Tri-reforming of methane over Ni/ZrO2 catalyst derived from Zr-MOF for the production of synthesis gas

The increasing concentration of CO2 and CH4 in the environment is a global concern. Tri-reforming of methane (TRM) is a promising route for the conversion of these two greenhouse gases to more valuable synthesis gas with an H2/CO ratio of 1.5-2. In this study, a series of Zr-MOF synthesized via the solvothermal method and impregnation technique was used to synthesize the nickel impregnated on MOF-derived ZrO2 catalyst. The catalyst was characterized by various methods, including N2-porosimetry, X-ray diffraction (XRD), temperature programmed reduction (TPR), CO2-temperature programmed desorption (CO2-TPD), thermo-gravimetric analysis (TGA), chemisorption, field-emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM). Characterization results confirmed the formation of the Zr-MOF and nickel metal dispersed on MOF-derived ZrO2. Further, the tri-reforming activity of the catalyst developed was evaluated in a downflow-packed bed reactor. The various catalysts were screened for TRM activity at different temperatures (600-850 °C). Results demonstrated that TRM was highly favorable over the NZ-1000 catalyst due to its desirable physicochemical properties, including nickel metal surface area (2.3 m2/gcat-1), metal dispersion (7.1%), and nickel metal reducibility (45%), respectively. Over the NZ-1000 catalyst, an optimum H2/CO ratio of ~ 1.6-2 was achieved at 750 °C, and it was stable for a longer period of time.

Coke-Resistant Ni/CeZrO2 Catalysts for Dry Reforming of Methane to Produce Hydrogen-Rich Syngas

Dry reforming of methane was studied over high-ratio zirconia in ceria-zirconia-mixed oxide-supported Ni catalysts. The catalyst was synthesized using co-precipitation and impregnation methods. The effects of the catalyst support and Ni composition on the physicochemical characteristics and performance of the catalysts were investigated. Characterization of the physicochemical properties was conducted using X-ray diffraction (XRD), N2-physisorption, H2-TPR, and CO2-TPD. The results of the activity and stability evaluations of the synthesized catalysts over a period of 240 min at a temperature of 700 °C, atmospheric pressure, and WHSV of 60,000 mL g−1 h−1 showed that the 10%Ni/CeZrO2 catalyst exhibited the highest catalytic performance, with conversions of CH4 and CO2 up to 74% and 55%, respectively, being reached. The H2/CO ratio in the product was 1.4, which is higher than the stoichiometric ratio of 1, indicating a higher formation of H2. The spent catalysts showed minimal carbon deposition based on the thermo-gravimetry analysis, which was <0.01 gC/gcat, so carbon deposition could be neglected.

Biogas Reforming to Syngas: A Review

Interest in novel uses of biogas has increased recently due to concerns about climate change and greater emphasis on renewable energy sources. Although biogas is frequently used in low-value applications such as heating and fuel in engines or even just flared, reforming is an emerging strategy for converting biogas to syngas, which could then be used to obtain high-value-added liquid fuels and chemicals. Interest also exists due to the role of dry, bi-, and tri-reforming in the capture and utilization of CO2. New research efforts have explored efficient and effective reforming catalysts, as specifically applied to biogas. In this paper, we review recent developments in dry, bi-, and tri-reforming, where the CO2 in biogas is used as an oxidant/partial oxidant. The synthesis, characterization, lifetime, deactivation, and regeneration of candidate reforming catalysts are discussed in detail. The thermodynamic limitation and techno-economics of biogas conversion are also discussed.

Reforming of methane with carbon dioxide over cerium oxide promoted nickel nanoparticles deposited on 4-channel hollow fibers by atomic layer deposition

CeO₂ can significantly enhance the catalytic performance of Ni/Al₂O₃ catalysts prepared by atomic layer deposition for dry reforming of methane.

Facile synthesis of highly disperse Ni-Co nanoparticles over mesoporous silica for enhanced methane dry reforming

A synergistic approach was made to develop a highly stable and carbon resistant catalyst system based on cobalt and nickel supported over modified mesoporous silica for the dry reforming of methane (DRM). Modified mesoporous silica is prepared by a hydrothermal method, and the total Co & Ni composition is taken at around 5% by using the deposition-precipitation technique. CO2 reforming with methane was performed at 400-800 °C under atmospheric pressure as well as at a pressure of 1 MPa, keeping the CH4/CO2 ratio equal to unity. The catalyst assembly before and after the reaction was thoroughly characterized by a wide range of analytical techniques including N2 physisorption, XRD, TPR, TPO, TPH, XPS, SEM, TEM, elemental mapping, TG-DTG. The physicochemical characterization results confirmed the homogeneous distribution of nanosized metal particles into the hexagonal framework of modified silica, which plays a vital role towards a stronger metal support interaction that renders carbon deposition upon the active metal surface as well as avoids metal sintering at higher temperatures. At the same time, the coexistence of nanosized Co and Ni into the mesopores produced a synergy which provides better stability without any deactivation at high pressure reaction conditions. In situ DRIFT analysis evidenced that the reaction proceeds over these catalysts through an initial pathway in which both methane and carbon dioxide initially dissociate over the metal along with a bifunctional pathway in which methane dissociates over the active metal and carbon dioxide activated over the basic support surface via a formate intermediate. Density Functional Theory (DFT) calculations were also performed and further support the proposed mechanism from DRIFT studies.

Pt–CeO2 nanoporous spheres – an excellent catalyst for partial oxidation of methane: effect of the bimodal pore structure

Bimodal pore size distribution played the most important role for the catalyst's superior activity during POM.