Weiwen Wang

Abstract Developing low‐cost electrocatalysts for efficient and robust oxygen evolution reaction (OER) is the key for scalable water electrolysis, for instance, NiFe‐based materials. Decorating NiFe catalysts with other transition metals offers a new path to boost their catalytic activities but often suffers from the low controllability of the electronic structures of the NiFe catalytic centers. Here, we report an interfacial atom‐substitution strategy to synthesize an electrocatalytic oxygen‐evolving NiFeV nanofiber to boost the activity of NiFe centers. The electronic structure analyses suggest that the NiFeV nanofiber exhibits abundant high‐valence Fe via a charge transfer from Fe to V. The NiFeV nanofiber supported on a carbon cloth shows a low overpotential of 181 mV at 10 mA cm −2 , along with long‐term stability (>20 h) at 100 mA cm −2 . The reported substitutional growth strategy offers an effective and new pathway for the design of efficient and durable non‐noble metal‐based OER catalysts.

Abstract Developing reactive oxygen species (ROS)‐scavenging nanostructures to protect and regulate stem cells has emerged as an intriguing strategy for promoting tissue regeneration, especially in trauma microenvironments or refractory wounds. Here, an electronic modulated metal oxide is developed via Mn atom substitutions in Co 3 O 4 nanocrystalline (Mn‐Co 3 O 4 ) for highly efficient and multifaceted catalytic ROS‐scavenging to reverse the fates of mesenchymal stem cells (MSCs) in oxidative‐stress microenvironments. Benefiting from the atomic Mn‐substitution and charge transfer from Mn to Co, the Co site in Mn‐Co 3 O 4 displays an increased ratio of Co 2+ /Co 3+ and improved redox properties, thus enhancing its intrinsic and broad‐spectrum catalytic ROS‐scavenging activities, which surpasses most of the currently reported metal oxides. Consequently, the Mn‐Co 3 O 4 can efficiently protect the MSCs from ROS attack and rescue their functions, including adhesion, spreading, proliferation, and osteogenic differentiation. This work not only establishes an efficient material for catalytic ROS‐scavenging in stem‐cell‐based therapeutics but also provides a new avenue to design biocatalytic metal oxides via modulation of electronic structure.