Currently, RuO 2 is a benchmark acidic oxygen evolution reaction (OER) catalyst. Nevertheless, its wide applications are always restricted by slow dynamics and limited durability. This paper reports a type of Mn-doped RuO 2 nanocrystals for boosting the OER catalytic performance in acidic media. The catalyst (named Mn-RuO 2 ) is prepared through annealing of Ru-exchanged Mn-based derivative at 300 °C. Such Mn-RuO 2 exhibits excellent acidic OER activity, with an overpotential of 158 mV at 10 mA cm −2 and a stability of 5000 cycles in the presence of sulfuric acid (0.5 mol/L). Both structural characterization and theoretical analysis show that the Mn doping in RuO 2 can tune the d-band center of Ru active sites and lower antibonding surface-adsorbate states, which leads to a decreased free energy of the rate-determining step, ultimately enhancing the intrinsic activity of RuO 2 .

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.

Most previous efforts are devoted to developing transition metals as electrocatalysts guided by the d‐band center model. The metals of the s‐block of the periodic table have so far received little attention in the application of oxygen reduction reactions (ORR). Herein, a carbon catalyst with calcium (Ca) single atom coordinated with N and O is reported, which displays exceptional ORR activities in both acidic condition (E1/2 = 0.77 V, 0.1 m HClO4) and alkaline condition (E1/2 = 0.90 V, 0.1 m KOH). The CaN, O/C exhibits remarkable performance in zinc–air battery with a maximum power density of 218 mW cm–2, superior to a series of catalysts reported so far. X‐ray absorption near‐edge structure (XANES) characterization confirms the formation of N‐ and O‐atom‐coordinated Ca in the carbon matrix. Density functional theory (DFT) calculations reveal that the high catalytic activity of main‐group Ca is ascribed to the fact that its p‐orbital electron structure is regulated by N and O coordination so that the highest peak (EP) of the projected density of states (PDOS) for the Ca atom is moved close to the Fermi level, thereby facilitating the adsorption of ORR intermediates and electron transfer.