Atomic interface regulation is thought to be an efficient method to adjust the performance of single atom catalysts. Herein, a practical strategy was reported to rationally design single copper atoms coordinated with both sulfur and nitrogen atoms in metal-organic framework derived hierarchically porous carbon (S-Cu-ISA/SNC). The atomic interface configuration of the copper site in S-Cu-ISA/SNC is detected to be an unsymmetrically arranged Cu-S 1 N 3 moiety. The catalyst exhibits excellent oxygen reduction reaction activity with a half-wave potential of 0.918 V vs. RHE. Additionally, through in situ X-ray absorption fine structure tests, we discover that the low-valent Cuprous-S 1 N 3 moiety acts as an active center during the oxygen reduction process. Our discovery provides a universal scheme for the controllable synthesis and performance regulation of single metal atom catalysts toward energy applications.

By the in situ X-ray absorption results, the gradually decrease of Cu oxidation state under applied potential implied that low-valence Cu (+1) species in the atomic interface of Cu–N4–C8S2 may work as the catalytic sites during an ORR process.

The engineering coordination environment offers great opportunity in performance tunability of isolated metal single-atom catalysts. For the most popular metal–N x (MN x ) structure, the replacement of N atoms by some other atoms with relatively weak electronegativity has been regarded as a promising strategy for optimizing the coordination environment of an active metal center and promoting its catalytic performance, which is still a challenge. Herein, we proposed a new synthetic strategy of an in situ phosphatizing of triphenylphosphine encapsulated within metal–organic frameworks for designing atomic Co1–P1N3 interfacial structure, where a cobalt single atom is costabilized by one P atom and three N atoms (denoted as Co-SA/P-in situ). In the acidic media, the Co-SA/P-in situ catalyst with Co1–P1N3 interfacial structure exhibits excellent activity and durability for the hydrogen evolution reaction (HER) with a low overpotential of 98 mV at 10 mA cm–2 and a small Tafel slope of 47 mV dec–1, which are greatly superior to those of catalyst with Co1–N4 interfacial structure. We discover that the bond-length-extended high-valence Co1–P1N3 atomic interface structure plays a crucial role in boosting the HER performance, which is supported by in situ X-ray absorption fine structure (XAFS) measurements and density functional theory (DFT) calculation. We hope this work will promote the development of high performance metal single-atom catalysts.

Main group antimony (Sb) species are promising electrocatalysts that promote CO2 reduction reaction (CO2RR) to formate, which is an important hydrogen storage material and a key chemical intermediate in many...

Oxygen-involved electrochemical reactions are crucial for plenty of energy conversion techniques. Herein, we rationally designed a carbon-based Mn–N2C2 bifunctional electrocatalyst. It exhibits a half-wave potential of 0.915 V versus reversible hydrogen electrode for oxygen reduction reaction (ORR), and the overpotential is 350 mV at 10 mA cm–2 during oxygen evolution reaction (OER) in alkaline condition. Furthermore, by means of operando X-ray absorption fine structure measurements, we reveal that the bond-length-extended Mn2+–N2C2 atomic interface sites act as active centers during the ORR process, while the bond-length-shortened high-valence Mn4+–N2C2 moieties serve as the catalytic sites for OER, which is consistent with the density functional theory results. The atomic and electronic synergistic effects for the isolated Mn sites and the carbon support play a critical role to promote the oxygen-involved catalytic performance, by regulating the reaction free energy of intermediate adsorption. Our results give an atomic interface strategy for nonprecious bifunctional single-atom electrocatalysts.