| Hydrogen is a renewable and clean energy source.The use of solar energy to achieve full decomposition of water for production of hydrogen is one of the most efficient way to utilize hydrogen energy and has been extensively studied.The total decomposition of water includes oxidation of water to produce O2 and reduction of water for H2 production.Water oxidation process is considered as a bottleneck of water decomposition,so it is essential to explore and develop inexpensive and efficient water oxidation catalysts（WOCs）.Transition metal oxides have become a research hotspot due to their high catalytic activity and good stability.Metal-organic frameworks（MOFs）,as a class of coordination compounds,are tunable which are formed by self-assembly of metal ions and organic ligands.The Prussian blue analogue（PBA）is a kind of MOFs.In this paper,a series of PBAs were prepared as precursors based on the simple self-assembly synthesis method by tunability of PBAs.The PBAs was directly added to the water oxidation system for the synthesis of bimetallic oxides,and the catalytic activity of the catalyst was evaluated by catalytic water oxidation reaction,also the stability of the catalyst also was investigated.The detail work as follows:（1）The Fe3O4/CuO bimetallic oxide was prepared in situ by using Cu-Fe PBA nanocubes as precursor,while the morphology,size and chemical composition of the catalyst were characterized by using characterization techniques,such as XRD,SEM,HR-TEM,mapping,XPS and other analytical methods.All the techniques have confirmed that the active material is Fe3O4/CuO bimetallic oxide.Oxygen evolution results demonstrated that the bimetallic catalyst Fe3O4/CuO exhibited excellent chemical catalytic water oxidation activity,the production rate of O2 is about 4406?mol·g-1·h-1,and the maximum yield of O2 is 83.2%.The NaOH concentration,catalyst dosage and Na2S2O8 concentration were investigated to obtain the optimal reaction conditions.The mechanism of catalyst-catalyzed water oxidation in water oxidation system was also explored.（2）The Fe3O4/NiO bimetallic oxide was prepared in situ by using Ni-Fe PBA nanocubes as precursor.The results of oxygen evolution show that the bimetallic catalyst Fe3O4/NiO exhibited excellent catalytic water oxidation activity,the production rate of O2 is about 1594.3?mol·g-1·h-1.The morphology and chemical composition of the precursor and bimetallic oxides were analyzed by a series of characterization methods such as XRD,SEM,XPS,mapping and FT-IR.The effect of different NaOH concentration,catalyst dosage and Na2S2O8 concentration were also investigated.（3）The bimetallic oxide HNiFe-2 as WOCs were prepared by annealing above-mentioned Fe3O4/NiO amorphous bimetallic oxide.In the water oxidation experiment,the results of oxygen evolution show that the catalyst exhibits efficient photocatalytic activity and chemocatalytic activity than Fe3O4/NiO bimetallic oxide,and the photocatalytic performance is superior to the chemical catalytic performance.The HNiFe-2 as active substance was confirmed by using characterization techniques such as XRD,SEM,mapping and XPS,and the stability of the catalyst was also evaluated.The effects of different NaOH concentrations,catalyst dosage and Na2S2O8concentration were also studied. |
