Lattice distortion of PtCo nanoparticles encapsulated in TiO2 nanotubes boosts methanol oxidation

Exploring highly efficient, CO-tolerant and stability catalyst, such as Pt-based bimetallic catalyst for methanol oxidation reaction (MOR) is pressingly demanded towards commercialization of direct methanol fuel cells (DMFCs). Herein, the PtCo nanoparticles are encapsulated in bamboo-like highly ordered TiO2 nanotubes (PtCo/TNTs/Ti) by a facile electrochemical method. The obtained PtCo/TNTs/Ti electrode exhibits a large electrochemical active area of 1220.4 cm2/mgpt. Its mass activity reaches to 1148 mA/mgPt, which is 3.6 times and 7.5 times than that of Pt/TNTs/Ti and PtC, respectively. The lattice spacing of (111) and (200) faces are respectively reduced by 3.5% and 7.1%, caused by Co incorporated into Pt lattice. The lattice strain is an important reason for improving catalytic performance. In addition, an insight into growth mechanism is proposed according to the first-principle calculations. Co atoms that alloyed with Pt on the surface provide active sites for the following reduction of Pt, promoting the deposition efficiency. The obtained PtCo/TNTs/Ti is expected as the candidate electrode to output high power density in DMFCs. [Display omitted] •Preparation of PtCo nanoparticles encapsulated in TiO2 nanotubes.•The lattice compressive strain caused by PtCo bimetallic catalysts boosting MOR.•An insight into growth mechanism is proposed by the first-principle calculations.