Catalysis Communications最新文献

Methane decomposition for hydrogen production is classified as blue turquoise, an intermediate between green and blue hydrogen. It does not generate greenhouse gas (GHG) emissions and does not require installation of carbon capture, utilization, and storage (CCUS) processes, becoming environmentally competitive among technologies, as the only byproduct is solid carbon. This research contributes to optimize temperature and gas hourly space velocity parameters for methane conversion adopting design of experiment (DoE) concept to collect data and identify significant factors through a 3² factorial design. Highest methane conversion, considering thermodynamic equilibrium limit of reaction, was obtained at 900 K and 6000 mL.h⁻¹.g⁻¹. The catalyst used was characterized by SEM, BET, and XRD.

A novel bimetallic central covalent coupling catalytic system (Porp.Co@Zn-C6) based on Tris(4-Cl)(4-OH)Co and Tris(4-Cl)(4-OH)Zn was established to improve cycloalkanes oxidation. In particular, the partially-oxidized product's selectivity rose from 86.4% to 97.5% and the cyclohexane conversion was boosted from 3.80% to 4.41%. Simultaneously achieved improvements in conversion and selectivity. In this system, Co(II) was employed to activate molecular oxygen, Zn(II) was utilized to strengthen the utilization of cyclohexyl hydroperoxide and to be avoided its thermal decomposition in disorder state. This proposal can be very suitable for other cycloalkanes as well, which will improve the conversion and selectivity concurrently.

Solar-driven CO₂ reduction to CO production is often hampered by the kinetically sluggish water photooxidation and fast recombination of photocarriers. Herein, we report a photoredox system of CO₂ reduction coupled with biomass-based amines oxidation. Double-shelled CdS nanocages (CdS DSNC) are synthesized by a successive etching‑sulfuration strategy, which delivers impressive CO and difurfurylamine yields of 1226.4 and 5526.5 μmol·g⁻¹·h⁻¹, respectively. Mechanism studies uncover that the double-shelled structure endows CdS DSNC with high accessibility of active sites and short transfer distance for photocarriers. Besides, furfurylamine serves as both the electron donor and the capturer of CO₂, thus boosting the photoredox performance.

Catalytic efficiency in hydrogenation reactions can be increased due to the stability achieved with nanomaterials prepared by homogeneously immobilizing multiple metal nanoparticles onto porous solid materials. Herein, porous carbon (PC)-supported bimetallic (AgNi/PC) and trimetallic nanoparticles (AgNi/PC@Mn) were developed and evaluated as catalysts in the NaBH₄-mediated reduction of 4-nitrophenol to 4-aminophenol. AgNi/PC@Mn catalysts were synthesized using a two-step synthesis strategy. The highest and excellent catalytic efficiency under ambient conditions was obtained by the trimetallic catalyst. Both catalysts proved to be easily separated from the reaction medium and usable for up to five consecutive cycles without losing their catalytic activity.

Yolk-shell nanoreactors feature numbers of advantages in promoting catalytic performance. This work demonstrates the fabrication of yolk-shell Fe₃O₄@SiO₂/Al₂O₃-T (T = 500–900 °C) from metal-organic framework. Characterizations indicate the Fe₃O₄ yolk and SiO₂/Al₂O₃ shell of the obtained nanoreactors. Fe₃O₄@SiO₂/Al₂O₃–800 showed excellent performance in furfural acetalization to 2-(dimethoxymethyl)furan, achieving a 97% yield at 60 °C, atmospheric pressure within 5 h. Control experiments reveal the high reactivity of Fe₃O₄ yolks for furfural acetalization, and acidic Al species are favorable for reactivity promotion. Besides, porous SiO₂/Al₂O₃ shells facilitate mass transfer and increase the accessibility of active sites, also contribute to the high performance and stability.

This review highlights Carbon Quantum Dots (CQDs) as promising photocatalysts for breaking down organic pollutants, particularly in advancing CQDs-based systems for degrading organic dyes. CQDs, used alone or combined with semiconductors, enhance performance. In scenarios with narrow bandgaps, CQDs assist in separating charges, whereas in wider bandgaps, they enable visible/NIR activity through up-conversion luminescence. When integrated into Z-scheme heterostructures, CQDs reduce recombination by facilitating electron transfer. Synthesis methods—both top-down and bottom-up—are explored along with crucial physicochemical properties. Furthermore, modifying CQDs through doping and integrating functional groups on their surface adjusts their characteristics, promising more effective CQDs-modified photocatalysts in future research.

The impact of binder selection on catalytic performance of real catalyst extrudates is still limitedly shown in biomass catalysis. Herein, we have prepared two zeolite-based bifunctional extrudates (Ni/LaY-Al₂O₃ and Ni/LaY-SiO₂). Compared with Ni/LaY-Al₂O₃, Ni/LaY-SiO₂ shows a markedly enhanced durability and sustained performance for 936 h in the continuous liquid-phase hydrogenation of γ-valerolactone into methyl pentanoate. Complementary characterization studies reveal that choosing SiO₂ as binder could efficiently mitigate metal agglomeration, coke formation and support dealumination during catalysis. These findings showcase that binder selection is essential for catalyst durability in the development of the industrial-level bifunctional catalysts for biomass valorization.

This study presents a straightforward chemical approach to induce cationic surface defects on SrCoO_3-δ (SCO) perovskites by selectively etching a-site Sr elements on the surface. The modified SCO-30 catalyst from this method exhibits an optimized thickness of cobalt-rich amorphous layer enriched with oxygen vacancies. This modification enhances the trifunctional catalytic activity for oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and hydrogen evolution reaction (HER) in an alkaline electrolyte. Importantly, the perovskite's structure remains unchanged during the surface engineering process. These findings underscore cationic defect engineering as an effective strategy for the rational design of high-performance electrocatalysts, showcasing potential applications in diverse electrochemical processes.

In the present study, siliceous self-pillared pentasil (SPP) zeolite with regular mesopores was synthesized and used as a support for anchoring bimetallic PdAg clusters through a facile impregnation-reduction method. The as-prepared PdAg/SPP catalysts with different Pd/Ag ratios were demonstrated to catalyze formic acid dehydrogenation for hydrogen production. XRD results confirmed the formation of PdAg alloy on the surface of SPP zeolite. The Pd₇Ag₃/SPP catalyst showed high activity at 80 °C with an initial turn-over frequency (TOF) of 1263.6 h⁻¹, proving the strategy using hierarchical SPP zeolite as carrier is advantageous over bulky zeolites for making highly active formic acid dehydrogenation catalysts.

Developing high-performance mercury removal catalysts is essential for addressing atmospheric mercury pollution. Notably, conventional mineral adsorbents are ineffective for high-temperature flue gases (>300 °C). In this study, confinement catalysis was utilized to modify CuMn₂O₄. Under the chlorine-free catalytic condition, the temperature window of T₉₅ was widened by 150 °C (for 50–400 °C) toward high-temperature. Mechanistic studies suggest that nanoconfinement effects significantly improve the catalytic performance. Molecular oxygen adsorption and activation capacity were dramatically enhanced, as demonstrated by NAP-XPS. The plentiful grain boundaries effectively adjust the defect species and electronic structure of the catalysts in favor of Hg⁰ catalysis, whereas the porous structure improves the reactant adsorption properties.