scholarly journals Improved Thermochemical Energy Storage Behavior of Manganese Oxide by Molybdenum Doping

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 583
Author(s):  
Javier Moya ◽  
Javier Marugán ◽  
María Orfila ◽  
Manuel Antonio Díaz-Pérez ◽  
Juan Carlos Serrano-Ruiz
Keyword(s):  
Energy Storage ◽  
Power Plants ◽  
Chemical Properties ◽  
Precipitation Method ◽  
Scanning Calorimetry ◽  
Storage Behavior ◽  
Solar Power Plants ◽  
Coral Morphology ◽  
Temperature Programmed ◽  
Adsorption Desorption

To improve the thermochemical energy storage (TCS) behavior of Mn2O3, several Mn–Mo oxides with varying amounts of MoO3 (0–30 wt%) were prepared by a precipitation method. The physico-chemical properties of the solids were studied by N2 adsorption–desorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), and H2-temperature-programmed reduction (TPR), while their TCS behavior was determined by thermogravimetric analysis coupled with differential scanning calorimetry (TGA-DSC). Apart from Mn2O3 and MoO3 phases, XRD revealed a mixed MnMoO4 phase for MoO3 loadings equal or higher than 1.5 wt%. All samples showed a well-formed coral-like surface morphology, particularly those solids with low MoO3 contents. This coral morphology was progressively decorated with compact and Mo-enriched MnMoO4 particles as the MoO3 content increased. TPR revealed that the redox behavior of Mn2O3 was significantly altered upon addition of Mo. The TCS behavior of Mn2O3 (mostly oxidation kinetics and redox cyclability) was enhanced by addition of low amounts of Mo (0.6 and 1.5% MoO3) without significantly increasing the reduction temperature of the solids. The coral morphology (which facilitated oxygen diffusion) and a smoother transition from the reduced to oxidized phase were suggested to be responsible for this improved TCS behavior. The samples containing 0.6 and 1.5 wt% of MoO3 showed outstanding cyclability after 45 consecutive reduction–oxidation cycles at high temperatures (600–1000 °C). These materials could potentially reach absorption efficiencies higher than 90% at concentration capacity values typical of concentrated solar power plants.

scholarly journals CO2 Hydrogenation on NixMg1−xAl2O4: A Comparative Study of MgAl2O4 and NiAl2O4

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1026
Author(s):  
Boseok Seo ◽  
Eunhee Ko ◽  
Jinho Boo ◽  
Minkyu Kim ◽  
Dohyung Kang ◽  
...  
Keyword(s):  
Density Functional ◽  
Chemical Properties ◽  
Density Functional Theory Calculations ◽  
Co2 Hydrogenation ◽  
Precipitation Method ◽  
Co2 Methanation ◽  
Temperature Programmed ◽  
Fundamental Insight ◽  
Adsorption Desorption ◽  
Physical And Chemical

Due to the increasing attention focused on global warming, many studies on reducing CO2 emissions and developing sustainable energy strategies have recently been performed. One of the approaches is CO2 methanation, transforming CO2 into methane. Such transformation (CO2 + 4H2 → CH4 + 2H2O) provides advantages of carbon liquification, storage, etc. In this study, we investigated CO2 methanation on nickel–magnesium–alumina catalysts both experimentally and computationally. We synthesized the catalysts using a precipitation method, and performed X-ray diffraction, temperature-programmed reduction, and N2 adsorption–desorption tests to characterize their physical and chemical properties. NiAl2O4 and MgAl2O4 phases were clearly observed in the catalysts. In addition, we conducted CO2 hydrogenation experiments by varying with temperatures to understand the reaction. Our results showed that CO2 conversion increases with Ni concentration and that MgAl2O4 exhibits high selectivity for CO. Density functional theory calculations explained the origin of this selectivity. Simulations predicted that adsorbed CO on MgAl2O4(100) weakly binds to the surface and prefers to desorb from the surface than undergoing further hydrogenation. Electronic structure analysis showed that the absence of a d orbital in MgAl2O4(100) is responsible for the weak binding of CO to MgAl2O4. We believe that this finding regarding the origin of the CO selectivity of MgAl2O4 provides fundamental insight for the design methanation catalysts.

scholarly journals Integration of energy storage with hybrid solar power plants

2018 ◽  
Vol 151 ◽  
pp. 182-186 ◽  
Author(s):  
Ruben Bravo ◽  
Daniel Friedrich
Keyword(s):  
Energy Storage ◽  
Power Plants ◽  
Solar Power ◽  
Solar Power Plants

scholarly journals Synthesis of DME by CO2 hydrogenation over La2O3-modified CuO-ZnO-ZrO2/HZSM-5 catalysts

2017 ◽  
Vol 23 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Yajing Zhang ◽  
Yu Zhang ◽  
Fu Ding ◽  
Kangjun Wang ◽  
Wang Xiaolei ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Direct Synthesis ◽  
Catalytic Performance ◽  
Co2 Hydrogenation ◽  
Precipitation Method ◽  
X Ray ◽  
Temperature Programmed ◽  
And Performance ◽  
Co Precipitation ◽  
Adsorption Desorption

A series of La2O3-modified CuO-ZnO-ZrO2/HZSM-5 catalysts were prepared by an oxalate co-precipitation method. The catalysts were fully characterized by X-ray diffraction (XRD), N2 adsorption-desorption, hydrogen temperature pro-grammed reduction (H2-TPR), ammonia temperature programmed desorption (NH3-TPD), and X-ray photoelectron spectroscopy (XPS) techniques. The effect of the La2O3 content on the structure and performance of the catalysts was thoroughly investigated. The catalysts were evaluated for the direct synthesis of dimethyl ether (DME) from CO2 hydrogenation. The results displayed that La2O3 addition enhanced catalytic performance, and the maximal CO2 conversion (34.3%) and DME selectivity (57.3%) were obtained over the catalyst with 1% La2O3, which due to the smaller size of Cu species and a larger ratio of Cu+/Cu.

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