Reactive carbon capture (RCC), an integrated CO2 capture and conversion process that does not require generating a purified CO2 stream, is an attractive carbon management strategy that can reduce costs and energy requirements associated with traditionally separate capture and conversion processes. Dual function materials (DFMs) comprised of co-supported sorbent sites and catalytic sites have emerged as a promising material design to enable RCC. DFMs have been extensively studied for methane production, but the noncompetitive economics of methane necessitates the development of DFMs to target more valuable, useful, and versatile products, like methanol. Herein, we report the development of modified Cu–Zn–Al mixed oxide (Alk/CZA, Alk = K, Ca) DFMs for combined capture and conversion of CO2 to methanol. CO2 chemisorption, in situ DRIFTS characterization, and co-fed hydrogenation performance revealed that K and Ca have different effects on the CO2 capture and catalytic behavior of the parent CZA. K-modification resulted in the greatest promotional effect on capture capacity but the most detrimental effect on co-fed hydrogenation catalytic activity. Interestingly, when used in a cyclic temperature-and-pressure-swing RCC operation, K/CZA exhibited a greater conversion of adsorbed CO2 (94.4%) with high methanol selectivity (46%), leading to greater methanol production (59.0 μmol gDFM−1) than the parent CZA or Ca/CZA (13.2 and 18.9 μmol gDFM−1, respectively). This study presents the foundational methodology for the design and evaluation of novel DFMs to target renewable methanol synthesis, highlighted by a critical learning that co-fed CO2 hydrogenation performance is not an effective indicator of RCC performance.

Abstract: Methanol steam reforming (MSR) is one of the most feasible methods for online hydrogen production and has broad prospects. However, the current development of online hydrogen production is limited by long cold start times and high catalyst activation temperatures. In this study, electromagnetic induction heating (EIH) was used in combination with 3D-printed NiFe2O4 porous catalyst supports for hydrogen production by MSR. The EIH system based on porous NiFe2O4 ceramics can quickly heat to 300 °C within 50 s and directly transfer heat to the loaded catalyst, which eliminates the traditional heat transfer from the outside to the inside of the reactor and significantly improves the catalyst activity and energy utilization efficiency. Under the EIH system, the methanol conversion rate of the MSR reaction reached 100%, and the hydrogen selectivity reached 78.9% at 300 °C, demonstrating its excellent performance in methanol conversion rate and hydrogen selectivity. Keywords: MSR 3D; printing catalyst support; EIH; NiFe2O4

Abstract : In situ quick X-ray absorption spectroscopy (QXAFS) at the Cu and Zn K-edge under operando conditions has been used to unravel the Cu/Zn interaction and identify possible active site of CuO/ZnO/Al2O3 catalyst for methanol synthesis. In this work, the catalyst, whose activity increases with the reaction temperature and pres- sure, was studied at calcined, reduced, and reacted conditions. TEM and EDX images for the calcined and reduced catalysts showed that copper was distributed uniformly at both conditions. TPR profile revealed two reduction peaks at 165 and 195 °C for copper species in the calcined catalyst. QXAFS results demonstrated that the calcined form consisted mainly of a mixed CuO and ZnO, and it was progressively transformed into Cu metal particles and dispersed ZnO species as the reduction treatment. It was demonstrated that activation of the catalyst precursor occurred via a Cu+ intermediate, and the active catalyst predominantly consisted of metallic Cu and ZnO even under higher pressures. Structure of the active catalyst did not change with the temperature or pressure, indicating that the role of the Zn was mainly to improve Cu dispersion. This indicates the potential of QXAFS method in studying the structure evolutions of catalysts in methanol synthesis. Keywords: In situ Quick X-ray absorption spectroscopy; CuO/ZnO/Al2O3 catalyst; Operando condition

Keywords: Alumina, thermal stability, HT water gas shift catalyst

This thesis discusses the investigation of the catalytic partial oxidation on rhodium-coated honeycomb catalysts with respect to the conversion of a model surrogate fuel and commercial diesel fuel into hydrogen for the use in auxiliary power units.

Keywords: Ammonia decomposition; Heterogeneous reactions; Velocity slip; Temperature jump; Concentration jump; Microchannel.