Lactide, a key raw material for polylactic acid, is prone to hydrolysis during synthesis from lactic acid using zeolite beta, reducing yield. To address this issue, zeolite beta with hydrophobic pores was synthesized by template-free method with in situ silicon source modification by tetraethoxyfluorosilane (TEFS). The effect of TEFS addition on the morphology, acidity, and wettability of the synthesized zeolite beta was investigated. The modification with F groups increases the total acid amount and the strength of strong acid sites, especially the Brønsted acid sites; simultaneously, the hydrophobicity of pores was also improved. F group–modified zeolite beta achieved a lactide yield of 84%, significantly higher than the 70% yield of unmodified zeolite beta. This enhancement could be attributed to the increase in Brønsted acid sites and the improvement of the hydrophobic pore microenvironment. This could improve the catalytic reaction activity; additionally, the rapid removal of water from near acid sites could promote the forward movement of the reaction equilibrium and inhibit the hydrolysis of lactide. This work provides a new approach to improve the hydrophobicity of the pores of zeolites as solid acid catalysts, which is beneficial to the efficient production of lactide.
CsPbBr3 nanocrystals (NCs) with highly efficient narrow-band green emission are promising candidates in display applications. However, the poor stability of CsPbBr3 NCs is always a challenge for future development. Herein, we designed and prepared CsPbBr3 NCs encapsulated into zeolite Beta (denoted as CsPbBr3-Beta) composite via an optimized high temperature solid-state method, and the as-obtained power materials exhibited green emission peaking at 520 nm with a narrow full-width at half-maximum (FWHM) of 25 nm and a high photoluminescence quantum yield (∼61%). We further demonstrated the ultra-high luminescent stability of CsPbBr3-Beta composite by treating under a 150 °C treatment, soaking in water over 30 days, as well as applying in 450 nm light-emitting devices (LED) for 20 days. Ultimately, white-light-emitting devices (WLEDs) constructed by the green-emitting CsPbBr3-Beta composite and commercial blue chip and red K2SiF6:Mn4+ phosphor achieved a color gamut of 123.5% National Television System Committee standard (NTSC) and high luminous efficiency (LE = 95 lm W−1). This work highlights the encapsulation process and feasible solid-state reaction methodology to fabricate CsPbBr3 NCs confined in a microporous molecular sieve with high luminescent stability and performance, significantly expanding its great potential to be used in optoelectronic fields.
危险品化学品经营许可证（带存储）