In recent years, the utilization, conversion, and emission reduction of carbon dioxide have attracted extensive research interest. Lignin, which is rich in carbon, can be processed into carbon quantum dots (CQDs) to enhance the photocatalytic CO2 reduction performance, showing broad application prospects. In this study, alkaline lignin was used as the carbon source to prepare a Cu-BiVO4-CQDs composite, achieving efficient CO2 conversion. Characterization results from XRD, Raman spectroscopy, SEM, XPS, and TEM confirmed the successful preparation of the Cu-BiVO4-CQDs composite. Photocatalytic tests revealed that the introduction of CQDs reduced the impedance of the Cu-BiVO4-CQDs composite, enhanced the separation efficiency of photogenerated electrons and holes, and broadened the light absorption range. Photocatalytic CO2 reduction tests showed that with an optimal amount of CQDs, the Cu-BiVO4-CQDs-50 composite achieved the highest CH4 yield of 27.5 μmol·g−1, which was 3.15 times that of the Cu-BiVO4 composite. The maximum photocatalytic CO2 reduction rate reached 9.166 μmol·g−1·h−1. The preparation of carbon quantum dots using lignin not only enables the high value-added transformation of lignin, converting it from a low-value by-product to a carbon quantum dot with practical application value, but also contributes to environmental protection and sustainable development.
This study introduces a simple and step-by-step strategy for the fabrication of magnetic nanocatalysts [Fe3O4@SiO2@THAM-Schiff base-Ni(II)]. This synthetic approach is based on coating the superparamagnetic magnetite core with a silica protective layer and subsequently surface modification with a Schiff base ligand derived from tris(hydroxymethyl)aminomethane (THAM) and salicylaldehyde. The presence of coordinated Ni(II) centers within the THAM-derived Schiff base framework provided highly efficient active sites for organic transformations. The physicochemical properties of the catalyst were evaluated using various spectroscopic and microscopic techniques, such as FT-IR, XRD, SEM, TGA, DSC, EDX mapping, EDX, and AAS. The catalytic performance in the synthesis of 5-substituted 1H-tetrazoles was evaluated, yielding isolated products in 91–98
Toluene, as a typical and difficult-to-degrade volatile organic pollutant (VOCs), posed serious threats to the environment and human health. The catalytic performance of metals loaded onto molecular sieve carriers largely depended on the role of lattice oxygen. Exploring how metal species regulated lattice oxygen and the correlation between metal-induced electronic structure regulation and oxygen cycling was of crucial important. In this study, Cu, Co, Mn, and Ce were loaded onto the HY molecular sieve carrier to prepare catalysts. The 15
This work explores the use of a palladium(II) complex derived from an unsymmetrical salophen-type Schiff base, specifically 4-[(E)-(2-[(E)− 2-hydroxybenzylidene)amino]phenylimino)methyl]benzene−1,3-diol, supported on γ-Fe2O3 magnetic nanoparticles (designated as γ-Fe2O3@Pd(salophen-OH)) as a heterogeneous nanocatalyst for alcohol oxidation. This nanocatalyst was tested for oxidizing both primary and secondary alcohols, employing 30
Herein, a new magnetically recoverable Cu(II)–Schiff base heterogeneous catalytic system based on an epichlorohydrin-modified Fe₃O₄@SiO₂ core–shell support was fabricated through immobilization of a Schiff base ligand derived from 2,6-diaminopyridine and subsequent coordination with Cu(II) species. The synthesized nanocatalyst was characterized using standard physicochemical techniques, confirming the successful formation of the functionalized magnetic structure. The catalytic activity was evaluated in two model reactions, one-pot synthesis of polyhydroquinoline and pyrano[2,3-c]pyrazole derivatives, under benign conditions. Under the optimized conditions, polyhydroquinoline products were obtained in 70–95
