In this study, a Mn-modified Pt-based catalyst loaded on nitrogen-doped Ketjen black (Mn-Pt/NKB) is prepared using a simple ethylene glycol reduction method. The size of Pt nanoparticles (NPs) is effectively controlled by doping with Mn and N. With the smallest average particle size of 1.7 nm, Mn-Pt/NKB demonstrates half-wave potentials of 0.890 and 0.688 V in the alkaline and neutral electrolytes, respectively, which are superior to those of commercial platinum on activated carbon (Pt/C). When applied as an air cathode in aluminum-air battery, it exhibits ultra-high power densities of 190 (alkaline) and 26.2 mW·cm⁻² (neutral). Moreover, the voltage remains stable after 5 h of discharge. The practical application performance of the Mn-Pt/NKB catalyst in an aluminum-air battery is better than that of commercial Pt/C. Furthermore, the oxygen reduction reaction (ORR) mechanism on surfaces with different particle sizes is analyzed using density functional theory. Oxygen cracking is the major pathway on the surface of the small particles with lower energy consumption of 0.5 eV, while water molecule cleavage is the major pathway on the surface of the large particles with higher energy consumption of 0.97 eV. The lower energy consumption of the oxygen cracking pathway further confirms the ORR mechanism for higher activity on small-sized surfaces. This study provides a direction for the rational design of Pt-based catalysts for ORR and sheds light on the commercial development of aluminum-air batteries.

The repair and treatment of tumor bone defects is a difficult problem to solve urgently in clinical medicine. After tumor resection, patients are not only faced with a large area of bone defect, but also may have the risk of tumor recurrence, which can easily cause huge physical and mental harm to patients. In this study, we successfully designed and constructed an organic/inorganic composite microgel bone powder (S-H-M_3%Ce/3%Se) based on cerium (Ce) and selenium (Se) elements co-doped mesoporous bioactive glass (M_3%Ce/3%Se), sodium alginate (SA), and recombinant human-like collagen (HLC). The obtained S-H-M_3%Ce/3%Se could inhibit the growth of osteoma cells and promote the growth of normal cells, and effectively promote the repair of defect bone. The integration of the “treatment and repair” organic/inorganic composite microgel bone powder provided a new strategy for the treatment of cancerous bone defects.

Solar dermatitis is an acute or chronic high incidence of skin injury caused by ultraviolet (UV) radiation based on strong sunlight, which seriously endangers people's health. In this study, we designed and demonstrated enzyme-catalyzed semi-inter penetrating polymer network (Semi-IPN) sprayable nanodrug-loaded hydrogels based on gelatin, 3-(4-hydroxyphenyl) propionic acid (HPA), polyvinyl alcohol (PVA), glycerol, and dexamethasone sodium phosphate (DEXP) for solar dermatitis. The hydrogels had high water content, excellent biocompatibility, effective encapsulation and sustained release of nanodrugs, anti-inflammatory, and strong anti-ultraviolet B (anti-UVB) radiation properties based on glycerol and phenol functional groups, but also controllable spray gelation mode to make them adhere well on the dynamic skin surfaces and achieve continuous transdermal drugs delivery for solar dermatitis. The sprayable nanodrug-loaded hydrogel systems could be used as a highly effective therapeutic method for solar dermatitis, and also provide a good strategy for designing novel nanodrug-loaded hydrogel delivery systems.