Co₃O₄/TiO₂catalysts studiedin situduring the preferential oxidation of carbon monoxide: the effect of different TiO₂polymorphs

Abstract

Co3O4 nanoparticles were supported on different TiO2 polymorphs, viz., rutile, anatase, and a 15:85 mixture of rutile and anatase (also known as P25), via incipient wetness impregnation. The Co3O4/TiO2 catalysts...

In situ and Operando Characterisation in the Preferential Oxidation of Carbon Monoxide over Base Metal Oxide Catalysts: A Review

“…For instance, anchoring Co 3 O 4 on support materials such as Al 2 O 3 , TiO 2 , and SiO 2 improves the reduction resistance of Co 3 O 4 and delays the formation of undesired CH 4 . [21,22,33,41] The improved reduction resistance is attributed to the existence of strong Co 3 O 4 -support interactions. Similarly, Lukashuk et al [16] promoted Co 3 O 4 with 10 wt .…”

“…In the absence and presence of H 2 , the CO oxidation activity and selectivity of Co 3 O 4 can be affected by the catalyst preparation method, [32,33] particle size, [17,34] particle shape, [35,36] and the presence of a promoter [37,38] or support. [21,22,[39][40][41] However, changes to the surface and bulk structure of Co 3 O 4 have not been reported when CO oxidation is carried out in the absence of H 2 . More specifically, in a feed containing an inert gas, CO, and excess O 2 (relative to CO), the surface and bulk structure of Co 3 O 4 are protected from reduction by CO owing to the excess O 2 present.…”

“…[16,20] At high reaction temperatures (> 200 °C), Co 3 O 4 can reduce to CoO and ultimately metallic Co (Co 0 ). [16,17,20,21,33,36,41] The reduction takes place because H 2 is present in great excess relative to O 2 ; therefore, when O 2 is fully consumed by the combination of CO and H 2 oxidation, Co 3 O 4 becomes susceptible to reduction by the unreacted H 2 . This way, the Co 3 + , and subsequently, the Co 2 + species are lost, making it difficult for CO to be converted to CO 2 via the MvK mechanism.…”