It is known that the main-group metals and their related materials show poor catalytic activity due to a broadened single resonance derived from the interaction of valence orbitals of adsorbates with the broad sp-band of main-group metals. However, Mg cofactors existing in enzymes are extremely active in biochemical reactions. Our density function theory calculations reveal that the catalytic activity of the main-group metals (Mg, Al and Ca) in oxygen reduction reaction is severely hampered by the tight-bonding of active centers with hydroxyl group intermediate, while the Mg atom coordinated to two nitrogen atoms has the nearoptimal adsorption strength with intermediate oxygen species by the rise of p-band center position compared to other coordination environments. We experimentally demonstrate that the atomically dispersed Mg cofactors incorporated within graphene framework exhibits a strikingly high half-wave potential of 910 mV in alkaline media, turning a s/p-band metal into a highly active electrocatalyst.

Ion migration has been recognized as a critical step in determining the performance of numerous devices in chemistry, biology, and material science. However, direct visualization and quantitative investigation of solid-phase ion migration among anisotropic nanostructures have been a challenging task. Here, we report an in-situ ChemTEM method to quantitatively investigate the solid-phase ion migration process among coassembled nanowires (NWs). This complicated process was tracked within a NW and between NWs with an obvious nanogap, which was revealed by both phase field simulation and ab initio modeling theoretical evaluation. A migration "bridge" between neighboring NWs was observed. Furthermore, these new observations could be applied to migration of other metal ions on semiconductor NWs. These findings provide critical insights into the solidphase ion migration kinetics occurring in nanoscale systems with generality and offer an efficient tool to explore other ion migration processes, which will facilitate fabrication of customized and new heteronanostructures in the future.

The nontrivial topology is investigated in a dodecagonal quasicrystal made of 30° twisted bilayer graphene (TBG). Based on tight-binding model with both exchange field and Rashba spin–orbit coupling, the topological index, chiral edge states, and quantum conductance are calculated to distinguish its unique topological phase. A high Bott index (B = 4) quantum anomalous Hall effect (QAHE) is identified in TBG quasicrystal, which is robust to a finite perturbation without closing the nontrivial gap. Most remarkably, we have found that the multiple Dirac cone replicas in TBG quasicrystal are only a spectra feature without generating extra chiral edge states. Our results not only propose a possible way to realize the QAHE in quasicrystal, but also identify the continuity of nontrivial topology in TBG between crystal and quasicrystal.