Energy & Fuels最新文献

Metallic-phase MoS₂ (1T-MoS₂) is considered a promising catalyst for the hydrogen evolution reaction (HER) in acidic media, largely due to the abundant surface active sites induced by sulfur vacancies (S_V). However, existing defect engineering approaches for MoS₂ often involve corrosive chemicals or specialized equipment, hindering its practical scalability. In this work, 1T-MoS₂ is synthesized via a facile one-step hydrothermal method, and defect engineering is achieved simply by modulating the sulfur-to-molybdenum (S/Mo) molar ratio in the precursor solution. The optimized catalyst exhibits a low HER overpotential of 266 mV at −10 mA cm^–2 and a Tafel slope of 72 mV dec^–1 in a 0.5 M H₂SO₄ electrolyte. It also shows outstanding operational stability, with only a 15 mV increase in overpotential at −10 mA cm^–2 after 150 h of continuous HER testing under −0.7 V vs RHE (∼200 mA cm^–2). The enhanced performance is attributed to multiple synergistic effects induced by S_V defects, including reduced charge transfer resistance, accelerated reaction kinetics, and an enlarged electrochemically active surface area. Overall, this work offers a simple, scalable route to prepare S_V-tuned 1T-MoS₂, and it provides useful design insights for developing efficient and durable MoS₂-based HER electrocatalysts.

This study addresses the current challenge of balancing high-temperature resistance and environmental performance in fluid loss reducers. Using grape extract (GE), 2-acrylamide-2-methylpropanesulfonic acid (AMPS), acrylamide (AM), and sodium lignosulfonate (LS) as monomers, we successfully synthesized an environmentally friendly fluid loss reducer, GE/AMPS/AM/LS polycopolymer (GE-AAS), that can withstand temperatures of 200 °C through copolymerization and cross-linking reactions. The successful synthesis of GE-AAS was validated using Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (¹H NMR) spectroscopy, and scanning electron microscopy (SEM), which also highlighted its linear molecular structure characteristics. Thermogravimetric analysis (TG) results indicate that thermal decomposition begins at 290 °C and demonstrate excellent thermal stability. The filtration loss experiment showed that after 16 h of aging at 200 °C, the medium-pressure fluid loss (API) and high-temperature, high-pressure filtration loss (HTHP) of the base mud containing 3% GE-AAS were 8.8 and 34.2 mL, respectively, demonstrating excellent filtration loss reduction performance. The mechanism of action of GE-AAS was revealed through analyses such as particle size distribution, zeta potential, atomic force microscopy (AFM), and scanning electron microscopy (SEM). It was strongly adsorbed onto the bentonite surface primarily via hydrogen bonds, ionic bonds, and electrostatic interactions, which increased the electrostatic repulsion among bentonite particles, facilitated their dispersion, and led to the formation of a thin, dense mud cake. In addition, GE-AAS showed a half-maximal effective concentration (EC₅₀) of 5.6 × 10⁵ mg/L and a biochemical oxygen demand (BOD₅)/chemical oxygen demand (COD_Cr) ratio of 33.6%, indicating that it is nontoxic and biodegradable.

Metallic-phase MoS₂ (1T-MoS₂) is considered a promising catalyst for the hydrogen evolution reaction (HER) in acidic media, largely due to the abundant surface active sites induced by sulfur vacancies (S_V). However, existing defect engineering approaches for MoS₂ often involve corrosive chemicals or specialized equipment, hindering its practical scalability. In this work, 1T-MoS₂ is synthesized via a facile one-step hydrothermal method, and defect engineering is achieved simply by modulating the sulfur-to-molybdenum (S/Mo) molar ratio in the precursor solution. The optimized catalyst exhibits a low HER overpotential of 266 mV at −10 mA cm^–2 and a Tafel slope of 72 mV dec^–1 in a 0.5 M H₂SO₄ electrolyte. It also shows outstanding operational stability, with only a 15 mV increase in overpotential at −10 mA cm^–2 after 150 h of continuous HER testing under −0.7 V vs RHE (∼200 mA cm^–2). The enhanced performance is attributed to multiple synergistic effects induced by S_V defects, including reduced charge transfer resistance, accelerated reaction kinetics, and an enlarged electrochemically active surface area. Overall, this work offers a simple, scalable route to prepare S_V-tuned 1T-MoS₂, and it provides useful design insights for developing efficient and durable MoS₂-based HER electrocatalysts.

The carbon dioxide (CO₂) sequestration combined with enhanced natural gas recovery is a promising technology. Injecting CO₂ into hydrocarbon reservoirs induces a competitive adsorption process between CO₂ and CH₄, which not only facilitates significant CO₂ storage underground but also enhances hydrocarbon recovery. Clay minerals, which are abundant in oil- and gas-rich strata, provide numerous gas adsorption sites. This study employs a combined Grand Canonical Monte Carlo (GCMC) and Molecular Dynamics (MD) approach to investigate the competitive adsorption behavior of CO₂/CH₄ binary mixtures on clay minerals with different structures, specifically kaolinite and montmorillonite. Van der Waals forces predominantly govern the interaction of CO₂ and CH₄ with clay surfaces. The cations located between the isomorphously substituted montmorillonite layers exert stronger electrostatic interactions with CO₂, leading to an increased adsorption selectivity of montmorillonite for CO₂/CH₄. As pore size, pressure, and temperature increase, the selectivity of binary mixtures decreases, but adsorption sites undergo temperature-dependent redistribution. Under higher hydration conditions, selectivity improves, primarily because gases adsorbed between layers are mainly captured by H₂O molecules rather than by the surfaces of clay minerals. Within the pores of two hydrated clay minerals, in addition to the competitive adsorption mechanism, the “water-mediated synergistic adsorption” mechanism predominates in the adsorption of gases.

This study addresses the current challenge of balancing high-temperature resistance and environmental performance in fluid loss reducers. Using grape extract (GE), 2-acrylamide-2-methylpropanesulfonic acid (AMPS), acrylamide (AM), and sodium lignosulfonate (LS) as monomers, we successfully synthesized an environmentally friendly fluid loss reducer, GE/AMPS/AM/LS polycopolymer (GE-AAS), that can withstand temperatures of 200 °C through copolymerization and cross-linking reactions. The successful synthesis of GE-AAS was validated using Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (¹H NMR) spectroscopy, and scanning electron microscopy (SEM), which also highlighted its linear molecular structure characteristics. Thermogravimetric analysis (TG) results indicate that thermal decomposition begins at 290 °C and demonstrate excellent thermal stability. The filtration loss experiment showed that after 16 h of aging at 200 °C, the medium-pressure fluid loss (API) and high-temperature, high-pressure filtration loss (HTHP) of the base mud containing 3% GE-AAS were 8.8 and 34.2 mL, respectively, demonstrating excellent filtration loss reduction performance. The mechanism of action of GE-AAS was revealed through analyses such as particle size distribution, zeta potential, atomic force microscopy (AFM), and scanning electron microscopy (SEM). It was strongly adsorbed onto the bentonite surface primarily via hydrogen bonds, ionic bonds, and electrostatic interactions, which increased the electrostatic repulsion among bentonite particles, facilitated their dispersion, and led to the formation of a thin, dense mud cake. In addition, GE-AAS showed a half-maximal effective concentration (EC₅₀) of 5.6 × 10⁵ mg/L and a biochemical oxygen demand (BOD₅)/chemical oxygen demand (COD_Cr) ratio of 33.6%, indicating that it is nontoxic and biodegradable.

The carbon dioxide (CO₂) sequestration combined with enhanced natural gas recovery is a promising technology. Injecting CO₂ into hydrocarbon reservoirs induces a competitive adsorption process between CO₂ and CH₄, which not only facilitates significant CO₂ storage underground but also enhances hydrocarbon recovery. Clay minerals, which are abundant in oil- and gas-rich strata, provide numerous gas adsorption sites. This study employs a combined Grand Canonical Monte Carlo (GCMC) and Molecular Dynamics (MD) approach to investigate the competitive adsorption behavior of CO₂/CH₄ binary mixtures on clay minerals with different structures, specifically kaolinite and montmorillonite. Van der Waals forces predominantly govern the interaction of CO₂ and CH₄ with clay surfaces. The cations located between the isomorphously substituted montmorillonite layers exert stronger electrostatic interactions with CO₂, leading to an increased adsorption selectivity of montmorillonite for CO₂/CH₄. As pore size, pressure, and temperature increase, the selectivity of binary mixtures decreases, but adsorption sites undergo temperature-dependent redistribution. Under higher hydration conditions, selectivity improves, primarily because gases adsorbed between layers are mainly captured by H₂O molecules rather than by the surfaces of clay minerals. Within the pores of two hydrated clay minerals, in addition to the competitive adsorption mechanism, the “water-mediated synergistic adsorption” mechanism predominates in the adsorption of gases.

Electrochemical systems such as fuel cells, redox flow batteries (RFBs), and electrolyzers have emerged as promising green energy technologies to replace conventional fossil fuel-based sources. Among the critical components in these systems, the bipolar plate (BPP) plays a pivotal role, as its material properties and structural characteristics directly influence overall device performance. Recent years have seen considerable efforts focused on advancing BPP technology to meet the specific demands of various electrochemical applications. However, existing review articles tend to focus on either material development or fabrication techniques within a single electrochemical system, without adequately addressing the broader implications of BPP design across different systems. To bridge this gap, the present review provides a comprehensive overview of the recent progress and persistent challenges in BPP development from a cross-platform perspective, encompassing fuel cells, electrolyzers, and RFB. Particular emphasis is placed on the selection of BPP materials tailored to the specific operational environments of each system. Furthermore, the influence of BPP material characteristics on device performance is critically examined, and potential directions for future research are proposed.

Poorly soluble inorganic salts forming deposits in wells and flow lines during the production of oil and gas are known as scales. If left untreated, these deposits can cause blockages, reducing the flow of hydrocarbons. Barium(II) sulfate (Barite) is probably the hardest scale to manage. Its formation can be prevented using chemical scale inhibitors, of which aminophosphonates are a well-known class. However, aminophosphonates have never been considered as scale dissolvers. Instead, salts of polyaminocarboxylic acids are used as Barite dissolvers, with salts of diethylenetriamine-N′,N′,N″,N‴,N‴-pentaacetic acid (DTPA) at high pH being the most common. We have now discovered that aminophosphonates, if the ligand is fully deprotonated and the phosphonates are doubly charged at very high pH (13–14), are capable of dissolving Barite scale. It was shown, e.g., for the decapotassium salt of diethylenetriamine-N′,N′,N″,N‴,N‴-pentakis(methylenephosphonic acid) (K₁₀DTPMP) or the hexapotassium salt of amino-tris(methylenephosphonic acid) (K₆ATMP). Dissolver efficiency was reduced for sodium salts, as it was also seen previously for DTPA. The Barite dissolution kinetics and dissolver capacity improved further using the octapotassium salt of the macrocyclic polyamino-polyphosphonic acid 3,6,14,17,23,24-hexaazatricyclo[17.3.1.1(8.12)]tetracosa-1(23),8,10,12(24),19,21-hexaene-3,6,14,17-tetrakis(methylenephosphonic acid) (K₈PYTP). The macrocycle is a ligand preorganized for complexation of large metal ions such as Ba(II), and its complex exhibits a lower charge repulsion, leading to better dissolving of Barite scale than K₁₀DTPMP does. Surprisingly, the tetrakis-monoethylester of PYTP, PYTP^OEt, was not able to dissolve Barite scale at all. An explanation of the observed facts was suggested on the basis of basicity of the chelators and on DFT calculations, which suggested that macrocyclic chelators derived from PYTA might prefer different isomers of their Ba(II) complexes, exhibiting a different strain in their structure. These results indicate that polyamino-polyphosphonic acid scale inhibitors can also function as Barite scale dissolvers at very high pH, and a rational design of the scale inhibitors is possible.

To design visbreaking processes for bitumen upgrading, it is necessary to predict the product properties. This study examines the impact of visbreaking on the density and viscosity of two bitumens, a vacuum bottom and a deasphalted oil. The oils were visbroken at different combinations of temperature and space time (with conversions up to 38%) by using an in-house continuous visbreaker. In all cases, the gas yields were below 1.5 wt %, and no coke was detected. The products were separated into distillates, saturates, aromatics, resins, and asphaltenes (DSARA). The density and viscosity of the oils and each of their fractions were measured directly or indirectly from measured whole oil, maltene, and residue properties over temperatures from 20 to 150 °C, depending on the fraction. The product density was modeled with a volumetric mixing rule, and the viscosity was modeled with the Expanded Fluid model. Existing correlations for the input DSARA property parameters as a function of conversion were updated. The models with the updated correlations and a new tuning procedure were evaluated by using measured feed properties, conversion, and product compositions as inputs. The average deviations in the modeled product densities and viscosities were 2.2 kg/m³ and 28%, respectively. The models were further tested using default feed properties, and product compositions correlated to conversion. This approach eliminated the need for measured product composition and properties and had minimal impact on the accuracy of the updated models.

The escalating environmental degradation and the ongoing energy crisis linked to fossil fuel consumption have intensified worldwide attention to developing and utilizing sustainable clean energy solutions. Consequently, there is an urgent need to enhance and adopt various energy conversion and storage technologies to support the efficient production and utilization of clean energy sources. Innovative electrode design is essential for performing energy conversion and storage applications together. This work aims to fabricate a nanocomposite electrode and an electrocatalyst by integrating reduced graphene oxide with La₂Ni_1.8Fe_0.2O₆ (LNF) nanoparticles, harnessing the superior electrical conductivity of rGO for improved performance. Comprehensive physical, electrochemical, and electrocatalytic characterizations are conducted to evaluate the properties of the prepared electrodes. The composite of 20% rGO with LNF (L20@Ni-F) has good electrochemical and electrocatalytic performance compared to the other composites (0, 5, 10, and 25% rGO). The fabricated asymmetric hybrid device attained a specific capacity of 471 C g^–1, a maximum specific energy of 77.16 W h kg^–1, and a specific power of 589.76 W kg^–1 at the specific current of 1 A g^–1. The same electrode as an electrocatalyst has an overpotential of 420 mV (@10 mA cm^–2) with a Tafel slope of 197 mV dec^–1 and an outstanding overpotential of 271 mV (@-10 mA cm^–2) with a Tafel slope of 94 mV dec^–1 for oxygen evolution reaction and hydrogen evolution reaction, respectively. These results offer a novel strategy for the promising development and fabrication of bifunctional catalysts for supercapacitor and water splitting applications.