Preparation Of RuO₂ And IrO_x Catalyst And Their Electrocatalytic Performance

Hydrogen industry is often considered as the most promising component of future energy.Using hydrogen as medium,proton exchange membrane fuel cells(PEMFCs)and electrocatalytic water splitting can provide and store energy via chemical bonds effectively.Electrocatalyst can increase the reaction rate with the order of magnitudes,and its development influences the commercialization of the hydrogen industry.Currently,an economic-efficient approach to produce H2 is coming from reforming hydrocarbons,but is always contains trace of unaccep table CO.The trace of CO lead to the rapid deactivation of the Pt-based catalyst that it is m ost popular hydrogen oxidation reaction(HOR)electrocatalyst for PEMFCs.Besides,H2O splitting can produce pure hydrogen.It is environmentally friendly process but limited by the high cost of precious metal electrocatalysts.Especially,since the OER involves multistep proton-coupled electron transfer reaction pathways,the energy conversion efficiency of whole water splitting is restricted by the naturally sluggish kinetics of the oxygen evolution reaction(OER).It usually requires large amount of precious metal catalyst.Currently,much efforts have been devoted to improving the electrocatalytic activity and stability through manipulating the morphology,electronic structure and surface structure of the nanomaterials.Lowing the usage of electrocatalyst,especially for noble electrocatalysts,is another principle for the large-scale commercialization.Therefore,how to tailor catalyst properties to obtain both superior catalytic performance and atomic efficiency in electrocatalytic is attractive subject.The main contents of this paper are as follows:1.Developing anti-CO tolerance electrocatalyst for HOR in PEMFC.We used a hydrolysis method to synthesize Ru-MOx(M=Ti,Nb and Ta)catalysts.Transition metal oxide can weaken the interaction between Ru and CO,inhibiting the adsorption of CO via adjusting electronic band structure of Ru.Moreover,the oxophilic Ru forms OH species to oxidize CO at a lower overpotential.Compare to the comm ercial PtRu electrocatalyst,the Ru-MOx showed enhanced electrocatalytic stability under 0.1%CO/H2 condition.Particularly.Ru-TiO2 can remain 95%initial activity after 20 hours test.This study indicates that constructing new catalytic active interface between metal and metal oxide can significantly improves the precious metal catalysts to tolerate poisonous species.2.Optimizing size effect of IrO2/TiO2 for OER in water splitting.A series amount of Ir loadings were supported in multilayer TiO2,and the OER performance was investigated on these electrocatalysts.As the loading of Ir decreases from 17%to 0.24%,the size of the nanoparticles is decreased from 3.6 nm to 1.1 nm.In addition,an atomic dispersion Ir was observed on 0.24%IrO2/TiO2.The IrO2/TiO2 with single atom provides an ideal approach to maximize the efficiency of atom utilization and boosts the electrocatalytic performance on acid OER with the mass activity of 7088.7 A gIr-1.It is underlined that the advantages of a suitable oxide support and size effect of the IrO2 can drastically reduce iridium loading and with high atomic utilization.