(1. 桂林電子科技大學(xué) 材料科學(xué)與工程學(xué)院，桂林 541004；
2. 賀州學(xué)院 材料與化學(xué)工程學(xué)院，賀州 542899；
3. 華南理工大學(xué) 材料科學(xué)與工程學(xué)院，廣州 510640；
4. 中南大學(xué) 粉末冶金研究院，長(zhǎng)沙 410083)
摘 要: BCC結(jié)構(gòu)的V基固溶體有良好的氫滲透性能，在氫分離膜中具有應(yīng)用潛力。采用第一性原理方法研究Pd摻雜V(100)表面的H吸附和滲透機(jī)理，討論氫覆蓋對(duì)氫吸附和擴(kuò)散的影響。計(jì)算結(jié)果表明：Pd優(yōu)先取代V(100)表面的第一層V原子。在V-Pd(100)表面不同位置吸附H原子的穩(wěn)定性由大到小依次為洞位、橋位、頂位，Pd摻雜降低了表面H原子的吸附能力，有利于H原子的解離和締合效率。Pd摻雜的V(100)表面，H原子從表面擴(kuò)散到次表面的擴(kuò)散能壘降低，提高了氫滲透率。隨著H原子覆蓋度的增加，H吸附于V(100)表面的能力減弱，而吸附于V-Pd(100)表面的能力增強(qiáng)。差分電荷密度的計(jì)算結(jié)果表明，Pd—H鍵比V—H鍵弱，故Pd元素的摻雜能夠改善H的滲透性能和解氫能力。
關(guān)鍵字: V基固溶體；Pd摻雜；表面；氫滲透性；第一性原理計(jì)算
（1. School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin 541004, China;
2. College of Materials and Chemical Engineering, Hezhou University, Hezhou 542899, China;
3. School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China;
4. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:The V-based solid solution with BCC structure has good hydrogen permeability and potential application in hydrogen separation membranes. The first-principles method was used to systematically research the hydrogen adsorption and permeation mechanism on the Pd-doped V(100) surface, and the influence of hydrogen coverage on hydrogen adsorption and diffusion was discussed. The calculation results show that Pd preferentially replaces V atom in the first layer on V(100) surface. The stability of adsorbed H atoms at different positions on the surface of V-Pd(100) is as follows: hole position＞bridge position＞top position. Pd doping reduces the adsorption capacity of surface hydrogen atoms, which is conducive to the dissociation and association efficiency of hydrogen atoms. On the Pd-doped V(100) surface, the diffusion energy barrier of hydrogen atoms from the surface to the subsurface is reduced, which improves the hydrogen permeability. With the coverage of hydrogen atoms increasing, the ability of hydrogen to adsorb on the surface of V(100) decreases, while the ability to adsorb on the surface of V-Pd(100) increases. The calculation results of the differential charge density show that the Pd—H bond is weaker than the V—H bond, so Pd doping can improve the hydrogen permeability and hydrogen desorption ability.
Key words: V-based solid solution; Pd doping; surface; hydrogen permeability; first-principles calculation
