Platinum-modulated cobalt nanocatalysts for low-temperature aqueous-phase Fischer-Tropsch synthesis.

Fischer-Tropsch synthesis (FTS) is an important catalytic process for liquid fuel generation, which converts coal/shale gas/biomass-derived syngas (a mixture of CO and H2) to oil. While FTS is thermodynamically favored at low temperature, it is desirable to develop a new catalytic system that could allow working at a relatively low reaction temperature. In this article, we present a one-step hydrogenation-reduction route for the synthesis of Pt-Co nanoparticles (NPs) which were found to be excellent catalysts for aqueous-phase FTS at 433 K. Coupling with atomic-resolution scanning transmission electron microscopy (STEM) and theoretical calculations, the outstanding activity is rationalized by the formation of Co overlayer structures on Pt NPs or Pt-Co alloy NPs. The improved energetics and kinetics from the change of the transition states imposed by the lattice mismatch between the two metals are concluded to be the key factors responsible for the dramatically improved FTS performance.

Study on the Pyrolysis and Adsorption Behavior of Activated Carbon Derived from Waste Polyester Textiles with Different Metal Salts.

In this study, the effects of the catalysis of heavy metals on the pyrolysis of waste polyester textiles (WPTs) and the adsorption behaviors of the pyrolysis products of WPTs for Cr(VI) were explored. TG-DTG analysis indicated that the metal ions catalyzed the pyrolysis process by reducing the temperature of the decomposition of WPTs. The surface morphology and pore structure of the carbons were analyzed using SEM and BET. The results demonstrated that Zn-AC possessed the largest specific surface area of 847.87 m2/g. The abundant acidic functional groups on the surface of the activated carbons were proved to be involved in the Cr(VI) adsorption process via FTIR analysis. Cr(VI) adsorption experiments indicated that the adsorption process was more favorable at low pH conditions, and the maximum adsorption capacities of Zn-AC, Fe-AC, and Cu-AC for Cr(VI) were 199.07, 136.25, and 84.47 mg/g, respectively. The FTIR and XPS analyses of the carbons after Cr(VI) adsorption, combined with the adsorption kinetics and isotherm simulations, demonstrated that the adsorption mechanism includes pore filling, an electrostatic effect, a reduction reaction, and complexation. This study showed that metal salts catalyze the pyrolysis processes of WPTs, and the activated carbons derived from waste polyester textiles are promising adsorbents for Cr(VI) removal.