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 electro-chemical 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.

Automated summary

In this study, PtCo nanoparticles were encapsulated in bamboo-like highly ordered TiO2 nanotubes (PtCo/TNTs/Ti) using an electrochemical method. The obtained PtCo/TNTs/Ti electrode showed a large electrochemical active area and mass activity, which was 3.6 times and 7.5 times higher than that of traditional Pt/TNTs/Ti and PtC electrodes, respectively. Lattice strain was identified as an important factor for improving catalytic performance.