ABSTRACT A metal–organic framework (MOF)‐derived sulfur‐doped NiO/NiS heterostructure was constructed for selective photocatalytic CO 2 methanation by coupling sulfur‐induced electronic modulation with interfacial charge transfer. High‐resolution transmission electron microscopy (HRTEM) reveals an intimate S‐NiO/NiS heterointerface, while ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS) shows enhanced visible‐light absorption and bandgap narrowing from 3.14 to 3.00 eV. The optimized NiOS‐15 achieves a CH 4 production rate of 13.41 µmol·g −1 ·h −1 , which is 5.94 times that of pristine NiO, together with a CH 4 selectivity of 92.12%. Work‐function calculations reveal interfacial electron redistribution and Schottky‐junction‐assisted charge transfer. In situ irradiation x‐ray photoelectron spectroscopy (XPS) further verifies directional photoinduced charge redistribution, while in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) identifies key intermediates involved in CO 2 ‐to‐CH 4 conversion. This work integrates MOF‐derived porous architecture, sulfur‐induced electronic regulation, and S‐NiO/NiS interfacial engineering for efficient and selective CO 2 methanation.
ABSTRACT The exploration of the catalytic activity of lignin‐derived compounds into high‐value‐added chemicals is essential to meet the rising energy demands and to provide an alternative to fossil fuels. In this study, a non‐noble metal catalyst was used for the vanillin hydrodeoxygenation (HDO) process. The low‐cost Ni/HAP catalyst was prepared using the wet impregnation method with varying nickel loadings on a hydroxyapatite (HAP) support. Comprehensive physiochemical characterization was carried out using XRD, SEM‐EDX, XPS, NH 3 ‐TPD, CO chemisorption, HR‐TEM, and Nitrogen adsorption‐desorption analysis. Among the studied catalysts, the 1‐Ni/HAP catalyst exhibited superior catalytic activity for vanillin HDO to 2‐methoxy‐4‐methylphenol (MMP). The catalyst shows broader applicability for other lignin‐derived aromatic aldehyde compounds. The Langmuir‐Hinshelwood‐Hougen‐Watson (LHHW) model was developed to understand the reaction kinetics and mechanism. The activation energy of 88.76 kJ/mol indicates that the vanillin HDO reaction is kinetically controlled. These findings establish Ni/HAP as an active, selective, and non‐noble metal catalyst for lignin‐derived aldehyde valorization.
ABSTRACT With increasing environmental concerns and regulatory pressures, the industry is shifting toward bio‐based alternatives to traditional synthetic chemicals. Chitosan, a biodegradable and biocompatible biopolymer, has gained attention due to its multifunctionality in improving paper properties. This paper explores the chemical modifications of chitosan, such as molecular weight (MW) adjustments and functional group modifications, which enhance paper strength, water resistance, and antimicrobial properties. The impact of these modifications on the performance of chitosan as a retention agent, strengthening agent, and barrier coating is discussed, along with its applications in sustainable papermaking. The review further examines how chitosan‐based additives contribute to the United Nations Sustainable Development Goals (SDGs) through waste valorization, circular production, safer materials, cleaner process water, and biodegradable paper products. Additionally, challenges such as cost‐effectiveness, scalability, and process compatibility are highlighted, along with emerging solutions and future research directions. Chitosan's potential to replace synthetic additives and contribute to environmentally responsible papermaking practices is emphasized, underscoring its role in the development of high‐performance, eco‐friendly paper products.
ABSTRACT Green laser‐induced graphene (gLIG) emerges as a promising candidate to meet the demand for sustainable, high‐performance carbon nanomaterials. In this work, gLIG was synthesized from cellulose and lignin (L) fractions obtained from a pilot‐scale biorefinery that processes Pinus elliottii bark as feedstock. Fractions obtained through sequential extraction were engineered to produce nanostructured films based on cellulose nanofibrils (CNFs), L, and 2‐hydroxyethyl cellulose (HEC). The gLIG patterns were fabricated by single‐step CO 2 direct laser writing lignographic (DLW) under ambient conditions, without additional chemical promoters. Raman spectroscopy confirmed the formation of graphitic domains in all formulations, while the engineered composite containing HEC significantly improved structural ordering and electrical performance, reducing defect density (I D /I G down to 0.24) and sheet resistance (R s ) (from 1513.85 ± 2324.62 to 39.29 ± 6.57 Ω sq −1 ). Multitechnique characterization revealed extensive deoxygenation (C/O > 30) and the development of sponge‐like porosity (specific surface area (S BET ) between 30.353 and 69.577 m 2 g −1 . These results establish a scalable route that integrates biorefinery‐derived feedstocks with laser nanofabrication to convert an abundant agroindustry residue into functional graphene‐like materials for sustainable electronics and sensing platforms, contributing to Sustainable Development Goals (SDGs) 9 (Industry, Innovation, and Infrastructure) and 12 (Responsible Consumption and Production).
ABSTRACT High‐performance thermoelectric materials are vital to the transition toward clean energy technologies and require a unique combination of electrical and thermal properties. While those properties are often strongly intertwined in conventional materials, topological materials can decouple the electrical and thermal properties, providing an avenue to independently optimize each property. In this study, the topological insulator YCuSb 2 and Te‐doped derivatives were synthesized, characterized, and their thermoelectric properties were measured. Low electrical resistivity (77–355 µΩ·cm) with relatively low lattice thermal conductivity (<8 W m −1 K −1 ) was found at 300 K. The thermal conductivity is mostly dominated by the electrical contribution. Despite these favorable transport characteristics, a low Seebeck coefficient (<8 µV K −1 ) limits the overall thermoelectric performance of YCuSb 2 . Comparison of the experimental results with electronic structure calculations indicates that the nearly constant density of states near the Fermi level is responsible for the low thermoelectric figure of merit (∼0.001 at 300 K). These findings identify the electronic structure near the Fermi level as the primary limitation to enhancing the thermoelectric performance and therefore, band‐structure engineering might be a promising strategy for improving the thermoelectric properties of YCuSb 2 ‐based materials.
