PtCo catalyst with modulated surface characteristics for the cathode of direct methanol fuel cells

• A PtCo/C catalyst is synthesized by the sulfite complex route.
• Carbothermal reduction and pre-leaching are efficient to modulate catalyst features.
• A primitive cubic ordered phase and suitable alloy degree are reported.
• Surface characteristics indicate an efficient effect of pre-leaching process.
• PtCo/C catalyst presents better performance than benchmark Pt at DMFC cathode.

A PtCo catalyst with an ordered cubic primitive structure was synthesized and investigated for the application as a cathode in direct methanol fuel cells. The synthesis involved the preparation of an amorphous PtOx/C precursor by the sulfite complex route, an impregnation with Co(NO3)2, a high temperature (800 °C) carbothermal reduction and, finally, a leaching procedure. This method led to the occurrence of a Pt3Co/C catalyst with a primitive cubic ordered (L12) phase and a mean crystallite size of 3.3 nm, as well as a suitable degree of alloying. This electrocatalyst was investigated for the oxygen reduction reaction in a direct methanol fuel cell (DMFC) operating in the range 30–90 °C. At 60 °C, under atmospheric pressure, a maximum power density of 40 mW cm−2 was obtained with the new PtCo catalyst formulation at low noble metal loading on the electrode (1 mg cm−2). This performance was 2.3 times higher than a benchmark Pt catalyst used for comparison.