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Seeking efficient, stable, and inexpensive electrocatalysts applied to water splitting and fuel cells in acidic media is still challenging for the development of renewable energy. Herein, we propose a single atom catalyst based on heterojunction composed of Pd–C4N and XMoY (X, Y = S, Se, Te), and conduct a detailed exploration of its oxygen reduction reaction (ORR), oxygen reduction reaction (OER), and hydrogen evolution reaction (HER) catalytic performance using density functional theory methods. First, all Pd–C4N/XMoY is proven to have good stability by calculating binding energy. Then, the ORR/OER electrocatalytic behavior of Pd–C4N/XMoY is investigated, and the potential-determining step of most catalysts for ORR is *OH reduction, while for the OER, it is *OH to *O. Additionally, all catalysts exhibit good catalytic activity for the ORR/OER, but only five have better catalytic activity than Pt(111). In particular, Pd–C4N/SMoSe exhibits a negligible potential barrier for the HER (−0.004 V). Pd–C4N/SeMoTe presents immense trifunctional activities toward ORR/OER/HER with overpotentials of 0.32/0.28/–0.02 V. The electronic structure analysis proves that the high activity is attributed to the good conductivity of the material itself and the adjustable binding ability of the *OH. Our report contributes to comprehending and designing more efficient single-atom catalysts to meet the demand for multifunctional catalysts.
Liu et al. (Mon,) studied this question.