Siirt University

Increasing global energy demand and environmental concerns have increased interest in sustainable and clean energy technologies. In this context, hydrogen is considered one of the most important energy carriers of the future due to its high energy density and environmentally friendly properties. In this study, a nitrogen/sulfurdoped activated carbon-supported copper oxide composite (CuO@N,S@AC) was successfully synthesized for hydrogen production via the methanolysis of sodium borohydride (NaBH4), and its performance as a heterogeneous catalyst was investigated. The structural, morphological, surface, and chemical properties of the catalyst were comprehensively characterized using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface area analysis, and Fourier transform infrared spectroscopy (FTIR) techniques. XPS results showed the successful presence of sulfur and copper species in the research spectrum confirmed the formation of the activated carbon-supported heteroatom-doped CuO composite structure. In NaBH4 methanolysis experiments, the catalyst exhibited high catalytic activity and reached a hydrogen production rate (HGR) of 13.782 mL min- 1 g- 1 at a volume of 0.25 g NaBH4. Kinetic studies calculated the activation energy (Ea) as 33.2 kJ mol-1, indicating that the catalyst has a low energy barrier for the reaction. The superior performance obtained was attributed to the synergistic interactions between CuO nanoparticles, sulfur doping, and porous activated carbon support. These interactions increased the active center density, facilitated electron transfer, and improved hydrogen production kinetics. Consequently, the CuO@N,S@AC catalyst stands out as a highly efficient and promising heterogeneous catalyst for NaBH4-based hydrogen production systems and is a significant candidate that can contribute to the development of sustainable hydrogen energy technologies.

A sustainable biopolymer-based composite catalyst, Chitosan@CeO2@P, was developed from biomass-derived chitosan through the incorporation of cerium oxide nanoparticles and phosphate functionalities, aiming at efficient biomass-inspired hydrogen production systems. The catalyst design aligns with bioresource valorization and bioenergy integration strategies for low-carbon energy technologies. Comprehensive physicochemical characterization confirmed the successful formation of a hybrid bio-based catalytic structure with enhanced surface functionality. The catalytic performance was evaluated in the alcoholysis of NaBH4 as a chemical hydrogen carrier relevant to renewable energy storage. Solvent engineering played a decisive role in performance enhancement: while pure methanol provided a hydrogen generation rate (HGR) of 3832 mL min-1 g-1, a methanol/glycerol (1:1 v/v) mixture-containing a biomass-derived polyol-significantly increased the HGR to 10518 mL min-1 g-1. The improved activity originates from synergistic interactions between CeO2 active centers and phosphate-modified chitosan, promoting efficient catalytic pathways. Kinetic studies revealed favorable reaction dynamics with an activation energy of 30.4 kJ mol-1. This study demonstrates the potential of biomass-derived catalytic materials for sustainable hydrogen generation and advanced bioenergy applications.

The development of highly active and durable catalysts is essential for on-demand hydrogen generation from chemical hydrides. In this study, Pd@N-doped activated carbon (Pd@N-doped AC) was synthesized via a facile hydrothermal method using commercial activated carbon, palladium (II) nitrate, and urea. Structural and surface characterization confirmed the formation and dispersion of Pd nanoparticles on the nitrogen-functionalized activated carbon support. The catalytic performance was evaluated for NaBH4 methanolysis under different temperatures and NaBH4 concentrations. The catalyst achieved a maximum hydrogen generation rate (HGR) of 15,742 mL min−1 gcat−1 at 30 °C, with a low apparent activation energy of 18.74 kJ mol−1. The catalyst also maintained satisfactory activity over five consecutive cycles, demonstrating good reusability. The enhanced performance is associated with the combined effects of well-dispersed Pd nanoparticles, nitrogen-containing surface functionalities, and the porous carbon framework. The novelty of this work lies in integrating nitrogen-functionalized commercial activated carbon with Pd through a simple hydrothermal synthesis to obtain a highly active catalyst combining high HGR, low activation energy, and good reusability for NaBH4 methanolysis. These results demonstrate the potential of Pd@N-doped AC for efficient on-demand H2 generation.

Soil salinization poses a significant threat to potato crops, particularly in arid and semi-arid regions. This study investigated the effects of foliar application of cerium oxide nanoparticles (CeO2-NPs) at concentrations of 0, 10, 20, and 40 mg L−1 on the growth, biochemical, and physiological responses of potato plants under both non-saline and saline conditions. Saline treatments included control, moderate salt stress (MSS) = 75 mM and severe salt stress (SSS) = 150 mM NaCl salinity. The results demonstrated that both MSS and SSS substantially affected the plant performance. However, application of CeO2-NPs at the 40 mg L−1 significantly enhanced growth, biomass, physiology, and photosynthetic traits of potato plants. The severity of saline stress was associated with increased generation of reactive oxygen species (ROS). However, treatment with 40 mg L−1of CeO2-NPs resulted in marked increase in soluble sugars (47.35

The development of proton exchange membrane fuel cells (PEMFCs) requires cost-effective, efficient, and durable electrocatalysts with reduced noble metal content. In this study, La2O3 nanoparticles were synthesized via a green route using bean shell extract and employed as oxide supports for Pt-based cathode catalysts. Two catalyst structures, denoted as Pt–La2O3/C and Pt/La2O3–C, were prepared through a chemical reduction method. The structural, morphological, and compositional properties of the catalysts were systematically characterized using XRD, XPS, TEM, SEM, and EDX. Electrochemical analyses revealed that the Pt–La2O3/C catalyst exhibited a higher electrochemically active surface area (137 m2gPt− 1) and improved electrochemical performance compared to Pt/La2O3–C (118 m2gPt− 1). PEMFC performance tests conducted at 70 °C demonstrated that Pt–La2O3/C achieved a maximum current density of 397 mAcm− 2, outperforming Pt/La2O3–C (269 mAcm− 2), despite employing a lower platinum loading. Furthermore, durability assessments showed that the Pt–La2O3/C catalyst retained approximately 78