Dry reforming of methane (DRM) offers an efficient route to simultaneously convert CH4 and CO2 into synthesis gas (H2/CO), a key intermediate to produce fuels and valuable chemicals. Ni-based catalysts are regarded as the most promising candidates due to their high activity and low cost; however, their stability remains a major obstacle under the DRM conditions. Perovskite-type oxides such as SrTiO3 possess high thermal stability, tunable composition, and strong metal-support interactions, making them ideal to enhance the dispersion and durability of Ni species. In this study, Ni/SrTiO3 catalysts were synthesized via co-precipitation (CP), hydrothermal (HT), and sol-gel (SG) methods, and were comprehensively characterized before and after the reaction. The characterizations revealed that all samples preserved the perovskite framework after reduction and reaction. Among them, Ni/HT-STO and Ni/SG-STO exhibited larger surface areas (18.8 and 13.9 m2·g−1) and higher initial CH4 conversions (66.3% and 68.9%) than Ni/CP-STO (44.8%). However, Ni/HT-STO underwent rapid deactivation, with CH4 conversion decreasing to 21.2% after 60 h due to severe carbon accumulation (12.4 wt%) and notable Ni particle growth. In contrast, the sol-gel derived Ni/SG-STO maintained a higher activity (25.6% after 60 h) with moderate carbon deposition (9.2 wt%) and showed the smallest Ni particle growth of only 2.64 nm (from 14.91 to 17.55 nm), compared with 4.29 nm for Ni/CP-STO (25.83 to 30.12 nm) and 6.08 nm for Ni/HT-STO (27.12 to 33.20 nm). Temperature-programmed surface reaction (TPSR) analysis further revealed that Ni/SG-STO exhibited a more balanced CH4 activation and CO2 dissociation, enabling efficient carbon-oxygen coupling and inhibiting graphitic carbon formation. Overall, these results demonstrate that the sol-gel method effectively enhances the anti-sintering and anti-coking performance of Ni/SrTiO3 catalysts.
The dye extract of Curcuma longa (turmeric), which is very rich in curcumin, was chemically modified by complexation reaction with Zn2+, Cu2+, and Fe3+ ions to enhance its stability, electron transfer and photovoltaic performance. The dye and complexes were characterized by Ultraviolet-Visible (UV-Vis) absorption and Fourier Transform Infra-Red (FTIR) spectroscopy of potential chromophores and functional groups. The spectral data obtained indicated that the curcuminoid ligands were successfully coordinated with the metal centers, resulting in red-shifted absorption bands from beyond 460 nm and C=O vibrational frequency decreasing below 1650 cm−1. Complexation reaction resulted in improved photochemical response and enhanced light-harvesting potential. When compared, the solar cells fabricated with titanium dioxide (TiO2) photoanodes sensitized by the complexes afforded improvement in the magnitude of short-circuit current density as well as power conversion efficiency compared to the devices sensitized with the crude extract. Among the three complexes, the Zn-complex afforded the highest efficiency (1.20%), attributed to favourable electronic coupling and reduced recombination losses. Computational studies conducted through quantum chemical calculations based on the curcumin structure supported the experimental findings. The findings from this study demonstrate that metal ions-natural dye complexes have potential for application as low-cost, eco-friendly and sustainable sensitizers, thereby opening a novel horizon in green photovoltaic technologies.
The efficiency of lignocellulosic biorefineries is limited because of the high recalcitrance and low reactivity of lignin. The reactivity of lignin can be enhanced through various chemical and biochemical approaches. Demethylation is one of the methods that improve the availability of phenolic hydroxyl groups in lignin, thereby enhancing its reactivity and application in sustainable adhesives. The goal of this study is to integrate microbial and chemical approaches to aid in the demethylation of lignin. Towards that end, lignin was first extracted and purified from the rice straw biorefinery solid residue obtained post ethanol fermentation. This rice straw lignin was then subjected to chemical and microbial demethylation. For microbial demethylation under alkaline conditions, Pseudomonas putida and Pseudomonas fluorescens were employed, while demethylation under neutral conditions was conducted using Trametes versicolor. Integrated treatment using Pseudomonas putida followed by hydrogen iodide yielded an increase in the phenolic hydroxyl content by approximately 39–43%. Demethylation using chemical methods and biological methods alone provided approximately 18–27% increases in phenolic hydroxyl content, respectively. Furthermore, to assess the physical and chemical properties of demethylated lignin, FT-IR, TGA, and morphological analytical tools were employed.
Habanero pepper (Capsicum chinense Jacq.) leaves, a major by-product of pepper cultivation in the Yucatán Peninsula, are an underexploited source of phenolic compounds with relevant antioxidant potential. In this work, phenolic-rich extracts obtained with a choline chloride–glucose Natural Deep Eutectic Solvent (NADES) and ultrasound-assisted extraction were microencapsulated by spray-drying using maltodextrin and Guar gum. The microcapsules were analyzed using Raman spectroscopy, total polyphenol content (TPC), and antioxidant capacity (Ax), and were subsequently subjected to in vitro gastrointestinal digestion to assess their bioaccessibility. Raman spectra confirmed the formation of a maltodextrin–Guar-gum matrix with broad glycosidic bands (480–1450 cm−1) and CH-stretching at ≈2900 cm−1, indicative of polymer–phenolic interactions. From de experimental design, the formulation containing 5% Guar gum at 100 °C reached the highest intestinal TPC (31.00 ± 0.30 mg GAE/100 g powder) and increased TPC bioaccessibility at the intestinal phase (283.28 ± 3.22%), evidencing efficient enzymatic release of bound phenolics. The greatest pre-digestion antioxidant capacity (19.56 ± 0.33% DPPH inhibition) corresponded to 7.5% GG at 104 °C, while intestinal antioxidant recovery peaked at 17.34 ± 0.14% (7.8% GG, 89.4 °C). The optimal TPC bioaccessibility value obtained was 358.3%, under optimal spray-drying conditions, consisting of 4% guar gum and an inlet temperature of 104 °C. Overall, the synergy between NADES-based extraction and optimized spray-drying enabled a stable, digestion-responsive encapsulation system that substantially enhanced phenolic retention and intestinal bioaccessibility, supporting its application as a sustainable strategy to valorize C. chinense leaves into antioxidant-rich functional ingredients.
For the first time, a well-defined all-solid-state lithium battery (denoted as ASS-LTO/Li) assembled by an electrode of lithium titanate (Li4Ti5O12, LTO), a metal-organic framework (MOF) of wetted quasi [Zn4O(bdc)3] and a metallic lithium foil is prepared in this work, in which the wetted quasi [Zn4O(bdc)3] is not only employed as a separator but also used as the solid-state electrolyte. The initial charge and discharge capacities of the as-prepared ASS-LTO/Li at 0.2 C are as high as 187.4 and 286.4 mAh·g−1, respectively, corresponding to a Coulombic efficiency of about 65.4%. More importantly, the discharge capacity of ASS-LTO/Li after 100 cycles at 1 C is still as high as 125 mAh·g−1. After a thorough characterization, the greatly attenuated CV peak area, the evidently increased charge transfer resistance, as well as the decomposition of the quais [Zn4O(bdc)3] during cycling, are analyzed to be the main reasons providing the ASS-LTO/Li with an evident decay of the electrochemical performance in the long-term test of 100 cycles at 1 C. An all-solid-state battery (denoted as ASS-Gr/Li) that is constructed by a pure graphite electrode (abbreviated as Gr), a wetted quasi [Zn4O(bdc)3], and a metallic lithium foil is also prepared in this work. The initial discharge capacity of ASS-Gr/Li at 0.2 A·g−1 is about 169 mAh·g−1, a value evidently lower than the theoretical value of graphite (372 mAh·g−1). The discharge capacity of ASS-Gr/Li at 1.0 A·g−1 is about 24 mAh·g−1, which decreases to about 12 mAh·g−1 after 100 cycles. Although the battery performances of the above two newly developed batteries are poor as compared to the state-of-the-art all-solid-state lithium batteries reported recently, this work sheds light on a novel approach for the further exploration of all-solid-state lithium battery.
Escalating atmospheric CO2 levels and the consequent climate crisis have become urgent imperatives for advancing efficient carbon capture technologies. Porous carbon adsorbents stand out as a leading candidate in this field, owing to their inherently high specific surface areas, tailorable pore architectures, and cost advantages over conventional solid adsorbents. This review focuses on recent progress in the rational engineering of porous carbons for boosted CO2 capture performance, with a particular emphasis on three complementary modification pathways: pore structure refinement, surface functional group regulation, and metal oxide incorporation. We begin by clarifying the distinct mechanisms of CO2 physisorption and chemisorption on carbonaceous surfaces, while also elucidating how key operating parameters (temperature, pressure) and real-world flue gas components (e.g., water vapor, SO2) modulate adsorption behavior. Critical evaluation is then given to strategies for enhancing three core performance metrics—CO2 uptake capacity, selectivity over N2, and cyclic stability—including the construction of sub-nanometer micropores (<0.8 nm) for efficient low-pressure CO2 capture, the introduction of nitrogen- and oxygen-containing moieties to strengthen dipole–quadrupole interactions with CO2 molecules, and the loading of alkaline metal oxides (e.g., MgO, CaO) to enable reversible chemisorption, which is especially beneficial under humid conditions. Finally, we outline the key challenges that hinder the practical application of porous carbon adsorbents, such as the design of hierarchical pores for both high uptake and fast mass transfer, the precise control of heteroatom doping sites and concentrations, and the mitigation of competitive adsorption in complex multicomponent flue gases. Corresponding future research priorities are also proposed, with a focus on scalable and sustainable synthesis routes using biomass or waste precursors. Ultimately, this review seeks to provide targeted insights for the rational design of high-performance porous carbon adsorbents, thereby accelerating their deployment in sustainable CO2 capture systems.
The aggregation and leaching of nanoparticles often reduce catalytic activity and hinder the long-term application of catalysts. Here, we synthesis a hollow Ni/SiO2-AEH catalyst with small Ni nanoparticles (NPs) encapsulated by nickel phyllosilicate (NiPS) via an ammonia evaporation-hydrothermal method. Compared with the Ni/SiO2-AE only synthesized via ammonia evaporation method, the Ni/SiO2-AEH catalyst after further hydrothermal treatment possesses more nickel phyllosilicate (NiPS) species, which enhances the stability of Ni NPs through the strong metal-support bonding (Si–O–Ni) in NiPS. By controlling the size of Ni NPs to 3.6 nm along with the presence of NiPS, we find that Ni/SiO2-AEH displays superior catalytic performance for maleic anhydride (MA) hydrogenation and vanillin hydrodeoxygenation, achieving yields of 97% for succinic anhydride (SA) and 99% for 2-methoxy-4-methylphenol (MMP), respectively. Importantly, the deactivation of Ni/SiO2-AEH is remarkably suppressed, with only a slight decrease in activity after five or six runs. The excellent catalytic activity and stability of phyllosilicate materials imply an extensive application in other industrial catalytic reactions.
