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Ferrihydrite nanoparticles with nominal sizes of 3 and 6 nm were assembled within ferritin, an iron storage protein. The crystallinity and structure of the nanoparticles (after removal of the protein shell) were evaluated by high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), and scanning tunneling microscopy (STM). HRTEM showed that amorphous and crystalline nanoparticles were copresent, and the degree of crystallinity improved with increasing size of the particles. The dominant phase of the crystalline nanoparticles was ferrihydrite. Morphology and electronic structure of the nanoparticles were characterized by AFM and STM. Scanning tunneling spectroscopy (STS) measurements suggested that the band gap associated with the 6 nm particles was larger than the band gap associated with the 3 nm particles. Interaction of SO2(g) with the nanoparticles was investigated by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, and results were interpreted with the aid of molecular orbital/density functional theory (MO/DFT) frequency calculations. Reaction of SO2(g) with the nanoparticles resulted primarily in SO(3)2- surface species. The concentration of SO3(2-) appeared to be dependent on the ferrihydrite particle size (or differences in structural properties).

The typical preparation route of carbon‐supported metallic catalyst is complex and uneconomical. Herein, we reported a thiol‐assisted one‐pot method by using 3‐mercaptopropionic acid (MPA) to synthesize carbon‐supported metal nanoparticles catalysts for efficient electrocatalytic reduction of carbon dioxide (CO2RR). We found that the synthesized Au−MPA/C catalyst achieves a maximum CO faradaic efficiency (FE) of 96.2% with its partial current density of −11.4 mA/cm2, which is much higher than that over Au foil or MPA‐free carbon‐supported Au (Au/C). The performance improvement in CO2RR over the catalyst is probably derived from the good dispersion of Au nanoparticles and the surface modification of the catalyst caused by the specific interaction between Au nanoparticles and MPA. This thiol‐assisted method can be also extended to synthesize Ag−MPA/C with enhanced CO2RR performance. [ABSTRACT FROM AUTHOR]

Porous Fe 2 O 3 was prepared by simple annealing of preformed Prussian blue that was synthesized from a wet chemistry method. The obtained porous Fe 2 O 3 nanoparticles were then mixed with sulfur and used as cathode for lithium–sulfur batteries. The porous Fe 2 O 3 acts as an internal polysulfide reservoir, and thus reduces the shuttle effect. Composite cathode containing 5% porous Fe 2 O 3 shows improved cycling performance as compared to that without porous Fe 2 O 3 . A stable reversible discharge capacity of 574.3 mAh/g was obtained after 50 cycles at 0.5 C. [ABSTRACT FROM AUTHOR]

[Display omitted] • Few-layered Ti 3 C 2 MXene is prepared by solution-phase flocculation strategy. • NiCo 2 Se 4 nanoparticles are anchored on few-layered MXene forming 3D structures. • The hybrids exhibit superior sodium storage performance. • Dual sodium storage mechanisms have been verified by ex-situ XRD technique. In order to facilitate the sluggish Na+ insertion/extraction kinetics and improve the poor structural durability of sodium-ion batteries (SIBs) anodes, we for the first time rationally fabricate few-layered Ti 3 C 2 /NiCo 2 Se 4 3D architectures (f-Ti 3 C 2 /NiCo 2 Se 4) as anodes for SIBs via a facile solvothermal approach with assistance of solution-phase flocculation strategy to avoid restacking issue of few-layered Ti 3 C 2 MXene nanosheets (f-Ti 3 C 2 MXene). The 0D bimetallic selenide NiCo 2 Se 4 nanoparticles as a Na+ reservoir with higher redox activity are uniformly decorated on f-Ti 3 C 2 MXene, effectively preventing the self-restacking of f-Ti 3 C 2 MXene. A fast electron/Na+ transport ability and high surface-to-volume ratio provided by the unique f-Ti 3 C 2 MXene substrate endow the composites with rapid charge transfer kinetics and intimate contact between electrolyte and electrode. Meanwhile, f-Ti 3 C 2 MXenes are able to act as a flexible skeleton to facilitate strain relief and restrain pulverization of NiCo 2 Se 4 nanoparticles during cycling. As a result, the 0D/2D NiCo 2 Se 4 /f-Ti 3 C 2 hybrids exhibit superior cyclic stability and outstanding rate performance when applied in SIBs. Furthermore, dual sodium storage mechanisms of conversion reaction for NiCo 2 Se 4 and intercalation/de-intercalation for f-Ti 3 C 2 MXene among the hybrids have been verified by ex-situ XRD technique. The presented strategy can also be used to tackle the intrinsic problems of various bimetallic selenides by integrating them with few-layered MXene to fabricate hybrids for SIBs anodes. [ABSTRACT FROM AUTHOR]