Renewable Energy最新文献

The photocatalyst film, composed of tetragonal BiOI nanosheets and cubic phase CuI nanoparticles, was synthesized on the FTO substrate by a simple electro-deposition method. The orderly crisscrossed nanosheet structure caused exterior hydrophobic property, resisting the excess H₂O molecules and further inhibiting the competitive H₂O reduction process. The novel BiOI/CuI catalyst exhibited excellent photocatalytic ability of CO₂ reduction into CO with 100 % selectivity in H₂O vapor. Typically, the optimal 150BiOI/CuI photocatalyst exhibited CO yield of 7237.65 μmol/cm² after 11 h of simulated sunlight illumination, achieving quantum efficiency of 2.5 % at 380 nm. The excellent performance of the BiOI/CuI composite film in photocatalytic CO₂ reduction can be attributed to the construction of hydrophobic surface and S-scheme heterojunction with I₃⁻/I⁻ redox mediator, as confirmed by the in-situ XPS, hole injection test and cyclic voltammetry results. This study lays the groundwork for employing highly efficient iodide-based photocatalysts in gas-liquid-solid triphase catalytic systems.

In this study, the efficiency of applying the KF/waste glass catalyst was tested in the transesterification of crambe oil under pressurized conditions for the synthesis of esters and glycerol carbonate (GLC). For this, a miscella pressurized extraction was used. The influence of temperature on different residence times was evaluated, and to verify the effect of the catalyst on the process, non-catalytic reactions were conducted. In reactions without the use of catalyst, a temperature of 250 °C was required to obtain >90 % esters yield. In the catalytic reactions, the operating conditions were reduced to 225 °C, to obtain ∼96 % esters yield, also providing the synthesis of a greater quantity of GLC, and a glycerol-free sample. The wet modification of powdered glass waste with KF results in the K₂SiF₆, NaF, CaF₂, and KCaF₃ phases. The laser-induced breakdown spectroscopy analyses showed the presence of fluorinated compounds in the catalyst. Furthermore, calcium and sodium ions from the glass waste matrix support were the source for the crystalization of K₂SiF₆/CaF₂/KCaF₃ and NaF phases, respectively. The catalyst showed a good catalytic activity, promoting high ester and GLC formation at 225 °C, 10 min and 10 MPa, remaining with good performance even after 8h of reaction, but it is important to mention that the stability of the catalyst needs to be improved due to the leaching of K to Ca.

This work was focused on the evolution process of alkali lignin with a macromolecular structure in supercritical water gasification reactions. Using Quantum chemistry calculations and molecular dynamics simulations, the effects of different factors on the reaction process were studied, and the detailed pathways of main products were obtained. The results indicate that the presence of sulfur significantly inhibits the pyrolysis behavior of alkali lignin macromolecular structures. Sulfur significantly impacts the morphology of the intermediate molecular fragments of products containing 5–10 carbon atoms. Sulfur also has a significant inhibitory effect on the ring opening reaction of the benzene ring. Still, its effect on the final gas product distribution is not significant from a microscopic perspective. In addition, high temperature has a significant impact on improving the gasification efficiency of alkali lignin, while the scale of the reaction system has no significant effect on the distribution of gas products. This study will provide theoretical guidance for further improving the supercritical water gasification efficiency of lignin.

High entropy perovskite oxide (HEPO) is a potential electrocatalyst for the oxygen evolution reaction (OER), but insufficient activity remains a problem. Oxygen vacancies can activate the lattice oxygen to induce the lattice oxygen-mediated mechanism (LOM), which can avoid the kinetic limitation present in adsorbate evolution mechanism (AEM), thereby improving the OER activity. Herein, we select the appropriate doping element (S) through analysis of ionic radius, electronegativity, and oxygen vacancy formation energy, and report an effective two-step oxygen vacancy strategy for introducing oxygen vacancies into HEPO through electrospinning and sulfurization treatment. This strategy optimizes the e_g orbital filling electron number and significantly increases the active area, oxygen vacancy content and electroconductivity. Furthermore, the apparent pH dependence and the TMA⁺ inhibition phenomenon suggest the involvement of the LOM. Consequently, the resulting S/LMO-E has a lower overpotential (314 mV at 10 mA cm⁻²) and faster kinetics, and shows excellent stability. Meanwhile, the water splitting is achieved at 1.59 V to afford 10 mA cm⁻² current density for S/LMO-E⎪⎢Pt/C, which is smaller than that of RuO₂⎪⎢Pt/C (1.62 V). This work provides an attractive OER electrocatalyst for efficient water splitting to produce renewable hydrogen and opens a new way for the design of effective and stable high entropy material electrocatalysts.

The limitation in bio-oil quality hampers its further utilization in the fuel or chemical industry. This study employed a combination of tetra propylammonium hydroxide (TPAOH) and NaOH solutions for HZSM-5 desilication to enhance the yield of monocyclic aromatic hydrocarbons in the catalytic co-pyrolysis of wheat straw with polyethylene. Results revealed hierarchical HZSM-5, prepared with equal mole concentrations of NaOH and TPAOH, exhibited optimal catalytic performance. The bio-oil from this process had an aromatic content of 72 %, with monocyclic aromatic hydrocarbons (MAHs) constituting 56.26 %. Further optimization was achieved through iron modification of hierarchical HZSM-5. The addition of 0.5 % iron-modified hierarchical HZSM-5 increased the aromatic hydrocarbons to 80.57 %, with BTX compounds (benzene, toluene, and xylene) reaching a selectivity of 61.9 %. This approach reduced polycyclic aromatic hydrocarbons (PAHs), contributing to less coke formation, presenting a promising method for high-quality bio-oil.

Understanding the interactions between metals, corrosion products, and bio-oil (BO) is crucial for safe and efficient BO operations. This study explored BO aging and BO + steel (carbon steel (CS) and stainless steel (SS)) immersion at 80 °C for 168 h, alongside experiments adding synthetic Fe₂O₃ and Cr₂O₃ powders to BO. Gas generated was analyzed via gas chromatography (GC). Results showed 80 °C was an optimal pre-heating temperature for BO without gas evolution. BO aging at up to 220 °C for 24 h increased CO₂ and CO evolutions. CS immersion at 80 °C produced more H₂ and CO₂ than those at 50 °C, due to higher corrosion rates. The BO + Fe₂O₃ trial released less H₂ but more CO₂ compared to BO + CS immersion, due to internal BO reactions catalyzed by Fe₂O₃. BO + SS304L and BO + Cr₂O₃ trials showed similar H₂ and CO₂ production, highlighting the catalytic effect of Cr₂O₃. Leached Fe ions in BO formed chelate complexes with organic compounds, causing phase separation. These findings have significant implications for producing renewable biofuels via BO co-processing operations by emphasizing the need to optimize preheating temperatures, validate the compatibility of construction materials, and implement safety measures to mitigate gas accumulation risks.

Accurate prediction of photovoltaic power generation is essential to promoting the active consumption and low-carbon protection. The complex uncertainty of the photovoltaic system itself leads to the deviation in the photovoltaic power prediction. Therefore, we propose a new prediction model for coupled intelligence optimization. First, the photovoltaic power is decomposed into effective mode components using VMD optimized by GWO. Statistical techniques were used to analyze multidimensional uncertainty and extract features, then, optimize the performance of the coupled model. Second, the Zebra optimization (ZOA) establishes an appropriate balance between exploration and utilization to achieve the optimization of the model parameters. In addition, the CNN is used to extract complex features and enhance the correlation between input values and output values. Finally, the power was predicted using the BiLSTM. The results show that applying the statistical technique to the coupled prediction model not only reveals the uncertainty of photovoltaic systems but reduces the prediction error. Among them, the $R^2$ increased by 0.42 %, the values of MAPE, MSE, RMSE, and MAE were reduced to different degrees. It can better optimize the allocation and reasonable consumption of renewable energy, which provides the decision basis for the adjustment of renewable energy structure.

Underground salt cavern storage has become the preferred medium for storing gas energy and strategic substances. Salt caverns are suitable for storing small molecular gases due to the low porosity and permeability of salt rocks. This paper comprehensively analyzes the physical properties of four gases - hydrogen, helium, methane, and carbon dioxide - under subsurface temperature and pressure conditions. It categorizes the flow regimes of these gases in salt rocks under geological pressure conditions based on the Knudsen number. In a typical 1000 m salt cavern, the predominant permeation flow regime of four gases in the surrounding rock is Klinkenberg flow, with helium potentially undergoing transitional flow at low operation pressures. A 3D numerical model is established for an actual salt cavern to compare the permeation and leakage characteristics of these gases within salt rock formations. Results indicate that, under identical operation conditions, the permeation range of the gases decreases in the following order: hydrogen > methane > helium > carbon dioxide. Under the cyclic operation pressures, the cumulative leakage amount of hydrogen, helium, and methane increases over time, while that of carbon dioxide initially rises and then decreases. This behavior is attributed to the fact that the reverse-permeation rate of carbon dioxide at low pressures exceeds its permeation rate at high pressures. Over 30 years cyclic operation, the leakage ratios of the gases are as follows: hydrogen (13.29 %), methane (9.34 %), helium (7.47 %), and carbon dioxide (0.93 %), with hydrogen exhibiting the highest and carbon dioxide the lowest leakage ratios. Larger permeability results in a larger permeation range, while larger porosity leads to a smaller permeation range. When the permeability of salt layer is greater than 1e-20 m², the permeation range of hydrogen significantly increases. Gas leakage ratios increase with permeability nonlinearly and increase with porosity linearly. The impact of salt layer permeability on leakage ratios is greater than that of porosity. This study provides crucial guidance for the selection of geological formations for storing hydrogen, helium, methane, and carbon dioxide in salt caverns, as well as the investigation of gas permeation characteristics in salt layers.

We examined the internal behavior of an electrochemical hydrogen compressor under high-pressure conditions. In doing so, we focused on the changes in compressor efficiency and power consumption in response to intensified hydrogen back-diffusion under high pressures and various values of other parameters. First, as the operating temperature increased, the power consumed to achieve the same pressure ratio increased. This increased in power consumption was attributed to the fact that as the temperature increased, hydrogen back-diffusion intensified, which necessitated a net forward flux and induced flow losses. Second, as the relative humidity increased, power consumption decreased, and compressor efficiency increased. Although higher relative humidity intensifies back-diffusion, leading to flow losses, the accompanying significant decrease in ohmic losses increases compressor efficiency. By adjusting factors such as temperature and relative humidity, compressor efficiency can potentially be increased by up to 1.78 times. At high pressure ratios, hydrogen back-diffusion was inherently strong, and it became stronger at higher temperatures and relative humidities. Therefore, the compressor was more efficient when it was operated at lower temperatures and higher relative humidities. At the optimal operating temperature of 50 °C and 100 % relative humidity, the compressor efficiency peaked at 97.507 % when the pressure ratio was 100.

Water resources are under increasing pressure from ever-increasing demand from industry and society. However, water is a limited resource that must be sustainable and protected. This problem is highlighted in desert areas, where water quality and abundance are scarce. Solar-powered water treatment systems are an inexpensive solution to ensure water quality for human consumption. This research analyzes solar ultraviolet radiation (UVR) in three populated Chilean cities to study the potential feasibility of the solar-powered photo-Fenton process for wastewater remediation. To generate long-term UVR values, satellite and reanalysis data and the Radiative Transfer Model were used. Results show high daily levels of solar ultraviolet irradiation, 1299.95kJm⁻² for Antofagasta. The shortest treatment time for summer operation was observed in Santiago (21 min), followed by Antofagasta (34 min), and Concepción (35 min). Santiago presented the lowest volume of photoreactors during the summer (297 L) and Antofagasta during the winter (1589 L). This is the first preliminary analysis showing the possibilities of exploiting the potential of UVR in Chilean cities to provide tools for integrating water treatment technologies. This research motivates further studies on spectral radiation and emerging advanced oxidation technologies and the development of prospects for water and wastewater treatment.