| The development and utilization of clean and sustainable energy sources are particularly important,owing to the decrease of traditional fossil fuels and the increasing severity of environmental problems.Currently,researchers have proposed numerous energy storage and conversion technologies to meet the demand for clean energy with high-power and high-efficiency.Hydrogen,as an alternatively clean energy,is one of the most promising energy carriers.Compared to other fuels,it has high energy density and high quality and it is clean and environmentally friendly.Moreover,it can be acquired from abundant renewable energy sources.In addition,fuel cells(FC),such as direct methanol fuel cell(DMFC)and direct formic acid fuel cell(DFAFC),are the hot topics among those research.So far,noble metals(platinum,rhodium,iridium,etc.)have better catalytic activity and corrosion resistance than non-noble metals(iron,cobalt,nickel,etc.)so that noble metals are still considered to be the best electrocatalysts for hydrogen evolution reaction(HER)and the anode parts of the methanol oxidation or formic acid oxidation fuel cells.Unfortunately,noble metals have high cost and low reserves in nature,which greatly limit their applications in hydrogen production and fuel cells.Therefore,the development of an alternative catalyst with low cost,high efficiency and good durability has become a hot research topic.One method is to reduce the using amount of noble metals by controlling their morphology and content.Another is to introduce other non-noble materials to replace noble metals for the design of multifunctional catalysts.This paper focuses on the design and research of noble metal based catalysts with high efficiency and low cost,which may lay the foundation for the practical application of electrocatalysis.The details are as follows:(1)We synthesized Pt-Ag/slicon nanowires(Pt-Ag/SiNW)composites with diffcrent dosages of Pt,using inexpensive Ag as a co-catalyst and SiNWs as carriers,and tested their catalytic performance in hydrogen evolution reaction.The results showed that the optimal composition of Pt:Ag:Si=4.1:21.5:74.4 in mass ratio.With such a low amount of Pt,the Pt-Ag/SiNW catalyst exhibited exciting HER performance.This design greatly increased the utilization ratio of Pt,which may open a new way for preparation of other noble metal based catalysts.(2)We showed the design and fabrication of the rhodium nanoparticles modified fluorine-doped graphene(Rh/F-graphene)catalyst using silicon nanowires(SiNWs)as the sacrifice template.The optimized Rh/F-graphene catalyst(Rh/F-graphene-2)had a low Rh mass fraction of 9.4%and F doping of 4.0%.Rh/F-graphene-2 served as a proton-adsorption-dominated multifunctional electrocatalyst for both HER and formic acid oxygen reaction(FAOR)with the performance and stability superior to 20 wt%Pt/C in acidic solution.This design for multifunctional catalysts may provide a new avenue for the preparation of other noble metal-based catalysts.(3)Broccoli-like gold particles with average size of 100 nm coated with gold(?)urea complexes([Au(urea)4]Cl3·2H2O),named as Au@urea complex,were synthesized in the urea hydrogen peroxide adduct(UHP)solution.During the preparation,UHP worked both as reducing agent and shell source.The as-synthesized Au@urea complex was applied as the electrocatalyst for methanol oxidation reaction(MoR).Enhanced anode current density of 15 mA·cm-2 was obtained at 0.2 V(vs.SCE)in solutions of 0.5 M KOH and 1.0 M CH3OH at a scan rate of 20 mV·s-1,which is much higher than those of most gold particles reported.In addition,the Au@urea complex catalyst also had a relatively good stability for methanol electro-oxidation. |
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