Study Of Novel Ag₂s/CuS Nanomaterial Catalyst And Its Hydrogen Evolution Reaction Properties

Preparation of hydrogen by electrolysis of water have many advantages such as environmental friendly,abundant materials and pure hydrogen.Pt is a good hydrogen evolution catalyst but the scarcity and high cost of Pt limit its application.Hence,it is a study tendency that preparated a new catalyst to instead Pt.In this article,Ag₂S/CuS nanomaterial catalysts were synthesized by Ti-Cu-Ag amorphous ribbons reacted in sulfide acid.Meanwhile,the ribbon content,reaction time,reaction temperature and H₂SO₄ concentration would effect morophology,content and property of Ag₂S/CuS and we study the formation mechanism of Ag₂S/CuS catalyst.In this article,the CuS-based catalysts were synthesized by a kind of Ti₃₀Cu_70-xAg_x?x = 0,1,3,5,7,respectively?amorphous ribbons reacted with 15 mol/L H₂SO₄ at 90 ? for 48 hours.With the increase of the Ag content,the original ribbon is changed from amorphous to crystalline Ag + amorphous(Ti₃₀Cu₆₃Ag₇),which makes the morphology of catalyst changed from porous to particle.Meanwhile,the content of Ag₂S in the composite catalysts also increased with the increase of Ag and its corresponding catalysts' property for hydrogen evolution reaction?HER?increased firstly and then decreased.The Ag5 shows the maxium value which current density is 8 times higher than that of pure CuS?when overpotential is 0.4 V vs.RHE?and Ag₂S/CuS catalyst exhibits good stability in acid solution.The composite catalyst synthesized by Ti₃₀Cu₆₅Ag₅ ribbon shows the best property for HER because of the specific area of catalyst which determine the number of active sites and the content of Ag₂S in composite catalyst.Additionally,the different morphologies of catalysts were prepared by Ti₃₀Cu₆₅Ag₅ amorphous ribbon reacted with 13 mol/L H₂SO₄ at 120 ?fordifferent time.With the increase of reaction time?1h 72h?,the catalyst sulfurized gradually to Ag₂S/CuS and then Ag₂S resolved.The change rule of micro morphologes is nanosheet transformed to nanoparticle and then to nanosheet.The result of tested HER of catalysts indicated the current density of Ag₂S/CuS composite catalyst?48h?is 3 times higher than that of pure CuS?72h?when overpotential is 0.4 V vs.RHE.In addition,the composite catalyst shows good durability in acid solution for 14 hours.The results of reaction temperature and H₂SO₄ concentration indicate that it will effect the sulfuration degree of Cu.The catalyst transformed from Cu2 S to CuS if the reaction temperature changed from 90? to 120? or H₂SO₄ concentration changed from 11 mol/L to 15 mol/L.