To overcome the problem of the sluggish kinetics of the oxygen evolution reaction (OER), it is of great significance to develop an efficient and stable non-noble metal-based OER catalyst for electrocatalytic energy conversion and storage. Herein, a complex of a metal–organic framework and hydroxide is synthesized by performing a ligand etching strategy on FeMn co-doped Ni(OH)2 nanosheets in situ grown on nickel foam (FeMn-Ni(OH)2@MOF/NF). Benefiting from the unique sheet-on-sheet hierarchical structure, multi-metal active nodes and two active materials grown in situ, the resulting FeMn-Ni(OH)2@MOF/NF demonstrated brilliant OER activity with an overpotential of 199 mV to achieve a current density of 10 mA cm−2 and long-term stability. This research will provide a new strategy for the design of high-performance OER electrocatalysts.
Jun Lu,Zhipan Wen,Yalei Zhang,Gang Cheng,Rui Xu,Xiaohu Gong,Xin Wang,Rong Chen
A series of ordered mesoporous Fe Mn bimetal oxides (OMFMs) were fabricated by using a novel inverse micelle method, and the texture, nanostructure and interface chemistry properties of OMFMs were closely correlated to the calcination temperature. Due to the amorphous regular inner-connected nanostructure and bimetallic synergistic effect, the obtained OMFMs exhibited superior arsenic sequestration performance than pure mesoporous Fe oxides (PMF) and Mn oxides (PMM). The optimum ratio of Fe/Mn and calcination temperature for arsenic removal was 3/1 and 350 °C (OMFM-3), and the maximum As(III) and As(V) adsorption capacities of OMFM-3 were 174.59 and 134.58 mg/g, respectively. Solution pH value negligibly affected the uptake of arsenic (ranged from 3.0 to 7.0), while SiO 3 2− /PO 4 3− ions and humic acid (HA) displayed significant inhibitory effect on arsenic removal by OMFM-3. According to the mechanism of arsenic removal, which simultaneously analyzed the arsenic redox transformation in aqueous phase and on solid phase interface, it was concluded that manganese oxides in OMFM-3 mainly played the role as a remarkable As(III) oxidant in water, whereas iron oxides dominantly acted as an excellent arsenic species adsorbent. Finally, the prominent arsenic sequestration behavior and performance in surface water suggested that OMFM-3 could be a promising and hopeful candidate for arsenic-contaminated (especially As(III)) surface water and groundwater remediation and treatment.