High-efficiency Ce-modified ZSM-5 nanosheets for waste plastic upgrading

Zeolite-based catalyst hydrocracking of plastics is a potential strategy for mitigating the environmental impacts of plastic wastes and recycling valuable resources,but difficult mass transfer,low concentration of acid sites,and high cost are still barriers to their practical applications.In this paper,we report an excellent hydrocracking catalyst of ZSM-5 nanosheets(Ce/b-ZSM-5)modified by Ce species with high conversion up to 96.3%,C_(3)−C_(5)selectivity up to 80.9%,and good stability during the hydrogenation of low-density polyethylene.Through comprehensive studies,b-ZSM-5 shows higher molecular diffusion efficiency and acid site concentrations compared with normal ZSM-5(n-ZSM-5)and hollow ZSM-5(h-ZSM-5).The introduction of Ce species into b-ZSM-5 further increases the density of Brønsted(B)and Lewis(L)acid sites as active sites,which enhances the adsorption of substrates and facilitates the formation of intermediates and desorption of products.As a result,the hydrocracking activity of Ce/b-ZSM-5 is significantly improved.

Expanding the Coverage of Metabolic Landscape in Cultivated Rice with Integrated Computational Approaches

Genome-scale metabolomics analysis is increasingly used for pathway and function discovery in the post-genomics era.The great potential offered by developed mass spectrometry(MS)-based technologies has been hindered,since only a small portion of detected metabolites were identifiable so far.To address the critical issue of low identification coverage in metabolomics,we adopted a deep metabolomics analysis strategy by integrating advanced algorithms and expanded reference databases.The experimental reference spectra and in silico reference spectra were adopted to facilitate the structural annotation.To further characterize the structure of metabolites,two approaches were incorporated into our strategy,i.e.,structural motif search combined with neutral loss scanning and metabolite association network.Untargeted metabolomics analysis was performed on 150 rice cultivars using ultra-performance liquid chromatography coupled with quadrupoleOrbitrap MS.Consequently,a total of 1939 out of 4491 metabolite features in the MS/MS spectral tag(MS2T)library were annotated,representing an extension of annotation coverage by an order of magnitude in rice.The differential accumulation patterns of flavonoids between indica and japonica cultivars were revealed,especially O-sulfated flavonoids.A series of closely-related flavonolignans were characterized,adding further evidence for the crucial role of tricin-oligolignols in lignification.Our study provides an important protocol for exploring phytochemical diversity in other plant species.