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Ammonia borane (AB) is considered to be a promising solid hydrogen carrier. In this work, poly(N-vinyl-2-pyrrolidone) (PVP)-protected platinum nanoparticles are supported on γ-methacryloxypropyltrimethoxysilane (γ-MPS) modified silica spheres (Pt-PVP/SiO 2 (M)), which are firstly used as highly efficient catalysts for hydrolysis of AB. Platinum nanoparticles possess a tiny size of 2–3 nm and are uniformly dispersed over modified silica spheres. Pt-PVP/SiO 2 (M) catalysts with a Pt loading amount of 1.30 wt% show the highest catalytic activity with a turnover frequency (TOF) value of 371 mol H2 mol Pt −1 min−1 (866 mol H2 mol Pt −1 min−1 corrected for the surface atoms) at 25 °C. The activation energy is calculated to be 46.2 kJ/mol. Furthermore, owing to the synergistic effect between the modifier of silica spheres and the capping agent of metal nanoparticles, Pt-PVP/SiO 2 (M) catalysts have a higher loading amount (8.7 and 6.5 times) and TOF value (4.8 and 5.5 times) than the counterparts prepared without γ-MPS and PVP, respectively. [Display omitted] • PVP-protected Pt nanoparticles were uniformly dispersed on modified SiO 2 spheres. • This catalyst showed superior catalytic activity for hydrolysis of ammonia borane. • The highest TOF value of 371 mol H 2 mol Pt−1 min−1 at 25 °C was achieved. • The synergistic effect between the PVP and the modifier of silica was studied. [ABSTRACT FROM AUTHOR]

[Display omitted] • Thermosensitive pseudohomogeneous catalysts (Pt, Pd, and Au) are synthesized. • Thermoresponsive PNIPAM polymer serves as the capping agent. • These catalysts show superior catalytic activity for reduction of nitroarenes. • PNIPAM-Pd can realize the homogenous reaction and heterogeneous separation. The reduction of nitroarenes is usually catalyzed by heterogeneous catalysts. In this work, highly stable aqueous dispersions of monodisperse Pt, Pd, and Au nanoparticles stabilized by thermosensitive polymer, poly(N-isopropylacrylamide) (PNIPAM), are conveniently synthesized with the average sizes of 2.3, 3.1, and 2.3 nm, respectively. The modulation of the hydrophilic-hydrophobic nano-environments of the catalysts can be selectively provided by utilizing the temperature-responsive characteristics of PNIPAM. They are effective and thermosensitive pseudohomogeneous catalysts for nitroarenes reduction. The decreasing trend of catalytic activity is as follows: PNIPAM-Au > PNIPAM-Pd > PNIPAM-Pt. The catalytic reduction of nitrobenzene (NB), 4-nitrophenol (4-NP), and o-nitroaniline (o-NA) follow the pseudo-first-order kinetics, and the catalytic rates can be tuned by utilizing their temperature-responsive behavior. PNIPAM-Au nanocatalysts exhibit high turnover frequencies (TOF) up to 84, 12.9, and 40 min−1 for catalytic reduction of NB, 4-NP, and o-NA at 20 °C, respectively, which are one of the highest values ever reported. [ABSTRACT FROM AUTHOR]

• The highly stable dispersions of ultrasmall ZnO nanocrystals were prepared. • They were used as pseudohomogeneous catalyst for chemical depolymerization of PET. • ZnO nanodispersions displayed an excellent catalytic activity at 170 °C. • The methanolysis had shorter reaction time and higher activity than the glycolysis. Chemical depolymerization and recycling of polyethylene terephthalate (PET) is a sustainable way to preserve the resources and protect the environment. In this work, methanol and ethylene glycol dispersions of ultrasmall ZnO nanoparticles are firstly adopted as pseudohomogeneous catalysts for alcoholysis of PET. The as-prepared ZnO nanoparticles have a uniform size of 4 nm and can be stable in dispersions for 6 months. In the methanolysis process of PET, the effects of various parameters on the conversion of PET and the yield of dimethyl terephthalate (DMT) were investigated. The results show that higher temperature (170 °C) was beneficial to the conversion of PET and the yield of DMT, which can reach about 97% and 95% after 15 min, respectively. The excellent activity of 553 g PET h−1 (g ZnO)−1 was achieved. Furthermore, the methanolysis of PET have shorter reaction time (1/4) and higher activity (4.7 times) than the glycolysis of PET. [ABSTRACT FROM AUTHOR]

The acellular dermal matrix (ADM) and turbinate flap (TF) have been widely used in the reconstruction of skull base defects. However, owing to the lack of reported data, the therapeutic effects have been controversial. The purpose of the present study was to compare the effect of the ADM and TF on cerebrospinal fluid (CSF) rhinorrhea after nasal endoscopic resection of a skull base tumor. The data from 46 patients who had undergone nasal endoscopic resection of a skull base tumor and repair of CSF rhinorrhea were retrospectively analyzed. The patients were divided into ADM and TF groups according to the difference in repair materials used. We compared and analyzed the intraoperative information and postoperative outcomes. The operation time, blood loss, defect area, and need for blood transfusion were not significantly different between the ALT and TF groups. The postoperative length of hospital stay (14.33 ± 3.66 vs. 16.76 ± 5.51 days; P = 0.669) and the incidence of complications, including wound infection (1 vs. 0; P = 0.270), intracranial infection (1 vs. 1; P = 0.900), hemorrhage (2 vs. 3; P = 0.788), 15-day CSF leak (1 vs. 2; P = 0.658), and respiratory infection (2 vs. 1; P = 0.450) were comparable between the 2 groups. The 6-month (0 vs. 0; P = 1.000) and 12-month (0 vs. 0; P = 1.000) incidence of recurrence also showed no significant differences. The use of the ADM for patients with CSF rhinorrhea showed comparable results in terms of postoperative outcomes compared with the use of TF. ADM could serve as a safe and feasible alternative for endoscopic repair of CSF rhinorrhea after nasal endoscopic resection of skull base tumors. [ABSTRACT FROM AUTHOR]