Preparation Of Titanium Dioxide Based Electrocatalyst And Its Hydrogen Evolution Property

The energy demand in today's world still depends on non-renewable fossil energy such as coal and oil etc..However,the excessive development and use of fossil energy have caused serious resource depletion and environmental pollution.Therefore,seeking green and sustainable energy has become a problem.Therefore,the hydrogen is best energy source instead of fossil energy sources,because it has high combustion value,zero pollution,and environmental friendliness.At present,in many industries uses natural gas steam reforming process for the production of hydrogen gas.But,during this process emits a large amount of greenhouse gases and which is not in line with the concept of green sustainable development.In recent years,photocatalytic process used for hydrogen production but due to the low utilization of sunlight,production technology is not mature and other issues limit its widespread application.Considering these facts,the electrochemical water splitting is promising process for generation of high purity hydrogen gas.In this process,a certain voltage is required for the generation of high-purity hydrogen gas.So that the use of electrolyzed water to produce hydrogen and broad application prospects.The key step in hydrogen production from electrolyzed water is Hydrogen Evolution Reaction?HER?,in which the reduced water is hydrogen and released.This process requires high activation energy and high-efficiency catalysts.Platinum-based catalysts are the best performing HER.But,platinum is a precious metal.The reserves in the natural world are scarce and therefore expensive,and it is difficult to adapt to large-scale production and utilization in the future.However,the development of low-cost,abundant,high-efficiency and stable HER catalyst has become a hot spot in the field of hydrogen production from splitting of water.Based on the above research,to prepare composite materials with different TiO₂ groups and using the synergistic effect between the components.The HER catalyst with excellent hydrogen evolution performance is obtained.The specific research contents are as follows:?1?The TiO₂ nanobelts were synthesized by hydrothermal method using P₂₅ as raw material,and the WS₂@TiO₂ catalyst was synthesized by hydrothermal method using the synthesized TiO₂ nanobelts as the substrate.The electrocatalytic performance were tested using three-electrode system.The results show that the banded TiO₂ surrounded by the WS₂ sheet showed good electrocatalytic activity due to the synergistic effect arising from both WS₂ and TiO₂.Also,the effect of hydrothermal time on the morphology of the synthesized WS₂@TiO₂ composite were studied.The WS₂@TiO₂ catalyst exhibits better electrolysis hydrogen evolution performance than that of TiO₂ and WS₂ catalysts in alkaline electrolyte.It shows a low overpotential of 150 mV at a current density of 10 mA cm^-2 with a Tafel slope of 120 mV dec^-1,and the high retention rate is 88.10% in alkaline electrolyte for 24 h.It indicates that the WS₂@TiO₂ catalyst has excellent stability.?2?Aniline was used as carbon and nitrogen source,and phosphomolybdic acid was used as molybdenum source.TiO₂ nanospheres were added to synthesize NC/Mo₂C@TiO₂ catalyst during aniline polymerization.The effect of TiO₂ addition on the electrolysis hydrogen evolution performance of catalysts were investigated.The NC/Mo₂C@TiO₂ catalyst were used to study the HER performances in 1 M KOH.The catalyst electrode material has abundant active sites and exhibits excellent hydrogen evolution activity.It has an extremely low overpotential of 150 mV at 10 mA cm^-2,and a small Tafel slope(158 mV dec^-1).Furthermore,it has high retention rate of 92.88%in alkaline electrolyte for 35h.It suggests that the NC/Mo₂C@TiO₂ has remarkable stability in 1 M KOH.?3?The g-C₃N₄ was used as carbon and nitrogen source.The Co,NC@TiN/TiO₂ nanocomposite structures were synthesized by using tetrabutyl titanate,cobalt nitrate and ammonia water.The three-electrode system was used to study the hydrogen evolution performance of synthesized catalysts.The results show that the Co,NC@TiN/TiO₂ has good hydrogen evolution performance.It has an overpotential of 124mV to drive a current density of 10 mA cm^-2 with Tafel slope is 146 mV dec^-1.The synthesized Co,NC@TiN/TiO₂ catalyst has excellent stability in alkaline electrolyte for 50 h and 97.00% retention rate.