In Situ Pulse Diffuse Reflection Infrared Fourier Transform Spectroscopy (DRIFTS) Mass Spectrometry Study of the Water-Gas Shift Reaction on Nickel(II) Oxide–Zinc(II) Oxide Catalysts. Issue 2 (February 2014)

• Record Type: Journal Article
• Authors: Tang, Chih-Wei; Chuang, Steven S.C.
• Is Part Of: Applied spectroscopy. Volume 68:Issue 2(2014)
• Page Start: 238
• Page End: 244
• Publication Date: 2014-02
• Subjects: In situ pulse DRIFTS-MS -- Diffuse reflection infrared Fourier transform spectroscopy -- Mass spectrometry -- NiO–ZnO -- Hydrogen production -- Water-gas shift reaction; Spectrum analysis -- Periodicals; 543.505
• DOI: 10.1366/13-07042
• Languages: English
• ISSNs: 0003-7028

Abstract

The water-gas shift (WGS) reaction has been studied by pulsing carbon monoxide (CO) into a steady-state water (H2 O)-Ar flow over nickel(II) oxide–zinc oxide (NiO–ZnO) catalysts using in situ diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) coupled with a mass spectrometer method using the pulse technique (in situ pulse DRIFTS-MS) for different flow rates (gas hourly space velocity [GHSV] of 24 000–72 000 h −1 ) and reaction temperatures (250–350 °C). The results obtained from the in situ pulse DRIFTS-MS revealed that there are two types of water adsorption bands on the surface of the catalyst: (i) molecular adsorption (infrared [IR] bands in the 2500–3600 cm −1 range and at 1640 cm −1 ), and (ii) dissociative adsorption at 3700 cm −1, where carboxyl bands are formed at 1461 and 1368 cm −1 and the gas-phase CO is adsorbed at 2187 and 2111 cm −1 on the surface of the catalyst. After using a GHSV = 24 000 h −1 H2 O/Ar flow, we probed the existence of two active intermediates via the formation of two hydrogen production peaks. The products of hydrogen gas (H2 ) and carbon dioxide (CO2 ) had two pathways: the redox process and the associative process via the intermediate of the carboxyl group. In situ pulse DRIFTS-MS proves to be an effective approach for studying the nature of adsorbed species on the catalyst surface and the nature of the reaction product.