Low temperature propane oxidation over Co3O4 based nano-array catalysts: Ni dopant effect, reaction mechanism and structural stability

Abstract

a b s t r a c tLow temperature propane oxidation has been achieved by Co 3 O 4 -based nano-array catalysts featuring low catalytic materials loading (15 mg under flow rate of 150 mL/min). The increased Ni doping into the Co 3 O 4 lattice has led to 100% propane conversion at low temperature (<400 • C) and has enhanced reaction kinetics by promoting the surface lattice oxygen activity. In situ DRIFTS investigations in tandem with isotopic oxygen exchange reveals that the propane oxidation proceeds via a Mars-van Krevelen mechanism where surface lattice oxygen acts as the active site whereas O 2 in the reaction feed does not directly participate in CO 2 formation. The Ni doping promotes the formation of less stable carbonates on the surface to facilitate the CO 2 desorption. The thermal stability of Ni doped Co 3 O 4 decreases with increased Ni concentration despite the increased catalytic activity. A balance between enhanced activity and compromised thermal stability is considered in the Ni doped Co 3 O 4 nano-array catalysts for hydrocarbon oxidation. This study provides useful and timely guidance for rational catalyst design toward low temperature catalytic oxidation.

Scalable Integration of Highly Uniform MnxCo3−xO4 Nanosheet Array onto Ceramic Monolithic Substrates for Low‐Temperature Propane Oxidation

“…Interestingly, the nanosheets are observed with inner connections, which can give a superior mechanical stability to the nanofilm if it suffers the flushing of gas flow. Also, the gaps and hollows formed within the nanosheet array will be good for capture and diffusion of reactants . Moreover, every single nanosheet has a size of several hundred nanometers and a thickness of several nanometers.…”

Facet‐Dependent Activity of Co3O4 Catalyst for C3H8 Combustion

“…C 3 H 8 , mainly comes from the LPG, is a kind of VOCs in atmosphere and should be eliminated through appropriate methods. Due to the high stability of C 3 H 8 , it usually acts as a model reactant for catalytic combustion . Investigating the Co 3 O 4 crystal plane effect on C 3 H 8 combustion activity can help us to have a deep understanding of the reaction mechanism and develop highly active Co 3 O 4 catalysts.…”

Nano-Array Integrated Structured Catalysts: A New Paradigm upon Conventional Wash-Coated Monolithic Catalysts?

“…The corresponding HRTEM images in Figure 10c,d revealed the crystalline nature of the nanowires. Figure 10e,f shows the catalytic methane [18] and propane [17] oxidation performance of Ni x Co 3-x O 4 nano-arrays with controlled Ni concentration. The Co 3 O 4 nano-arrays doped with Ni exhibited better methane and propane oxidation activity at low temperatures than the pristine Co 3 O 4 nano-arrays, and could achieve complete CH 4 and C 3 H 8 combustion below 600 • C and 400 • C, respectively.…”

“…In addition to the manipulation of geometry shapes and enclosed crystal planes, the catalytic activity of nano-array-based monolithic catalysts could also be modified by introducing guest atoms and defects [17,18]. As an example, Ni was doped into the Co3O4 lattice to enhance the catalytic activity for methane and propane oxidation.…”

“…After the reactors cooled to room temperature, the obtained products were rinsed with distilled water or ethanol, and then dried or annealed at desired temperature. In our previous research, Co3O4 nanowire array-based catalysts were fabricated onto large commercial cordierite monolithic substrates following a low-temperature hydrothermal process [16][17][18]. As shown in Figure 3, a commercial honeycomb support of 392.5 mL was used for growing Co3O4-based nanowire arrays.…”