No abstract

Keto-alcohols, which are traditionally produced from fossil resources with multisteps, are considered as important intermediates for diversified high-value-added fine chemical synthesis due to their involved carbonyl and hydroxyl groups. Herein, direct cellulose hydrogenolysis to C3-C4 keto-alcohol products (hydroxyacetone and 1(3)-hydroxy-2-butanone) was achieved over Ni-WO x /C catalysts with an W/Ni atom ratio of 1.0–5.0. The keto-alcohol yield was proposed to strongly depend on the W/Ni ratio and the catalyst annealing temperature. The highest keto-alcohol yield of 63% was obtained at the optimal balance of basic/acidic WO x species and metallic Ni. The introduction of Ni facilitated the formation of the basic W5+ sites, which enhanced the formation of basic sites at the Ni-WO x interface. The synergistic effect between the basic W5+ and acidic oxygen vacancy (Vö) could activate the target C–O/CO bonds, promoting the isomerization of glucose and C3-C4 aldehyde intermediates with the assistance of the interfacial Ni. The cooperative adsorption of the −OH and −CO groups at the Ni-O-W-Vö interface stabilized the adjacent ketone and hydroxyl groups and kept the other hydroxyl groups for hydrogenolysis, obtaining the final C3-C4 keto-alcohols. This work expanded the application of cellulosic biomass, enabling the green and sustainable synthesis of the high-value C3-C4 keto-alcohol products using lignocellulosic biomass as a raw material.

The broad application of plastic products has resulted in a considerable release of microplastics (MPs) into the ecosystem. While MPs in other environmental matrices (e.g., soil and water) have been studied for a long time, the atmospheric fine particulate matter (PM 2.5 )bound MPs are rarely investigated due to the lack of an appropriate analytical approach. The prevalently used visual and spectroscopic means (e.g., optical microscopy, Fourier-transform infrared spectroscopy, and Raman spectroscopy) suffer from obvious drawbacks that cannot precisely detect MPs of tiny sizes and provide quantitative information. In the present study, a novel strategy that does not require sample pretreatment was developed to first effectuate accurate quantification of polyethylene MP (PE-MP) in PM 2.5 based on pyrolysis-gas chromatography−tandem mass spectrometry (Pyr-GC-MS/MS). It featured acceptable recoveries (97%−110%), high sensitivity (LOD = 1 pg), and qualified precisions (RSD of 3%−13%). Employing this approach, for the first time, exact atmospheric concentrations of PE-MPs in PM 2.5 from megacities in North (Zhengzhou and Taiyuan) and South (Guangzhou) China were obtained, and relatively serious pollution was found in Taiyuan. The 100% sample detection rates also suggested the widespread occurrence and possible human exposure risks of PM 2.5 -bound PE-MPs. In brief, the new strategy could conduct direct, sensitive, and accurate quantification of PE-MP in PM 2.5 , favoring further studies of environmental fates, distributions, and toxicities of atmospheric MPs.

A series of Ni-based catalysts, including Ni/SiO2–ZrO2, Ni/HZSM-5, Ni/Al2O3, Ni/SiO2, Ni/AC and Ni/CMK-3, were prepared to produce H2 from the aqueous phase reforming (APR) of methanol.