RuN4 Doped Graphene Oxide, a Highly Efficient Bifunctional Catalyst for Oxygen Reduction and CO2 Reduction from Computational Study

The searching of highly efficient bifunctional catalysts for both oxygen reduction reaction (ORR) and CO 2 reduction reaction (CO 2 RR) for energy conversion and storage has attracted particular attention in recent years. In this work, through computational design, we have studied both ORR and CO 2 RR for RuN 4 doped graphene (RuN 4 -Gra) and modified RuN 4 -Gra by an oxygen atom (RuN 4 /O-Gra). For ORR, our calculations indicated that RuN 4 /O-Gra has better catalytic performance both kinetically and thermodynamically. The calculated energy barrier is 0.39 eV at the rate-determining step, much smaller than 0.80 eV for pure Pt and 0.56 eV for FeN 4 -Gra. The predicted working potential is 0.54 V, larger than 0.38 V for FeN 4 -Gra. For CO 2 RR, the formation of HCOOH is prevented due to the strong adsorption of CO and strong hydrogen evolution reaction (HER) for RuN 4 -Gra. However, after the modification of RuN 4 -Gra with an oxygen atom, the reaction pathway is changed and the formation of CO is prevented. RuN 4 /O-Gra has high selectivity toward HCOOH, and HER is also prevented. Therefore, RuN 4 /O-Gra is a highly efficient bifunctional catalyst for both ORR and CO 2 RR.