Bimetallic Pt-Co Catalysts for the Liquid-Phase WGS

Abstract

Bimetallic Pt-Co catalysts derived from cobalt aluminate spinel were investigated in the liquid-phase water–gas shift (WGS) reaction and CO hydrogenation. Liquid-phase WGS is a key reaction in the aqueous-phase reforming (APR) of polyols; thus, WGS activity is essential to formulate good APR catalysts. In this work, catalysts with different Pt/Co molar ratios were synthesized together with a reference Pt/alumina. All the synthesized catalysts were characterized by various techniques in order to gain knowledge on their structural and surface characteristics. WGS activity was tested with a feedstream of CO/H2O = 1/15 (space-time of 76.8 kgcat·s/molCO), isothermal operation at 260 °C and 50 bar, for 10 TOS. Bimetallic Pt-Co catalysts showed improved activity in liquid-phase WGS in comparison to bare Co or Pt catalysts, which was ascribed to the synergistic effect. Despite being subjected to an increased hydrogen concentration in the feedstream (H2/CO between 0 and 12/3), these catalysts maintained a preferential selectivity towards WGS activity. In addition, the effect of temperature (220–260 °C) and pressure (25–50 bar) was investigated over a catalyst with 0.3Pt/CoAl. CO conversion and CO2 yield were more sensitive to temperature, while a higher pressure favored methane production. The measured activation energy in the 220–260 °C temperature range was 51.5 kJ/mol.

Optimized Pt–Co Alloy Nanoparticles for Reverse Water–Gas Shift Activation of CO2

“…Because these metals show interesting behavior and interaction during the RWGS reaction in their pristine or oxide forms, we wanted to extend our knowledge to their alloys. In general, bimetallic nanoparticles have the potential to be exceptional catalysts due to the synergetic effect exhibited by alloying. , Pt–Co systems are explored as high-performing catalysts for different reactions like O 2 reduction reaction, CO oxidation, and water–gas shift reaction − and are also effective in the RWGS reaction. Alayoglu et al have analyzed the properties of PtCo bimetallic particles in the RWGS reaction at high pressure (5.5 bar) and only for a Pt:Co ratio of 1:1.…”