Single-Atom Low-Valent Alkaline-Earth-Metal Catalysts for Electrochemical Nitrogen Reduction with an Acceptance-Backdonation Mechanism.
Zhilin WenHaifeng LvXiao-Jun WuPublished in: ACS applied materials & interfaces (2022)
Single-atom catalysts (SACs) have drawn great attention in developing highly active and low-cost catalysts for electrocatalytic nitrogen reduction reaction (NRR) in ammonia synthesis, but the atomic metal centers are mainly limited to transition metals. Here, four stable alkaline-earth-metal (AEM)-based SACs are proposed by anchoring AEM on nitrogen-doped graphene nanoribbons, based on first-principles calculations. All SACs exhibit excellent NRR performance with competitive limiting potentials compared to stepped Ru (0001), and Ca-based SAC achieves optimal activity with a potential of -0.716 V. It is revealed that the low oxidation state of AEM is crucial for the activation of N 2 through an acceptance-backdonation mechanism. The antibonding 2π* orbital of N 2 can accept residual s electrons of low-valent AEM and backdonate electrons to the empty d orbitals of AEM, resulting in activation of N 2 molecules. In particular, the activation degree of N 2 and NRR activity is linearly associated with the charge states of AEMs. Our work reveals the underlying mechanism of AEMs for N 2 activation and reduction and presents the potential of AEM SACs as efficient electrochemical NRR catalysts.
Keyphrases
- highly efficient
- low cost
- molecular dynamics
- metal organic framework
- electron transfer
- gold nanoparticles
- human health
- transition metal
- density functional theory
- randomized controlled trial
- working memory
- risk assessment
- hydrogen peroxide
- molecular dynamics simulations
- high resolution
- single cell
- clinical trial
- quantum dots
- climate change
- heavy metals
- reduced graphene oxide
- energy transfer