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1、1 Paper Review 李俊乾 化学工程 专 14102932 Synthesis of bimetallic Pt Pd nano tubes and their enhanced catalytic activity in methanol electro oxidation 双金属铂 钯纳米管的合成和其在甲醇电氧 化增强的催化活性 2 Literature source 3 Contents Introduction 1 2 Experimental section 1 Conclusions 2 3 4 Results and discussion 4 1 Introductio
2、n The shortage of traditional energy resources and serious environmental pollution due to combustion emissions have resulted in a number of scientific studies on the development of sustainable and clean energy including fuel cells 5 1 Introduction Methanol oxidation in a direct methanol fuel cell DM
3、FC can generate electrochemical energy DMFC S working principle Cathode Polymer Anode membrane CO2 H2O H2O CO2H2O O2 H CH3OH e e Loading e Cathode catalyst Anode catalyst Waste heat Anode CH3OH H2O CO2 6H 6e 0 0 046V Cathode 3 2 O2 6H 6e 3H2O 0 1 229V CH3OH 3 2 O2 CO2 2H2O E0 1 183V This oxidation u
4、sually needs a catalyst to lower the reaction barrier to make the process efficient So far platinum Pt is the most efficient catalyst in the field Scarcity of Pt which causes its high cost inevitably impedes the active development of both scientific research and practical utilization The utilization
5、 of single component Pt in DMFCs suffers from serious carbon monoxide CO poisoning CO one of the main intermediate molecules can easily stain Pt atoms which deteriorates their catalytic activity 6 The article thought In this study we achieved higher catalytic activity for methanol oxidation using th
6、e perpendicular bimetallic Pt Pd NT array as a catalyst The investigation of the catalytic properties of bimetallic materials paves a way to substituting expensive Pt with cost competitive materials in the future 7 Experimental section2 8 2 Experimental section 5 mM PdCl2 5 mM H2PtCl6 40 mM HCl used
7、 for deposition The lengths of the NTs can be controlled by using 0 3 to 2 C AAO a vertically aligned bimetallic Pt Pd nanotube array Scheme 1 Schematic drawing of the ion distribution in a porous alumina nano template Dashed lines show the electrical double layer of the classical Gouy Chapman Stern
8、 s model between b diffusion layer and c bulk layer regions in a nanochannel Region a depicts a compact layer 9 2 3Results and discussion 10 3 Results and discussion The average outer diameter and wall thickness of the Pt Pd NTs were measured as 217 39 nm and 37 12 nm respectively As shown in the SE
9、M images the resulting morphology of the nanostructures was quite homogeneous over a large area of the sample Synthesis of bimetallic Pt Pd nano tubes and morphology analysis 11 3 Results and discussion As the Pt Pd ratio increased i e the proportion of Pt4 increased the nanostructures became rod sh
10、apes As the Pt Pd ratio decreased i e the concentration ofPd2 increased the nanostructures gradually started to show an open nano tubular ONT shape 12 3 Results and discussion When 5 mM Pd and 5 mM Pt precursor ions were in the plating solution Pt49 Pd51 NTs could be prepared A plot of atomic of Pt
11、in Pt Pd bimetallic nanostructures vs amount of Pt source 13 3 Results and discussion A TEM image of Pt Pd NTs with 1 C 2 4 0 4 mm shows the totally tubular structure from bottom to top B TEM image of a Pt Pd NT and line scanning profiles in the radial direction indicating Pt red trace and Pd green
12、trace distributions The corresponding elemental mapping images are shown for C Pt and D Pd 14 3 Results and discussion FE SEM images BSE mode of the Pt Pd NTs The lengths of the Pt49 Pd51 NTs were tuned by using A 0 3 C B 1 C and C 2 C D The Pt Pd NTs have average lengths from 1 1 0 1 mm to 4 9 0 9
13、mm 15 3 Results and discussion 返回 Electro catalytic properties A Cyclic voltammograms CVs of Pt and or Pd nanostructures with same lengths ca 2 4 mm in 0 5 M H2SO4 solution at room temperature As shown in Fig A the value of the surface charge of the Pt Pd NT catalysts was found to be 1 7 times large
14、r than that of the Pt Pd NRs 16 3 Results and discussion B Anodic striping of CO oxidation in 0 5M H2SO4 aqueous solution for different catalysts only the oxidative CO removal region is shown The observed peak intensity of CO oxidation on the Pt Pd NRs was two times higher than that of the pure Pt a
15、nd Pd NRs Interestingly the onset potential of CO oxidation for the Pt Pd bimetallic nanostructures 0 61 V appeared at a lower potential compared tothe pure Pt NRs 0 69 V and the pure Pd NRs 0 79 V 17 3 Results and discussion C Cyclic voltammograms of methanol oxidation using different catalysts The
16、 inset image shows the magnified onset potential region of the CVs The Jf Jb ratios of the Pt Pd NTs and Pt NRs were determined to be 1 6 and 1 2 respectively The Vonset was found to be in the order Pt Pd NTs 0 42 V Pt Pd NRs 0 44 V Pt NRs 0 49 V 18 3 Results and discussion D Comparison of chronoamperograms of methanol oxidation for different catalysts at 0 4 V vs Ag AgCl Electrolyte for methanol oxidation 0 5 M H2SO4 and 0 2 M CH3OH solution at room temperature Scan rate 50 mV s 1 We found that
