Developing highly active and durable non-platinum catalysts for methanol oxidation is of great significance for direct methanol fuel cells. However, their electrocatalytic efficiency is still insufficient mainly due to their poor electrical conductivity and slow reaction kinetics. Herein, a non-Pt electrocatalyst AgNi 0.8 Co 0.2 O 2 with a delafossite structure is facilely constructed via a cation-exchange strategy for the methanol oxidation reaction in alkaline media. The introduction of Co atoms is favorable to crystallization for boosting the synthesis procedure. Meanwhile, the uniform distribution of Co and Ni in the structure brings about additional oxygen vacancies in the materials, thereby improving the intrinsic methanol oxidation reaction activity of the catalysts, and the introduced Co atoms can help to oxidize intermediates such as formaldehyde. Therefore, the electrocatalyst exhibits excellent electrocatalytic performance (77.6 mA cm −2 , 220 mA mg −1 ) and high selectivity, and it can effectively inhibit the oxygen evolution reaction (310 mV difference from the oxygen evolution reaction potential at 10 mA cm −2 ). This work not only provides a material system using cheap and effective non-Pt catalysts based on Ag-based delafossite oxides but also sheds light on the engineering of oxygen vacancies of electrocatalysts for developing highperformance direct methanol fuel cells.

Delafossite type oxide CuAlO2 as a highly efficient methanol oxidation reaction catalyst support has been investigated in this work. Utilizing the sustained release of copper from CuAlO2 layered structure, we developed a composite catalyst that was in situ formed PtCu alloy upon oxide via solvothermal method. Owing to the metal-support interaction between PtCu alloy and CuAlO2, abundant oxygen defects and adsorbed hydroxyl groups were generated on the surface of composite catalyst, which were verified by structural characterizations and surface analysis. Density functional theory simulation further revealed that the in situ formation of PtCu alloy accompanied with superficial defects dramatically changed the geometry and electronic structures of the composite catalyst, resulting in a higher mass activity (990 mA/mgPt), specific activity (3.30 mA cm−2 ECSA), and a superior reaction kinetics of MOR performance. This work proves delafossite type oxide CuAlO2 as a potential support to facilitate the anti-CO poisoning ability of Pt-based catalysts.

Nowadays, the high cost and poor durability of commercial catalyst Pt/C for methanol oxidation reaction have impeded the further development of direct methanol fuel cells. Herein, we firstly introduced a delafossite CuCoO2 to act as the support of noble metal Pt. The strong metal support interaction between Pt and CuCoO2, abundant hydroxide species and active sites on the surface of catalyst may be the key factors for enhanced performances of methanol oxidation. Pt‐CuCoO2/C achieved a mass activity of 1.16 A mgPt−1, which obtained 3.02 times enhancement compared with commercial Pt/C (0.38 A mgPt−1). The If/Ib value of Pt‐CuCoO2/C is 1.96, much higher than that of Pt/C (0.76), demonstrating favorable anti‐poisoning ability. After 200 times cycling, Pt‐CuCoO2/C still maintained 77.1 % of its initial activity, exhibiting superior COads intermediate tolerance and stability. Low cost, better performances and stability of Pt‐CuCoO2/C reveal that it can be seen as a hopeful catalyst.