Novel hetero-bimetallic coordination polymer as a single source of highly dispersed Cu/Ni nanoparticles for efficient photocatalytic water splitting

A new strategy for depositing highly dispersed Cu and Ni nanoparticles on the surface of TiO2 from a single source is demonstrated for photocatalytic hydrogen production. We used a newly synthesized cyanide-bridged hetero-bimetallic coordination polymer [{Cu-II(4,4-dipy)(2)}{Ni(CN)(4)}](n)0.7(C2H6O2).1.6(H2O) (CP-1) (4,4-dipy = 1,3-di(4-pyridyl)propane) as a single-source precursor of Cu-Ni nanoparticles. The structure of CP-1 was established by single-crystal X-ray diffraction analysis; CP-1 crystallizes in the monoclinic space group C2/c with = 111.67(3)degrees. CP-1/TiO2 composites containing different weight percentages of CP-1 were achieved by hydrolyzing titanium isopropoxide in the presence of CP-1. Highly dispersed Cu and Ni nanoparticles were deposited on TiO2 by the calcination of the CP-1/TiO2 composites at different temperatures (420 degrees C, 470 degrees C and 520 degrees C) in air followed by reduction in H-2/Ar atmosphere at 470 degrees C for 2 h. XRD, DRS/UV-Vis, TEM, Cu/Ni 2p XPS, and photoluminescence spectroscopy demonstrated the presence of CuO/Cu-0 and NiO/Ni-0 as active co-catalysts on the surface of TiO2. The 1 wt% Cu-Ni/TiO2-470 photocatalyst showed the maximum H-2 production activity of 8.5 mmol h(-1) g(-1) in a glycerol/water mixture (20 vol%). The results are anticipated to direct the future development of efficient, low-cost and noble metal-free semiconductor photocatalysts for solar H-2 production.