No abstract

In this work, a low-cost silicon-based multi-metal oxide sphere (glass bead, GB) and its derivatives were used as novel catalysts to depolymerize poplar lignin. The surface morphology (flaky structure) and specific surface area of GB could be effectively changed by the subcritical water treatment. The treated GBs were further loaded with nonprecious metals (Ni and Mn) to obtain GB derivatives. Based on the results of product analysis, it was found that the introduction of nonprecious metals could effectively prevent the departure of the methoxy group from the aromatic hydrocarbon structure, thus reducing lignin polycondensation (Ni: 8.8 wt % solid residue and 3.5 wt % char, Mn: 5.1 wt % solid residue and 1.7 wt % char) and increasing the yield of monomer products (Ni: 13.4 wt %, Mn: 15.5 wt %). Furthermore, GB derivatives could be recycled to catalyze depolymerization of lignin, and the monomeric product yield remained above 12 wt %.

No abstract

The present endeavor is to develop a highly-intelligent catalytic reactor prototype which is able to autonomously adapt to the environment and provides an in-situ double-shift catalytic ability. By seeking inspiration from nature, this objective is achieved by developing a self-adaptive hydrogel catalytic reactor which held a catalytic trilaminar structure capable of reverse thermosensitive properties. With increasing temperatures, the catalytic tri-layers of this catalytic reactor would function in a sequential way (i.e., one negative temperature response layer, one support layer and one positive temperature response layer) and as a result, led to the single-tandem double-shift catalytic ability. This catalytic reactor individually presented single/tandem catalytic process at relatively low temperatures or high temperatures through the cooperative work of the three layers. In this way, this catalytic reactor showed the single-tandem controllable catalytic ability. The novel protocol not only provides a new solution to complicated catalytic processes but also inspires the further application of smart polymers in a broader spectrum of areas.

Inspired by the polymeric ''soft'' properties and divisional isolation of tandem processes in natural systems, an artificial reactor with self-screened catalytic ability was fabricated with a polymeric tri-layer architecture. The non-responsive middle layer encapsulated catalytic metal nanoparticles, while the two outer layers consisted of a negatively and a positively thermosensitive imprinted polymer. The inverse responsiveness of the outer layers induced switchable shapes, which led to alterable tandem channeling to the reactive middle layer and, as a result, the divisional admission of different substrates. This way, the reactor led to the formation of self-screened catalytic ability. The design for this artificial reactor offers promising prospects for struggling tandem catalysts, suggesting opportunities to develop schedulable tandem processes.