The Preparation Of Cobalt-nitrogen Doped Porous Carbon Materials And Study Of Electrocatalytic Hydrogen Production

Because of the rapid development of science and technology,our life has undergone great changes in the past decades,while human beings are facing unprecedented energy problems.For example,some non-renewable energy is consumpted.As a kind of energy which is clean,non-polluting,high calorific and widely distributed worldwide,hydrogen is favored by people.The most commonly method of hydrogen production is electrolysis water,this method is very productiveness,easy to operate and environment friendly.For this preparation method,it is very important to select an efficient electrode material,so it is the key point to produce a kind of electrode material which can reduce the hydrogen evolution reaction over potential.Recently,the transition metal doped carbon and nitrogen materials have been widely concerned.In this paper,cobalt-nitrogen doped porous carbon materials with high activity,low price and good stability were synthesized by different templates,the structure and hydrogen-evolution activity were studied.This paper mainly includes the following three parts:1.The Co,N/C materials are obtained by solvent-induced self-assembly?EISA?method.The electrocatalytic properties of obtained materials are controlled by controlling different carbonization temperatures.When comparing the current density in the linear scan curve?LSV?with the same value,the potential and Tafel slope sizes are needed to analyze the electrocatalytic hydrogen production activity of the materials.Under acidic condition,the MFCo800 sample is-166 mV when the current density is 10 mA cm^-2,and the Tafel slope is 88.1 mV dec^-1;In alkaline condition,the over potential is-203 mV,the Tafel slope is 69.8 mV dec^-1.Above data show that MFCo800 has good electrochemical properties.2.There is a disadvantage of the EISA method,the complex evaporation process,it is difficult to produce carbon materials,resulting in low yield.In order to solve this problem,we adopt a kind of simple operation,high yield of molten salt method to synthesize Co,N/C material.After the structural characterization and electrochemical properties of the obtained materials,under acidic condition,when the current density is 10 mA cm^-2,the CoNPC over potential is-171 m V,less than the-340 mV of CoPC,and the Tafel slope of CoNPC is 75.9 mV dec^-1,far less than 204 m V dec^-1of CoPC.Similarly,in alkaline condition,the CoNPC over potential is-202 m V,less than the-367 mV of CoPC,and the Tafel slope is 105.7 mV dec^-1,less than 241.5 mV dec^-11 of CoPC.3.The synthesis method used in experiment three is similar to that of experiment two.On the basis of experiment two,the difference is that a raw material ZnCl₂ is removed,and CoCl₂·6H₂O is substituted for Co?NO₃?₂·6H₂O as cobalt source,and molten salt.By controlling the different dosage of CoCl₂·6H₂O,the electrochemical properties of obtained materials are controlled,and three kinds of materials of CoNDC-0.5,CoNDC-1.0 and CoNDC-1.5 are obtained.The CoNDC-1.5 has the lowest over potential and Tafel slope,respectively,-168 mV and 62.8 m V dec^-1,when the electrochemical activity is measured under acidic conditions and the current density is 10 mA cm^-2.