Operando DRIFTS-MS Study of WGS and rWGS Reaction on Biochar-Based Pt Catalysts: The Promotional Effect of Na

Abstract

Abstract:Biochar-based Pt catalysts, unpromoted and Na-promoted, were prepared by an incipient wetness impregnation method and characterised by Inductively coupled plasma mass spoectrometry (ICP-MS) analysis, X-ray diffraction, N 2 adsorption and transmission, and scanning electron microscopy. It was demonstrated that a sodium promoter modifies the acid-base properties of the support, altering the Pt-support interaction. An operando Diffuse reflectance infrared fourier transform spectroscopy-mass spectrometry (DRIFTS-MS) study was performed to gain insights into the reaction pathways and the mechanism of the Water-Gass-Shift (WGS) and the Reverse Water-Gass-Shift (rWGS) reactions. It was demonstrated that the addition of Na enhances the catalytic performance due to the changes induced by the alkali in the electronic structure of the Pt active sites. This effect favours the activation of H 2 O molecules during the WGS reaction and the dissociation of CO 2 during the rWGS reaction, although it may also favour the consecutive CO methanation pathway.

Catalytic Reduction of CO2 to CO via Reverse Water Gas Shift Reaction: Recent Advances in the Design of Active and Selective Supported Metal Catalysts

“…On the basis of XAS and X-ray photoelectron spectra (XPS) results, Yang et al [86] proposed the formation of a Pt-O(OH)-Pt interface, which serves as an active site to adsorb CO 2 and form an active intermediate of bridge-bonded formate. Similarly, Santos et al [84] reported that the addition of Na to Pt/C can improve the RWGS reaction with a reduced activation energy. They suggested that the addition of Na modifies the electronic structure of Pt and favors CO 2 dissociation.…”

“…The addition of alkali metals to Pt-and Au-based catalysts can greatly improve the activity of a water gas shift (WGS) reaction [83][84][85]. The addition of an appropriate amount of Na to Pt/TiO 2 can improve reducibility and surface basicity and form strong Pt-O-Na interactions by donating electrons from Pt to NaO x , which creates an active site at the interface of Pt-NaO x for the WGS reaction [83].…”

Carbon Supported Gold Nanoparticles for the Catalytic Reduction of 4-Nitrophenol

“…Carbon obtained by pyrolysis of commercial microcrystalline cellulose in CO 2 atmosphere (CC) (Santos et al, 2018a).…”

Improving Fe/Al2O3 Catalysts for the Reverse Water-Gas Shift Reaction: On the Effect of Cs as Activity/Selectivity Promoter

“…Additionally, reducible oxides boost oxygen mobility which in turns prevents coking [20]. In addition to the support, the active phase can also be promoted by adding an alkali metal [21]. Indeed the addition of alkali metals has repeatedly shown to improve CO 2 adsorption, as the presence of these species significantly modifies the electronic density of the catalyst's surface as well as improves the dispersion of the active phase [22,23].…”