Combining the abundance and inexpensiveness of their constituent elements with their atomic dispersion, atomically dispersed Fe–N–C catalysts represent the most promising alternative to precious-metal-based materials in proton exchange membrane (PEM) fuel cells. Due to the high temperatures involved in their synthesis and the sensitivity of Fe ions toward carbothermal reduction, current synthetic methods are intrinsically limited in type and amount of the desired, catalytically active Fe–N4 sites, and high active site densities have been out of reach (dilemma of Fe–N–C catalysts). We herein identify a paradigm change in the synthesis of Fe–N–C catalysts arising from the developments of other M–N–C single-atom catalysts. Supported by DFT calculations we propose fundamental principles for the synthesis of M–N–C materials. We further exploit the proposed principles in a novel synthetic strategy to surpass the dilemma of Fe–N–C catalysts. The selective formation of tetrapyrrolic Zn–N4 sites in a tailor-made Zn–N–C material is utilized as an active-site imprint for the preparation of a corresponding Fe–N–C catalyst. By successive low- and high-temperature ion exchange reactions, we obtain a phase-pure Fe–N–C catalyst, with a high loading of atomically dispersed Fe (>3 wt %). Moreover, the catalyst is entirely composed of tetrapyrrolic Fe–N4 sites. The density of tetrapyrrolic Fe–N4 sites is more than six times as high as for previously reported tetrapyrrolic single-site Fe–N–C fuel cell catalysts.

Surface deactivation for partial methanol oxidation to methyl formate on Au(332) under oxygen-deficient conditions at low temperatures suggests a small number of highly active sites for methyl formate formation.

Carbon-based materials doped with metal and nitrogen (M-N-Cs) have promising potential in electrocatalytic applications with the advantage of material sustainability. MN4 motifs incorporated into a carbon lattice are generally known to be responsible for the activity of these materials. While many computational studies assume the tetrapyridinic MN4 motifs, recent studies have elucidated the role of tetrapyrrolic MN4 motifs in electrocatalysis. Using density functional theory, we constructed and compared various structural models to study the incorporation of tetrapyrrolic and tetrapyridinic MN4 motifs in 2D carbon materials and analyzed the type of interactions between each metal species and the N4 site. We further quantified the relative affinity of various metal species to the two types of N4 site. Upon analysis of energies, bond lengths, electronic population and charges, we found that metals that exhibit highly ionic binding characters have a greater affinity towards tetrapyrrolic MN4 motifs compared to species that participate in covalent interactions with the π-system. Furthermore, the binding strength of each species in the N4 site depend on the electronegativity as well as the availability of orbitals for accepting electrons from the π-system.

Diabetic ulcers induced by multidrug‐resistant (MDR) bacteria have severely endangered diabetic populations. These ulcers are very challenging to treat because the local high glucose concentration can both promote bacterial growth and limit the immune system's bactericidal action. Herein, a glucose oxidase‐peroxidase (GOx‐POD) dual‐enzyme mimetic (DEM) bionanocatalyst, Au@CuBCats is synthesized to simultaneously control glucose concentration and bacteria in diabetic ulcers. Specifically, the AuNPs can serve as GOx mimics and catalyze the oxidation of glucose for the formation of H2O2; the H2O2 can then be further catalytically converted into OH via the POD‐mimetic copper single atoms. Notably, the unique copper single atoms coordinated by one oxygen and two nitrogen atoms (CuN2O1) exhibit better POD catalytic performance than natural peroxidase. Further DFT calculations are conducted to study the catalytic mechanism and reveal the advantage of this CuN2O1 structure as compared to other copper single‐atom sites. Both in vitro and in vivo experiments confirm the outstanding antibacterial therapeutic efficacy of the DEM bionanocatalyst. This new bionanocatalyst will provide essential insights for the next generation of antibiotic‐free strategies for combating MDR bacterial diabetic ulcers, and also offer inspiration for designing bionanocatalytic cascading medicines.

Catalysts are required to ensure electrochemical reduction of CO2 to fuels proceeds at industrially acceptable rates and yields. As such, highly active and selective catalysts must be developed. Herein, a density functional theory study of p‐block element and noble metal doped graphene‐based single‐atom catalysts in two defect sites for the electrochemical reduction of CO2 to CO and HCOOH is systematically undertaken. It is found that on all of the systems considered, the thermodynamic product is HCOOH. Pb/C3, Pb/N4 and Sn/C3 are identified as having the lowest overpotential for HCOOH production while Al/C3, Al/N4, Au/C3 and Ga/C3 are identified as having the potential to form higher order products due to the strength of binding of adsorbed HCOOH.