Du Xi, Zhang Wenjun, Zhang Maliang, Ji Yanhong, Su Kunmei, Li Zhenhuan
State Key Laboratory of Separation Membranes and Membrane Processes, Tiangong University, Tianjin 300387, China.
School of Materials Science and Engineering, Tianjin Key Laboratory of Advanced Fibers and Energy Storage, Tiangong University, Tianjin 300387, China.
Materials (Basel). 2022 Jun 12;15(12):4170. doi: 10.3390/ma15124170.
The construction of highly ordered hierarchical nanoarrays is crucial for obtaining effective transition metal carbon nanomaterial electrocatalysts for oxygen evolution reaction (OER) in water splitting. Herein, we adopted a Co metal zeolitic imidazolate framework (Co-ZIF) as a precursor by ion-exchange/etching reaction with Fe(NO) to obtain hierarchical N-doped Co-Fe layered double hydroxide (CoFe-LDH) in situ generated in Co-ZIF nanoarrays based on a self-supported carbon cloth (CC) substrate noted as CoFe-LDH@Co-ZIF@CC. Benefiting from the synergistic effect of these species and their highly ordered self-supported nanoarray structure, the catalytic active sites were fully exposed and highly protected in alkaline electrolyte, which significantly promoted electron transport and improved electrochemical performance. The CoFe-LDH@Co-ZIF@CC exhibited the low overpotentials of about 225 and 319 mV at 10 and 100 mA cm with a small Tafel slope of 81.8 mV dec recorded in a 1.0 M KOH electrolyte. In addition, it also showed a long-term durability without obvious decay after 30 h. Therefore, its remarkable OER activity demonstrates this material's promising application in the green hydrogen energy industry.
构建高度有序的分级纳米阵列对于获得用于水分解中析氧反应（OER）的有效过渡金属碳纳米材料电催化剂至关重要。在此，我们采用钴基金属沸石咪唑酯骨架（Co-ZIF）作为前驱体，通过与Fe(NO)进行离子交换/蚀刻反应，在基于自支撑碳布（CC）基底的Co-ZIF纳米阵列中原位生成分级N掺杂的钴铁层状双氢氧化物（CoFe-LDH），记为CoFe-LDH@Co-ZIF@CC。受益于这些物种的协同效应及其高度有序的自支撑纳米阵列结构，催化活性位点在碱性电解质中得到充分暴露并受到高度保护，这显著促进了电子传输并改善了电化学性能。在1.0 M KOH电解质中，CoFe-LDH@Co-ZIF@CC在10和100 mA cm时表现出约225和319 mV的低过电位，记录的小塔菲尔斜率为81.8 mV dec。此外，它还表现出长期耐久性，在30小时后没有明显衰减。因此，其卓越的OER活性证明了这种材料在绿色氢能产业中的应用前景广阔。
