Phosphotungstic acid modification boosting the cathode methanol tolerance for high-temperature direct methanol fuel cells

High-temperature direct methanol fuel cells (HT-DMFCs) show extensive application prospects in the future. However, the sluggish kinetics of oxygen reduction reaction (ORR) and unsatisfied methanol tolerance at cathode severely restrict its application. Herein, phosphotungstic acid H3PW12O40 (HPW) is exploited to promote the methanol tolerance ability of cathode catalyst with enhanced ORR activity, thus boosting HT-DMFCs performance. Attenuated adsorption energy of methanol on Pt surfaces achieved by HPW modification restrains the occurrence of competitive methanol oxidation side reaction. Reinforced anti-poisoning capability of Pt with optimal d-band center modulated by HPW facilitates the removal of methanol oxidation intermediates, guaranteeing more available active sites for ORR and thus resulting in excellent cathode activity. Accordingly, the as-fabricated platinum-based catalyst achieves a high peak power density of 149 mW cm(-2) in HT-DMFCs, surpassing the performance of majority reported literature. This work provides guidance to develop satisfactory methanol resistant ORR electrocatalyst for HT-DMFCs.

Automated summary

High-temperature direct methanol fuel cells (HT-DMFCs) have great potential for future applications, but the slow kinetics of the oxygen reduction reaction (ORR) and poor methanol tolerance at the cathode limit their performance. This study demonstrates that phosphotungstic acid (HPW) can enhance the methanol tolerance and ORR activity of the cathode catalyst, leading to improved performance of HT-DMFCs.