, Ni, and Zn consistently presented a release-precipitation-release trajectory with an oxic-hypoxic-anoxic-reoxic transition, characterized with highly variable behavior in the hypoxic-anoxic hotmoments. In parallel, changing DO dynamics significantly activated a repartitioning process of Co, Ni, and Zn among several species and elevated their risk in sediments, promoting the formation of more labile species in the 0–10 mm hotspots, where metals sensitively responded. Over DO transition, metal cycling was tightly co-related with Fe, Mn, and S elements. It was found that Mn was dominated in low oxygen-hypoxic period, but switched to S and Fe in anoxic stage, limiting sustained metal liberation to overlying water. Enlarging this experiment to practice, released Zn fluxes from sediments in hypoxic summer could contribute about ∼2.0% to their stocks in water column, while increase to 20% (1 m bottom water) in highly-stratified zones. This study has certain significance in understanding the long-term metal behavior and fate in estuarine regions, even lakes and reservoirs.
研究领域:
环境科学
·
地球化学
·
水生生态学
·
污染生态学
·
生物地球化学
·
环境毒理学
·
河口学
✓ 已验证
DOI
高影响因子
Catalysts
·
2025
·Vol. 15
·期 6
·545
·
IF 4
Xiaohong Yao,Jian Zhang,Chao Long
This study explored how pore size engineering in Nb-Mn/MCM-41 catalysts affects plasma-catalytic toluene oxidation. Adjusting the pore diameter (2.49–3.98 nm) modulated metal-support interactions and oxygen dynamics, with pore expansion to 3.73 nm (M3) optimizing the Mn4+/(Mn2++ Mn3+) ratio (XPS: 36.8%), the amount of lattice oxygen species (O2-TPD: 0.222 mmol/g), and crystallite size control (1.5 ± 0.2 nm, TEM). Smaller pores (M1: 2.49 nm) enhanced toluene adsorption but limited active site accessibility, while oversized pores (M4: 3.98 nm) reduced oxygen storage capacity (0.600→0.412 mmol/g). The Nb-Mn/M3 catalyst achieved superior performance with 96.8% toluene conversion, 55.0% CO2selectivity, and 85.4% carbon balance, while minimizing organic byproducts (GC-MS). Mechanistic studies revealed pore-mediated oxygen storage-transport cycles as critical for decoupling adsorption and oxidation steps. This study reveals fundamental mechanisms linking pore architecture to plasma-catalytic synergy in toluene oxidation, offering critical insights for the systematic design of energy-efficient, plasma-catalytic systems targeting industrial VOCs remediation.
研究领域:
催化化学
·
环境化学
·
材料科学
·
等离子体化学
·
纳米技术
·
表面科学
✓ 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）