Journal of Materials Science: Materials in Engineering20 (2025): 140 

https://doi.org/10.1186/s40712-025-00340-6

Hydrogen offers a high-energy, carbon-free fuel alternative; however, conventional flame-based hydrogen combustion poses challenges, including NO_x emissions and the risk of flame flashback. Catalytic combustion provides a safer, low-temperature approach to hydrogen utilization, but realizing it within compact, integrated systems have remained a significant challenge. This study introduces an innovative approach to hydrogen catalytic combustion by directly integrating noble metal single quantum-crystallites of Pt and Ru within a porous silica aerogel matrix embedded in a silicon chip. This configuration enables deep nanoparticle (np) penetration throughout the aerogel network, maximizing the catalytic surface area and providing efficient on-chip hydrogen combustion. The np@aerogel systems are systematically synthesized and incorporated within silicon chips equipped with a polyimide membrane and Pt thermal structures. This unique setup allows for direct, real-time characterization of hydrogen catalytic combustion by measuring resistance changes in an embedded thermistor. The Pt@SiO₂ system demonstrates a rapid and substantial temperature increase of up to 40 K upon hydrogen exposure, independent of both preheating and Pt concentration, underscoring its robustness and adaptability for micro-scale hydrogen combustion. This on-chip integration of np@aerogel catalysts marks a significant advancement for hydrogen-based energy applications, offering a compact, scalable platform for efficient catalytic combustion. This approach opens pathways for applications in thermoelectric generators and other micro-reactor technologies where controlled, localized energy generation is critical.

Powder Technology 465 (2025): 121318

https://doi.org/10.1016/j.powtec.2025.121318

The synthesis of Cu₁.₈S, ZnS, and Cu₁.₈S-ZnS composite nanoparticles is achieved via reactive spray combustion, wherein rapid vaporization of thiophene initiates micro-explosions that promote high-temperature vapor-phase reactions under reducing conditions. High-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) analyses reveal that the synthesized nanoparticles consist of agglomerated spherical primary crystallites, with average sizes of 12.2 nm for Cu₁.₈S, 10 nm for ZnS, and 10.8 nm for the Cu₁.₈S-ZnS composite. Elemental analysis via energy-dispersive X-ray spectroscopy (EDX) coupled with scanning transmission electron microscopy (STEM) confirms homogeneous spatial distribution of Cu and S in Cu₁.₈S, elevated surface oxygen content in ZnS attributed to physisorption, and substantial Cu incorporation into the ZnS lattice within the Cu₁.₈S-ZnS composite system. Structural analysis indicates that the contrast features observed in Cu₁.₈S, ZnS, and Cu-Zn mixed sulfides are consistent with their respective crystallographic symmetries, where sulfur atoms adopt well-ordered lattice positions, while copper exhibits partial site occupancy and electron density disorder attributed to the comparable ionic radii of Cu²⁺ and Zn²⁺ ions. This study underscores the efficacy of oxygen-deficient, reducing flame environments in facilitating the synthesis of binary and mixed-metal sulfide nanomaterials, enabling the formation of metastable phases providing a scalable, cost-effective route for producing advanced functional materials with broad application potential.

Small 21 (2025): 2409993

https://doi.org/10.1002/smll.202409993

The objective of this study is to investigate the influence of various process parameters, such as the fuel-to-oxygen ratio, precursor flow rate, co-flow rate, and different metal-to-sulfur ratios on the properties of metal sulfide particles synthesized via flame spray pyrolysis (FSP). The particle size increases with increasing dispersion oxygen flow and copper sulfide is obtained only when the fuel-to-oxygen ratio is equal to or higher than 1.5. The temperature of the flame rises with an increasing precursor flow rate and copper sulfide is formed at a precursor flow rate of 5 mL min⁻¹ or lower, while contamination occurs above 5 mL min⁻¹. A Co-flow rate above 100 L min⁻¹ is required to cool the aerosol stream before deposition on the filter. A pure copper sulfide phase is produced when sulfur is more than 5 times in molar ratio compared to Cu in the liquid solution and particle size decreases with increasing sulfur concentration. This research will contribute to a better understanding of the fundamental formation process of metal sulfides under oxygen-lean gas-phase conditions and serve as a milestone in optimizing synthesis parameters for various applications.