Integration of plasmonic AgPd alloy nanoparticles with single-layer graphitic carbon nitride as Mott-Schottky junction toward photo-promoted H2 evolution

Photo-enhanced dehydrogenation of formic acid on Pd-based hybrid plasmonic nanostructures

Coupling visible light with Pd-based hybrid plasmonic nanostructures has effectively enhanced formic acid (FA) dehydrogenation at room temperature. Unlike conventional heating to achieve higher product yield, the plasmonic effect supplies a unique surface environment through the local electromagnetic field and hot charge carriers, avoiding unfavorable energy consumption and attenuated selectivity. In this minireview, we summarized the latest advances in plasmon-enhanced FA dehydrogenation, including geometry/size-dependent dehydrogenation activities, and further catalytic enhancement by coupling local surface plasmon resonance (LSPR) with Fermi level engineering or alloying effect. Furthermore, some representative cases were taken to interpret the mechanisms of hot charge carriers and the local electromagnetic field on molecular adsorption/activation. Finally, a summary of current limitations and future directions was outlined from the perspectives of mechanism and materials design for the field of plasmon-enhanced FA decomposition.

Novel GdTaO4 phase for efficient photocatalytic degradation of organic dye under visible light irradiation: An X-ray spectroscopic investigation

The novel GdTaO4 phase exhibits good photocatalytic activity under visible light irradiation and holds great promise for the removal of organic dyes from industrial wastes. The GdTaO4 samples were synthesized using the hydrothermal and calcination process with different weight ratios of gadolinium nitrate hydrate (G) and tantalum pentachloride (T), and their structural studies confirmed the formation of the GdTaO4 (GT) phase. Among the samples, GT-4 (with a weight ratio of 4:1) exhibited the highest photocatalytic activity for the degradation of Methyl Orange (MO) dye under visible light irradiation. To enhance the photocatalytic performance, H2O2 was used as a green additive, and the photocatalytic abilities were examined by varying dye types and concentrations. X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) revealed the local atomic and electronic structures around Ta and Gd and highlighted the contribution of Gd3+ to the GT system, which is a crucial factor in supporting the enhanced photocatalytic performance. Moreover, in-situ XAS at Gd M5-edge and O K-edge were examined under illumination/dark conditions to explore the electronic structures of photo-excited electron transition in the photocatalytic process. The analytical results provided strong evidence correlating the electronic structure and photocatalytic property of the GT. This study demonstrates that GdTaO4 exhibits good photocatalytic activity under visible light irradiation, making it a promising new Ta-based photocatalyst for the effective removal of organic dyes from industrial wastes.

Copper-Zinc Bimetallic Single-Atom Catalysts with Localized Surface Plasmon Resonance-Enhanced Photothermal Effect and Catalytic Activity for Melanoma Treatment and Wound-Healing

Nanomaterials with photothermal combined chemodynamic therapy (PTT-CDT) have attracted the attention of researchers owing to their excellent synergistic therapeutic effects on tumors. Thus, the preparation of multifunctional materials with higher photothermal conversion efficiency and catalytic activity can achieve better synergistic therapeutic effects for melanoma. In this study, a Cu-Zn bimetallic single-atom (Cu/PMCS) is constructed with augmented photothermal effect and catalytic activity due to the localized surface plasmon resonance (LSPR) effect. Density functional theory calculations confirmed that the enhanced photothermal effect of Cu/PMCS is due to the appearance of a new d-orbital transition with strong spin-orbit coupling and the induced LSPR. Additionally, Cu/PMCS exhibited increased catalytic activity in the Fenton-like reaction and glutathione depletion capacity, further enhanced by increased temperature and LSPR. Consequently, Cu/PMCS induced better synergistic anti-melanoma effects via PTT-CDT than PMCS in vitro and in vivo. Furthermore, compared with PMCS, Cu/PMCS killed bacteria more quickly and effectively, thus facilitating wound healing owing to the enhanced photothermal effect and slow release of Cu2+ . Cu/PMCS promoted cell migration and angiogenesis and upregulated the expression of related genes to accelerate wound healing. Cu/PMCS has potential applications in treating melanoma and repairing wounds with its antitumor, antibacterial, and wound-healing properties.

Polymeric graphitic carbon nitride layers decorated with erbium oxide and enhanced photocatalytic performance under visible light irradiation

Developing and implementing visible light active organic-inorganic hybrid semiconductor nanomaterials with enhanced photocatalytic properties find newer environmental and energy treatment capabilities. Here, we are reporting polymeric g-C₃N₄ layers coated with different propositions of erbium oxide nanoparticles, characterized using XPS, UV-Vis-DRS, FT-IR, HR-TEM, FE-SEM, elemental mapping, XRD and surface area techniques and its photocatalytic activities were evaluated under visible light irradiations. The hybrid nanocomposite materials possess better crystalline nature and erbium oxide particles were on the surface of polymeric g-C₃N₄. The surface area and bandgap energy of the polymeric g-C₃N₄-erbium oxide (5 wt%) nanohybrid composite were 99.9 m²/g and 2.52 eV. The photocatalytic activities as prepared nanohybrid composites were assessed for the oxidation of orange G dye molecules in the presence of visible light and were highly active in a broader range of pH with the presence of various inorganic anions. The rate of photocatalytic oxidation of dye molecules varied from 4.79 × 10^-4 to 1.77 × 10^-4 min^-1 for the initial concentration of 5 to 20 ppm and retained its activities above 95% up to three cycles of reusability. Hence, the organic-inorganic novel catalytic nanohybrid composite may find more comprehensive applications in the area of environmental and energy applications.

Catalytic hydrolysis of sodium borohydride for hydrogen production using phosphorylated silica particles

Hydrolysis of sodium borohydride (NaBH₄) offers substantial applications in the production of hydrogen but requires an inexpensive catalyst. Herein, silica (SP) and phosphorylated silica (SP-PA) are used as a catalyst for the generation of hydrogen from NaBH₄ hydrolysis. The catalyst is prepared by sol-gel route synthesis by taking tetraethyl orthosilicate as the precursor of silica whereas phosphoric acid served as the gelation and phosphorylating agent. The prepared catalyst is characterized by FT-IR spectroscopy, XRD, SEM, and EDAX. The hydrogen generation rate at SP-PA particles (762.4 mL min^-1 g^-1) is higher than that of silica particles (133 mL min^-1 g^-1 of catalyst). The higher catalytic activity of SP-PA particles might be due to the acidic functionalities that enhance the hydrogen production rate. The kinetic parameters (activation energy and pre-exponential factor) are calculated from the Arrhenius plot and the thermodynamic parameters (enthalpy, entropy, and free energy change) are evaluated using the Erying plot. The calculated activation energy for NaBH₄ hydrolysis at SP-PA catalyst is 29.92 kJ.mol^-1 suggesting the high catalytic activity of SP-PA particles. The obtained entropy of activation (ΔS‡ =  - 97.75 JK^-1) suggested the Langmuir-Hinshelwood type associative mechanism for the hydrolysis of NaBH₄ at SP-PA particles.