Electrocatalytic CO 2 reduction into CO has been regarded as one of the most promising strategies for sustainable carbon cycles at ambient conditions, but still faces challenges to achieve both high product selectivity and large current density. Here, we report a Ni 4 N/Ni 3 ZnC 0.7 heterostructured electrocatalyst embedded in accordion-like N-doped carbon through a simple molten salt annealing strategy. The optimal Ni 4 N/Ni 3 ZnC 0.7 electrocatalyst achieves a high CO Faraday efficiency of 92.3% and a large total current density of −15.8 mA cm −2 at −0.8 V versus reversible hydrogen electrode, together with a long-term stability about 30 h. Density functional theory results reveal that the energy barrier for *COOH intermediate formation largely decreased on Ni 4 N/Ni 3 ZnC 0.7 heterostructure compared with Ni 4 N and Ni 3 ZnC 0.7 , thus giving rise to enhanced activity and selectivity. A rechargeable Zn-CO 2 battery is further assembled with Ni 4 N/Ni 3 ZnC 0.7 catalyst as the cathode, which shows a maximum power density of 0.85 mW cm −2 and excellent stability.
Bacterial and drug-resistant bacterial infections pose significant challenges to the treatment of skin wounds. Among various non-antibiotic strategies, nanozymes which mimic the activities of natural bioenzymes and possess broad-spectrum antibacterial properties, hold promise for antibacterial therapy in infected wounds. However, the catalytic activity and biosafety of most current nanozymes remain insufficient to meet clinical requirements. Herein, we innovatively synthesized novel heterostructured nanozymes (HNiZn) comprising Ni 4 N/Ni 3 ZnC 0.7 embedded in accordion-shaped nitrogen-doped carbon using a simple molten-salt pyrolysis method. Combined with injectable hyaluronic acid (HA) as a carrier, these nanozymes facilitate low-temperature (43.5°C) photocatalytic and photothermal therapy for bacterially infected wounds. Based on density functional theory (DFT) calculations, the Ni 4 N/Ni 3 ZnC heterostructured nanozymes exhibit richer electron cloud distribution, stronger interactions between heterogeneous atoms, lower electron escape work function, stronger adsorption energy for free radicals, and electron transfer efficiency than individual Ni 4 N or Ni 3 ZnC phases, resulting in efficient peroxidase (POD)-like and glutathione peroxidase (GPx)-like activities. Additionally, HNiZn exhibits a high photothermal conversion efficiency (51.01%) under near infrared (NIR) irradiation. Through combined photocatalytic and photothermal effects, it effectively kills Escherichia coli ( E. coli ), clinically isolated methicillin-resistant Staphylococcus aureus (MRSA), and their biofilms. Mechanistic studies using metabolomics analysis revealed that HNiZn induces bacterial apoptosis by disrupting bacterial biosynthesis and metabolism, affecting the cell cycle, and perturbing redox balance. In vivo experiments further confirmed the favorable biosafety and antibacterial efficacy of HNiZn, which promoted skin wound healing. This study provides a novel strategy for constructing effective nanozymes and treating bacterial infections.
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