A high-efficiency microwave approach to synthesis of Bi-modified Pt nanoparticle catalysts for ethanol electro-oxidation in alkaline medium

The Bi-modified Pt nanoparticle catalysts using multi-walled carbon nanotubes as supports are prepared through microwave treatment and long-term standing approaches. Bi can easily modify Pt catalyst because of the strong affinity between Bi and Pt. However, only limited amount of Bi and uneven Bi-modified Pt catalyst are obtained through the long-term standing approach. The microwave approach can complete the synthesis rapidly and get uniform Bi–Pt/CNT catalysts. X-ray photoelectron spectroscopy shows that Bi (III) and Pt (0) species are the main form in the Bi–Pt/CNT catalyst. Cyclic voltammetry indicates that the modification of Bi on Pt/CNTs leads to an enhanced activity up to 260% compared to Pt/CNTs for ethanol electro-oxidation. The current of Bi–Pt/CNTs (0.1:1) is 44.8 times higher than that of Pt/CNTs at −0.3 V for 1800 s. Linear current sweep results reveal that the electro-oxidation of residual intermediate species can be effectively promoted because the adsorption of OHad species is enhanced by the addition of Bi to Pt/CNTs, which is characterized by the higher open circuit potential.

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► The microwave way can accelerate the Bi3+ diffusion in the solution.
► Abundant OHad species were formed on the Bi-containing catalyst.
► Current of EOR on Bi–Pt/CNTs (0.1:1) was 2.6 times higher than that on Pt/CNTs.
► Anti-poisoning ability of this novel catalyst was greatly improved.
► The Bi deposition mechanism on Pt/CNT catalysts was studied in its synthesis.