| Ni/C catalyst is widely used in various hydrogenation reactions due to its excellent catalytic performance,low cost and simple preparation.However,there are still many problems with such catalysts.For example,the particle size of Ni is too large and the loading of Ni is too low.In order to solve the above problems,Ni@C catalyst with high loading,nano-size and uniformity was obtained by calcination method under the condition of nitrogen atmosphere by using two kinds of Ni-based metal organic framework precursors.XRD,BET,TEM,SEM and XPS were used to determine the effect of structure and treatment method on the particle size of the catalyst.The results show that the particle size of the catalyst is smaller at the calcination temperature at the beginning of the skeleton collapse.The MOF precursor of the aliphatic ligand is easier to decompose than the MOF of the aromatic ligand,and the size of the catalyst particles is smaller.We selected nitrobenzene hydrogenation as the probe reaction and found that when the temperature rose from room temperature to 100 ?,the conversion rate and selectivity have reached 99%,after four cycles of experiments,can still maintain a good catalyst effect.Next,the precursor of the core-shell structure SPS-CO-AA@ZIF-8 was prepared by using sulfonated polystyrene as the core and ZIF-8 as shell.The precursor containing Pd2+ was obtained by impregnation,and then the polystyrene balls were removed in a roasted manner to obtain a Void@ZIF-8/Pd catalyst having a hollow structure in the middle.From the results of XRD,TEM,IR and other means of characterization,it demonstrated that the polystyrene ball which was sulfonated for three hours was more conducive to the growth of core-shell structure,ZIF-8 structure remained intact and Pd nanoparticles uniformly dispersed in the channel.We used it in the selective hydrogenation of cinnamaldehyde.At 80 ?,the conversion of cinnamaldehyde reached 99%,the selectivity of phenylpropionaldehyde was 99%. |
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