N-doped nestlike carbon nanosheets (NCNs-N x ) were prepared successfully by a two-step strategy, namely, the in situ self-assembly hydrothermal synthesis using glucose as the carbon source in the presence of magnesium nitrate and sodium carbonate and the controlled nitrogen doping carbonization using urea as the nitrogen source. The performance of the corresponding Pd/NCNs-N x catalysts was investigated for the selective hydrogenation of quinolines. The characterization of transmission electron microscopy, nitrogen sorption isotherm measurement, powder X-ray diffraction, X-ray photoelectron spectra, temperature-programmed desorption of pyridine and benzene, and the pyridine adsorption experiments showed that the very high catalytic activities and selectivity of the Pd/NCNs-N x catalysts were related with the high Pd dispersion and the electronic structure of Pd species as well as the adsorption capacity and the adsorption type of quinoline molecule on the catalyst surface.

As we all know, star graphs are very useful in physics, chemistry, biology and other fields, but few people have studied the existence of solutions to differential system on star graphs.In this paper, we investigate the existence of solutions to a fractional differential system on star graphs with p-Laplacian operator. Ulam's stability and existence of the solutions to the fractional differential system on star graphs are proved. In addition, two examples under different background graphs (star graphs and formaldehyde graphs) and the approximation graphics for the solutions are provided to illustrate the application of our main results. The interesting point of this article is that it not only studies the existence of solutions to fractional differential system on the star graphs, but also gives approximate graphs of solutions by using the iterative methods and numerical simulation.

The influence of the surface chemical properties of the carbon support on the Pd dispersion, activity and stability of Pd(OH)2/C catalyst for the hydrogenolytic debenzylation of tetraacetyldibenzylhexaazaisowurtzitane (TADB) was studied in detail. The flowerlike nanosheet carbon material (NSC) was chosen as the pristine support, meanwhile chemical oxidation with nitric acid and physical calcination at 600 °C treatments were used to modify its surface properties, which were denoted as NSCox-2 (treated with 20 wt% HNO3) and NSC-600, respectively. The three carbon supports and the corresponding catalysts of Pd/NSC, Pd/NSC-600, and Pd/NSCox-2 were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), nitrogen sorption isotherm measurement (BET), powder X-ray diffraction (XRD), Raman spectra, X-ray photoelectron spectra (XPS), temperature-programmed desorption (TPD), temperature-programmed reduction (H2-TPR), thermogravimetric analysis (TG), and element analysis. The debenzylation activities of Pd/NSC, Pd/NSC-600, and Pd/NSCox-2, as well as the three catalysts after pre-reduction treatment were also evaluated. It was found that the activity and stability of the Pd(OH)2/C catalysts in the debenzylation reaction highly depended on the content of surface oxygen-containing groups of the carbon support.

Chemical graph theory is an interdisciplinary mathematics and chemistry discipline that obtains mathematical information about the structure of target compounds and is an important research branch in theoretical pharmacology and nanomedicine. This paper study a coupled Hadamard type sequential fractional differential system on glucose graphs and establishes the Ulam’s stability and existence of the system solutions. Furthermore, we examine examples against different background graphs and provide approximate graphs of the solutions. The novelty of this paper is that the origin of each edge is not fixed in modeling the glucose graphs, and one of the two vertices of the corresponding edge can be arbitrarily chosen as the origin to build the system and give the approximate graphs of the solutions using iterative methods and numerical simulation.