| At present,human society mainly uses fossil energy such as oil and coal,which are not regeneratively depleted,and a series of side reactions are generated during the combustion process,producing a large number of harmful gases(CO,CO2,etc.),which not only cause great harm to the environmental,but also cause the global greenhouse effect.For the sustainable development of mankind,it is urgent to develop new energy sources.As a new energy source,hydrogen energy has the advantages of high efficiency,cleanliness,and greenness.Therefore,if a large amount of hydrogen energy can be produced,the demand for oil can be greatly relieved,and there is no pollution to the environment.Therefore,how to efficiently produce hydrogen has attracted wide attention.Photocatalytic hydrogen evolution can produce a large amount of hydrogen by using renewable energy solar energy,so extensive research has been conducted on photocatalysis.In the photocatalytic dye sensitization system,the dye absorbs light,then transfers electrons to the hydrogen evolution co-catalyst to reduce the hydrogen protons adsorbed on the surface to generate hydrogen gas.In this process,the co-catalyst effectively separates the electrons and reduces the overpotential of hydrogen evolution,so as to produc hydrogen efficiently.Therefore,finding cheap and abundant co-catalysts has become the key to improving the photocatalytic hydrogen production abilityTransition metals such as Fe,Co,Ni and others have been widely used in photocatalytic systems due to their abundant and cheap resources in nature.In this paper,the core-shell structure of iron boride alloy coated with metal nickel or metal cobalt nanoclusters was prepared as a co-catalyst,eosin Y was used as a photosensitizer,under the condition of trimethylamine as an electron donor,and the reaction was carried out under visible light,for efficient and stable hydrogen production.The paper is mainly divided into the following two parts:(1)Applying the principle of electrochemical displacement to convert Fe-B@Fe into Fe-B@Ni after immersed in NiC12 solution in a glove box filled with Ar in one step.Compared with the precursor,the prepared Fe-B@Ni exhibits excellent electrocatalytic and photocatalytic hydrogen evolution activity.The highest quantum effciency in the dye-sensitized system at 420 nm reaches 51%,which is higher than many reported dye-sensitivity non-precious metal hydrogen production data.In the electrocatalytic system,when the current density is 10 mA cm-2,the overpotential is only 202 mV in 1 M KOH solution with a pH of 14.The significant hydrogen production activity was attributed to the fact that after the metal Fe in Fe-B@Fe was replaced by the metal Ni,the desorption energy of the formed H2 on the metal Ni is lower than that on the metal Fe,which is beneficial to the H2 desorption,so the activity of hydrogen production is improved;and because both Ni and Fe-B alloys are magnetic,the catalyst is easy to be recycled from the reaction system.(2)The core-shell structure of Fe-B alloy coated with metal cobalt was prepared in CoCl2 solution under the same conditions as(1)by the same electrochemical corrosion principle.We found that the photocatalytic activity increased in the same way,the best catalyst Fe-B@Co-2.97 in the photocatalytic system is 1.61 times the hydrogen production activity of the precursor Fe-B@Fe,and by comparing Fe-B@Co and Fe-B@Ni proves that the binding energy of metal to H atom has a significant effect on hydrogen evolution activity. |
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