Preparation And Properties Of Phosphide Hydrodeoxygenation Catalyst

Graphite graphite powder（325 mesh）,sodium hypophosphite and nickel chloride were used as raw materials.Graphene oxide（GO）was prepared by the Hummer method,and nickel phosphide/reduced graphene oxide（Ni₂P/RGO）catalyst was further prepared.The Ni₂P/RGO catalysts were characterized by SEM,EDS,BET and XRD.The catalytic performance of Ni₂P/RGO catalysts was evaluated by the benzaldehyde HDO test.The preparation conditions of Ni₂P/RGO catalysts were investigated and optimized by single factor experiments and orthogonal experiments.In the experimental investigation,the activity and selectivity of the Ni₂P/RGO catalyst initially kept increasing and then decreasing with the increase of nickel-phosphorus molar ratio（A）,loading（B）,and calcination temperature（C）.The effect of baking temperature is relatively significant.Orthogonal experimental investigation results show that the optimal preparation conditions of the catalyst are:the molar ratio of nickel to phosphorus is 2:1.5,the loading is 20%,and the calcination temperature is 300°C.At the same time,the benzaldehyde HDO reaction conditions were investigated and optimized through single-factor experiments and orthogonal experiments.Within the range of experimental investigation,with the changes of reaction temperature（T）,reaction pressure（P）and reaction time（t）,the activity and selectivity of Ni₂P/RGO catalysts will all change,and the influence of reaction pressure is relatively significant.Orthogonal experimental results show that the optimal conditions for the hydrogenation of benzaldehyde are reaction temperature 300°C,reaction pressure 2.5 MPa,and reaction time 4.0 h.In addition,the reactivity and selectivity of the catalysts at different storage times were investigated.Experiments show that the catalyst stability is good overall after 50 days of storage under normal conditions（room temperature and pressure dehumidification）.Under multiple optimal conditions,Ni₂P/RGO catalysts can convert the benzaldehyde HDO to more than 94%and toluene selectivity to nearly 90%.The catalytic performance is relatively good.The synergistic effect of different carriers and Ni₂P was also investigated.GO and pseudo-boehmite were chemically reduced to a solution in a certain proportion.After thorough mixing,they were reduced to prepare RGO-Al₂O₃ composite carriers;and the benzaldehyde HDO experiments were used.The performances of Ni₂P/Al₂O₃,Ni₂P/RGO and Ni₂P/RGO-Al₂O₃ catalysts were evaluated,and the adsorption-dissociation of benzaldehyde on the surface of RGO-Al₂O₃ composite carrier was studied.The results show that the RGO-Al₂O₃ composite carrier has two characteristics of RGO and Al₂O₃.In the benzaldehyde HDO process,the catalytic performance of Ni₂P/RGO-Al₂O₃ is superior to the other two catalysts.The RGO-Al₂O₃ composite supports a better synergy with Ni₂P and can be considered as a suitable carrier for supporting phosphides.