A novel carboxylated lactose/sodium lignosulfonate/polyacrylic acid hydrogel composites with self-reduction capacity was successfully synthesized by self-assembly method. The hydrogel with well-developed porous structure provided abundant anchoring points and reduction capacity for transforming Ag⁺ into silver nanoparticles. Silver nanoparticles dispersed among the network of hydrogel and the composites exhibited catalytic capacity. The catalytic performance was evaluated via degradation of p-nitrophenol, rhodamine B, methyl orange and methylene blue, which were catalyzed with corresponding reaction rate constants of 0.04338, 0.07499, 0.04891, and 0.00628 s^–1, respectively. In addition, the catalyst exhibited stable performance under fixed-bed condition and the corresponding conversion rate still maintained more than 80% after 540 min. Moreover, the catalytic performance still maintained effective in tap water and simulated seawater. The catalytic efficiency still remained 99.7% with no significant decrease after 8 cycles.

The oxygen vacancy formation energy and chemical looping dry reforming of methane over metal-substituted CeO₂ (111) are investigated based on density functional theory calculations. The calculated results indicate that among the various metals that can substitute for the Ce atom in the CeO₂(111) surface, Zn substitution results in the lowest oxygen vacancy formation energy. For the activation of CH₄ on CeO₂ (111) and Zn-substituted CeO₂ (111) surfaces, the calculated results illustrate that the dissociation process of CH_3(ads) is very difficult on pristine surfaces and unfavorable for CHO_(ads) on substituted surfaces. Furthermore, the dissociative adsorption of CO and H₂ on the Zn-substituted CeO₂ (111) surface requires high energy, which is unfavorable for syngas production. This work demonstrates that excessive formation of oxygen vacancy can lead to excessively high adsorption energies, thus limiting the conversion efficiency of the reaction intermediates. This finding provides important guidance and application prospects for the design and optimization of oxygen carrier materials, especially in the field of chemical looping dry methane reforming to syngas.

The Fe-Mn bimetallic catalyst is a potential candidate for the conversion of CO₂ into value-added chemicals. The interaction between the two metals plays a significant role in determining the catalytic performance, however which remains controversial. In this study, we aim to investigate the impact of tuning the proximity of Fe-Mn bimetallic catalysts with similar nanoparticle size. And its effect on the physicochemical properties of the catalysts and corresponding performance were investigated. It was found that closer Fe-Mn proximity resulted in enhanced CO₂ hydrogenation activity and inhibited CH₄ formation. The physiochemical properties of prepared catalysts were characterized using X-ray diffraction, H₂ temperature programmed reduction, and X-ray photoelectron spectroscopy, revealing that a closer Fe-Mn distance promoted electron transfer from Mn to Fe, thereby facilitating Fe carburization. The adsorption behavior of CO₂ and the identification of reaction intermediates were analyzed using CO₂-temperature programed desorption and in situ Fourier transform infrared spectroscopy, confirming the intimate Fe-Mn sites contributed to CO₂ adsorption and the formation of HCOO* species, ultimately leading to increased CO₂ conversion and hydrocarbon production. The discovery of a synergistic effect at the intimate Fe-Mn sites in this study provides valuable insights into the relationship between active sites and promoters.

A class of supramolecular binary hydrogels is formed from dodecylamine or tridecylamine and sparing carboxylic acids (with amine/acid molar ratio ≥ 18). These hydrogels exhibit a remarkable thermally reversible four-phase transition. On heating, they transition from gel one (G¹)-to-sol one (Sol¹), then to gel two (G²)-to-sol two (Sol²). On cooling, they revert from Sol²-to-G²-to-Sol¹-to-G¹. Additionally, several G¹ and G² hydrogels undergo thermally reversible gel-to-gel phase transitions, which are reflected by translucent-opaque and opaque-translucent changes in their appearance. The nature of the four-phase transformation was analyzed using a range of techniques. Scanning electron microscopy images confirmed that the fibers of the opaque hydrogel at high temperatures were considerably larger than those of its translucent counterpart at low temperatures. Fluorescence emission spectra demonstrated that higher temperatures, higher amine/acid ratios, and greater acid hydrophobicity increased the hydrophobic interactions. Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopic analyses confirmed the existence of hydrogen-bonding interactions and aggregation in the hydrogels. X-ray diffraction profiles indicated that the hydrogels adopt lamellar structures. The findings advance our current understanding of the phase transition of supramolecular gels and facilitate the constitution of binary or multicomponent gels, providing a practical way to create new smart functional materials.