Water Gas Shift Catalysts Research Articles

Optimizing Mo2C-based catalytic system for efficient CO2 conversion and CO selectivity through carbon-nitrogen supporting and potassium promotion

Preparing highly active, stable, and selective catalysts for the reverse water gas shift (RWGS) reaction is challenging because of the aggregation of the active catalyst at high RWGS reaction temperatures and deactivation of the active sites. Herein, we present a comparative evaluation and optimization of a molybdenum carbide system using a carbon-nitrogen (CN) support and alkali promotion. Hydrothermally prepared MoO3 nanorods were carburized at 700 °C using H2:CO (4:1) to prepare unsupported Mo2C, while CN-supported Mo2C (Mo2C@CN) was prepared using Mo-based metal-organic framework (Mo-MOF) as a sacrificial template. The as-prepared Mo2C@CN catalytic system was found to be highly active in the RWGS reaction in comparison with the unsupported Mo2C, where CO2 conversion percentage was around 76 % at 700 °C, combined with high CO selectivity (87 %) and very reduced CH4 selectivity (2 %). The addition of potassium as a promoter enhanced CO selectivity (99 %). The active catalyst performance was stable during the catalysis process and for up to 100 h, which imposes the effect of the CN support in preventing the aggregation of Mo2C and keeping its active sites in direct contact with the reactant. This work presents an effective strategy for improving the active catalyst dispersion and reducibility in synergy with the promoter effect to optimize the RWGS reaction output.

In situ Mössbauer spectroscopy study of the activation and reducibility of chromium- and aluminium-doped iron oxide based water-gas shift catalysts under industrially relevant conditions

The influence of chromium and aluminium doping on the over-reduction during activation of iron-oxide-based water-gas shift catalysts was investigated using Mössbauer spectroscopy for the first time. In situ Mössbauer spectra of catalysts exposed to industrially relevant gas compositions were recorded with increasingly reducing R factors R = [CO]*[H2]/[CO2]*[H2O]. Whereas α-Fe and cementite formed during exposure of a non-doped iron-oxide catalyst to process conditions with an R factor of 2.09, such phases were only observed at R = 4.60 for a chromium-doped catalyst, showing that chromium stabilizes the catalyst. Over-reduction was enhanced to R = 2.88 in a chromium-copper co-doped catalyst. α-Fe was already observed at R = 1.64 in an aluminium-doped catalyst, while cementite formation occurred at R = 2.09, showing that over-reduction was enhanced, the presence of aluminium delaying carburization. Co-doping copper in the aluminium-doped catalyst showed cementite formation at R = 2.09, the same as a non-doped catalyst.

The role of Ga and Y on binary Al2O3-Y2O3 and Al2O3-Ga2O3 mixed oxides nanoparticles towards potential Ni water-gas shift catalysts

This work focuses on the study of binary Al2O3-Y2O3-x and Al2O3-Ga2O3-x mixed oxides with varying Y2O3 or Ga2O3 nominal loading (x=25, 50) prepared by hydrothermal synthesis assisted by Triton X-100. The mixed oxides were used to prepare Ni-based (5 wt%) catalysts for the Water Gas Shift Reaction. The Al2O3 sample presented urchin-like hollow nanosphere morphology, which evolved to solid nanospheres with Y2O3 or Ga2O3 in the mixed oxides. The physicochemical characterization indicated good integration of the mixed oxides, especially on the low-content additive oxides. The theoretical results confirmed that Ga goes deeper into the alumina matrix than Y, partially explaining the XPS and HRTEM results in which the Ni dispersion was better in the Ni/AlGa-x samples. The FTIR in-situ measurements of the reaction allowed us to propose that the reaction occurs minimally through the carbonyl mechanism at low temperatures (<300 °C) and the formate mechanism at high temperatures (>300 °C).

Alkali treatment modulated borate anions in layered double hydroxides as precursors of highly efficient Au-based catalysts for water-gas shift reaction

Layered double hydroxides (LDHs) as an adjustable layered materials were considered as good candidates for the supports of water-gas Shift (WGS) catalysts. However, there is rare report about the exfoliation preparation and WGS application of LDHs containing BO33− as intercalated anions. Herein, we reported a mild alkali treatment modulation of the intercalated borate anions in LDHs for improving the WGS catalytic performance of Au-based catalysts. Compared with inactive Au supported LDHs without alkali treatment, the moderate alkali treatment consumes intercalated BO33− anions in LDHs, arousing the WGS activities of Au-based catalysts. Among the different alkali treatment concentration, Au-LDHs-1M treated with 1 M NaOH present the highest WGS activity and excellent stability with a reduction of only 10 % for 60 h. The moderate alkali treatment promotes the exfoliation of LDHs into nanosheets covered Co3O4 small nanoparticles, which facilitated the high dispersion of Au species and also easily converted into active Fe3O4 and metallic Co phases. While Au-LDHs-5M presents such large Au particles that it exhibits low activity, and Au-LDHs-0M is inactive due to the formation of B2O and Fe23B6 poison phases for the WGS reaction.

Modeling analysis of water-gas-shift reaction on catalyst-packed ceramic-carbonate dual-phase membrane reactor for hydrogen production

Water-gas shift (WGS) reaction for hydrogen production and CO2 removal/capture in a catalyst-packed CO2-permselective membrane reactor is studied experimentally and simulated with a computational model. The reactor utilizes a tubular dense ceramic-carbonate dual-phase membrane with a commercial high-temperature WGS catalyst. Equations governing CO2 permeation through the membrane and WGS reaction kinetics on the catalyst were obtained through independent CO2 permeation experiments and a fixed-bed reaction kinetic study. The simulation results using the validated model are presented to examine the effects of feed gas composition, steam/CO ratio, gas hourly space velocity, temperature, reactor pressure, sweep to feed molar flow rate ratio, and the membrane area to catalyst volume ratio on the performance of the membrane reactor for WGS with CO2 removal. Under optimized conditions, the catalyst-packed membrane reactor for WGS demonstrates significantly enhanced CO conversion and product H2 purity by effectively removing/capturing CO2 from the WGS reaction side.

Cu/MgO Reverse Water Gas Shift Catalyst with Unique CO2 Adsorption Behaviors.

Activation of inert CO2 molecules for the reverse water gas shift (RWGS) reaction is tackled by incorporating magnesium oxide as a support material for copper, forming a Cu/MgO supported catalyst. The RWGS performance is greatly improved when compared with pure Cu or carbon supported Cu (Cu/C). Operating under a weight hourly space velocity (WHSV) of 300,000 mL ⋅ g-1 ⋅ h-1, the Cu/MgO catalyst demonstrates high activity, maintaining over 70 % equilibrium conversion and nearly 100 % CO selectivity in a temperature range of 300-600 °C. In contrast, both Cu/C and commercial Cu, even at ten-times lower WHSV, can only achieve up to 40 % of the equilibrium conversion and quickly deactivated due to sintering. Based on the studies of in-situ temperature resolved infrared spectroscopy and temperature programmed desorption, the improved RWGS performance is attributed to the unique adsorption behavior of CO2 on Cu/MgO. Density functional theory studies provides a plausible explanation from a surface reaction perspective and reveals the spill-over property of CO2 from MgO to Cu being critical.

Microfluidic-Aerosol Hyphenated Synthesis of Metal-Organic Framework-Derived Hybrid Catalysts for CO2 Utilization.

A new and efficient technique is developed by combining the hyphenated microfluidic- and aerosol-based synthesis with the coupled differential mobility analysis for the effective and continuous synthesis and simultaneous analysis of metal-organic frameworks (MOFs)-derived hybrid nanostructured products. HKUST-1, a copper-based MOF, is chosen as the representative to fabricate Cu-based hybrid catalysts for reverse water-gas shift (RWGS) reaction, an effective route for CO2 utilization. The effect of precursor concentration and carrier selection on the properties of the resulting products, including mobility size distribution, crystallization degree, surface area, and metal dispersion are investigated, as well as the correlation between the material properties of the synthesized catalysts and their catalytic performance in RWGS reaction in terms of conversion ratio/rate, selectivity, and operational stability. The results indicate that the continuous microfluidic droplet system can successfully synthesize MOF colloids, followed by the continuous production of MOF-derived hybrid materials through the tandem aerosol spray-drying-reaction system. High catalytic activity and low initiate temperature toward RWGS (turnover frequency = 0.0074s-1; 450°C) are achievable. The work facilitates the production and the designed concept of relevant MOF-derived hybrid nanostructured catalysts in the continuous synthesis system and the enhancement of applications in CO2 capture and utilization.

Ca2Fe2O5-Based WGS Catalysts to Enhance the H2 Yield of Producer Gases

Ca2Fe2O5-based catalysts were synthesized from siderite and calcite precursors, which were processed in the form of pelletized samples and tested as water gas shift catalysts. Catalytic tests were performed in a tubular reactor, at temperatures in the range 400–500 °C and with different H2O:CO ratios, diluted with N2; this demonstrates the positive impact of Ca2Fe2O5 on conversion of CO and H2 yield, relative to corresponding tests without catalyst. The catalytic performance was also remarkably boosted in a microwave-heated reactor, relative to conventional electric heating. Post-mortem analysis of spent catalysts showed significant XRD reflections of spinel phases (Fe3O4 and CaFe2O4), and SiO2 from the siderite precursor. Traces of calcium carbonate were also identified, and FTIR analysis revealed relevant bands ascribed to calcium carbonate and adsorbed CO2. Thermodynamic modelling was performed to assess the redox tolerance of Ca2Fe2O5-based catalysts in conditions expected for gasification of biomass and thermochemical conditions at somewhat lower temperatures (≤500 °C), as a guideline for suitable conditions for water gas shift. This modelling, combined with the results of catalytic tests and post-mortem analysis of spent catalysts, indicated that the O2 and CO2 storage ability of Ca2Fe2O5 contributes to its catalytic activity, suggesting prospects to enhance the H2 content of producer gases by water gas shift.

Hindering nanoparticle growth in reverse microemulsion synthesized CeO2/γ-Al2O3 reverse water gas shift catalyst

Efficient CO2 conversion to fuels and chemicals is of paramount importance for mitigating greenhouse gas emissions that accelerate climate change. In CO2 conversion reactions, catalyst nanoparticle growth and sintering under reaction conditions pose significant challenges, limiting the catalytic performance and catalyst stability. In this study, high surface area CeO2/γ-Al2O3 nano-catalysts were synthesized via the reverse microemulsion method and evaluated for reverse water gas shift. The effect of the active phase dispersion on the CeO2 nanoparticle growth was investigated via X-ray diffraction and gas adsorption. The 47.9 wt% CeO2/Al2O3 catalyst showed complete selectivity to CO generation, while attaining nearly equilibrium values for CO2 conversion at 600 °C and 8000 mL/(g h). As compared to bulk CeO2, nanoparticle growth in the CeO2/Al2O3 catalyst was hindered significantly, resulting in a relatively stable catalytic performance, similar to that of the bulk CeO2. Our findings reveal that the reverse microemulsion synthesized γ-Al2O3 support significantly decreases CeO2 nanoparticle growth and agglomeration. This reduction in nanoparticle sintering contributes to the enhanced catalytic performance and stability, facilitating efficient CO2 reduction.

Gold supported on Gd-doped CeO2 nanorods applied as water-gas shift catalyst under H2 rich stream

In this work, we report the synthesis of catalysts based on ceria nanorods (CeO2NRs) doped with 3% and 5% mol gadolinium. The supports were obtained from cation co-precipitation hydrothermal synthesis over which gold nanoparticles (AuNPs) were deposited by the deposition-precipitation (DP) methodology, allowing the Au nanoparticles size control at around 3 nm. The catalysts were evaluated in water gas shift reaction and showed high activity under a H2 rich stream (7%CO/7%CO2/14%N2/42%H2/30%H2O) with steam/process gas molar ratio (S/G) of 0.3 at 300 and 250 °C. The results revealed that Gd-doping increased the oxygen vacancies concentration due to the insertion of a trivalent cation in ceria lattice. In addition, the synergistic effect between AuNPs and Gd-doped CeO2 provided the increase of reducibility and oxygen storage capacity (OSC). These properties were associated with the catalytic activity in water gas shift reaction. The nanostructured materials decreased the CO concentration under conditions of H2 rich stream, indicating the catalysts potential for industrial applications after further studies. The catalyst doped with 5% mol Gd was the most active and achieved 24% of CO conversion at 300 °C.

Trapping and Methanation of CO2 in a Domestic Microwave Oven Using Combinations of Sorbents and Catalysts

CO2 trapping and methanation allow to reduce greenhouse gas emissions and recycle CO2 into a sustainable fuel, provided renewable H2 is employed. Microwave (MW)-based reactors provide an efficient means to use electrical energy for upgrading chemicals, since MW can selectively heat up the load placed in the reactor and not the reactor itself. In this study, CO2 capture and methanation were investigated using solid adsorbents (ZrO2 and Fe3O4), microwave absorbers (SiC and Fe3O4) and Ru/SiO2 as CO2 the methanation catalyst. The sorption and catalyst beds were located in a domestic MW oven that was used to trigger CO2 desorption and methanation in the presence of H2. The working Fe-based structure turned out to be a mixture of FeO and Fe, which allowed for MW absorption and local heating; it also acted as a CO2 sorbent and reverse water–gas shift catalyst. Various reactor configurations were used, leading to different performances and selectivity to CO and CH4. To the best of our knowledge, this is the first report of its kind showing the potential of using inexpensive microwave technology to readily convert trapped CO2 into valuable products.

Understanding the promotion effect of Pt in the reaction system of water gas shift reaction catalyzed by Pt/α-MoC from theoretical perspectives

Pt/α-MoC is an outstanding catalyst for the low-temperature water gas shift (WGS, CO + H2O → H2 + CO2) reaction, exhibiting elevated activity, stability, and selectivity. In this study, three significant active site models (α-MoC-111, Pt-111, and Pt1/α-MoC-111) in Pt/α-MoC catalyst were established to investigate the promotion effect of Pt on the WGS reaction catalyzed by Pt/α-MoC. The results indicate that a synergistic effect at the metal-carbide interface enhances chemical activity compared to pure Pt-111 and α-MoC-111. Firstly, the surface of Pt1/α-MoC-111 exhibits strong metal-support interaction between Pt single atom and α-MoC-111 surface. Compared to the α-MoC-111 surface, the introduction of Pt strengthens the Mo−Mo bond while weakening the Mo−C bond. Secondly, adding a Pt atom significantly increases adsorption strength for CO and H2O, while decreasing it for products (CO2), oxides (O atom), and by-products (C atom). The advantage of suppressing surface carbon deposition and oxidation is observed on the surface of Pt1/α-MoC-111. Furthermore, elementary reactions from the three mainstream reaction pathways of the WGS reaction are systematically calculated to evaluate catalytic performance among these three active sites. On the Pt1/α-MoC-111 surface, activation energy barriers for H2O dissociation and CO oxidation are reduced. This provides theoretical ideas for designing high-efficiency α-MoC based catalysts in the future.

Accelerated discovery of multi-elemental reverse water-gas shift catalysts using extrapolative machine learning approach

Designing novel catalysts is key to solving many energy and environmental challenges. Despite the promise that data science approaches, including machine learning (ML), can accelerate the development of catalysts, truly novel catalysts have rarely been discovered through ML approaches because of one of its most common limitations and criticisms—the assumed inability to extrapolate and identify extraordinary materials. Herein, we demonstrate an extrapolative ML approach to develop new multi-elemental reverse water-gas shift catalysts. Using 45 catalysts as the initial data points and performing 44 cycles of the closed loop discovery system (ML prediction + experiment), we experimentally tested a total of 300 catalysts and identified more than 100 catalysts with superior activity compared to those of the previously reported high-performance catalysts. The composition of the optimal catalyst discovered was Pt(3)/Rb(1)-Ba(1)-Mo(0.6)-Nb(0.2)/TiO2. Notably, niobium (Nb) was not included in the original dataset, and the catalyst composition identified was not predictable even by human experts.

Design of Cr-Free Promoted Copper-Iron Oxide-Based High-Temperature Water-Gas Shift Catalysts.

The effect of Ce addition to the Cr-free Al-promoted Cu-Fe oxide-based catalysts is investigated. Catalyst characterization (X-ray diffraction (XRD), in situ Raman spectroscopy, high-sensitivity low-energy ion scattering (HS-LEIS), Brunauer-Emmett-Teller (BET) analysis), CO-temperature-programmed reduction chemical probing, and steady-state WGS activity reveal that (i) in the absence of Al, Ce addition via coprecipitation has a detrimental effect on the catalytic activity related to the poor thermostability and formation of less active Ce-Cu-O NPs, (ii) the addition of Ce via coprecipitation also does not improve the performance of the CuAlFe catalyst because of the formation of a thick CeOx overlayer on the active Cu-FeOx interface, and (iii) impregnation of Ce onto the CuAlFe catalyst exhibits significant improvement in catalytic performance due to the formation of a highly active CeOx-FeOx-Cu interfacial area. In summary, Al does not surface-segregate and serves as a structural promoter, while Ce and Cu surface-segregate and act as functional promoters in Ce/CuAlFe mixed oxide catalysts.

Effect of precipitation variables on the performance of CeO2-based catalysts for waste-to-hydrogen

Waste-to-hydrogen technology, a future net-zero energy mix as a clean hydrogen source, is currently a research hotspot. To upcycle waste to high-value chemicals such as hydrogen, it is necessary to study customized catalysts for water-gas shift (WGS) reactions considering waste-derived synthesis gas. Herein, we aimed to enhance the physicochemical properties of CeO2 supported Pt catalysts by controlling the precipitation variables to develop a highly sulfur-tolerant WGS catalyst using waste-derived synthesis gas. The CeO2 support was prepared by the classic precipitation method. During precipitation, the precipitating agent was injected at different methods and rates. In the case of the normal titration method, the KOH solution was injected into the Ce precursor dissolved solution at rates of 5, 20, and 50 mL/min. In the case of the reverse titration method, the Ce precursor dissolved solution was injected into the KOH solution at rates of 5, 20, and 50 mL/min. The as-prepared Pt/CeO2 catalysts were applied to the WGS reaction with 500 ppm H2S. This work demonstrated that the titration method and titration rate affected the oxygen vacancy concentration and the active metal dispersion of the catalysts, respectively. And these properties worked in combination to determine the sulfur resistance of the catalysts. Subsequently, the high sulfur tolerance and catalytic performance of Pt/CeO2 catalyst prepared by normal titration method with the titration rate of 50 mL/min were due to the high Pt dispersion and concentration of oxygen vacancies.

Molecular-level understanding of interfacial carbonates in stabilizing CuO-ZnO(Al2O3) catalysts

A descriptor of active CuO-ZnO(Al2O3) methanol-synthesis and water–gas-shift catalysts is the presence of high-temperature carbonates (HT-CO3) in the oxidic catalyst precursor. Previous reports have shown that such HT-CO3 lead to an appropriate interaction between the oxides; as a result, a high Cu surface area (or Cu-Zn or Cu/ZnO interphase areas) can be achieved. Yet, their nature is not well understood. In this study, the nature of these carbonates was investigated by experimental and theoretical methods in the oxidic precatalyst. A calcined Cu-Zn-Al hydrotalcite model compound revealed to have well-dispersed ZnO and CuO phases, together with highly stable HT-CO3. It was hypothesized that these HT-CO3 groups may be placed at critical locations at nano-scale as a glue, thus avoiding the growth of the oxide crystallites during calcination. This is an excellent pre-condition to achieve a high Cu surface area (or Cu-Zn or Cu/ZnO interphase areas) upon reduction, and therefore a high activity. To prove that, first-principles calculations were carried out based on the density functional theory (DFT); alumina was not considered in the model as the experimental data showed it to be amorphous but it may still have an effect. Comprehensive calculations provided evidence that such carbonate groups favourably bind the CuO and ZnO together at the interface, rather than being isolated on the individual oxide surfaces. The results strongly suggest that the HT-CO3 groups are part of the structure, in the calcined precatalyst, where they would prevent thermal sintering through a bonding mechanism between CuO and ZnO particles, which is a novel interpretation of this important catalyst descriptor.

Modification of Copper-Ceria Catalyst via Reverse Microemulsion Method and Study of the Effects of Surfactant on WGS Catalyst Activity

Some major drawbacks encountered in the synthesis of copper-ceria (Cu-CeO2)-based Water Gas Shift (WGS) catalyst via the conventional Impregnation (IMP) method are aggregate formation and nanoparticles’ instability. These lead to the poor interaction between Copper and Ceria, thereby impeding the catalytic activity with the inefficient utilization of active sites. To overcome these drawbacks, in this study, we described the synthesis of the Cu-CeO2 catalyst via the Reverse Microemulsion (RME) method with the help of the organic surfactant. This development of insights and strategies resulted in the preparation of porous particles with uniform size distribution and improved interaction within the composites, which were evident through XRD, XPS, BET Surface area, TPR, TEM and SEM analysis results. Remarkably, the optimum 20% Cu-CeO2 catalyst prepared by RME method was found to have superior Water Gas Shift (WGS) catalytic activity than the conventionally Impregnated catalyst when their CO conversion efficiencies were tested in WGS reaction at different feed gas compositions with and without CO2. Moreover, the 20% Cu-CeO2 sample prepared by RME method exhibited sustained catalytic activity throughout the entire 48 h period without any signs of deactivation. This observation highlights RME method as the potential pathway for developing more effective nanoparticle catalysts for hydrogen production, contributing to the growing demand for clean and sustainable energy sources.

Hydrogenation of CO2 over Mn-Substituted SrTiO3 Based on the Reverse Mars–van Krevelen Mechanism

Oxygen storage materials (OSMs) such as CeO2 have attracted great attention as catalysts for the reverse water gas shift (RWGS) reaction, replacing metal-supported catalysts from the perspectives of thermal stability and CO selectivity. Because perovskite-type oxides are also known to be powerful OSM candidates, here we employed perovskite-type Mn-substituted SrTiO3 as a catalyst for RWGS and investigated the effects of oxygen vacancies on the activity toward CO generation. Among the solid solutions with different Mn ratios, SrTiO3 with 20% Mn substitution exhibited the highest activity. It is suggested that oxygen vacancies generated by the substitution of Mn ions for Ti ions in SrTiO3 exhibit selective activity toward CO2 splitting, whereas the redox of bulk Mn oxides does not have the capacity for CO generation in the control experiments. Quantitative H2-temperature programmed reduction and CO2-temperature programmed oxidation experiments revealed that half of the oxygen vacancies in Mn-substituted SrTiO3, which were generated by reduction with H2, were used as active sites for CO2 splitting. We conclude that this generated active oxygen vacancy, which is attributed to the valence change of the Mn ions, contributes to efficient CO2 splitting to form CO through the reverse Mars–van Krevelen mechanism.

CO2 methanation vs reverse WGS activity on Co/γ-Al2O3 catalysts at atmospheric pressure: effect of cobalt loading and silica addition on selectivity and stability

Catalysts containing 5 wt% and 13.6 wt% cobalt on pure alumina and 5 wt% silica-containing alumina were prepared by conventional impregnation procedure and calcined at 1023 K for 5 h. The samples were characterized both as prepared, pre-reduced and after reaction by means of X-ray Diffraction, FTIR and DR-UV-Vis-NIR spectroscopies and by X-ray Pholotoelectron Spectroscopy. After pre-treatment in H2/N2 atmosphere, they were tested in CO2 hydrogenation at atmospheric pressure in the temperature range 523–773 K. The material with 5 wt% Co on pure γ-Al2O3 was found predominantly active as a reverse Water Gas Shift (rWGS) catalyst producing mainly CO and approaching rWGS forecasted thermodynamic equilibrium at the highest temperatures. The addition of silica decreases selectivity to CO, with an enhanced methanation activity. Instead, the materials with 13.6 wt% Co on pure γ-Al2O3 was found to act mainly as a methanation catalyst, although with the coproduction of limited amounts of CO. The rWGS catalytic activity is apparently stable while slight deactivation for methanation was found, attributed to deposits of stick-like carbon residues. Investigated 13.6 wt% Co/γ-Al2O3 is less selective for methanation than comparable Ni/γ-Al2O3 catalysts while but more stable than unsupported cobalt and Co/SiO2 catalysts. Silica addition to 13.6 wt% Co does not modify significantly the catalytic activity while it slightly decreases stability. The effect of silica is a combination of two partially contrasting phenomena, i.e. the increase of the total surface area of the support and the decrease of the available surface area fraction for cobalt dispersion.

Data-Driven Design and Understanding of Noble Metal-Based Water–Gas Shift Catalysts from Literature Data

Catalyst informatics and catalyst design have the potential to facilitate and speed up catalyst discovery, as this is a complex undertaking involving variables associated with the catalysts themselves and operating conditions. Herein, a Machine Learning (ML)-assisted methodology coupled with data visualization to design descriptors for catalyst materials are proposed using a previously reported literature data set of the Water–Gas Shift (WGS) reaction. This entails two different approaches to represent catalysts as part of the input and propose catalysts based on their predicted CO conversion. The analysis covers the design of the descriptors employed by the models, as well as the results of an inverse prediction, that uncovered potential catalysts that can be researched for high CO conversion (≥95%), with Random Forest Regression predicting promoted Au/CeO2–ZrO2 and Support-Vector Regression predicting promoted Au/CeO2, Ru/CeO2, and Rh/CeO2 as the best overall catalyst candidates, and Yb/Au/CeO2–ZrO2 to be of interest for WGS applications at low temperatures.