Processes
·
2024
·Vol. 13
·期 1
·15
·
IF 2.8
Bo Zhang,Peiyu Yao,Fei Li,Li Pan,Wuwan Xiong,Yang Zhang,Xiang Li
Hydrogen production through the catalytic pyrolysis of low-value organic solid waste offers a promising low-carbon and environmentally friendly pathway. However, the design of efficient hydrogen-producing catalysts remains a significant challenge. Herein, NiO/Al2O3as a catalyst precursor was utilized to investigate the effects of reduction temperature gradients (300–800 °C) on the distribution of three-phase products and the composition of gaseous products during the pyrolysis of waste textiles. Compared to unreduced NiO/Al2O3, increasing the reduction temperature (300–700 °C) led to a gradual decrease in liquid-phase products and a notable increase in gas-phase products, with the latter rising by 10.59% at 700 °C. Most strikingly, hydrogen gas production increased by 6.42% under the same conditions. Multi-characterization analyses, including XRD, TEM, and H2-TPR, revealed significant aggregation of highly dispersed Ni species in NiO/Al2O3at higher reduction temperatures. The emergence of XRD characteristic peaks and the (111) crystal face of metallic Ni (Ni0) became apparent at 700 °C. More importantly, the XPS test inferred that the increasement of hydrogen-rich gas production was ascribed to the appropriate Ni0/Ni2+ratio, and the highest hydrogen yield of 41.50% was achieved as the Ni0/Ni2+ratio reached about 1.57. This work not only provides an effective solution for the consumption of waste textiles, but also converts it into high value-added hydrogen-rich gas.
研究领域:
能源科学
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环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
KOREAN JOURNAL OF CHEMICAL ENGINEERING
·
2016
·Vol. 34
·期 1
·41-53
·
IF 1.408
Rong Jian,Zhang Tao,Qiu Fengxian,Chen Mingliang
Hierarchical porous NiO/Al 2 O 3 composites were successfully prepared by two-steps. First, the core-shell structured Al 2 O 3 microspheres were prepared via a template-free hydrothermal route using KAl(SO 4 ) 2 ·12H 2 O and Al 2 (SO 4 ) 3 ·18H 2 O as aluminum source. Then, the NiO/Al 2 O 3 composites with micro- and nano-hierarchical structures were prepared by a hydrothermal method combining the subsequent calcination process. The obtained characterization result presented that the morphology of hierarchical Al 2 O 3 microsphere tuned to irregular platelets by simply varying Ni/Al ratios. The BET analysis showed that the special surface area from 52.12m 2 g −1 to 214.8m 2 g −1 after two hydrothermal complex process. Effects of Ni/Al ratio, adsorbent dosage, Congo red (CR) concentration, coexisting ions, adsorption time and temperature were investigated. The obtained results indicated that NiO/Al 2 O 3 composite had the high adsorption efficiency (99.6%) and great adsorption capacity (186.9mg g −1 ) under the optimum conditions. The adsorption isotherm and kinetics data were found to be well fitted and in good agreement with the Langmuir isotherm model and pseudo-second order model, respectively. The hierarchical porous NiO/Al 2 O 3 composites presented remarkably higher adsorption efficiency during five recycling, which showed their potential as the highly efficient adsorbent for removal of CR in wastewater.
研究领域:
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
ACS Sustainable Chemistry & Engineering
·
2018
·
IF 6.14
Guohua Zhu,Kui Wu,Liang Tan,Weiyan Wang,Yanping Huang,Diyu Liu,Yunquan Yang
Magnetic colloidal sol was first prepared and added in the mixed solution of Ni(NO3)2 and Al(NO3)3. After the constant-pH coprecipitation and calcination, magnetic NiO–Al2O3@Fe3O4 mixed oxides were formed and used as supports for Pt-based catalysts. The activities of these magnetic Pt/NiO–Al2O3@Fe3O4 catalysts were tested in the hydrodeoxygenation (HDO) of phenols such as 4-ethylphenol, 4-methylphenol, and guaiacol. These exhibited high HDO activity, and aromatic hydrocarbons were produced through a coupling process of hydrodeoxygenation and dehydrogenation. The addition of Fe enhanced both the conversion and aromatic hydrocarbons selectivity, which was attributed to the electron transfer between metallic Pt and Fe. For example, after the liquid phase HDO of 4-ethylphenol at 300 °C and 2.0 MPa for 1.5 h, 97.9% conversion and 18.3% toluene selectivity were obtained. When the reaction time was prolonged to 8 h, ethylbenzene selectivity increased to 88.0%. Moreover, these Pt/NiO–Al2O3@Fe3O4 catalysts were easily recycled from the liquid reaction mixture by employing an external magnet, but the dehydrogenation stability needs to be further improved.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL RESEARCH
·
2024
·
IF 7.7
Yubiao Li,Yu Liu,Xueqian Wang,Yixing Ma,Ping Ning,Langlang Wang,Xiang Li,Rui Cao
Activated alumina-based composite oxide support is a commonly used support in hydrodesulfurization (HDS) catalysts, which not only retains the performance advantages of each component in the composite oxide support, but also significantly improves the defects of a single activated alumina support, such as the strong metal-support force of interaction. In this study, NiO-Al 2 O 3 composite support was prepared by introducing NiO-modified Al 2 O 3 , and MoS 2 /NiO-Al 2 O 3 catalysts were prepared for the hydrodesulfurization of COS by liquid phase reduction method. In the COS hydrogenation reaction, the MoS 2 /NiO-Al 2 O 3 catalyst achieved complete conversion of COS at 220 °C and showed more than 99.9% H 2 S selectivity. In stability tests, the catalyst maintained a COS conversion of over 99% throughout the 23-h hydrogenation reaction. Various characterization results show that the NiO-Al 2 O 3 composite support prepared by introducing NiO-modified Al 2 O 3 weakens the metal-support interaction force between MoS 2 and NiO-Al 2 O 3 composite support, which is conducive to the synthesis of MoS 2 with multilayer and long wafer structures. And it can significantly increase the formation rate of MoS 2 to 87.9%, which greatly improves the active site content of the catalyst. Furthermore, the dual modulation of MoS 2 and Al 2 O 3 by NiO modulated the surface alkalinity of the catalysts and promoted the formation of a large number of active edge sites in the MoS 2 /NiO-Al 2 O 3 catalysts, which in turn significantly improved the HDS performance of the catalysts. In addition, EPR characterization combined with experiments showed that the sulfur vacancies are the active sites for catalytic COS hydrodesulfurization over MoS 2 -based catalysts.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Processes
·
2022
·Vol. 10
·期 8
·1542
·
IF 3.352
Feng Cheng,Xiuwei Li
The reduction of metal oxides by biochar is an important reaction for many biomass utilization technologies. This work investigated the temperature–programmed reduction (TPR) of NiO/Al2O3by in situ generated biochar from citric acid pyrolysis. Firstly, NiO/Al2O3was loaded with citric acid by impregnation and then heated from ambient temperature to 900 °C in a N2flow. The process was on–line analyzed by the TGA–FTIR technique. Secondly, a series of intermediates was obtained and characterized by XRD, CHNO elemental analysis, and temperature programmed oxidation (TPO). Lastly, a control experiment of unsupported NiO was conducted to show the influence of Al2O3support on the NiO reduction. Results showed that the whole heating process could be resolved into two parts that is citric acid pyrolysis and NiO reduction at a heating rate of 5 °C/min. The NiO reduction occurred above 400 °C with the biochar from citric acid pyrolysis as reductant. In the temperature–programmed reduction process, the Al2O3–supported NiO exhibited three reduction phases in contrast with only one reduction phase for the unsupported NiO. A hypothesis was proposed to explain this. The presence of Al2O3support may result in different deposition sites of biochar (on NiO or on Al2O3), and consequently different reduction mechanisms.Keywords:metal oxide reduction;biomass pyrolysis;solid–state reaction;biochar gasification
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Qibao Yang,Shaobai Sang,Yawei Li,Tianbin Zhu,Heng Wang
The development of highly oxidation-protective and stable coatings is crucial for significantly reducing the oxidation of 06Ni9DR alloy steels during heating before hot rolling, thereby enabling the products with superior surface quality. In this study, three types of coatings—Al 2 O 3 -glass coating, a 10 wt% NiO-90 wt% Al 2 O 3 ceramic coating, and a double-layer coating Al 2 O 3 -glass top layer and NiO-Al 2 O 3 ceramic bottom layer)—were prepared, and their oxidation protection and underlying mechanisms were systematically investigated. The results revealed that the oxidation protection ratio of the glass coating sharply decreased from 96.6 % for 10 min to 44.9 % for 180 min at 1200 °C. In contrast, the oxidation protection of the ceramic coating increased slightly with the oxidation time. Notably, the excellent oxidation protection ratio of the double-layer coating was obtained as 86.2 % for 180 min. The rapid densification of the Al 2 O 3 -glass layer in the double-layer design provided good oxidation protection and significantly reduced the formation of iron oxides in the initial oxidation stage; NiO-Al 2 O 3 ceramic layer reacted with Fe 2+ to form a relatively dense composite spinel barrier layer, which further improved the thermal stability of the Al 2 O 3 -glass layer, and greatly enhanced the oxidation protection and stability of the double-layer coating.
研究领域:
材料科学
·
冶金学
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表面工程
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陶瓷材料
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高温氧化
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2025
·
IF 8.1
Zixuan Sheng,Khomidov Fakhriddin Gafurovih,Kadyrova Zulayho Raimovna,Bingying Gao,Linqiang Mao
The widespread use of NiO/Al 2 O 3 catalysts in the petrochemical industry generates hazardous spent materials due to the formation of refractory nickel-aluminum spinel (NiAl 2 O 4 ), which complicates metal recovery and exacerbates resource inefficiency. Traditional direct acid and alkali leaching cannot recover Ni and Al due to excellent stable structure of NiAl 2 O 4 . Here, we propose a simple soda roasting-water leaching strategy to disrupt the spinel lattice and recover Ni and Al with high efficiency. By roasting spent catalysts with Na 2 CO 3 at 1000 °C, Na + ions substituted Al 3+ in the octahedral sites, which destroyed the spinel framework and converted Al 2 O 3 /NiAl 2 O 4 into water-soluble NaAlO 2 . Over 98.31 % of Al was selectively leached at 90 °C, followed by pH-controlled precipitation and calcination at 600 °C to regenerate γ-Al 2 O 3 with the purity of 98.21 %. Residual NiO was recovered via 2 M H 2 SO 4 leaching, with Fe impurities removed through pH-selective precipitation. The kinetic analysis revealed a chemically controlled leaching mechanism ( E a = 47.61 kJ/mol). Final Ni(OH) 2 through calcination at 400 °C yielded reusable NiO. This approach achieved >98 % metal recovery, minimized waste, and aligned with circular economy principles by transforming hazardous spent catalysts into high-purity industrial feedstocks.
研究领域:
冶金学
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环境工程
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化学工程
·
材料科学
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产业生态学
·
废弃物管理
✓ 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）