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We study the generalized free energy of the dyonic AdS black hole in an ensemble with varying electric charge qE and fixed magnetic charge qM. When we adjust the temperature T and the electric potential ΦE of the ensemble, the Ricci scalar curvature R and electromagnetic potential Au usually diverge at the horizon. We regularize them and incorporate the off-shell corrections into the Einstein-Hilbert action. Alternatively, we find that the off-shell corrections can also be obtained by adding a boundary near the horizon to exclude the singularities. Ultimately, we derive the generalized free energy which is consistent with the definition of the thermodynamic relations. Based on the generalized free energy landscape, we can describe the dynamics of state transition as a stochastic process quantified by the Langevin equation. The path integral framework can be formulated to derive the time-dependent trajectory of the order parameter and the time evolution of the transition probability. By comparing the probability with the result of the classical master equation, we attribute the contribution to the probability of one pseudomolecule or antipseudomolecule (the instanton and anti-instanton pairs) to the rate of state transition. These results are consistent with the qualitative analysis of the free energy landscape. [ABSTRACT FROM AUTHOR]

Based on the equations of state, one can infer the underlying interaction potentials among the black hole molecules in the case of Schwarzschild-AdS and charged AdS black holes. The microscopic molecules with the interaction potential arrange in a specific way to form the mesostructure, whose size is between the macro (black hole system) and the micro (black hole molecules). As a result, the mesostructure leads to the emergence of the macroscopic phase. However, the information about the mesostructure of the AdS black hole are still elusive. In this paper, the radial distribution function is introduced to probe the mesostructure of the AdS black hole. We find that the mesostructure of the Schwarzschild-AdS black hole behaves as the ideal gas when the temperature is high. Furthermore, we find the mesostructure for the liquid-like (gas-like) phase of the small (large) charged AdS black hole. A sudden change of the mesostructure emerges from the liquid-like phase to the gas-like phase when the charged AdS black hole undergoes a phase transition from the small to large black hole, consistent with the viewpoint that the phase transition of the charged AdS black hole is reminiscent of that of the vdW fluid. This study provides a new angle towards understanding the black hole from its mesostructure. [ABSTRACT FROM AUTHOR]

After modifications of rare earth and phosphorus, the acidity density and the strength in the pores of zeolite Y (PREUSY) are improved effectively; the surface acidity is suitably reduced and weakened owing to the interaction of rare earth cation and phosphate anion. NH3-TPD analysis showed that the acid distribution of the modified zeolite is more concentrated on the range of intermediate and strong acidity. This kind of modification can direct more hydrocarbons to enter into the pores to be converted and remarkably reduces the possibility of naphtha olefins forming through a surface cracking reaction. In addition, because naphtha olefin reduction does not completely depend on olefin saturation through secondary hydrogen transfer reaction, this kind of reaction mode can decrease the excessive cracking of mediate distillate and can improve the diesel oil yield (LCO) effectively. Some reaction pathways were proposed. [Copyright &y& Elsevier]

The interactions between heavy metals (vanadium and nickel) and kaolin had been investigated by X-ray diffraction and MAT test. In the process of phase transformation of kaolin containing 1–5% vanadium, vanadium-mullite phase emerged surprisingly at 660–700 °C. The unit cell size of the mullite was found to increase with increment of vanadium content. As compared with hydro-kaolin, acid-modified kaolin (AMK) and caustic-modified kaolin (CMK) reacted with vanadium to form much more mullite; CMK could even be reacted with nickel to form a rather stable NiAl10O16 compound, and this compound protected zeolite in fluid catalytic cracking catalyst effectively. The catalyst containing AMK had greater MAT activity retention than that of the contrastive catalyst with hydro-kaolin in the identical level of heavy metal contamination. [Copyright &y& Elsevier]

The enhancement of photo-Fenton performance in BiOBr via a synergistic approach of efficient adsorption and reduced recombination of photogenerated carriers is an innovative strategy. This research employs an in-situ precipitation process to incorporate modified TiO₂ onto the surface of BiOBr, while integrating polyethylene glycol to create an S-type heterojunction material (FT-OVs/PEG-BiOBr). The incorporation of hydroxyl groups by PEG facilitates π-π conjugation and hydrogen bonding, thereby enhancing the adsorption capacity of FT-OVs/PEG-BiOBr. The presence of oxygen vacancies extends the absorption spectrum into the infrared region, and the electron trap mechanism substantially decreases the recombination of photogenerated carriers. The developed S-type heterojunction structure efficiently directs electron transport along a specific pathway. Photoluminescence (PL) studies reveal a further reduction in the recombination of photogenerated carriers. Remarkably, there is a significant synergistic effect between adsorption and low recombination of photogenerated carriers. A profound photo-Fenton synergistic effect is observed at pH 3, leading to degradation rates of RhB and TCH of approximately 98% and 85%, respectively, within 10 min. The degradation pathway of RhB has been investigated using LC-MS analysis, and 1O₂ has been identified as the primary active species through ESR testing. This study presents a novel structural approach to significantly enhance the efficiency of catalysts in Fenton systems. [ABSTRACT FROM AUTHOR]

Regeneration has been considered as an ideal way for the post-treatment of waste FCC catalyst (ECat). In this work, the degeneration mechanism of ECat was firstly researched and attributed to the increasing of strong acid sites accessibility of ECat in contrast with fresh FCC catalyst by adsorption FTIR. Based on the proposed degeneration mechanism, ECat was successfully regenerated through suitable weakening for strong acid sites by boron modification. Characterization and evaluation results suggested that, the strong acid sites of regenerated ECat (R-ECat) were apparently decreased by boron modification which had significantly improve the heavy oil catalytic cracking performance of R-ECat. Because of the excellent performance, R-ECat in this work could successfully substitute for partial fresh FCC catalyst in FCC unit, which would provide a practicable way for the reutilization of ECat. [ABSTRACT FROM AUTHOR]

[Display omitted] • A CuO x catalyst supported on P-doped porous g-C 3 N 4 is synthesized easily. • P-doping increases the number of unpaired electrons in the catalyst. • Porous defects increase the catalyst surface area and active sites. • The unpaired electrons in the catalyst can directly inject into Cu active sites. • Catalyst performance and H 2 O 2 utilization efficiency are simultaneously improved. Copper oxides were supported on porous P-doped g-C 3 N 4 (Cu/p-PCN) by a stepwise calcination process. Elemental analysis, XPS, and ESR results show that P atoms enter the network of g-C 3 N 4 , and the thus-fabricated configuration could provide additional electrons for the conjugated system of g-C 3 N 4. As verified by TEM, XRD, XPS, and FTIR results, copper is mainly present as oxides on the catalyst surface and undergoes Cu-π interactions with porous P-doped g-C 3 N 4 (p-PCN). During the reaction, unpaired electrons in p-PCN can be injected into the Cu active sites, prompting the decomposition of H 2 O 2 into hydroxyl radicals (•OH). The degradation begins with the activation of H 2 O 2 into •OH radicals by the Cu(I) active center. The depleted Cu(I) centers are then regenerated by electron injection from P atoms rather than by the reaction between H 2 O 2 and Cu(I). Thus, the catalyst performance and H 2 O 2 utilization are greatly enhanced. Equally significantly, the porous structure of Cu/p-PCN also contributes appreciably to its performance by increasing the specific surface area and active sites. Cu/p-PCN exhibits better performance than many reported catalysts in similar conditions, robust resistance to interference from various ions, high degradation efficiency over a wide pH range, and excellent degradation ability for various pollutants. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cu-SSZ-13 catalysts with different Cu2+ species were synthesized successfully. • The balance between Cu2+-2Z and [Cu(OH)]+-Z exhibited optimal DeNOx performance. • The optimal ratio of Cu2+ species can promote the rapid formation of intermediates. In diesel vehicle exhaust after-treatment systems, high silica Cu-SSZ-13 has received increasing attention as a commercialized catalyst owing to its high efficiency in selective catalytic reduction reactions with NH 3 (NH 3 -SCR). However, research on the regulation of Cu2+ species within metal active centers in the pore structure of chabazite (CHA)-type zeolite to improve catalytic performance lacks sufficient depth. Herein, SSZ-13 zeolite with various Al distributions was prepared by adjusting the proportion of N,N,N-Trimethyl-1-adamantanaminiumhydroxide (TMAdaOH) and Na in the initial gel. Moreover, three representative Cu-SSZ-13 catalysts with different Cu2+ species were synthesized via an ion exchange method. 23Na MAS NMR and NO adsorption infrared spectroscopy results revealed that with increasing Na content and decreasing TMAdaOH concentration in the initial gel, the number of paired Al in the CHA framework gradually increased. Consequently, this increased the number of Cu2+-2Z sites near six-membered ring (MR) and reduced the amount of [Cu(OH)]+-Z sites near eight-MR. The fresh Cu-SSZ-13 catalyst, with a moderate amount of Cu2+-2Z and [Cu(OH)]+-Z, exhibited optimal catalytic performance across the entire temperature window. After hydrothermal aging, Cu-SSZ-13 with a higher concentration of Cu2+-2Z species featured optimal performance among all Cu-SSZ-13 catalysts above 400 °C. These findings indicated the significance of balancing the amount of both Cu2+-2Z and [Cu(OH)]+-Z in the Cu-SSZ-13 zeolite. Additionally, the results elucidated the reaction intermediates involved in the NH 3 -SCR process catalyzed by Cu-SSZ-13 with various Cu species. [ABSTRACT FROM AUTHOR]

SAPO-34 molecular sieves synthesized using calcined kaolin as partial raw material under three-stage of high-low-high temperature hydrothermal condition are explored systematically. Especially, the effect of kaolin calcination temperature on the crystallization mechanism of SAPO-34 and the methanol to olefin performance are investigated thoroughly. It is found that the sample (SP-500) synthesized by using kaolin calcined at 500 °C (MK-500) demonstrates clean cubic structure, large specific surface area and mild acidity, providing the initially activated Si and Al source for the synthesis of SAPO-34 molecular sieve due to the well scattered structure of MK-500. From the crystallization mechanism consideration, it can be proposed that the SAPO-34 molecular sieves will be controlled by the low degree of Si aggregation in metakaolin and quantity of Si (3Al,1Si) species. As a result, SP-500 displays excellent catalytic lifetime during methanol to olefin reaction for its special Si coordination environment, showing the highest stable light olefin yield of 80.6 % and a methanol conversion above 90 % for more than 720 min. In contrast, SP-800 sample with the most strong acid sites is only 390 min, even if showcasing the highest selectivity of light olefins (84.5%). SAPO-34 molecular sieves were designed and fabricated with cost-effective layered structure based on calcined kaolinite as entire Si and partial Al source. The SAPO-34 molecular sieves were more durable and possessed high catalytic in MTO reaction. [Display omitted] • SAPO-34 molecular sieves are prepared by calcined kaolin as total Si source and partial Al source. • The crystallization mechanism of SAPO-34 will be controlled by the aggregation degree of Si in metakaolin. • SAPO-34 obtained by using activated kaolin at 500 °C exhibits the best catalytic performance in MTO reaction. [ABSTRACT FROM AUTHOR]

• Mg species optimized microstructure, active species dispersion and basic sites. • Mg enhanced the ability to capture CO 2 and intermediate active species. • Zr and Mg synergistically promote CO 2 conversion and methanol selectivity. • CO 2 hydrogenation to methanol conforms to the formate path with Mg modification. Optimizing the microstructure of copper-based catalysts for CO 2 hydrogenation to methanol is an attractive and widely reported strategy, but there are still certain barriers to improving both carbon dioxide conversion rate and methanol product selectivity. Herein, Cu/ZnO/ZrO 2 /MgO (CZZ 1-x M x) catalysts were synthesized by co-precipitation method for CO 2 hydrogenation to methanol. Furthermore, the structural features and reaction processes were systematically characterized by XRD, TEM, nitrogen adsorption/desorption, H 2 -TPR, CO 2 -TPD and in-situ DRIFT. The results showed that Mg species optimized the microstructure of the catalyst, increased the dispersion of active species and constructed appropriate basic sites. This further enhanced the capture of reactive species and improved the CO 2 hydrotreating to methanol reaction performance, which was accompanied by a simultaneous increase in CO 2 conversion and methanol yield. It could be convinced that the highest space time yield (STY) of methanol (305.3 g MeOH kg cat −1 h−1) was obtained at 220 °C, WHSV = 18,000 mL g cat −1 h−1 and 3 MPa (X CO2 = 7.28%, S MeOH = 71.8%) for the optimized CZZ 0.8 M 0.2 catalyst, which exhibited twice the CO 2 conversion than Cu/ZnO/ZrO 2. This work elaborated a scheme for the preparation of efficient methanol catalysts. providing reference for the research of CO 2 hydrogenation to methanol process. [Display omitted] It can effectively enhance the adsorption of CO 2 with appropriate Mg added of copper-based catalysts. Moreover, The synergistic effect between Zr and Mg can promote CO 2 conversion and methanol selectivity. [ABSTRACT FROM AUTHOR]

The synergistic effect of Zn and Mg can improve the dispersion of Ag on Al 2 O 3 support and increase the proportion of Ag+ and Ag δ n + , which is beneficial to the selective catalytic reduction of NO by propylene. [Display omitted] • Zn and Mg promote the formation of ZnAl 2 O 4 and MgAl 2 O 4 spinels on the surface of γ-Al 2 O 3 carriers. • Inhibits active ingredient agglomeration and improves dispersion. • Facilitates the transitions regulation of Ag+, Ag δ n + and Ag0. • Improved NO conversion, water and sulfur resistance of AgAl catalysts at low temperatures. The effects of Zn and Mg on selective catalytic reduction (SCR) of NO with C 3 H 6 were studied by introducing Zn and Mg into Ag/Al 2 O 3 catalysts with the rotary evaporation method. The effects of Zn and Mg on the microstructure and denitrification performance were characterized by N 2 adsorption–desorption, XRD, UV–vis spectroscopy, H 2 -TPR, NO + O 2 -TPD, XPS and HR-TEM. The results showed that bimetallic Zn and Mg modification increased the proportion of ZnAl 2 O 4 and MgAl 2 O 4 spinels in Ag/Al 2 O 3 catalysts, regulated the dispersion of Ag on the Al 2 O 3 support, and promoted the conversion of Ag0 to active Ag+ and Ag δ n + , which enhanced the NO adsorption capacity and optimized denitrification performance at low temperature. Furthermore, in-situ DRIFTS suggested that enol and acetate generated by C 3 H 6 in the presence of H 2 will react with NO + O 2 to form more –NCO and –CN intermediate species, which facilitated the formation of N 2 and improved N 2 selectivity. Specially, Ag2.5Zn2.5MgAl exhibited more than 95 % NO x conversion, excellent water resistance and sulfur resistance at 300 °C with GHSV = 100 000 h−1. This process promotes the development of efficient vehicle exhaust treatment technology and the application of related products. [ABSTRACT FROM AUTHOR]

Abstract: Hydrothermally stable composite materials with hierarchical macro–meso–micro-porous structure were successfully synthesized via in situ assembly of preformed zeolite Y nanoclusters on kaolin using cetyltrimethylammonium bromide as template under alkaline conditions. The characterization results show that the mesophase in the composite contains primary and secondary structural building units of zeolite Y. The building units contribute micropores in the composite with acidity similar to that of zeolite Y, whereas the macroporous kaolin substrate contributes macropores. This hierarchical macro–meso–micro-porous structure increases the accessibility of the active sites in the composite to reactants and thus confers superior catalytic performance on the resulting catalyst in cracking heavy crude oil. The present work demonstrates that the in situ assembly of zeolitic nanoclusters on substrates (e.g., kaolin) can provide a novel route for fabricating composite materials with hierarchical pore structure. [Copyright &y& Elsevier]