Systematic analysis of dual-functional catalysts for simultaneous CO-NOx reduction: Toward an effective catalyst design strategy

Abstract

The development of a multifunctional catalyst suitable for application in existing facilities with limited space, with specific emphasis on its capability to concurrently remove CO and NOx is vital for meeting stringent environmental regulations. This is particularly pertinent to industries such as liquefied natural gas-based power plants and multipollutant-emitting industrial facilities. Another important consideration is that the catalyst should operate over a wide temperature range to facilitate its application across various industrial sites. In this study, we synthesized vanadium-based catalysts with a series of noble metals (Pt, Pd, and Au). The V–W–Pd/TiO2 catalyst achieved a simultaneous CO–NOx reduction efficiency greater than 90% in the widest temperature range, 228–321 °C. The excellent catalytic activities resulted from the Pd active sites, which oxidated CO and adsorbed NOx. This enables the catalyst to easily participate in the NH3-SCR reaction and facilitates NOx reduction. Moreover, we systematically analyzed the reaction properties of each catalyst using diffuse reflectance infrared Fourier transform and temperature programmed desorption methods. This enabled the elucidation of the reaction characteristics and competitive adsorption properties of the catalysts.