Wang Mengjun, Zhang Nan, Feng Yonggang, Hu Zhiwei, Shao Qi, Huang Xiaoqing
College of Chemistry, Chemical Engineering and Materials Science Soochow University, No.199, Ren'ai Road, Suzhou, 215123, Jiangsu, China.
College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
Angew Chem Int Ed Engl. 2020 Aug 17;59(34):14373-14377. doi: 10.1002/anie.202006422. Epub 2020 Jul 2.
Herein, we developed a partially controlled pyrolysis strategy to create evenly distributed NiO nanoparticles within NiFe-MOF nanosheets (MOF NSs) for electrochemical synthesis of H O by a two-electron oxygen reduction reaction (ORR). The elemental Ni can be partially transformed to NiO and uniformly distributed on the surface of the MOF NSs, which is crucial for the formation of the particular structure. The optimized MOF NSs-300 exhibits the highest activity for ORR with near-zero overpotential and excellent H O selectivity (ca. 99 %) in 0.1 m KOH solution. A high-yield H O production rate of 6.5 mol g h has also been achieved by MOF NSs-300 in 0.1 m KOH and at 0.6 V (vs. RHE). In contrast to completely pyrolyzed products, the enhanced catalytic activities of partially pyrolyzed MOF NSs-300 originates mainly from the retained MOF structure and the newly generated NiO nanoparticles, forming the coordinatively unsaturated Ni atoms and tuning the performance towards electrochemical H O synthesis.
在此，我们开发了一种部分可控的热解策略，以在NiFe-金属有机框架纳米片（MOF NSs）中制备均匀分布的NiO纳米颗粒，用于通过双电子氧还原反应（ORR）电化学合成H₂O。元素Ni可以部分转化为NiO，并均匀分布在MOF NSs的表面，这对于特定结构的形成至关重要。优化后的MOF NSs-300在0.1 m KOH溶液中对ORR表现出最高活性，过电位接近零，且具有出色的H₂O选择性（约99%）。MOF NSs-300在0.1 m KOH和0.6 V（相对于可逆氢电极，RHE）下也实现了6.5 mol g⁻¹ h⁻¹的高产率H₂O生成速率。与完全热解产物相比，部分热解的MOF NSs-300增强的催化活性主要源于保留的MOF结构和新生成的NiO纳米颗粒，形成了配位不饱和的Ni原子，并调节了电化学合成H₂O的性能。
