光催化产氢操作

Highly Selective Ammonia Synthesis from Nitrate with Photocatalytically Generated

Hydrogen on CuPd/TiO2

Miho Yamauchi,1, 2, 3, 4* Ryu Abe,1, 2, 3,Tatsuya Tsukuda,1 Kenichi Kato,3, 4, 5 Masaki Takata 4, 5 1CRC, Hokkaido University, Nishi 10, Kita 21, Kita-ku, Sapporo 001-0021, Japan, 2JST-PRESTO, Sanbancho 5, Chiyoda-ku, Tokyo 102-0075, 3JST-CREST, Sanbancho 5, Chiyoda-ku, Tokyo

102-0075, 4RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-gn, Hyogo 679-5148, Japan, 5Japan

Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-gun, Hyogo 679-5198, Japan

RECEIVED DATE (automatically inserted by publisher);

yamauchi@cat.hokudai.ac.jp

Experimental details

1. Sample preparation

2. TEM images of CuPd nanoalloys and Pd nanoparticles

3. XRD patterns of CuPd nanoalloys

4. IR spectra of CO adsorbed on CuPd nanoalloys and Pd nanoparticles

5. Photocatalytic hydrogen evolution over CuPd/TiO2, Pd/TiO2 and TiO2

6. Photocatalytic nitrate reduction over CuPd/TiO2 and Pd/TiO2

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Experimental Details

1.Sample preparation

[CuPd nanoalloy]

Copper(II) acetate monohydrate (98%, Sigma-Aldrich) and palladium (II) acetate (99.0%, Wako) were used as purchased. 1.5 mmol of copper acetate and 1.5 mmol palladium acetate were dissolved into a solution containing 250 ml water and 50 ml acetone. 150 mmol of polyvinylpyrrolidone (K30, Wako) was added into the solution and stirred vigorously. 7.5 mmol sodium tetrahydroborate (Wako) dissolved into 5 ml water was poured into the mixed solution which was warmed to 303 K. After addition of the aqueous NaBH4solution, the color of the solution immediately changed to dark brown. Stirring of the solution was continued for 1 hour at the same temperature. The resultant dark brawn colloid was collected by reprecipitation using acetone. The precipitate was washed 3 times with a mixture of 5 ml water and 30 ml acetone. ICP-AES measurement was made using an ICPE-9000 at the OPEN FACILITY, Hokkaido University Sousei Hall. The alloy composition and content were determined to be Cu:Pd = 52:48 and 7.2 wt.%, respectively.

[Pd nanoparticle]

Palladium nanoparticles were synthesized with palladium(II) chloride by ethanol reduction.1 50 ml of a 2 mM aqueous solution of palladium chloride, 1 mmol polyvinylpyrrolidone and 350 ml water were mixed and stirred for 15 min. After sufficient mixing of the metal ion and polyvinylpyrrolidone, 100 ml ethanol was added and the solution refluxed for 3 hours to yield a colloidal solution of Pd nanoparticles. The prepared nanoparticles were collected by evaporating the solvents. The metal content was calculated from the weight balance of starting materials.

[CuPd/TiO2, Pd/TiO2]

Photocatalysts were produced as follows. TiO2(AEROXIDE®, TiO2P25) kindly gifted by Nippon AEROSIL” was used as the oxide support. An aqueous solution of the CuPd nanoalloy containing 45µmol metal atoms was blended into 1 g TiO2P25 powder, to yield a catalyst containing a metal percentage of metal to whole catalyst was 0.37 wt. %. After 15 minutes of ultrasonification and filtration of the mixture, a gray paste was obtained. This paste was dried under vacuum at room temperature. A TiO2 supported catalyst containing palladium nanoparticles was prepared in a similar manner such that the molar content of palladium was the same as the CuPd/TiO2 catalyst, i.e., 0.46 wt. %.

[n-Cu-Pd/TiO2]

1.5 mmol of palladium acetate was dissolved into 10 ml acetone and 1g TiO2 added. The mixture was heated in a water bath and stirred until the acetone completely evaporated. The resultant residue was mixed with 10 ml aqueous 1.5 mmol copper acetate solution and again stirred while heating in a water bath until a powdery sample was obtained. This powder was calcined at 623 K for 6 hours and reduced under an H2 gas flow at 723 K for 2 hours.

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