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An appropriate electrode material is crucial for two-dimensional (2D) semiconductors, where a vanishing Schottky barrier is ideal but is a great challenge. Blue phosphorene (BlueP) is a promising 2D semiconductor for electronic and optoelectronic applications. Here, we report that Zr-, Hf-, and Nb-based 2D transition metal carbides (MXenes) are ideal electrode materials for BlueP based on extensive investigations of the electronic properties and interfacial Schottky barrier characteristics of BlueP/MXene heterojunctions by first-principles calculations. Our results show that the strong interaction between BlueP and bare MXenes destroys the semiconducting character of BlueP, and thus bare MXenes are not ideal contact electrodes. With the surface functionalization of MXene, the intrinsic electronic feature of BlueP is well preserved in the BlueP/surface-engineered MXene heterojunctions. Furthermore, the interfacial Schottky barriers of the heterojunctions are affected by the terminal surface groups on MXene...

The effects of the temperature, volatile content, and ash content on the volatilization kinetics of arsenic were discussed. Six Chinese coals were tested in an isothermal thermogravimetric reactor at 600–1300 °C. Sequential chemical extraction analysis was employed to know the speciation transformation of arsenic during coal combustion. Results show that the volatilization ratio of arsenic increases with the temperature, and most arsenic volatilizes between 700 and 1000 °C. The volatile content has a positive effect on the volatilization rate of arsenic in the initial stage of combustion. With the same level of ash content, high-volatile coals (>30%) own a larger volatilization rate of arsenic (0.55–0.6% s–1) than the low-volatile coals (