Xie Jiahao, Miao Yu, Liu Bin, Shao Siliang, Zhang Xu, Sun Zhiyao, Xu Xiaoqin, Yao Yuan, Hu Chaoyue, Zou Jinlong
Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, China.
MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150080, China.
Nanomaterials (Basel). 2023 Jan 29;13(3):543. doi: 10.3390/nano13030543.
Molybdenum carbide (MoC) with a Pt-like d-band electron structure exhibits certain activities for oxygen reduction and evolution reactions (ORR/OER) in alkaline solutions, but it is questioned due to its poor OER stability. Combining MoC with transition metals alloy is a feasible way to stabilize its electrochemical activity. Herein, CoFe-Prussian blue analogues are used as a precursor to compound with graphitic carbon nitride and Mo to synthesize FeCo alloy and MoC co-encapsulated N-doped carbon (NG-CoFe/MoC). The morphology of NG-CoFe/MoC (800 °C) shows that CoFe/MoC heterojunctions are well wrapped by N-doped graphitic carbon. Carbon coating not only inhibits growth and agglomeration of MoC/CoFe, but also enhances corrosion resistance of NG-CoFe/MoC. NG-CoFe/MoC (800 °C) exhibits an excellent half-wave potential (E = 0.880 V) for ORR. It also obtains a lower OER overpotential (325 mV) than RuO due to the formation of active species (CoOOH/β-FeOOH, as indicated by in-situ X-ray diffraction tests). E shifts only 6 mV after 5000 ORR cycles, while overpotential for OER increases only 19 mV after 1000 cycles. ORR/OER performances of NG-CoFe/MoC (800 °C) are close to or better than those of many recently reported catalysts. It provides an interfacial engineering strategy to enhance the intrinsic activity and stability of carbides modified by transition-metals alloy for oxygen electrocatalysis.
具有类铂d带电子结构的碳化钼（MoC）在碱性溶液中对氧还原和析氧反应（ORR/OER）表现出一定活性，但因其较差的OER稳定性而受到质疑。将MoC与过渡金属合金结合是稳定其电化学活性的一种可行方法。在此，钴铁普鲁士蓝类似物被用作前驱体与石墨相氮化碳和Mo复合，以合成铁钴合金和MoC共包覆的氮掺杂碳（NG-CoFe/MoC）。NG-CoFe/MoC（800℃）的形貌表明CoFe/MoC异质结被氮掺杂石墨碳很好地包裹。碳包覆不仅抑制了MoC/CoFe的生长和团聚，还增强了NG-CoFe/MoC的耐腐蚀性。NG-CoFe/MoC（800℃）对ORR表现出优异的半波电位（E = 0.880 V）。由于活性物种（原位X射线衍射测试表明为CoOOH/β-FeOOH）的形成，它还获得了比RuO更低的OER过电位（325 mV）。在5000次ORR循环后E仅偏移6 mV，而在1000次循环后OER过电位仅增加19 mV。NG-CoFe/MoC（800℃）的ORR/OER性能接近或优于许多最近报道的催化剂。它提供了一种界面工程策略，以增强过渡金属合金修饰的碳化物用于氧电催化的本征活性和稳定性。
