Materials
·
2022
·Vol. 15
·期 9
·3044
·
IF 3.748
Yu Shi,Shiwei Wang,Yiming Li,Fan Yang,Hongbo Yu,Yuting Chu,Tong Li,Hongfeng Yin
A series of NiP-x/Al2O3catalysts containing different ratio of metallic nickel to nickel phosphides, prepared by varying Ni/P molar ratio of 4, 3, 2 through a co-impregnation method, were employed to investigate the synergistic effect of metallic nickel-nickel phosphides in dry methane reforming reaction. The Ni/Al2O3catalyst indicates good activity along with severe carbon deposition. The presence of phosphorus increases nickel dispersion as well as the interaction between nickel and alumina support, which results in smaller nickel particles. The co-existence of metallic nickel and nickel phosphides species is confirmed at all the P contained catalysts. Due to the relative stronger CO2dissociation ability, the NiP-x/Al2O3catalysts indicate obvious higher resistance of carbon deposition. Furthermore, because of good balance between CH4dissociation and CO2dissociation, NiP-2/Al2O3catalyst exhibits best resistance of carbon deposition, few carbon depositions were formed after 50 h of dry methane reforming.Keywords:dry methane reforming;nickel catalysts;phosphides;coke-resistance;synergistic effect
研究领域:
催化
·
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2021
·
IF 6.609
Sheng Li,Jiming Wang,Guojie Zhang,Jun Liu,Yongkang Lv,Yongfa Zhang
Although tungsten carbide (WC) has similar properties, it is easily oxidized and deactivated during dry methane reforming (DRM). Therefore, it is of great significance to investigate the influence of carburizing atmosphere on the structure and properties of the prepared tungsten carbide material. Here, using ammonium metatungstate as the tungsten source and activated carbon (AC) as the matrix, under different carburizing atmospheres, a tungsten carbide-activated carbon (WC-AC) composite support was prepared through in-situ reduction and carbonization technology. After further loading cobalt (Co) and cerium (Ce), a series of Co-Ce/WC-AC catalysts were prepared. The catalytic performance for dry reforming was investigated. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (H 2 -TPR) and Thermogravimetric (TG) were used to characterize the crystal phase, microstructure and chemical composition of different samples. The results show that the main component of tungsten carbide prepared in a carburizing atmosphere containing CH 4 was bitungsten carbide (W 2 C); tungsten carbide prepared in a pure hydrogen carburizing atmosphere was composed of W 2 C and WC. After loading Co and Ce, the catalytic activity and stability of catalysts containing WC are significantly improved compared with those mainly containing W 2 C. Due to the presence of WC, the interaction between the metal and the carrier was enhanced, thereby improving the dispersibility and oxidation resistance of the active component Co species. At the same time, WC was helpful to transform Co 3+ to Co 2+ and Ce 4+ to Ce 3+ on the surface and inner of catalyst, which was conducive to the enrichment of chemically adsorbed oxygen on the catalyst surface and the formation of oxygen vacancies. It promoted the adsorption and activation of CO 2 , and improved the anti-carbon deposition performance of the catalyst.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2019
·
IF 2.846
Dingwen Kang,Jie Yu,Wenhui Ma,Min Zheng,Yunfei He,Pengfei Li
In this study, Cu/Ni-La 0.7 Sr 0.3 Cr 0.5 Mn 0.5 O 3– δ (LSCM) catalysts were synthesized via the citric acid-nitrate process (CNP) and chemical co-precipitation. The catalytic performance of Cu/Ni-LSCM catalysts on dry methane reforming was evaluated in a fixed-bed reactor at 550/650 °C and atmosphere pressure. Cu/Ni loading was investigated as an influencing factor, which led to 5 cases of samples according to the different Cu/Ni mass ratios. The catalysts were characterized by X-ray diffraction (XRD), field emission-scanning electron microscope (FE-SEM), Brunauer-Emmett-Teller (BET) measurement, X-ray photoelectron spectroscopy (XPS), hydrogen-based temperature-programmed reduction (H 2 -TPR) and thermos gravimetric analyzer (TGA). The results show that the methane conversion increases, the resistance against metal sintering increases and the carbon deposition drops after the copper is introduced. This optimum performance can be obtained under Case 3 (Cu:Ni:LSCM = 1:3:6 in mass ratio).
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
CATALYSIS LETTERS
·
2022
·Vol. 153
·期 9
·2787-2802
·
IF 2.936
Shi Yu,Li Yiming,Wang Shiwei,Chu Yuting,Yu Hongbo,Li Tong,Yin Hongfeng
A series of relative inert SiO 2 supported NiP-x/SiO 2 catalysts, containing different ratio of metallic nickel to nickel phosphides, were employed to clarify the synergistic effect of metallic nickel–nickel phosphides in dry methane reforming reaction. Ni/SiO 2 catalyst exhibits good activity but severe carbon deposition and visible nickel particles sintering in dry methane reforming, which results in evident deactivation after 50 h reaction. The presence of P increases the dispersion of nickel species, results in smaller nickel species particles size. The co-existence of metallic nickel and nickel phosphides species was confirmed by multiple characterizations. Because of the relative stronger CO 2 dissociation properties, NiP-x/SiO 2 catalysts exhibit higher resistance of carbon deposition. In addition, P content makes great difference to not only carbon deposition but also activity in dry methane reforming. NiP-3/SiO 2 , which has good activity, stability and anti-coking properties in dry methane reforming, is the optimal catalyst in our study scope. Graphical Abstract
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2022
·Vol. 12
·期 15
·4871-4883
·
IF 6.177
Yu Zhang,Zhoujie Liang,Guojie Zhang,Jun Liu,Ying Wang,Yuqing Zhao,Guoqiang Li,Yongkang Lv
Greenhouse effect has become one of the serious issues in the human development. Greenhouse gases are mainly composed of methane and carbon dioxide. Dry methane reforming (DMR) is an excellent technology owing to the direct utilization of greenhouse gases. However, there are severe catalyst sintering and coke deposits in the process of DMR. Therefore, it is necessary to synthesize catalysts with fantastic properties. Here, a series of cobalt catalysts modified by different transition metals (Y, Gd, and Mn) were synthesized applying the impregnation method. The Y-modified catalyst shows excellent catalytic activity and anti-coking ability. Under the reaction condition of 800 °C, the catalyst exhibits not only the highest CH4 conversion (83%) but also stable CO2 conversion (94%) after 10 h of reaction. N2 physisorption, TG, H2-TPR, XPS, XRD and TEM were applied to research the crystal phase, microstructure and texture characteristics of the catalysts. The results show that the Mn-modified catalyst exhibited a negative influence for the DMR reaction although the catalyst shows a large specific surface area. Gd- and Y-modified catalysts exhibited superior interaction between the metal and carrier, which improves the stability of active metal Co during DMR. Simultaneously, the introduction of Y maintains more number of oxygen vacancies and improves the dispersion of the active metal. The study found that both the activity and coke resistance of the catalyst can be concurrently enhanced due to the addition of Y through promoting the dispersion of the metal and the activation of CO2. Most noteworthily, after a 50 h stability test, the CH4 and CO2 conversion on the Y-modified catalyst dropped from 91% and 95% to 83% and 94%, respectively.
研究领域:
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Zhihao Zhou,Soomro Sarmad,Chao Huang,Guoshu Deng,Zhenkun Sun,Lunbo Duan
Ni-based catalysts supported on ordered mesoporous Al 2 O 3 with 2-D hexagonal and 3-D cubic pore structures are synthesized via evaporation-induced self-assembly for catalyzing dry CH 4 reforming to produce syngas . The Ni–Al 2 O 3 catalysts with 3-D pore structure exhibit higher activity in terms of CH 4 and CO 2 conversions than those with 2-D pore symmetry, due to the better mass transfer of the 3-D interconnected pore structure for the accessibility of Ni 0 active sites. And a higher Ni content slightly promotes catalytic activity , owing to more exposed active sites. However, a higher Ni content causes more severe carbon deposition during long-term reaction. During the long-term stability tests, the catalysts with 2.5 wt% Ni maintain the highest stability regardless of the pore structure, and the catalyst with 3-D pore structure is more advantageous to both activity and stability. Meanwhile, the catalyst with 2.5 wt% Ni and 3-D pore structure shows the lowest carbon deposition.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2021
·
IF 5.816
Sheng Li,Guojie Zhang,Jiming Wang,Jun Liu,Yongkang Lv
Carbon materials are widely used as catalysts or supports due to their excellent properties. In this paper, the tungsten carbide-activated carbon (WC-AC) composite support was successfully prepared by in-situ carburizing on AC matrix, which is characterized by the covalent anchoring of WC on the AC support. The active metal Co was supported on WC-AC for dry reforming of methane (DRM). Samples were analyzed by N 2 physisorption measurements, XRD , XPS , H 2 -TPR, H 2 -TPD, CH 4 &CO 2 -TPSR, TG-DTG. The WC-AC stabilizes the disturbance of C in AC, alleviates the gasification effect of CO 2 and increases the active sites for CH 4 cracking. Moreover, WC provides a resistance-less bridge suitable for the Co 3+ → Co 2+ , resulting in a high Co 2+ /Co 3+ ratio on the catalyst surface . This enhances the interaction between the Co species and the WC-AC, thereby enhancing the CH 4 activation. In the process of WC-AC promoting Co 3+ →Co 2+ , the catalyst surface is accompanied by the generation of oxygen vacancies . This can enhance the dissociative adsorption of CO 2 on surface of the WC-cobalt oxide, and at the same time increase the relative proportion of adsorbed oxygen on the catalyst surface, thereby effectively inhibiting the formation of coke. However, the small amount of graphitic carbon generated due to the strong coupling of WC and Co is the main reason for deactivation of Co/WC-AC.
研究领域:
催化
·
化学工程
·
材料科学
✓ 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）