Catalytic Reduction of Nitrate and Nitrite on Pt–Cu/Al2O3 Catalysts in Aqueous Solution: Role of the Interaction between Copper and Platinum in the Reaction

Abstract Bimetallic platinum copper catalysts were prepared by deposition of copper on a parent monometallic platinum catalyst. Two techniques were employed favoring the deposition of copper either on the parent metal or on the support. The activity and selectivity of copper and platinum monometallic catalysts are compared to those of their bimetallic counterparts. Copper reduces nitrates and nitrites according to a redox process but deactivates rapidly. Monometallic platinum catalysts are inactive for nitrate reduction, while nitrates are totally and rapidly reduced on Pt–Cu bimetallic catalyst when both metals are in close contact. In the bimetallic catalyst, the role of copper is to reduce nitrate to nitrite according to a redox process. In this step, the interaction between copper and platinum is of major importance to maintain copper in the metallic state by way of hydrogen adsorbed on platinum. However, copper has a negative influence on the selectivity toward nitrogen.

[1]  F. B. Noronha,et al.  Characterization of palladium-copper bimetallic catalysts supported on silica and niobia , 1991 .

[2]  J. A. Schwarz,et al.  Effect of calcination temperature of alumina on the adsorption/impregnation of Pd(II) compounds , 1991 .

[3]  K. Vorlop,et al.  Kinetic investigation of the catalytic nitrate reduction : Construction of the test reactor system , 1999 .

[4]  J. Domínguez,et al.  Preparation of platinum-gold bimetallic catalysts by redox reactions , 1994 .

[5]  J. Barbier,et al.  Preparation of PtReAl2O3 catalysts by surface redox reactions I. Influence of operating variables on Re deposit in the presence of hydrochloric acid , 1996 .

[6]  J. Dumas,et al.  Préparation de Pt-Cu/SiO2 par oxydo-réduction de surface , 1998 .

[7]  Francesco Pinna,et al.  Use of palladium based catalysts in the hydrogenation of nitrates in drinking water: from powders to membranes , 2000 .

[8]  K. Vorlop,et al.  Kinetische Charakterisierung von Katalysatoren zur selektiven Entfernung von Nitrat und Nitrit aus Wasser , 1993 .

[9]  U. Prüße,et al.  Improving the catalytic nitrate reduction , 2000 .

[10]  C. L. Pieck,et al.  Influence of PtRe interaction on activity and selectivity of reforming catalysts , 1995 .

[11]  G. Horányi,et al.  Electrocatalytic reduction of NO2− and NO3− ions at a platinized platinum electrode in alkaline medium , 1985 .

[12]  L. Baert,et al.  Chemo-denitrification of nitrate-polluted water. , 1990, Environmental pollution.

[13]  A. Bard,et al.  Standard Potentials in Aqueous Solution , 1985 .

[14]  I. Turunen,et al.  Kinetics of nitrate reduction in monolith reactor , 1994 .

[15]  K. Vorlop,et al.  Catalytical removal of nitrate and nitrite from drinking water: 1. Screening for hydrogenation catalysts and influence of reaction conditions on activity and selectivity , 1993 .

[16]  M. Hansen,et al.  Constitution of Binary Alloys , 1958 .

[17]  P. Sermon.  Characterization of palladium blacks: II. Comparison of various methods for estimating surface area or particle size , 1972 .

[18]  L. Lefferts,et al.  Electrocatalytic nitrate reduction on palladium based catalysts activated with germanium , 1999 .

[19]  M. Čeh,et al.  Characterization of supported Pd-Cu bimetallic catalysts by SEM, EDXS, AES and catalytic selectivity measurements , 1997 .

[20]  N. E. Skelly.  Separation of inorganic and organic anions on reversed-phase liquid chromatography columns , 1982 .

[21]  K. Vorlop,et al.  Optimierung von Trägerkatalysatoren zur selektiven Nitritentfernung aus Wasser , 1992 .

[22]  A. Pintar,et al.  Catalytic hydrogenation of aqueous nitrate solutions in fixed-bed reactors , 1999 .

[23]  A. Pijpers,et al.  The oxidation state of Ge on Pd/C catalysts investigated by XPS , 1999 .

[24]  S. Motoo,et al.  The electrochemical behavior of ad-atoms and their effect on hydrogen evolution: Part I. Order-disorder rearrangement of copper ad-atoms on platinum , 1976 .

[25]  Allen J. Bard,et al.  Encyclopedia of Electrochemistry of the Elements , 1978 .

[26]  J. Levec,et al.  Kinetics of the catalytic liquid-phase hydrogenation of aqueous nitrate solutions , 1996 .

[27]  C. Bennett,et al.  The Influence of Particle Size on the Catalytic Properties of Supported Metals , 1989 .

[28]  Thiruvenkatachari Viraraghavan,et al.  Nitrate Removal From Drinking Water—Review , 1997 .

[29]  O. Petrii,et al.  Electroreduction of nitrate and nitrite anions on platinum metals: A model process for elucidating the nature of the passivation by hydrogen adsorption , 1992 .

[30]  J. Levec,et al.  Hardness and Salt Effects on Catalytic Hydrogenation of Aqueous Nitrate Solutions , 1998 .

[31]  J. Lee.  Concise inorganic chemistry , 1965 .

[32]  M. Breiter.  Chemisorption of copper atoms on platinized platinum in sulphuric acid solution , 1969 .

[33]  K. Vorlop,et al.  Development of catalysts for a selective nitrate and nitrite removal from drinking water , 1993 .

[34]  S. Kuwabata,et al.  Assimilatory and dissimilatory reduction of nitrate and nitrite with a tris(tetrabutylammonium) nonakis(benzenethiolato)octasulfidohexaferratedimolybdate(3-) modified glassy-carbon electrode in water , 1986 .

[35]  Jeanne Burbank,et al.  Atlas D-Equilibres Electrochimiques , 1964 .

[36]  M. Primet,et al.  Infrared investigation of hydrogen adsorption on alumina-supported platinum , 1973 .

[37]  L. Lefferts,et al.  The electrocatalytic reduction of NO3− on Pt, Pd and Pt + Pd electrodes activated with Ge , 1997 .

[38]  P. G. Menon,et al.  Separate determination of Pt and Re in Pt$z.sbnd;Re$z.sbnd;Al2O3 reforming catalyst , 1973 .