Hydrogen Evolution Performance Of Iron Carbide/Carbon And Ruthenium/Carbon Composite Materials Prepared By Pyrolysis Of Metal Complexes

Hydrogen is a promising carrier,and has been considered as a good energy alternative fossil fule.Hydrogen can be produced during the electrolysis of water.Therefore,the development of efficient and economical electrocatalysts for hydrogen evolution reactions has become a hotspot in the field of catalysis.The main research contents and results of this thesis are as follows:?1?Synthesis of efficient and cost-effective electrocatalysts for the hydrogen evolution reaction?HER?is of great significance for solving energy crisis and fossil fuel shortage.Here we report the effective and simple preparation of iron carbide-embedded and N-doped carbon composites using an eight-coordinated iron complex bearing 2,2'-bipyridine-6,6'-dicarboxylic acid?H₂bpdc?ligand as the precursor.By controlled pyrolysis,the as-prepared material shows high HER activity with a low onset overpotential(53 mV for reaching a current density of 1 mA cm^-2)and a low overpotential(149 mV for reaching a current density of 10 mA cm^-2)in 0.5M H₂SO₄ solution.Such high performance is ascribed to the iron carbide surface with an optimized electron density by N-doped carbon.This work sheds light on the relationship between the carbon composites electrocatalysts and their metal complex precursors;it also implies a feasible way toward the design of efficient and low-cost electrocatalysts in energy conversion.?2?An efficient and stable HER electrocatalyst was prepared by a simple thermal decomposition process in which ruthenium nanoparticles were embeded in nitrogen doped carbon?NC?Ru@NC?1:5?was found to exhibit excellent HER activity and robust stability in alkaline media?1.0 M KOH?with low overpotential at 10 mA cm^-2?29 mV?,small Tafel slope(27 mV decade^-1)and a high turnover frequency?TOF?of0.96 s^-1 at an overpotential of 50 mV,which are comparable to the state-of-the-art commercial Pt/C catalyst.This high performance of Ru@NC?1:5?is ascribed to its smallest particle size?ca.2.1 nmdiameter?,large active site density and the synergistic effects with N-doped carbon support.Moreover,Ru@NC?1:5?also works well in acidic media?0.5 M H₂SO₄?.