镍钴硫活性阴极的研究

RASEARCH OF Ni—Co—S EFECTROCATALYTIC CATHODES FOR HYDROGEN EVOLUTION REACTION

本文研究了用电镀的方法在铁表面形成Ni—C0一S涂层的新方法,把铁电极放在台有硫脲的硫酸镍和硫酸钻的混合液中进行阴极极化,便会在铁电极表面形成一层对阴极析氢反应电催化活性高(60℃,5N NaOH溶液,200mA·cm^(-2)时的氢超电压75mV)、附着牢度好、寿命长(5N、NaOH溶液中,电解1500小时、催化活性未降低)的Ni—Co一S涂层,该涂层中除六方晶型Ni_3S_2(a_o=5.741A,Co=7.139A)外,还有CoNi_2S_4和NiCo_2S_4两种物相.本文还对电沉积Ni—Co一S涂层的反应机理进行了初步讨论.

In this paper,Ni—Co—S cathodic coating with high electrocatalytic activity was electroplated on iron substrate electrode by an electrochemical method not reported as yet. Through a series of crossed experiments,optimal process conditions were sieved out,with the composition of electroplating-solution being:NiSO_4. 6H_2O,COSO_4·6H_2O,(NH_2)_2CS,H_3BO_3 and additives,the electroplating operation condition being:2.SpH,50℃,15mA/cm^2 and 2 hours.The electro- catalytic activity of the coated cathode for hydrogen evolution was tested at 60℃,in 5 N NaOH solution,with current density of 200 mA/cm^2,the over- voltage was only 75 mV,which was maintained for 1500 hours in life-electro- lysis. The results of X-ray diffraction,X-ray fluorescence analysis,XPS ene- rgy spectrum analysis,scanning electron microscopy and microprobe analysis indicate that the coating is of a hexagonal system Ni_3S_2 crystal structure, a_0=5.741,c_0=7.139,besides,there was a little CoNi_2S_4 and NiCo_2S_4 in coating.The mechanism of coating electroplating reaction has been discus- sed.