Preparation Of Transition Metal Phosphide Coupled Ruthenium Nanomaterials And Study Their Electrolytic Water-splitting Performance

It is urgent to explore green,low-carbon and sustainable energy technologies for future societies.As one of the most promising strategies for carbon-free hydrogen production,electrolytic hydrogen production has attracted extensive attentions because of its green and high efficiency advantages.However,it is limited by the complex electron transfer process of the associated electrode reaction and the slow kinetics in solution,leading to higher thermodynamic potential than the ideal state.Therefore,the design and development of highly active and well-durable electrocatalysts to reduce the energy consumption of hydrogen production has become a hot research direction for electrolytic hydrogen production.Herein,this thesis focuses on the design and preparation of transition metal phosphides（TMPs）coupled with noble metal ruthenium（Ru）nanocatalysts to enhance TMPs-based electrocatalytic activity by coupling TMPs with Ru and optimally modulating the electronic structure with the help of morphology modulation,atomic doping and other strategies.In this thesis,a series of TMPs-coupled Ru nanomaterials were designed and prepared,and their applications in electrocatalysis were investigated,and the studies are summarized as follows:1.Faced with the problems of poor activity and low efficiency of TMPs-based catalysts.In this chapter,an atomically co-doped porous Ru/B-Co P catalyst was prepared using Na BH₄ assisted as well as inorganic synergistic phosphorization strategy.The unique porous nanosheet configuration was able to increase the number of active sites and the Ru,B atom doping modulated its electronic structure.As a result,the designed Ru/B-Co P catalysts exhibit excellent HER performance over a wide p H range,requiring only 39,52,82 and 87 m V overpotential to achieve 10 m A cm^-2 in 0.5 M H₂SO₄,1 M KOH,1 M KOH+seawater and 1 M PBS electrolytes.In addition,the assembly of a two-electrode electrolyzer to simulate hydrogen production from renewable energy-driven electrode reactions shows that Ru/B-Co P catalysts have great potential in the field of green and clean energy.2.To address the problems of single catalyst function and inadequate exposure of active sites in the previous system.In this chapter,Ru-doped 2D asymmetric Ru-Co P and Ru-Co₃O₄ catalysts were prepared by improved experiments.Thanks to the Ru and Co synergistic effect and the ultrathin 2D nanosheet structure providing abundant active sites.The Ru-Co P catalysts were enabled to exhibit excellent HER performance of 80,47 and 107 m V at 10 m A cm^-2 in 0.5 M H₂SO₄,1 M KOH and 1 M PBS.The Ru-Co₃O₄catalysts also exhibited excellent OER(269 m V@10 m A cm^-2)and ORR(E_1/2 0.79 V)activity and durability.The asymmetric electrode electrolyzer assembled with Ru-Co P and Ru-Co₃O₄ was simulated for coupling with renewable energy sources,verifying that the electrolyzer has significant potential in the field of energy conversion.3.Based on the work in the previous chapter,the catalysts were prepared for the complex catalyst preparation process as well as for the exploration of versatile catalysts suitable for large-scale preparation.In this work,Ru/B-Ni₂P/Ni₅P₄ catalysts were prepared using rapid reduction as well as gas-phase phosphorization strategies.The catalysts further enhance the catalytic activity,reduce the noble metal content with only6.28 wt.%of Ru atoms,and regulate the electronic structure based on atomic doping to optimize the kinetic process of the catalytic reaction.The experimental results show that the prepared Ru/B-Ni₂P/Ni₅P₄ exhibits superb activity for HER and OER in 1 M KOH,reaching 10 m A cm^-2 at only 31 and 270 m V,respectively,and its HER mass activity far exceeds that of Pt/C catalysts.It also has excellent UOR activity(140 m V@10 m A cm^-2).The developed electrocatalysts are expected to advance the future development of hydrogen production technology and open the way for the large-scale synthesis of high-efficiency electrocatalysts,especially in the UOR‖HER coupled electrolyzer,which requires a low voltage（1.48 V）to drive the electrode reaction for hydrogen production.