Structure Control And Electrocatalysis Of Mo-doped Pt Alloys

In the 21st century,fossil fuel shortage and how to solve energy problems have to be solved as soon as possible.The birth of hydrogen energy has created a clean and efficient way to develop new energy,which is beneficial to solving energy problems.Most of the cost in producing hydrogen is from hydrogen evolution catalysts,mainly due to high price of Pt.Therefore,decreasing the cost of catalyst is the best choice to improve development and utilization of hydrogen energy source.Alloying Pt and transitional metals such as cobalt and copper can lower prices of Pt-based catalysts and develop Pt efficiency.We use Mo?CO?₆ to reduce metal precursors so as to produce Mo-doped PtCo alloy nanowires and Mo-doped PtCu nanodendrites.The compositions analyses?XRD,ICP,XPS?,morphology analyses?TEM,HRTEM?and electrochemistry measurements?CV,LSV,HER and MOR?of as-obtained catalysts were conducted.Specific experiment contents are as follows:1.Mo-doped PtCo nanowires and were obtained by oleylamine-assisted reduction.They have many protrusion structures on the surfaces,which is conducive to enhancing surface areas.However,PtCo alloys produced by CO-assist reduction were ball-like particles,which indicates that Mo?CO?₆ can introduce trace of Mo in the alloy and affect morphologies of obtained particles by reduction method.Alloy obtained by Mo?CO?₆ reduction are with high hydrogen evolution and methanol oxidation catalytic performance.Mo and Co can change electron atmosphere states and cause strain and ligand effects,which induces small molecules absorbing and reactions between reactants.Catalytic performance can be improved through the effects.The electrochemistry measurements suggested that the overpotential of PtCoMo/C catalyst was only 21 mV,which is lower than commercial Pt/C?32 mV?.After 5000 CV cycles,the overpotential of PtCoMo/C catalyst increased by 9 mV,while commercial Pt/C increased by 15 mV.All that manifested the better performance of hydrogen evolution of PtCoMo/C.In MOR,the mass activity of PtCoMo/C was 0.87 A mg_Pt^-1,2.45 times of that of Pt/C.After 800 CV cycles,the activity of PtCoMo/C lossed by 32%,but Pt/C decreased by 60%.2.PtCuMo particles octahedron nanodendrites with corous surfaces are prepared are by a similar method.While PtCu alloy prodiuced by CO-assist reduction are hexapods,reiterating the morphology control effect of Mo?CO?₆ in solvothermal reduction.PtCuMo dendrites exhibited higher efficiency in producing hydrogen.The overpotential of PtCuMo/C was 28 mV,which shows that it can drive HER in a lower potential.After 5000 CV cycles,the overpotential increased by 4 mV,more stable than Pt/C,which thanks to protection of stable Cu in the alloy.The mass activity of MOR it is 1.02 A mg_Pt^-1,2.85 times than that of Pt/C.After 800 cycles,the activity of more stable PtCuMo/C decreased by 27%,which is mainly due to the stabilizing effect of Cu.Cu can remove intermediate product in catalytic reactions and maintain the continuous reaction.