Synthesis Of （DyPO₄）_m-Ni₂P Multifunctional Composite Catalyst And Its Hydrogen-Related Photoelectric And Thermal Catalytic Properties

In order to address the hazards caused by the use of fossil resources such as oil and natural gas,the development and utilization technology of renewable and green hydrogen energy has attracted great attention.From a development perspective,renewable hydrogen energy relies on the preparation of green hydrogen using water as raw material through photocatalytic and electrocatalytic processes;From the perspective of utilization,the utilization of green hydrogen mainly refers to the conversion and application of energy and high value-added chemicals based on the high atom economy of hydrogen molecules,both of which are severely constrained by the low cost performance of the catalytic system.For example,the photocatalytic or electrochemical conversion of hydrogen mainly rely on precious metal catalysts,but it is difficult to widely use due to its high cost;using hydrogen as a synthetic raw material,although inexpensive metals can be used as catalysts during the reaction process,the catalysts have problems such as poor performance and stability,and its practicality still needs improvement.In response to these problems,the development of novel catalytic materials involved in hydrogen conversion remains a major research and development priority.Therefore,this paper conducted the following research:（1）In this experiment,Dy（NO₃）₃·6H₂O,Ni（NO₃）₂·6H₂O and（NH₄）₂HPO₄ were used as raw materials to prepare six kinds of Dy-Ni-P samples with different proportions through hydrothermal,centrifugal,drying,calcining and reduction processes,and analyzed by XRD,XPS,TEM,HAADF-TEM and other characterization methods.It is confirmed that the catalysts were formed by Dy PO₄ and Ni₂P,which can be named as Dy（PO₄）_m/Ni₂P,where m ranges from 0.1 to 0.6.（2）With eosin as sensitizer and triethylamine as sacrificial agent,the hydrogen production under visible light could reach up to 6597μmol·h^-1·g^-1,and the yield was nearly 12 times higher than that of Ni₂P.By comparing the characterizations of a series of catalysts such as transient photocurrent response,UV-Vis absorption spectra as well as PL spectra at 387 nm excitation wavelength,the results showed that composite catalysts could significantly improve the separation of photo generated electrons and holes,as well as charge conduction efficiency,compared to single component catalysts,resulting in a significant improvement in photoelectric hydrogen production performance.（3）The Dy（PO₄）_m/Ni₂P catalysts were used for electrochemical hydrogen production,and the results showed that the HER reaction overpotential could be reduced from 312 m V on Ni₂P to 205 m V on（Dy PO₄）_0.4/Ni₂P;the Tafel slope could be reduced from 212 m V/dec of Ni₂P to 47 m V/dec of（Dy PO₄）_0.4/Ni₂P;the charge transfer resistance（EIS analysis）of the（Dy PO₄）_0.4/Ni₂P sample（67.74Ω）was also much lower than that of Ni₂P（331Ω）.（4）The thermochemical hydrogen conversion performance of（Dy PO₄）_m/Ni₂P were investigated through the hydrogenation of furfural（FFA）to cyclopentanone（CPO）.It was found that using different proportions of composite catalysts under 0.5MPa H₂ and 160℃condition for 10 hours can achieve FFA conversion rate of over95%and CPO yield of over 80%.Among them,（Dy PO₄）_0.4/Ni₂P showed the best performance（FFA conversion rate of 98.0%and CPO yield of 95.7%）.The above results revealed the properties and characteristics of REPO₄/TMP composite materials,represented by the synthesized Dy（PO₄）_m/Ni₂P,in hydrogen conversion catalysis from multiple perspectives.Its comprehensive advantages such as low cost,stable structure and excellent properties,which indicated that the class of materials may serve as interesting novel materials involved in hydrogen conversion catalysis for in-depth exploration and application development.