Low-dose Ir-doped TiO2 supported Pt-Co bimetallic nanoparticles: A highly active and CO-tolerant electrocatalyst towards methanol oxidation reaction

Summary Highly stable and cost-effective electrocatalysts are of importance in regulating energy conversion efficiency and commercial feasibility of direct methanol fuel cells (DMFCs). So far, integrating transition metals into Pt-based catalysts to enhance their catalytic performances for methanol electro-oxidation reaction (MOR) at the anode of DMFCs has received significant interest. This study witnessed the first time of depositing Pt 3 Co 1 alloy nanoparticles (NPs) on robust Ti 0.9 Ir 0.1 O 2 supports utilizing a modified reduction method that used NaBH 4 as a reducing agent in the absence of surfactants or stabilizers. This novel combination not only reduces the usage of costly and easily-deactivated Pt but also significantly improves catalytic activity and poisoning tolerance for MOR. Regarding electrocatalytic performance, the onset potential and the mass activity of the Pt 3 Co 1 /Ti 0.9 Ir 0.1 O 2 catalyst are ~0.1 V vs NHE and 316.16 mA/mg Pt , respectively, which are 4.5-fold lower and 1.5-fold higher than the corresponding figures for the commercial Pt/C (E-TEK) catalyst, ~0.45 vs NHE and 206.83 mA/mg Pt , indicating superior catalytic activity and CO-tolerance of the former over the latter. Furthermore, the superior anti-poisoning ability and stability of the Pt 3 Co 1 /Ti 0.9 Ir 0.1 O 2 catalyst are demonstrated by its 2.2-fold higher I f /I b ratio in MOR and lower degradation rate in the 60-min chronoamperometry (CA) and 3000-cycle scanning tests than the Pt/C counterpart. These enhancements could be abscribed to synergistic influence between the Pt-Co alloy NPs and the robust Ti 0.9 Ir 0.1 O 2 support. The addition of Co into the catalyst to promote removal of Pt-poisoning species as well as the use of highly corrosion-resistant Ir-doped TiO 2 as a catalyst support play a decisive role in boosting electrochemical behaviors of the Pt 3 Co 1 / Ti 0.9 Ir 0.1 O 2 catalyst. Generally, the success of this work in synthesizing high-performance Pt 3 Co 1 /Ti 0.9 Ir 0.1 O 2 catalyst could serve as groundwork for further development of TiO 2 -based material supported bimetallic catalysts for applications in the electrochemical catalysis field.