Hokkaido University

Miho Yamauchi

Ryu Abe

Disclosed are: a catalyst which is capable of reducing and converting nitrate ions into ammonia without adding a hydrogen gas thereto; a method for synthesizing ammonia using the catalyst, wherein nitrate ions are reduced without adding a hydrogen gas thereto; and a method for decreasing nitrogen oxide in water by reducing nitrate ions contained in the water. Disclosed is a photocatalyst composition that is obtained by loading a photocatalyst, which is capable of photoreducing protons into a hydrogen gas, with CuPd alloy nanoparticles. The photocatalyst composition is used for the purpose of producing ammonia by photoreducing nitrogen that is coexistent with water and nitrogen oxide. The CuPd alloy nanoparticles are (1) CuPd alloy nanoparticles having a B2 type crystal structure and represented by CuxPd(1-x) (wherein 0.3&#x2266;x&#x2266;0.7), (2) CuPd alloy nanoparticles having a bcc type crystal structure and represented by CuxPd(1-x) (wherein 0.3&#x3c;x&#x3c;0.7), (3) CuPd alloy nanoparticles having a fcc type crystal structure and represented by CuxPd(1-x) (wherein 0.01&#x2266;x&#x2266;0.99), (4) CuPd alloy nanoparticles having an L12 type crystal structure and represented by CuxPd(1-x) (wherein 0.7&#x2266;x&#x2266;0.98), or (5) CuPd alloy nanoparticles having a crystal structure wherein at least two of a B2 type portion, a bcc type portion, an fcc type portion, an L12 type portion and a phase separation type portion are mixed. Disclosed are a method for synthesizing ammonia using the photocatalyst composition, and a method for decreasing nitrogen oxide in water using the photocatalyst composition.

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Sapporo, Japan

Miho Yamauchi