Investivition Of The Preparation And Electrochemical Properties Of The Transition Metal Compounds

Energy crisis and environmental pollution are two huge challenges coming to us following with the rapid development of modern society. It is truly important and urgent to solve this problem. Being high-efficient?renewable?clean,hydrogen has been has received a huge amount of attention in these few years, which is believed to be the most promising substitute for fossil fuels. Producing hydrogen through water electrolysis?fossil fuels?biomass as well as photochemical water splitting are four main methods to the production of hydrogen. Water electrolysis has advantages of the simple equipment?higher hydrogen purity?the abundant of water resource as well as a lower cost, which will be the core technology in the hydrogen production with no doubt in the near future.However, there exist a big overpotential in the hydrogen evolution reaction, which will consume much more electric energy in the process of hydrogen production. It is necessary to search for catalysts of high HER activity and good stability for the accessible of commercial of water electrolysis. The platinum group expensive metals are the most used for HER at the moment. While a small storage and expensive hamper the wide spread of commercial. So we are expected to search for less expensive HER catalysts or loading Pt onto other base for the purpose of reducing the amount of Pt, in which ways they are hoped to low the cost of water electrolysis.In this text, we completed two works:?1? we obtained a high efficient electrochemical HER catalyst Pt/MoS₂/CC through a hydrothermal-electrodeposition method, the Pt nanoparticles were deposited onto the MoS₂ nanosheets through an electrodeposition step, in which the MoS₂ nanosheets served as a base for the first time. This method will certainly has a positive effect in the lowing the amount of Pt usage. The interaction between MoS₂ and Pt will enhance the HER process since the MoS₂ nanosheets itself is a good HER catalyst. Through the electrochemical tests toward HER, the Pt/MoS₂/CC deduced the overpotential to 0 m V comparable to commercial Pt/C. Besides, the stability of Pt/ MoS₂/CC is also rather optimal. The current density deduced from 20 m A cm-2 to 14 m A cm-2 after 50000 s in the I-t plot under a constant potential, almost 70% current density remaining in the test, indicating that the interaction between MoS₂ and Pt has a positive effect in the stability test;?2? Highly active HER catalyst of Mo₂C@MoO₂/MoS₂/CC through a hydrothermal-annealling method. According to the scanning electron microscope?SEM? ? transmission electron microscope?TEM? ? X-ray power diffraction?XRD? and X-ray photoelectron spectroscopy?XPS? technologies to anylsis the morphology?crystal lattice?crystal state and the elementary composition of the obtained samples. A high temperature annealling was used to collect all the HER merits of MoO₂?Mo₂C and MoS₂ and the obtained material will be highly active toward HER process. The electrochemical test result indicate that the onset overpotential of MoO₂@Mo₂C/ MoS₂/CC is 0 mv and the current density increased smartly with the negatice shift of overpotential, otherwise, the stability is also perfect. Such a good HER activity of our obtained material is benefit from the incerese of the active sites' number originated from MoO₂ and Mo₂C?the improve of electrical conductivity from the CC as well as the synergistic effect among all the active materials.