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Developing highly stable and active non-Pt oxygen reduction reaction (ORR) electrocatalysts for power generation device raises great concerns and remains a challenge. Here, we report novel truncated Pd tetrahedrons (T-Pd-Ths) enclosed by {111} facets with excellent uniformity, which have both low-coordinated surface sites and distinct lattice distortions that would induce “local strain”. In alkaline electrolyte, the T-Pd-Ths/C achieves remarkable ORR specific/mass activity (SA/MA) of 2.46 mA·cm−2/1.69 A·mgPd−1, which is 12.3/16.9 and 10.7/14.1 times higher than commercial Pd/C and Pt/C, respectively. The T-Pd-Ths/C also exhibits high in-situ carbon monoxide (CO) tolerance and 50,000 cycles durability with an activity loss of 7.69% and morphological stability. The rotating ring-disk electrode (RRDE) measurements show that a 4-electron process occurs on T-Pd-Ths/C. Theoretical calculations demonstrate that the low-coordinated surface sites contribute largely to the enhancement of ORR activity. In actual direct methanol fuel cell (DMFC) device, the T-Pd-Ths/C delivers superior open-circuit voltage (OCV) and peak power density (PPD) to commercial Pt/C from 25 to 80 °C, and the maximum PPD can reach up to 163.7 mW·cm−2. This study demonstrates that the T-Pd-Ths/C holds promise as alternatives to Pt for ORR in DMFC device.
This work was supported by the National Natural Science Foundation of China (No. 21571038), Education Department of Guizhou Province (No. 2021312), Foundation of Guizhou Province (No. 2019-5666), Science Foundation for Aftergraduated Students of Guizhou Province (No. YJSCXJH2020045), State Key Laboratory of Coal Mine Disaster Dynamics and Control (Chongqing University, No. 2011DA105287-ZR202101), State Key Laboratory of Physical Chemistry of Solid Surfaces (Xiamen University, No. 202009), and the Open Fund of the Key Lab of Organic Optoelectronics & Molecular Engineering (Tsinghua University). We gratefully acknowledge Analytical and Testing Center of Chongqing University.