Developing
efficient catalysts for the total oxidation of light
alkane at low temperatures is challenging. In this study, superior
catalytic performance in the total oxidation of light alkane was achieved
by modulating the acidity and redox property of a Pt/CeO2 catalyst through phosphorus modification. Surface modification with
phosphorus resulted in electron withdrawal from Pt, leading to platinum
species with high valency and the generation of Brönsted acid
sites, leading to increased acidity of the Pt/CeO2 catalyst.
Consequently, the ability of the Pt/CeO2 catalyst to activate
the C–H bond increased with increasing P content in the catalyst
owing to the synergistic effect of Ptδ+–(CeO2-PO
x
)δ− dipolar catalytic sites. In contrast, the redox property of the
Pt/CeO2 catalyst weakened at first; subsequently, it was
partially restored owing to the recovery of a part of the bare ceria
surface with increasing P content. The turnover frequency in propane
oxidation over the phosphate-modified Pt/CeO2 catalyst
with a P/Ce atomic ratio of 0.06 was 10-fold higher than that over
the unmodified Pt/CeO2 catalyst at 220 °C. This comprehensive
study not only sheds light on the mechanism underlying the surface
modification process but also offers a strategy for realizing higher
catalytic activity in the total oxidation of light alkanes.
An environmentally friendly and superefficient
flame retardant
poly(2-hydroxyethyl methacrylate phosphate) (PHEMAP) was synthesized
through precipitated polymerization of 2-hydroxyethyl methacrylate
phosphate (HEMAP). The cross-linked PHEMAP microscale particles exhibited
superior water resistance and high thermal stability, which could
effectively prevent the release of phosphorus-containing compounds
into the environment. Poly(lactide) (PLA) with only 0.5 wt % PHEMAP
achieved UL-94 V-0 rating, and its limited oxygen index (LOI) value
was 28%. Remarkably, the PLA/PHEMAP films maintained good transparency,
owing to their similar refractive indices and uniform dispersion of
PHEMAP microparticles in the PLA matrix. This study explored a kind
of sustainable, transparent, and superefficient flame-retardant PLA
blend film to expand its potential application in mobile phones, automotive
interiors, and three-dimensional (3D) printing fields.
Four types of TiO2 with different rutile/anatase crystalline phase compositions were used as supports, and the effect of the TiO2 phase composition on the catalytic properties of supported Rh catalysts in the synthesis of C2 oxygenates from syngas was studied.
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