Coupling a Main-Group Metal with a Transition Metal to Create Biatom Catalysts for Nitric Oxide Reduction

Developing efficient biatom catalysts for renewable energies is becoming increasingly worthwhile, yet it remains a great challenge. Herein, by means of large-scale first-principles calculations, we report a design principle of coupling main-group metal with transition metal (TM) to explore biatom catalysts for nitric oxide reduction reaction (NORR), namely, $\mathrm{Mg}/\mathrm{Al}/\mathrm{Ga}\ensuremath{-}\mathrm{TM}$ dimers anchored on nitrogen-doped graphene. We propose a comprehensive screening strategy to recognize promising candidates of such catalysts. Following this strategy, we screen $\mathrm{Mg}\ensuremath{-}\mathrm{Ni}@\mathrm{NC}$ and $\mathrm{Ga}\ensuremath{-}\mathrm{Cr}@\mathrm{NC}$ out of 24 candidates as promising biatom catalysts with high activity and selectivity for direct $\mathrm{NO}$-$\mathrm{to}$-${\mathrm{NH}}_{3}$ conversion. Such high catalytic activity is related to the synergetic interatomic interactions. Moreover, based on the interplay between main-group metal and TM centers, we propose a ``donation-backdonation-redonation'' mechanism to characterize $\mathrm{NO}$ activation. In addition, $\mathrm{\ensuremath{\Delta}}{\ensuremath{\epsilon}}_{s/p\ensuremath{\rightarrow}d}$ is identified as an efficient quantitative descriptor to prereduce the number of such catalyst candidates. Our work opens a strategy for rational design of biatom catalysts toward NORR.