Nankai University

About: Nankai University is a education organization based out in Tianjin, China. It is known for research contribution in the topics: Catalysis & Adsorption. The organization has 42964 authors who have published 51866 publications receiving 1127896 citations. The organization is also known as: Nánkāi Dàxué.

Nb2O5/TiO2 heterojunctions: Synthesis strategy and photocatalytic activity

Abstract: In the present study, in situ hydrolysis-loading of ultra-fine niobium oxide nanoparticles on the surface of rutile TiO 2 is developed as a new strategy to synthesize Nb 2 O 5 /TiO 2 heterojunctions. The physico-chemical properties of Nb 2 O 5 /TiO 2 heterojunctions are fully characterized by X-ray diffraction, Raman, UV–vis, X-ray photoelectron spectroscopy and transmission electron microscopy. The separation efficiency of photo-generated electron–hole pairs on Nb 2 O 5 /TiO 2 heterojunctions under irradiation is investigated by photoluminescence and electron spin resonance spectroscopy. The activity of Nb 2 O 5 /TiO 2 heterojunctions is examined in the selective photocatalytic oxidation of α-phenylethanol and the photocatalytic reforming of methanol. In both reactions, Nb 2 O 5 /TiO 2 heterojunctions exhibit distinct higher photocatalytic activity than pure rutile TiO 2 or Nb 2 O 5 . The photocatalytic activity of Nb 2 O 5 /TiO 2 heterojunctions is relevant with Nb/Ti ratio and the optimal activity is obtained at Nb/Ti = 0.12 with the highest separation efficiency of photo-generated electron–hole pairs. Integrating the physico-chemical and photocatalytic properties, the factors controlling the photocatalytic activity of Nb 2 O 5 /TiO 2 heterojunctions are discussed in detail.

BrowseRank: letting web users vote for page importance

Abstract: This paper proposes a new method for computing page importance, referred to as BrowseRank. The conventional approach to compute page importance is to exploit the link graph of the web and to build a model based on that graph. For instance, PageRank is such an algorithm, which employs a discrete-time Markov process as the model. Unfortunately, the link graph might be incomplete and inaccurate with respect to data for determining page importance, because links can be easily added and deleted by web content creators. In this paper, we propose computing page importance by using a 'user browsing graph' created from user behavior data. In this graph, vertices represent pages and directed edges represent transitions between pages in the users' web browsing history. Furthermore, the lengths of staying time spent on the pages by users are also included. The user browsing graph is more reliable than the link graph for inferring page importance. This paper further proposes using the continuous-time Markov process on the user browsing graph as a model and computing the stationary probability distribution of the process as page importance. An efficient algorithm for this computation has also been devised. In this way, we can leverage hundreds of millions of users' implicit voting on page importance. Experimental results show that BrowseRank indeed outperforms the baseline methods such as PageRank and TrustRank in several tasks.

High and anisotropic carrier mobility in experimentally possible Ti2CO2 (MXene) monolayers and nanoribbons

Abstract: MXene, a new kind of two-dimensional (2D) material, has a unique combination of excellent physical and chemical properties. Via computations on density functional theory and deformation potential theory, we investigated the electronic structure and predicted the carrier mobility of Ti2CO2 (a typical MXene) monolayers and nanoribbons. The Ti2CO2 monolayer is a semiconductor with a band gap of 0.91 eV, and the hole mobility in the monolayer reaches 104 orders of magnitude along both x and y directions, which is much higher than that of MoS2, while the electron mobility is about two orders of magnitude lower. The dramatic difference between the hole and electron mobilities also exists in nanoribbons. Moreover, our results suggest that width controlling and edge engineering would be effective in adjusting the carrier mobility of Ti2CO2 nanoribbons, and endow experimentally available Ti2CO2 with wide applications to field-effect transistors and photocatalysts.

Vapor-transportation preparation and reversible lithium intercalation/deintercalation of alpha-MoO3 microrods.

Abstract: We report on the preparation and electrochemical application of rechargeable lithium-ion batteries of alpha-MoO3 microrods. A simple and efficient vapor-transportation approach was developed to yield large-scale alpha-MoO3 microrods. The as-prepared products were present in long, uniform, rodlike structures with a diameter of approximately 2 approximately 6 microm, and the proportion of the rod morphology was about 95% according to the analysis of scanning electron microscopy (SEM). The electrochemical lithium intercalation/deintercalation characteristic of the as-prepared microrods was investigated by cyclic voltammetry and a galvanostatic charge-discharge method. The results showed that the alpha-MoO3 microrods exhibited high capacity (225 mAh g(-1)) and excellent cycling reversibility, and are thus promising cathode candidates in advanced rechargeable lithium-ion batteries. The correlation between the specific structural features of the microrods and their superior electrode performance is discussed in detail, revealing that the unique rodlike structure plays an important role in optimizing the electrochemical performance of the electrode.