| The high cost and poor catalysis of electrode materials in DEFC, together with other technical problems, block DEFC from commercialization. In order to low the cost of DEFC, and greatly drive the development of DEFC. It's important to in search of low-cost catalyzer to replace Pt, thus has an important effect on the development of fuel cell.In this paper we forecast the feasibility of Pd replace Pt in theory. CO adsorption on the three low index surfaces of Pd, i.e., (100), (110) and (111) was studied by the density-functional theory (DFT) with method of B3LYP. The three adsorption patterns of CO adsorption on Pd, top, hollow and bridge, respectively, were taken into account of calculation. By means of calculation results, that is, binding energy, geometrical structure, Mulliken population and net charge, it has concluded that a strongσ-πbond is formed with CO adsorption on Pd surfaces; the net electron transfer flows from Pdn to CO; CO adsorption on Pd surfaces prefers the bridge pattern to others; and the most severe CO poisoning happens on Pd (111). The poisoning to the three Pd surfaces decreases in sequence: Pd (111) > Pd (100) > Pd (110). Meanwhile, the degree of CO molecule activation with adsorption on Pd increases in the order: hollow > top > bridge. The results also disclosed that CO poisoning to Pd is not as severe as that to Pt.A great deal of energy is consumed in the process of water electrolysis because of the existence of the overpotential. In order to lower the energy consumption, it is crucial to develop new type materials with high catalytic activity of hydrogen evolution and oxygen evolution with low cost. Currently main concentration is focused on the catalyst of the non-noble metal in China, especially nickel group catalyst, because their catalytic activity is equal with noble metals in alkaline media. In this paper, we integrate experimental and theoretical to study the effect of P content and surface morphology of Ni-P alloy on hydrogen evolution catalytic activity.In experiment we prepared Ni-P alloys electrode with P content in the range from 5.8 to 10.0 wt% by means of changing deposition technique, and found Ni-P alloys electrode with P content of 6.0wt %(10.8at%) exhibited the best catalysis to hydrogen evolution in all investigated alloys. By analysis of XRD and SEM we found P content and surface morphology of Ni-P alloy have an important effect on catalytic activity of hydrogen evolution. It show that the structure of Ni-P alloy has already gradually presents amorphous with the increase of the P content, when the content of P is over 8.6wt% (11.89at%). the structure has already gradually presents amorphous.Theoretical study indicate the adsorption of H on NinP (n=1~11) and Nim (m=2~12) clusters is studied by the density-functional theory (DFT) with method of B3LYP. By means of Front Molecular Orbital (FMO) theory to analyze hydrogen evolution catalytic activity of NinP and Nim participated in electrochemical reaction (Volmer reaction) and electrochemical desorption reaction (Heyrovsky reaction), and binding energy is used to analyze the strength of H adsorption or the extent of electrochemical recombination reaction (Tafel reaction), and found Ni–P alloy has the higher catalytic activity than Ni; the content of P affect the mechanism of HER. If the mechanism of HER carries on the step of Volmer reaction and Heyrovsky reaction Ni-P alloy with P content in the range from 14.3at% to 11.1at% has the highest catalytic activity, but if the mechanism of HER carries on the step of reaction Volmer reaction and Tafel reaction, Ni-P alloy with P content in the range from 14.3at% to 9.1at% has the highest catalytic activity. In conclusion, whether the mechanism of HER carries on the step of electrochemical reaction and electrochemical desorption reaction or electrochemical reaction and electrochemical recombination reaction, the Ni–P alloy with the content of P in the range from 14.3at% to 9.1at% has the highest catalytic activity.
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