Core–shell structured nanomaterials with delicate architectures have attracted considerable attention for realizing multifunctional responses and harnessing multiple interfaces for enhanced functionalities. Here, we report a controllable synthesis of core–shell structured Mn3O4@SiO2NB nanomaterials consisting of Mn3O4 nanorods covered with a shell of SiO2 nanobubbles. A series of Mn3O4@SiO2NB catalysts with tunable secondary structures can be synthesized by simply tuning the feeding ratio and the modification conditions. The as-synthesized Mn3O4@SiO2NB catalysts exhibit excellent catalytic performance in the degradation of methylene blue (MB) because the Fenton-type reaction between Mn3O4 and H2O2 is confined in an MB-rich environment created by the SiO2 nanobubble shell. The confined Fenton-type catalysis maximizes the contact of MB molecules with the reactive oxygen species and significantly promotes the degradation efficiency of MB. Under optimal conditions, Mn3O4@SiO2NB-0.4 can reach a degradation efficiency of 92% at room temperature and neutral pH within 12 min, which outperforms most reported Mn-based catalysts.
To clarify the interactions between holocellulose and lignin, the hydrolysis behaviors of sawdust, holocellulose, lignin, and holocellulose–lignin mixture (HLM) in subcritical water were investigated in the present study, where HLM acted as a model of sawdust without covalent linkages between holocellulose and lignin. Holocellulose in sawdust showed negligible effects on lignin at low reaction temperatures, whereas it might promote the hydrolysis of lignin at higher reaction temperatures. In contrast, the hydrolysis of holocellulose in sawdust was inhibited by lignin due to the high bond dissociation energies of covalent linkages between them. The destruction of covalent linkages mainly occurred at the reaction temperatures of 273–315 °C, due to the high activation energy at this temperature range. However, they could barely be destroyed at the reaction temperatures of 192–273 °C. The lignin inhibited the ring scission and glycosidic bond cleavage of holocellulose, resulting in lower yields of total carbohydrates and furan derivates than those of HLM. In addition, it also suppressed the decomposition of holocellulose hydrolysate to levoglucosenone and aromatic-linked chars. The above results could provide the basis for developing models for predicting product distribution during the hydrolysis of biomass.
NOx storage and reduction with CH4 by a plasma process was proposed for NOx removal at ambient temperature. The efficiency of this new process for NOx removal could achieve 95% at ambient temperature. NOx removal via cyclic operation has also been investigated, maintaining efficieniency above 90%.
In recent time, class-EF power amplifiers are promising for the high power added efficiency (PAE) by turning output matching network (OMN) to control the even and odd harmonics at the drain. High quality factor (Q) of output matching network in the circuit is required. So it is difficult to design a broadband high efficiency power amplifier. A practical method of broadband design by using microstrip radial stub instead of normal open or short stub is proposed in this paper. A compact OMN topological structure is also proposed to reduce the size of circuit. Simulation results show that proposal class-EF GaN HEMT power amplifier has PAE of more than 60% and bandwidth of 850MHz from 1.7GHz to 2.55GHz. The output power is from 41.5dBm to 42.5dBm.
The synergistic effect between Pt0 and nearby partially reduced Bi2O3−x species was found to be efficient (conversion of 94.1 ± 2.7%, selectivity to aldehyde >99%) for benzyl alcohol oxidation at room temperature (26 °C) under base-free aqueous conditions.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)