1. Underpotential Deposition
欠电位沉积
报告人：王文心

2. Contents 1 Underpotential Deposition 2 The Mechanism of UPD 3
UPD on Different Metals 4
Application of UPD

3. Underpotential Deposition
Underpotential deposition (UPD)
is a phenomenon of electrodeposition of a species (typically reduction of a metal cation to a solid metal) at a potential less negative than the equilibrium (Nernst) potential for the reduction of this metal.
Beginning
Analysis
Mechanism
Application
1910s
1940s
1970s
now

4. The Mechanism of UPD

5. The Thermodynamic Mechanism of UPD

6. The Thermodynamic Mechanism of UPD

7. Under Potential Displacement
D. M. Kolb, M. Przasnyski, H. Gerischer, Underpotential deposition of metals and work function differences, Journal of Electroanalytical Chemistry, 1974, 54:25

8. The Common Characteristics
The work function and the side-action varies with the coverage changes
UPD potential affect the adsorption valences
UPD changes potential distribution and solvent molecules microscopic arrangement on interface
Common Characteristics
The first monolayer effects further deposition.
More than one UPD peak; lattice structure is different with different deposition potential; coverage increase when potential near the bulk peak

9. UPD on Different Metals
substrate material
solution
Different Metals
Contents
Reactants
Electrolyte
pH Value
Additive
Singlecrystal Surface
Polycrystal Surface
Ag+/Pt
Ag+/Pd
Ag+/Au
Cd2+/Pt
Cd2+/Au
Cd2+/Cu
Cd2+/Ag
ΔEUPD / V
0.44
0.30
0.51
0.96
0.23
0.16
Solution
H2SO4
HClO4
Na2SO4 C
/ mol/L
0.5
1.0
D. M. Kolb，Advances in Electrochemistry and Electrochemical Engineer. New York: John Wiliy,1978, 11:125

10. Different Systems Electrode UPD ions Pt
Ag+、Cu2+、Hg2+、Pb2+、Bi3+、Cd3+、Tl+、Sb3+、Ge4+、Sn4+ Au
Ag+、Cu2+、Hg2+、Pb2+、Bi3+、Cd3+、Tl+、Sb3+、Sn4+、Zn2+、Pd2+ Ag
Cu2+、Pb2+、Bi3+、Cd3+、Tl+、Sn4+、Zn2+ Pd
Ag+、Cu2+、Bi3+、Cd3+、Pb2+、Tl+、Sn4+ Cu
Cd3+、Pb2+、Tl+
Glassy Carbon
Ag+、Cu2+、Hg2+、Pb2+、Bi3+

11. Different Research Method
1. potential sweep method 1 5
4. XPS 2 4
5. Electrochemical spectroscopy
2. potential step method 3
3. RRDE method

12. Yangchuan Xing, et al. J. Phys. Chem. Lett. 2010, 1, 3238–3242
The Application of UPD
Cu UPD-galvanic replacement has become a useful method to prepare catalyst.
Models of pseudomorphic monolayers of Pt on three different substrates inducing compressive strain (Ru(0001) and Pd (111)) and tensile strain (Au(111))
R R Adzic, et al，Platinum monolayer fuel cell electrocatalysts. Topics in Catalysis, 2007, 46 (3–4): 249–262
Yangchuan Xing, et al. J. Phys. Chem. Lett. 2010, 1, 3238–3242

13. The Application of UPD
Facile Fabrication of Ultrathin Pt Overlayers onto Nanoporous Metal Membranes via Repeated Cu UPD and in Situ Redox Replacement Reaction

14. The Application of UPD Cu Cu UPD Pt UPD Au replacement
Cu UPD –Au replacement
R. Wang, et al., Adv. Mater. 2010, 22, 1845.

15. Thanks for your attention!