P-Induced Permeation of Nickel into WO3 Octahedra to Form a Synergistic Catalyst for Urea Oxidation.

Small-molecule induction can lead to the oriented migration of metal elements, which affords functional materials with synergistic components. In this study, phosphating nickel foam (NF)-supported octahedral WO3 with phosphine affords P-WO3 /NF electrocatalyst. Ni is found to form Ni-P bonds that migrate from NF to WO3 under the induction of P, resulting in the complex oxides W1.3 Ni0.24 O4 and Ni2 P2 O7 in the particle interior and nickel phosphide on the octahedral grain surface. The catalytic activity of P-WO3 /NF in the urea oxidation reaction (UOR) is improved by synergistic action of the components in the synthesized hybrid particles. A current density of 10 mA cm-2 can be reached at a potential of 1.305 V, the double layer capacitance of the catalyst is significantly increased, and the electron transfer impedance in catalytic UOR is reduced. This work demonstrates that small-molecule induction is suitable for constructing co-catalysts with complex components in a simple protocol, which provides a new route for the design of highly efficient urea oxidation electrocatalysts.

Transition behaviors of γ-ß0/ß in V-, Cr-, Mn-doped TiAl alloys.

The behavior of γ-ß/ß0 phase transition in TiAl alloy doped with ß stabilizers (V, Cr, Mn) are studied by using the first principles method. It is found that alloying addition as well as anharmonic lattice vibration and disordered atomic occupation contributes to enhance the stability of cubic structure and accordingly introduce the disordered ß phase into the high-temperature microstructure. The formation of low-temperature ß0 phase originates from not only the stabilization of cubic structure but also the destabilization of tetragonal structure. In particular, the latter is the main reason for the premature precipitation of the hard-brittle ß0 phase in the room-temperature microstructure at low nominal doping concentrations. We also find a special doping region in which the γ and the ß phases are stable, while the ß0 phase is unstable. The existence of this region provides an opportunity for the regulation of the contents of ß and ß0 phases.