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Graphitic carbon nitrides were employed to prepare the Ruthenium-based ammonia synthesis catalysts by thermal decomposition of Ru3(CO)12 under N2 or H2 atmosphere. Different pretreatment atmospheres significantly affected the interaction between Ru nanoparticles and the graphitic carbon nitride. The strong metal support interaction enhanced the electronic density transfer from rich-electron π-plane of the support to the Ru nanoparticles. And it further caused the upshift of d-band center of Ru nanoparticles. The upshift of d-band center improved the ability of surface to bond to N2, and consequently the ammonia synthesis activity was enhanced. Electron-rich and graphitic carbon nitride enhanced the electron density of Ru nanoparticles. And that caused the upshift of d-band center of Ru nanoparticles. This upshift of d-band center improved the ability of surface to bond to N2, and consequently the ammonia synthesis activity was enhanced.

Here we report that the electronic metal–support interaction influences the catalytic activity of ammonia synthesis. This effect produces an upwards shift of the d-band center of Ru nanoparticles. The upward shift of the d-band center of the Ru nanoparticles is considered to enhance the dissociation of the N2 molecule.

Two K/Mn-MgO supported catalysts were prepared by Fe(CO) 5 and Fe(NO 3 ) 3 as precursor respectively. The obtained Fe-K/Mn-MgO catalysts were tested for CO hydrogenation to light alkenes and characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectra (XPS), H 2 temperature-programmed reduction (H 2 -TPR), H 2 , CO and CO 2 temperature-programmed desorption (H 2 , CO/CO 2 -TPD) and transmission electron microscope (TEM). The results indicated that the catalyst with 10 wt% Fe loading prepared by Fe(CO) 5 as precursor showed better performance in syngas to light alkenes than ones obtained from Fe(NO 3 ) 3 as precursor, where the CO conversion was 62.50% and the selectivity was 55.95% at 350 ℃, 1.5 MPa and 1000 h −1 , respectively.

With various contents, Mn was introduced into carbon nanotubes (CNTs) supported cobalt catalysts and the obtained Mn-Co/CNTs catalysts were investigated for CO hydrogenation to light alkenes and characterized by N 2 adsorption, X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), H 2 temperature programmed reduction (TPR), CO temperature programmed desorption (TPD) and transmission electron microscope (TEM). The results indicate that the addition of a small amount of Mn (0.3 wt%) to CNTs-supported Co catalyst significantly increased the selectivity of C 2 －C 4 olefins and decreased the selectivity of CH 4 . However, with further addition of Mn to the cobalt catalysts, the CH 4 selectivity decreased obviously along with the increase of the C 5 ＋ selectivity. Compared with the unpromoted catalysts, the Mn-promoted cobalt catalysts increased the C 2 ＝ －C 4 ＝ /C 2 0 －C 4 0 molar ratio.