Preparation And MOR Performance Of Anode Catalyst For Direct Methanol Fuel Cell

In an ideal state,direct methanol fuel cell is regarded as a kind of clean energy.It has the advantages of high energy conversion rate,simple structure design,low raw material cost,and easy storage and transportation.It is an effective solution that can be used to alleviate energy shortage in the future.However,the preparation of anode catalyst for direct methanol fuel cell still faces some problems,and efforts should be continued to reduce the preparation cost and improve the activity and stability of the catalyst.Therefore,the development of anode catalyst with low noble metal loading rate and good toxicity resistance,which can support the long-term stable operation of direct methanol fuel cell,is of great significance for the final commercial application of direct methanol fuel cell.In this paper,several anode catalysts for direct methanol fuel cell were prepared and their catalytic performance was studied.The main work content and research results are as follows:（1）PtNi alloy can be prepared from transition metal Ni and precious metal Pt under different reaction temperatures by ethylene glycol reduction method,and it is supported on the surface of graphite oxide to obtain Pt_xNi_y/rGO catalyst.Structural analysis and morphology characterization of the prepared catalyst were carried out using testing methods such as SEM,TEM,XRD,XPS,etc.The performance of the catalyst was tested by cyclic voltammetry and chronoamperometry.The test results show that the metal particle dispersion is good,and the degree of PtNi alloying is high.The Pt₃Ni₁/rGO catalyst prepared at a Pt/Ni atomic ratio of 3:1,reaction temperature of 140℃,and reaction time of 4 hours has the best methanol catalytic activity,with a peak current density of 2367.12 mA.mg^-1 and a steady-state current density of 706.91 mA.mg^-1,both of which are superior to commercial Pt/C.While reducing the amount of precious metals used,the performance of the catalyst against CO_ads poisoning was improved.（2）Different contents of CeO₂ with special morphology were introduced into graphite oxide to prepare composite support CeO₂-rGO-x%.Pt was loaded on the support surface by ethylene glycol reduction method,and Pt/CeO₂-rGO-x%catalyst could be prepared under control.Structural analysis and morphology characterization of the prepared catalyst were carried out using testing methods such as SEM,TEM,XRD,XPS,etc.The performance of the catalyst was tested by cyclic voltammetry and chronoamperometry.The results showed that Pt particles were uniformly dispersed,and when CeO₂ doping accounted for 10%,the peak current density of the catalytic reaction reached 3716.13 mA.mg^-1,which is 2.19 times that of commercial Pt/C peak current density.The timing current test results show that Pt/CeO₂-rGO-10%can still maintain a relatively stable state after 3600s of testing,with an output current density greater than 3000 mA.mg^-1,which is superior to commercial Pt/C.Ce exists in the form of+3 and+4 valences in the catalyst,and the conversion of valence states enables it to have good oxygen storage capacity,which is conducive to removing toxic intermediate CO_ads generated during the catalytic reaction process and improving the stability of the catalyst.（3）A series of Pt_xNi_y/CeO₂-rGO catalysts loaded on CeO₂ and rGO composite carriers with different Pt/Ni atomic ratios were prepared using a two-step method.XRD,SEM,TEM,XPS and other methods were used to characterize the phase structure and morphology characteristics of the catalyst.The test results indicate that the calcination treatment and high-temperature reduction environment did not change the structure of CeO₂,and PtNi alloy particles were uniformly dispersed in carrier surface,and there is no obvious agglomeration phenomenon.The catalyst Pt₃Ni₁/CeO₂-rGO with a Pt/Ni atomic ratio of 3:1 exhibits the best catalytic performance,with a peak current density of 3952.20 mA.mg^-1,which is 2.3 times that of commercial Pt/C.The ratio of I_f/I_b is 8.63,indicating good detoxification performance.