Steam Reforming Of Methanol Research Articles

Improved CO-PROX selectivity of CuO/CeO2 catalysts by decorating with lanthanum via surface Cuξ+ redox site

Hydrogen purification is essential to satisfy the various purity requirements for different applications. Preferential oxidation of carbon monoxide (CO-PROX) is a promising strategy for removing CO from H2-rich reformate in proton exchange membrane fuel cells (PEMFCs). Nonetheless, the large proportion of H2 production via methanol steam reforming (MSR) will intensify oxidation competition between H2 and CO, and the CO conversion and CO2 selectivity decrease considerably with increasing temperature. The tolerance of the PEMFCs against the CO species absorbed upon the surface presents the biggest dilemma. This work modified the conventional CuO/CeO2 catalyst in the CO-PROX by doping the support with lanthanum (La). CuO/La-CeO2 catalyst can effectively eliminate CO (<10 ppm) in 70 vol% H2 and exhibit superior stability over 50 % selectivity in CO-PROX reaction. The surface properties of the catalyst before and after modification are characterized by XRD, N2 isothermal adsorption–desorption, H2-TPR, XPS, (HR)TEM Raman and Operando FT-IR, demonstrating that the La-CeO2 anchors CuO particle provides stable low-valence Cu sites (Cuξ+) with enhanced catalytic selectivity.

An efficient methanol pre-reforming gas turbine combined cycle with mid-temperature energy upgradation: Thermodynamic and economic analysis

A novel design has been developed to optimize the performance of the gas turbine combined cycle (GTCC) plant by integration with a methanol steam reforming (MSR) system based on the principle of the cascade utilization of chemical energy. In the integrated MSR-GTCC system, the methanol fuel releases its chemical energy through two successive processes: the thermal reforming reaction of primary fuel in the MSR, and the combustion reaction of reformate syngas in GTCC. The energy required for the endothermic MSR is provided by a portion of mid-temperature heat (MTH), which is extracted from the bottoming cycle of GTCC. By such incorporation, the loss in the conversion from chemical energy to physical energy is reduced and the power generation capability of MTH is improved effectively. Based on a 530 MW GTCC plant, the thermodynamic analysis reveals that the energy and exergy efficiencies are promoted by 7.3 % and 7.2 %, respectively. Besides, the profit of the integrated design is 193.9 M$ higher than that of the conventional system over the lifespan. Furthermore, sensitivity evaluation indicates that the non-reflux MSR process is suitable when the reaction temperature exceeds 250 °C and the optimal water-to-methanol ratio is approximately 1.0 for the integrated MSR-GTCC system.

Methanol steam reforming for hydrogen production driven by an atomically precise Cu catalyst

Plasmon-induced hot-electron transfer from metal nanostructures is being intensely pursed in current photocatalytic research, however it remains elusive whether molecular-like metal clusters with excitonic behavior can be used as light-harvesting materials in solar energy utilization such as photocatalytic methanol steam reforming. In this work, we report an atomically precise Cu13 cluster protected by dual ligands of thiolate and phosphine that can be viewed as the assembly of one top Cu atom and three Cu4 tetrahedra. The Cu13H10(SR)3(PR’3)7 (SR = 2,4-dichlorobenzenethiol, PR’3 = P(4-FC6H4)3) cluster can give rise to highly efficient light-driven activity for methanol steam reforming toward H2 production.

Performance of Cu/ZnO/Al2O3 Catalysts Prepared by Sol–Gel Methods on Methanol Steam Reforming

Cu/ZnO/Al2O3 catalysts were prepared for online methanol steam reforming (MSR) using a conventional sol–gel method in this study. The optimal preparation conditions, including the calcination temperature, Cu loading, molar ratio of citric acid to metal ions (CA/M), and pH, were investigated. CZA50 exhibited the highest MSR activity among all catalysts. It was prepared at a calcination temperature of 350 °C; Cu, Zn, and Al molar fractions of 50%, 30%, and 20%; CA/M of 1.5; and without adjusting pH. Furthermore, a modified sol–gel method was proposed to enhance the mechanical strength of Cu/ZnO/Al2O3 catalysts by using γ-Al2O3 powders as catalyst precursors instead of aluminum nitrates. In this modified method, part of Cu2+ and Zn2+ ions were impregnated firstly on γ-Al2O3 powders, and then the remaining metal ions formed sol–gel with citric acid. MCZA-0.25 catalysts prepared by this modified method showed superior catalytic activity at an Al/(Cu+Zn) ratio of 0.25. The methanol conversion rates of CZA50, MCZA-025, and CZA-Commercial were 82.9%, 79.4%, and 74.7% at the temperature of 200 °C and methanol liquid phase space velocity (LHSV) of 1.0/h, respectively. The average crushing strength of CZA50, MCZA-0.25, and CZA-Commercial were measured as 28 N/cm, 37 N/cm, and 32 N/cm, respectively.

Improving energy enterprise efficiency: Multi-aspect assessment and financially-driven optimization of a tri-generation plant

This research delves into a comprehensive financial analysis and optimization of a tri-generation plant that integrates power generation, cooling capacity, and hydrogen production. The plant design encompasses an organic flash cycle, a two-phase ejector, and methanol steam reforming. Our investigation extends beyond thermodynamic evaluations, encompassing a thorough assessment of economic factors including energy economics, exergy-based financial metrics, and sustainability considerations. Moreover, we calculate critical financial indicators such as payback period and levelized costs to determine the economic feasibility of the tri-generation system. The study showcases the tri-generation system's ability to yield 32.58 kW of power, 246.5 kW of cooling capacity, and 12.56 kg/h of hydrogen in the base case configuration. Optimal energetic and exergetic efficiencies, along with a calculated payback period of 3.92 years, underscore the financial viability of the system. Through meticulous parametric studies, we uncover the intricate interplay between methanol molar ratios, reactor temperatures, and overall economic performance. This comprehensive financial profiling, when disclosed, could enhance regulatory oversight and shape financial supervision policies within the energy sector.

ZnO-supported palladium catalysts via ball milling as an effective heterogeneous catalyst for methanol steam reforming

Methanol steam reforming (MSR) is considered an efficient hydrogen production approach in fuel cell applications, with the Pd-Zn catalysts being the most widely used. Prevailing Pd-Zn catalysts face the challenge of minimizing the Pd loading. To tackle this challenge, a PdZn nanoparticle (NP) catalyst and a Pd1/ZnO single-atom catalyst (SAC) were fabricated via a ball milling process. With methanol conversion maintained at 99.5 % and CO concentration below 0.71 %, 2PdZn/Al2O3 NP catalyst (Pd loading of 2 wt%) exhibited superior anti-oxidation ability and stability for 100 h with a WHSV of 7.2 h−1 at 350 °C. The TOF of 2PdZn/Al2O3 NP is 1.4 times that of 0.2PdZn SAC (Pd loading of 0.2 wt%). Intermediate species methoxy (*CH3O) and formate (*CHOO) were observed from both 2PdZn/Al2O3 NP and 0.2PdZn SAC by in situ temperature programmed DRIFTS (TP-DRIFTS). Density functional theory (DFT) calculations showed that the strong adsorption of water (H2O), formaldehyde (*CH2O) and hydroxyl (*OH) on Pd1/ZnO(001) surface of the SAC model resulted in higher activation energies of water dehydrogenation and *CH2OOH formation than PdZn(111) surface of the NP model. The 2PdZn/Al2O3 NP catalyst showed immense potential for the on-board hydrogen production for fuel cell vehicles.

Absorption-Enhanced Methanol Steam Reforming for Low-Temperature Hydrogen Production with Carbon Capture

Methanol is a prospective hydrogen storage medium that holds the potential to address the challenges of hydrogen storage and transportation. However, hydrogen production via methanol steam reforming faces several key obstacles, including high reaction temperature (e.g., 250–300 °C) and low methanol conversion (at &lt;200 °C), while the purification procedure of hydrogen is commonly required to obtain high-purity H2. A novel method of H2 absorption-enhanced steam reforming of methanol is proposed to overcome the challenges mentioned above. The method involves the absorption and separation of H2 using an absorbent to facilitate the forward shift of the reaction equilibrium and enhance reaction performance. A thermodynamic analysis using the equilibrium constant method presents that the separation of H2 can improve the methanol conversion rate and the total H2 yield. The feasibility of the method is validated through experiments in a fixed-bed reactor (4 mm diameter, 194 mm length) under the conditions of 200 °C and 1 bar. In the experiments, 1 g of bulk catalyst (CuO/ZnO/Al2O3) and 150 g of bulk hydrogen absorbent (Aluminum-doped lanthanum penta-nickel alloy, LaNi4.3Al0.7 alloy) are sequentially loaded into the reactor. As a proof of concept, a CO2 concentration of 84.10% is obtained in the reaction step of the first cycle, and a gas stream with an H2 concentration of 81.66% is obtained in the corresponding regeneration step. A plug flow reactor model considering the kinetics is developed to analyze the effects of the number of cycles and H2 separation ratio on the enhancement performance. The method indicates a high potential for commercialization given its low reaction temperature, high-purity H2, and membrane-free design.

Cu/REO (RE = La, Pr, Sm, Y, Ce) catalysts for methanol steam reforming: Understanding the interaction between Cu and individual REO supports

With the objective to develop applicable catalysts for methanol steam reforming (MSR) to generate H2, five individual REOs were prepared as supports for Cu/CuO to understand the Cu/CuO-support interaction. Pure REO supports with a cubic phase are successfully fabricated except that monoclinic La2O2CO3 carbonate is formed for La2O3 sample, which has negative effect on the reaction. The reaction performance ranks as 5 % Cu/CeO2 > 5 % Cu/Sm2O3 > 5 % Cu/Pr6O11 > 5 % Cu/Y2O3 > 5 % Cu/La2O3 for the samples. It has been disclosed that the quantities of surface basic sites, active O2– species, Cu+ contents/percentage and active Cu surface area are positively correlated to the reaction performance. Thus, the interaction together of these four factors decides the reaction performance. In addition, In-situ DRIFTS results of CH3OH adsorbing/steam reforming have demonstrated that on the optimal 5 % Cu/CeO2, the reactive monodentate m-HCOO* intermediate is formed, which is absent on 5 % Cu/Y2O3 with worse performance.

High-efficient sunlight-driven hydrogen production from methanol steam reforming on a novel photo-thermo-catalysis and thermo-catalysis dual-bed reactor

Sunlight-driven methanol-steam-reforming (MSR) reaction using solar energy promises efficient production and safe transportation of hydrogen energy while storing solar energy. However, the low efficiency of photo-reforming and the high cost of thermo-reforming, intrinsically due to limited usage of full-spectrum solar energy, pose a significant challenge to practical application. Here, we propose a sunlight-driven dual-bed photo-thermo-catalytic reactor (DBPTR) for high-efficient hydrogen production from MSR with the cascaded utilization of photo-thermo-catalysis (PTC) over Pt-CuO catalyst bed and thermo-catalysis (TC) over CuO/ZnO/Al2O3 catalyst bed, respectively. The experimental data verify that the overall solar-to-hydrogen (STH) efficiencies of DBPTR remarkably achieve 22.5% in the laboratory and 20.3% outdoors, respectively. These excellent performances are evidently attributed to the fact that our DBPTR could harvest the short-wave radiation (high-energy photons) in the PTC bed for photo-thermo-driven hydrogen production and confine the long-wave radiation (low-energy photons) in the TC bed for thermo-driven hydrogen production. Meanwhile, the proposed DBPTR has been proved to be scaled-up and operate under a reasonably concentrated irradiance of 16 kW m−2 with the above high STH efficiency, harmonizing the high-performance reactor, low-cost concentrator and moderate-accuracy sun-tracker. This work opens up a novel practical pathway towards high-efficient solar-to-chemical conversion.

Oxidizing- and sintering- resistant PdZn@ZnO catalyst concerning methanol steam reforming for on-board hydrogen production for fuel cell vehicles

For proton exchange membrane fuel cells (PEMFCs) powered vehicles using on-board H2 production by methanol steam reforming (SRM), how to enhance the anti-oxidation and anti-sintering abilities of SRM catalysts are two challenges. Herein, to address the two challenges, a PdZn@ZnO catalyst has been synthesized by in-situ transformation of Pd@ZnO core-shell structure under thermal treatment and H2 reduction, which is a facile and green method. The PdZn@ZnO catalyst exhibited an excellent anti-oxidation ability without obvious change in catalytic activity before and after oxidation treatment. Density functional theory calculations revealed that the abundant PdZn/ZnO interface sites of PdZn@ZnO catalyst could suppress O2 dissociation and subsequent oxidation of the PdZn catalyst. In addition, ZnO shell of PdZn@ZnO prevented the encapsulated PdZn alloys from sintering, resulting in its superior stability to those of the reported catalysts. The PdZn@ZnO catalyst showed great potential for the on-board production of hydrogen for PEMFC-powered vehicles.

Hydrogen Production via Methanol Steam Reforming over CuO/ZnO/Al2O3 Catalysts Prepared via Oxalate-Precursor Synthesis

CuO/ZnO/Al2O3 catalysts are commonly used for the methanol steam reforming reaction. The oxalate precursor of CuO/ZnO/Al2O3 catalysts were prepared via the co-precipitation method using oxalic acid as the precipitator, deionized water and ethanol as the solvent, and microwave radiation and water baths as aging heating methods, respectively. This suggests that ethanol selects the crystalline phase composition of oxalate precursors and limits their growth. Microwave irradiation prompted the isomorphous substitution between Cu2+ of CuC2O4 and Zn2+ of ZnC2O4 in the mother liquid; Zn2+ in ZnC2O4·xH2O was substituted with Cu2+ in CuC2O4, forming the master phase (Cu,Zn)C2O4 in the precursor. Moreover, the solid solution Cu-O-Zn formed after calcination, which exhibited nano-fibriform morphology. It has the characteristics of small CuO grains, a large surface area, and strong synergistic effects between CuO and ZnO, which is conducive to improving the catalytic performance of methanol steam reforming. The conversion rate of methanol reached 91.2%, the space time yield of H2 reached 516.7 mL·g−1·h−1, and the selectivity of CO was only 0.29%.

ZnFexAl2-xO4 spinel supported PdZnβ bifunctional catalyst for methanol steam reforming

PdZnβ alloy catalysts, long regarded as a very promising copper replacement, not only possess copper-like reactivity, but also have superior thermal and chemical stability as well as non-pyrophoric nature that copper catalysts lack. In this contribution, we successfully synthesized the ZnFexAl2-xO4 (x = 0.05–0.2) spinel support, i.e., by replacing Al with a small amount of Fe in ZnAl2O4 spinel. The synthesized support, featuring a high surface area and superior stability, enabled the PdZnβ alloy formation at extremely low Pd loadings (e.g., 1000 ppm Pd), which shows high reactivity and CO2 selectivity toward methanol steam reforming (MSR) reaction. Moreover, it has the unique advantage of constructing bi-functional sites with a specific interfacial structure like PdZn/Fe2O3, the latter of which can effectively enhance water dissociation. Thanks to the synergetic effect, the 0.1 wt% Pd/ZnFe0.1Al1.9O4 catalyst exhibits a much higher ATOF value during the MSR reaction than the 0.1 wt% Pd/ZnAl2O4 counterpart, demonstrating excellent atomic utilization efficiency of noble metal and great potential in the practical application.

Thermal coupling of methanol steam reforming and hydrogen combustion to produce fuel cell hydrogen: A comparative theoretical study between membrane and hydrogen-recycled shell-and-tube reactors

Methanol steam reforming (MSR) is one the most interesting routes for production of fuel cell grade hydrogen. As this reaction is endothermic, its energy supply is one of the most important problems. In this line, recycling and burning the unconverted hydrogen exits from the exhaust of the fuel cells on the shell side of a shell-and-tube reactor (HR) has been suggested in the literature as one the energy supply solutions. In this work, the performance of a membrane-assisted shell-and-tube reactor (MR-HCO), in which part of the hydrogen produced by the MSR is continuously transferred to the shell side through the membrane layer and burned to supply energy, is investigated and compared with HR reactor. To this end, a set of heterogeneous 1D and 2D models are employed to model the shell and the tube sides of the reactors, respectively. The influence of air and steam-methanol feed hourly space velocities on maximum combustion temperature and methanol conversion are examined. It is observed that the MR-HCO has higher methanol conversion, hydrogen flow, and thermal efficiency, while lower CO concentration compared with the HR reactor. Furthermore, the MR-HCO showed a good potential to control the shell temperature rise and prevent hot spots.

A flow-through catalytic membrane micro-reactor for hydrogen production by methanol steam reforming

A flow-through catalytic membrane micro-reactor (CMR) with Cu/ZnO/Al2O3 nanoparticles immobilized in porous membrane pores has been developed for hydrogen production by methanol steam reforming (MSR). The characteristics for CMR demonstrated Cu/ZnO/Al2O3 nanoparticles with almost 200 nm were successfully in situ immobilized in membrane pores. During MSR for hydrogen production in CMR by flow-through mode, hydrogen yield of 500 mmol h−1 g−1 and selectivity of 100% can be achieved under the condition of temperature being 360℃, molar ratio of water to methanol of 8.8 and weight hourly space velocity (WHSV) of 9.28 h−1. Compared with the commercial fixed bed reactor, the hydrogen productivity in CMR is one order of magnitude higher, owing to MSR confined in the space of membrane pore with micro-scale. The methanol conversion rate of over 95% can be expected, if five sheets of CMR with thickness of 5 mm were assembled in series.

Autothermal reforming of methanol for on-board hydrogen production in marine vehicles

The current systems for air independent propulsion systems are based on hydrogen stored in a limited number of cylinders for the continuous operation of the fuel cells in marine vehicles. Hydrogen generation by on-board steam reforming of methanol could extend the air-independent period. This study presents an autothermal reactor for the coupled endothermic (methanol steam reforming) and exothermic (oxidation) reactions in a compact reactor. A commercial Cu-based catalyst (ReforMax® M) was used. The kinetics of both reactions were evaluated over a wide range of conditions. This catalyst was found to be very stable under moderate operating conditions (<270 °C and O2/CH3OH <0.03), obtained by injecting oxygen at four different points along the reformer. Based on the catalytic performance, an integrated process was developed by a simulation program. The system was designed to operate for a long time (>500h). The combined process provides operational advantages, high energy efficiency (84.2%) and hydrogen yield (75.2%).

Coprecipitation dispersion of Cu-Zn-Zr mixed oxides nanocatalyst over Si and Al-Based supports applied in selective and stable hydrogen production from Methanol: Experimental study and rate of reaction engineering via intelligent optimization of CFD method

This study focused on evaluating different support materials made of silicon (Si) and aluminum (Al) for improving the properties of catalysts and their ability to produce high-purity hydrogen from methanol. Accordingly, four coprecipitation-supported nano-scale CuO/ZnO/ZrO2 catalysts were fabricated. Accordingly, MCM-41, γ-Al2O3, and activated alumina materials were used as supports for these catalysts. Various methods such as BET, EDX, FESEM, FTIR, PSD, and XRD were used to analyze the prepared catalysts. The results of FESEM and EDX indicated that using activated alumina as a support led to the smallest copper particle size and excellent dispersion on its surface, and prevented the agglomeration of particles. The catalyst made with activated alumina also had the largest surface area, which is beneficial for reactions. This catalyst showed strong methanol conversion ability and produced less undesirable CO during hydrogen production from methanol. Additionally, a stability test lasting 1220 min confirmed that this catalyst maintained consistent performance over time. A novel method combining CFD and genetic optimization algorithms was used to synthesize new catalysts for catalytic steam reforming of methanol. This approach accurately estimated reaction rates and activation energies, achieving an RMSE below 0.01 for all outcomes. The optimal catalyst, CZZ-Al2O3 (A), exhibited activation energies of 73.928 J/mol, 71.261 J/mol, 106.516 J/mol, and 143.217 J/mol with an RMSE of 0.0089.

Light-Induced Dynamic Restructuring of Cu Active Sites on TiO2 for Low-Temperature H2 Production from Methanol and Water.

The structure and configuration of reaction centers, which dominantly govern the catalytic behaviors, often undergo dynamic transformations under reaction conditions, yet little is known about how to exploit these features to favor the catalytic functions. Here, we demonstrate a facile light activation strategy over a TiO2-supported Cu catalyst to regulate the dynamic restructuring of Cu active sites during low-temperature methanol steam reforming. Under illumination, the thermally deactivated Cu/TiO2 undergoes structural restoration from inoperative Cu2O to the originally active metallic Cu caused by photoexcited charge carriers from TiO2, thereby leading to substantially enhanced activity and stability. Given the low-intensity solar irradiation, the optimized Cu/TiO2 displays a H2 production rate of 1724.1 μmol g-1 min-1, outperforming most of the conventional photocatalytic and thermocatalytic processes. Taking advantages of the strong light-matter-reactant interaction, we achieve in situ manipulation of the Cu active sites, suggesting the feasibility for real-time functionalization of catalysts.

Methanol steam reforming for hydrogen production over Ni/ZrO2 catalyst: Comparison of thermal and non-thermal plasma catalysis

Hydrogen (H2) is the promising clean energy which can contribute to the achievement of the Net Zero goals. Herein, the Ni/ZrO2 catalyst was developed for methanol steam reforming for H2 production. The catalyst possesses the features of good redox property, and the presence of surface chemisorbed oxygen, and large specific surface area. The Ni/ZrO2 composite together with the control of NiO and ZrO2 were assessed by thermal and non-thermal plasma (NTP)-activated methanol steam reforming reactions, and the results showed that NTP itself was able to initiate methanol conversion, whilst the inclusion of the composite catalyst did not improve the reaction significantly, e.g., hydrogen production rate = 0.162 mmol·min−1 over Ni/ZrO2 under the plasma condition (at 90 ℃ and 9.4 kV). This could be attributed to the change of reaction pathways for methanol conversion in the presence of Ni/ZrO2 under the NTP condition, compared to the thermal systems employing Ni/ZrO2. Comparatively, the thermal catalytic system was not active at 90 °C regardless the catalysts used. At 400 °C, the Ni/ZrO2 catalyst showed satisfactory activity with a hydrogen production rate of 0.708 mmol·min−1. In addition, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and DFT calculations were performed to understand the relevant reaction mechanisms, revealing that methoxy and formic acid species were the key intermediates for methanol steam reforming.

An InOx Surface Enrichment on the Cu Nanoparticles for the Methanol Steam Reforming

AbstractIn the realm of heterogeneous catalysts promoted by indium, indium often covers other active metals, thereby compromising catalytic activity. However, the inhibition mechanism remains poorly understood. In this study, we investigate the interaction between copper (Cu) and indium oxide (InOx), focusing on the role of the Cu−In interface during the methanol steam reforming (MSR) reaction. Utilizing a series of (quasi) in situ characterization techniques, we observe a decrease in intrinsic catalytic activity for MSR on the CuIn/Al2O3 catalyst, which can be attributed to the surface enrichment of InOx on Cu nanoparticles. Moreover, our findings reveal that the enrichment suppresses both the dehydrogenation of *CH3O and the dissociation of H2O, ultimately leading to a reduction in catalytic activity. This discovery has the potential to guide the rational design of enhanced indium‐based catalysts in the future.

Effects of P:Ni Ratio on Methanol Steam Reforming on Nickel Phosphide Catalysts.

This study investigates the influence of the phosphorus-to-nickel (P:Ni) ratio on methanol steam reforming (MSR) over nickel phosphide catalysts using density functional theory (DFT) calculations. The catalytic behavior of Ni(111) and Ni12P5(001) surfaces was explored and contrasted to our previous results from research on Ni2P(001). The DFT-predicted barriers reveal that Ni(111) predominantly favors the methanol decomposition route, where methanol is converted into carbon monoxide through a stepwise pathway involving CH3OH* → CH3O* → CH2O* → CHO* → CO*. On the other hand, Ni12P5 with a P:Ni atomic ratio of 0.42 (5:12) exhibits a substantial increase in selectivity towards methanol steam reforming (MSR) relative to methanol decomposition. In this pathway, formaldehyde is transformed into CO2 through a sequence of reactions involving CH2O*→ H2COOH* → HCOOH* → HCOO* → CO2. The introduction of phosphorus into the catalyst alters the surface morphology and electronic structure, favoring the MSR pathway. However, with a further increase in the P:Ni atomic ratio to 0.5 (1:2) on Ni2P catalysts, the selectivity towards MSR decreases, resulting in a more balanced competition between methanol decomposition and MSR. These results highlight the significance of tuning the P:Ni atomic ratio in designing efficient catalysts for the selective production of CO2 through the MSR route, offering valuable insights into optimizing nickel phosphide catalysts for desired chemical transformations.