Effect Of Metal Loading Research Articles

Progress of metal-loaded biochar-activated persulfate for degradation of emerging organic contaminants.

In recent years, studies on the degradation of emerging organic contaminants by sulfate radical (SO4-·) based advanced oxidation processes (SR-AOPs) have triggered increasing attention. Metal-loaded biochar (Me-BC) can effectively prevent the agglomeration and leaching of transition metals, and its good physicochemical properties and abundant active sites induce outstanding in activating persulfate (PS) for pollutant degradation, which is of great significance in the field of advanced oxidation. In this paper, we reviewed the preparation method and stability of Me-BC, the effect of metal loading on the physicochemical properties of biochar, the pathways of pollutant degradation by Me-BC-activated PS (including free radical pathways: SO4-·, hydroxyl radical (·OH), superoxide radicals (O2-·); non-free radical pathways: singlet oxygen (1O2), direct electron transfer), and discussed the activation of different active sites (including metal ions, persistent free radicals, oxygen-containing functional groups, defective structures, etc.) in the SR-AOPs system. Finally, the prospect was presented for the current research progress of Me-BC in SR-AOPs technology.

Oxygen evolution reaction activity of carbon aerogel supported Pd–Ni–Al catalysts synthesized by microwave irradiation method

The oxygen evolution reaction (OER) is a critical step for oxygen production during the electrochemical splitting of water. Effective OER catalysts support the development of clean energy technologies by increasing the energy efficiency of these processes. In this study, carbon aerogel (CA) was first synthesized as a catalyst support material using sol-gel, supercritical drying, and pyrolysis process. Then, mono-metallic (Pd/CA, Al/CA), bi-metallic (Pd–Al/CA, Pd–Ni/CA), and tri-metallic (Pd–Ni–Al/CA) catalysts were synthesized by microwave irradiation method. Inductively coupled plasma-mass spectrometry (ICP-MS), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy have been made to examine the structural properties of the synthesized catalysts. Electrochemical analysis was carried out through cyclic voltammetry (CV), chronoamperometry, and electrochemical impedance spectroscopy (EIS) in alkaline media (1 M KOH: Methanol) to examine the effect of metal loading of CA support material towards OER performance. All the compositions showed excellent activity toward OER, among all Pd–Ni/CA catalysts showed the highest activity. The OER peak current increased remarkably up to 48 mA cm−2 with methanol addition, which signifies the substantial application of carbon aerogel supported-Pd-Ni-Al catalysts in direct methanol fuel cells (DMFCs). Pd–Ni/CA display high OER performance with maximum diffusion coefficient, Do (6.6 × 10−8 cm2 s−1) and heterogeneous rate constant, ko (4.706 × 10−4 cm s−1), and smaller value of Tafel slope (128 mV dec−1). Electrochemical studies predicted that all the prepared carbon aerogel supported-Pd-Ni-Al catalysts can be used as efficient catalysts for OER and other related electrocatalysis applications.

Effect of Contact Time on Carbon Deposition and Catalytic Activity of Nickel Alumina Catalysts for Dry Reforming of Methane

AbstractDry reforming of methane (DRM) reaction is advantageous in producing syngas with a low H2/CO, relevant to many industries. Effect of contact time on catalytic activity and carbon deposition is studied for DRM using Ni−Al catalysts, along with the effect of metal loading, reaction temperature, and reactant partial pressure (CO2/CH4). Maximum CH4 conversion (58 %) and CO2 (59 %) were achieved at a higher contact time of 4.009 kg‐cat . h/kgCH4. A maximum of 46 % CH4 conversion was achieved at 1023 K with a contact time of 0.134 kg‐cat . h/kgCH4. Higher CH4 and CO2 conversion were achieved with an excellent H2 and CO yield due to the RWGS reaction with increased metal (Ni) loading (10–30 wt . %). When the reactant partial pressure (CO2) changed from 0.1–0.3, the CH4 conversion increased whereas CO2 conversion decreased. FESEM images revealed the formation of whisker‐like carbon fibers for all loadings. For the best syngas output and stability in a Ni‐based catalyst, a combination of a basic support (alumina) at a higher contact time (~4.009 kg‐cat . h/kgCH4) and a CO2/CH4 ratio of 1–1.5 at a moderate temperature of 873 K may provide best CO2 adsorption with minimal coking.

Heavy metal loading effects on special nuclear material and waste of an uprated Indonesian Reaktor Daya Eksperimental

This technical policy study investigated the effect of heavy metal loading (HML) quantity in the pebble fuel on the special nuclear material (SNM) and waste quantities in an uprated Indonesian pebble bed reactor design, the Reaktor Daya Eksperimental (RDE). A set of Monte Carlo simulations, performed using OpenMC, was deployed to simulate the pebble fuel depletion using an infinite lattice reactor calculation. This study considers HML, fuel residence time, leftover 235U, total Pu, medium- and long-lived wastes, number of depleted pebbles, and volume of waste at different HML values, at attainable discharged fuel burnup, at a target burnup of 80 GWd/MTU and at different reactor powers (10 and 40 MWt). Due to an over-moderation effect, a higher HML quantity shortened the attainable discharged fuel burnup level, which also translated to a lower fuel utilization. An 80% higher HML quantity resulted in about a 25% lower burnup level. Assuming a five-pass refueling scheme, this resulted in approximately three times more leftover 235U, 2.4 times more Pu, 1.4 times more medium-lived waste, and 1.5 times more long-lived waste collections per year. The study showed that a power uprating by a factor of four increased the SNM and waste quantities by four times.

Enhancing hydrogen adsorption through optimized magnesium dispersion on fibrous nano-silica scaffold: Kinetic and thermodynamic studies

Silica material, particularly, fibrous nano-silica (FNS) is one of the potential scaffolds for hydrogen storage, however, low hydrogen adsorption limits its application. To improve its adsorption capacities, the incorporation of active metal, particularly magnesium (Mg), was prepared. FNS with well-developed pore structures and a good surface area were synthesized. Various amounts of Mg (1–5 wt%) were infiltrated into the FNS. To study the effect of metal loading, the adsorbents were characterized by their chemical structure, crystal phase, morphology/elemental composition, and textural properties. Subsequently, hydrogen adsorption studies were conducted where different reaction conditions, including metal loading, catalyst loading, and temperature were studied. Furthermore, kinetic and thermodynamic studies were conducted based on the Langmuir and Van't Hoff models. The results of the characterizations show that the Mg metal was well dispersed into the porous FNS with no significant changes in the original structure. The optimum adsorption of 1.90 wt% was achieved at 1.0 wt% Mg loading, 0.1 g catalyst loading, and 423 K temperature. Kinetic studies demonstrated that the adsorption process fits the pseudo-second-order reaction. The 1%Mg/FNS adsorbents showed good reusability where 5 runs were conducted with <5 % loss in activity. Therefore, this result indicated that infiltration of Mg into the silica is one of the most active approaches in improving the hydrogen adsorption capacities of FNS.

Catalytic activity of Co/γ-Al2O3 catalysts for decomposition of ammonia to produce hydrogen

This paper aims to study the performance of Co/meso-Al2O3 catalysts for ammonia decomposition to produce hydrogen. High-performance Co/meso-Al2O3 catalysts were prepared using a sequential metal loading approach. The synthesized catalysts were analyzed by several techniques including X-ray diffraction (XRD), N2 physisorption analysis, temperature-programmed reduction (H2-TPR), temperature-programmed desorption (NH3-TPD) and transmission electron microscope (TEM). The effect of metal loading, decomposition temperature and weight hourly space velocity (WHSV) on the catalyst activity were studied. Temperature-programmed desorption (NH3-TPD) analysis showed the coexistence of weak acidic sites and strong acidic sites in the synthesized catalysts, indicative of weak metal–support interaction. The reaction activation energy of the catalysts followed the order of 26Co-CAT(A) < 9Co-CAT(A) < 16Co-CAT(A) < 5Co-CAT(A) < CAT(A). Particularly, 26 Co-CAT(A) exhibited significantly lower activation energy compared to the other catalyst, which was in line with its catalytic activity. This observation indicated that the cobalt loading in 26 Co-CAT(A) resulted in relatively weaker metal-support interactions, leading to lower desorption energy and thus allowing higher NH3 conversion at lower temperatures. These findings offer valuable insights for the development and optimization of advanced Co-based catalysts, facilitating the sustainable and efficient application of ammonia decomposition.

Nickel-tungsten co-doped biochar catalyst boosting ethylene glycol production from cellulose hydrogenolysis

Promoted ethylene glycol (EG) yield from cellulose hydrogenolysis is achieved via using Nickel-tungsten doped carbon catalysts prepared from glucose (x%Ni-y%WOx-GCT). Synchronously metal loading and carbon formation endow the catalyst excellent catalytic performance and high stability. Mechanistic investigations of the effects of metal loading and BrØnsted acid on EG yield are conducted. Increasing W loading promotes the content of polymerized WOx and consequently increases the amount of polytungstate species, thus lead to an improved BrØnsted acid content. Results reveal that promotion of B/L acid facilitates cellulose hydrolysis and suppresses isomerization of glucose to fructose. Besides, high W loading is beneficial for reduction of WOx to form W5+, producing oxygen vacancies to promote retro aldol condensation (RAC) of glucose to form acetaldehyde alcohol (an important intermediate for EG). By adopting the optimized 9%Ni-12%WOx-GC700 catalyst, a 100% cellulose conversion with a high EG yield of 65% is obtained due to the synergistic interactions between BrØnsted acid, W5+ and Ni0+ active sites.

Metal-Doped HZSM-5 Zeolite Catalysts for Catalytic Cracking of Raw Bio-Oil: Exploring Activity toward Value-Added Products

Catalytic cracking of bio-oil, conducted at atmospheric pressure without hydrogen supply, is a cost-effective and versatile approach for the targeted synthesis of biofuels and platform chemicals. The conversion of raw bio-oil follows intricate reaction pathways strongly influenced by the catalyst properties. In this work, we explore the use of various transition metals (Cr, Fe, and Zn) to modify the properties of HZSM-5 zeolite and assess their impact on the catalytic cracking of real raw bio-oil feedstock. The effect of metal loading on physical and chemical characteristics of metal-doped zeolite catalysts was studied through XRD, XRF, N2 physisorption, NH3-TPD, FTIR, H2-TPR. The behavior of each catalyst was evaluated in a continuous two-step catalytic cracking system (TS-CC) operating at 450 °C and space-time 0.7 gcatalysth/gfeed. The results highlight the importance of carefully selecting active metal species to optimize the performance of HZSM-5 in the catalytic cracking of bio-oil. Cr and Fe were found to be effective metals in increasing the selectivity of C2–C4 olefins in the gas product and mono-aromatics in the hydrocarbon liquid product, whereas the Zn-doped catalyst exhibits poor activity compared to bulk zeolite. Furthermore, a significant impact of the metal oxidation state on catalytic activity was observed, with reduced metals promoting the formation of H2, CO, and CO2 at the expense of hydrocarbon production.

Effect of zeolite structure and Si/Al ratio on cotton stalks hydropyrolysis

Zeolites, being acidic, act as the most promising catalytic materials for deoxygenating reactive oxygenated compounds produced during the pyrolysis of lignocellulosic biomass. Herein, two zeolites, HY and HZSM-5, with different Si/Al ratios, were employed to investigate the effect of zeolite structure on aromatic hydrocarbons (AHs) production during flash hydropyrolysis of cotton stalks (Temperature = 800 ˚C, H2 pressure = 10 bar). Both the zeolites enhanced AHs production. However, the pore structure and pore size of HZSM-5 marked a pronounced effect on the reduction of oxygenated compounds. With an increase in Si/Al ratio, AHs area% was found to decrease owing to the decrease in acidity. Ni/zeolite catalysts were also investigated to look into the effect of metal loading on the catalytic properties of zeolites. Ni/zeolite catalysts enhanced the aromatic and aliphatic hydrocarbon production by further conversion of phenolics and other oxygenated compounds due to the promotion of direct deoxygenation, decarbonylation and decarboxylation reactions.

Methodological Investigation of the Band Gap Determination of Solid Semiconductors via UV/Vis Spectroscopy

AbstractSeveral different evaluation methods (EM) to obtain the band gap energy (Eg) of semiconductors via UV/Vis diffuse reflectance spectroscopy (DRS) are used in literature and no clear consensus which EM to use is established. By using P25 as a model semiconductor, evaluating 32 literature sources and our own experiments, we show that the determined Eg energy is heavily influenced by the EM (differences in Eg of up to 0.87 eV). For P25 loaded with CuO even contradictive effects of metal loading on the Eg are observed using different EM. Different phase compositions of TiO2 are also shown to yield EM‐dependent results. This paper thus comprehensively investigates the most common EM on different relevant photocatalyst material classes, illustrates their mathematical and graphical determination, gives recommendations which method to use based on a quantitative indicator and illustrates common pitfalls in determining Eg via UV/Vis DRS.

Effects of metal loading and support modification on the low-temperature steam reforming of ethanol (LTSRE) over the Ni–Sn/CeO2 catalysts

This article presents the effect of metal loading and support modification with MgO on low-temperature steam reforming of ethanol (LTSRE) over Ni–Sn/CeO2 catalysts prepare by a single-pot solution combustion synthesis (SCS) method. Atmospheric pressure activity study of these catalysts (0.5 g) is performed at different temperatures (200–400 °C), H2O:EtOH = 12: 1 mol ratio, and feed flow rate 0.1 ml/min. After 10 h TOS at 400 °C, NiSn(5)/CM12 catalyst with 5 wt.% total metal loading, optimal Sn (Ni:Sn = 14:1), and Ce:Mg = 1:2 mol ratio shows EtOH conversion 100% and H2 selectivity 70% with low coke deposition. Physicochemical characterizations (XRD, Raman, FESEM, TEM, and N2 adsorption-desorption) reveal that addition of MgO in CeO2 and an optimal amount of Sn decrease both Ni and support particle sizes while oxygen storage capacity (OSC) of the support increases (by XPS). Alkaline characteristics of MgO reduces support's acidity and improves active metal-support interaction, as evaluated by NH3-TPD and H2-TPR.

The selective ethanol Guerbet condensation over alkali metal-doped sepiolite

In this study, alkali metal-doped sepiolite based catalysts were developed for the up-grading of ethanol through the Guerbet reaction mechanism. The catalysts were prepared by wetness impregnation with aqueous solution containing alkali metal precursors salts over calcined sepiolite, and finally activated at 500ºC in air. The catalysts have been characterized by XRD, SEM-EDS, TGA-DSC, N2-adsorption. In addition, TPD-CO2 and TPD-NH3 were used to determine the acid and basic characteristics of catalysts. The catalysts were tested into a quartz continuous gas-flow reaction system working at atmospheric pressure to investigate the effects of metal loading (wt%), the nature of the alkali metals and of the main reaction parameters (e.g., reaction temperature, weight hourly space velocity), on the production of n-butanol starting from ethanol. The highest yield (18%) was obtained at 400 ºC with the catalyst consisting in sepiolite, calcined at 500ºC, impregnated with 7 wt% of Cs. This study proves that ad hoc modified natural sepiolites with alkali metals are effective catalysts for the Guerbet upgrading of ethanol.

Rare earth element uptake mechanisms in plankton in the Estuary and Gulf of St. Lawrence

The global shift toward green energy alternatives escalates demands for new resources, including rare earth elements (REEs), as per their implications in various green innovations. However, our understanding of their environmental cycle, especially the interactions with aquatic organisms, remains deficient, ultimately hindering environmental protection efforts. Here, we investigate the accumulation of REEs and 18 other elements in bulk and sorted plankton collected with different net mesh sizes (30, 63, 200, 333, 500 μm) in the Estuary and Gulf of St. Lawrence in the summer and winter of 2020. We observed significant correlations between the concentrations of REEs and elements of different charge numbers and ionic radii (Ba, Co, Cs, Fe, Mn, Pb, Rb and V), indicating non-selective uptake of REEs into plankton. All these elements have their highest concentrations in the fluvial corridor and upper estuary, with more significant enrichment in phytoplankton ([La] = 26.4 ± 4.8 mg kg−1) than zooplankton ([La] = 11.6 ± 8.3 mg kg−1). Their concentrations decrease to the minimum in the Gulf of St. Lawrence, especially in zooplankton ([La] = 4.8 × 10−2 ± 3.2 × 10−2 mg kg−1). We also assessed REE patterns to identify differential REE fractionation processes and anomalies. The freshwater plankton exhibits enrichment of middle REEs (MREEs) relative to the light and heavy REEs (LREEs and HREEs), potentially because of the higher binding affinity of MREEs on cellular surface transporters and metal loading effects. In estuarine and marine settings, the REE patterns in biological samples align with suspended particles, exhibiting a linear trend with LREE enrichment. This process is more noticeable in sorted macrozooplankton, which have significant Eu anomalies (Eu/Eu* up to 2), indicating differential incorporation of REEs into the chitin shells. This study highlights the significant enrichment of REEs into freshwater primary producers and the accumulation pathway similar to other inorganic elements.

Ecological and health risk assessment of different land uses along with seasonal variation in toxic metal contamination around Varanasi city situated in Indo-Gangetic Plain.

Metal pollution load in soil environment has been enhanced during last few decades due to increasing industrialization and wide application of metals in all sectors. Due to the persistent and hazardous nature of metals, it can accumulate in the living system and cause severe risks to the ecosystem. The abundance of metals in soils from 5 different land use systems (industrial, industrial highway, brick kiln production area, residential highways and botanical gardens) in the Indo-Gangetic Plain region of India was analysed for three consecutive years (2018-2020) to evaluate the effects of metal load on soil properties and ecosystem health. Soil enzymatic activities, moisture, porosity, total nitrogen, and organic carbon were least at the industrial area of Ramnagar site and highest at Botanical garden area of BHU. Geochemical indices were calculated to compare the background status of metals in the soil where Cd, Cu, Cr, Co, Ni, Mn and Zn were increased in recent times. Contamination, enrichment and potential ecological risk factors with respect to Cu and Cd contents in soil were significantly higher at industrial area of Ramnagar and highway near industrial area. Maximum lifetime non-cancer and cancer health hazards were observed for Cd and Ni, respectively. The study clearly indicates that Cd, Cu and Ni are capable of posing health risk and cause imbalance in ecological functioning of soil due to chronic exposure of the potential toxic metals generated through change in land uses in sub-urban areas of Indo-Gangetic Plain region.

Microwave-assisted ammonia synthesis over Cs-Ru/CeO2 catalyst at ambient pressure: Effects of metal loading and support particle size

Industrially, ammonia is produced by Haber-Bosch process under high temperatures and pressures, consuming more than >2% of the world's energy production. This paper presents microwave-assisted catalytic synthesis of ammonia operated at atmospheric pressure and temperatures from 260 to 360 °C. A Cs-promoted Ru catalyst supported on cerium oxide with different metal loading (4–24 wt% Ru) and support particle size (25 nm, 50 nm and 5 μm) was investigated. The small size cerium oxide support resulted in the highest activity while the large cerium oxide support was less favorable, leading to lower activity associated to large Ru particle size and lower dispersion.

A methodology for structure dependent global kinetic models: Application to the selective catalytic reduction of NO by hydrocarbons

Global kinetic models capable of capturing experimentally observed features of catalytic reactions are vital in design and optimization studies. In this work, a detailed analysis of the selective catalytic reduction of NO and NO2, particularly in automotive exhaust control is undertaken. The prominent metal based catalysts for this reaction range from Pt, Au & Rh to cheaper options including Cu, Ag & Co supported on Al2O3, SiO2, and occasionally, zeolites. Here, we focus on Ag & Co supported on Al2O3 catalysts, and propose a computationally tractable kinetic model capable of capturing the observed SCR features across a range of catalyst synthesis and reactor operating conditions. In particular, the effects of metal loading on catalyst performance are closely examined. In SCR, an important aspect is the catalytic activity at higher inlet O2 concentrations. The global kinetic model proposed here is shown to predict the trends with respect to reactor temperature and inlet feed compositions (including O2), well, for both catalysts.

On the effect of metal loading on the reducibility and redox chemistry of ceria supported Pd catalysts.

The effect of Pd loading on the redox characteristics of a ceria support was examined using in situ Pd K-edge XAS, Ce L3-edge XAS and in situ X-ray diffraction techniques. Analysis of the data obtained from these techniques indicates that the onset temperature for the partial reduction of Ce(IV) to Ce(III), by exposure to H2, varies inversely with the loading of Pd. Whilst the onset and completion temperatures of the reduction of Ce(IV) to Ce(III) are different, both samples yield the same maximal fraction of Ce(III) formation independent of Pd loading. Furthermore, the partial reduction of Ce is found to be concurrent with the reduction of PdO and demonstrated that the presence of metallic Pd is necessary for the reduction of the CeO2 support. Upon passivation by room temperature oxidation, a full oxidation of the reduced ceria support was observed. However, only a mild surface oxidation of Pd was identified. The mild passivation of the Pd is found to lead to a highly reactive sample upon a second reduction by H2. The onset of the reduction of Pd and Ce has been demonstrated to be independent of the Pd loading after a mild passivation with both samples exhibiting near room temperature reduction in the presence of H2.

On the effect of metal loading on the performance of Co catalysts supported on mixed MgO-La2O3 oxides for ammonia synthesis.

Synthesis of ammonia from nitrogen and hydrogen is one of the largest manmade chemical processes, with annual production reaching 170 million tons. The Haber-Bosch process is the main industrial method for producing ammonia, which proceeds at high temperatures (400-600 °C) and pressures (20-40 MPa) using an iron-based catalyst. It is thus highly desirable to develop new catalysts with sufficient activity and stability under mild conditions. In this work, we report cobalt catalysts supported on magnesium-lanthanum mixed oxide with different Co loading amounts synthesised via a simple wet impregnation method. We have found a clear relationship between the ammonia synthesis rate and the Co loading amount. Specifically, the NH3 synthesis rate increased on increasing cobalt loading and reached a maximum at 40 wt% Co deposition. A further increase in Co loading did not change the activity significantly. Interestingly, the surface-specific activity (TOF) remained almost unchanged regardless of the Co loading amount in the catalysts. It revealed that the resultant ammonia synthesis rate over the studied catalysts did not depend on the size and structure of Co nanoparticles but strongly on the Co loading amount. Finally, it is believed that the use of this type of catalyst will be a starting point toward energy-efficient ammonia production.

Using Transient XAS to Detect Minute Levels of Reversible S-O Exchange at the Active Sites of MoS2-Based Hydrotreating Catalysts: Effect of Metal Loading, Promotion, Temperature, and Oxygenate Reactant

Modulation excitation spectroscopy (MES) coupled with time-resolved X-ray absorption spectroscopy (XAS) was applied to unpromoted and Co-promoted Mo-based hydrotreating catalysts (i.e., Mo and CoMo catalysts) for investigating the minute as well as instantaneous differences in active site composition under the influence of H2S and H2O. Transient experiments during alternating sulfur- and water-rich conditions were performed at temperatures between 400 and 500 °C using catalysts with varying Co/Mo metal loadings to study the correlative effect of these factors on the stability of the active sites. For both types of catalysts, the features of the demodulated Mo K-edge spectrum matching the difference spectra of the MoS2 and MoO3 references indicate a reversible oxidation–sulfidation process during H2O/H2S cycling. In the case of CoMo catalysts with increasing metal loadings, transient XAS at the Mo K- as well as Co K-edge revealed minute levels of S-O exchange at both sulfided Mo and Co sites, although 26 to 47% of the Co was bound as stable CoAl2O4, which does not form a bulk sulfide. Thus, even in the presence of multiple Co phases (oxide and sulfide) and a low number of active sites relative to the total number of Mo atoms, transient XAS can successfully detect the changes occurring over both the active Co and Mo sites. Furthermore, the comparison of the amplitude of the demodulated spectra showed that Mo atoms are more prone to S-O exchange with increasing temperature, while Co promotion stabilized the molybdenum sulfide. MES-coupled XAS experiments with 1-propanol performed to evaluate the degree of S-O exchange in the presence of another oxygenate reactant revealed the higher affinity of water toward these sulfided Mo sites as compared to 1-propanol.

Mesoporous CuO/TiO2 catalysts prepared by the ammonia driven deposition precipitation method for CO preferential oxidation: Effect of metal loading

Supported CuO catalysts onto a highly crystalline mesoporous TiO2 material are produced via an ammonium driven deposition precipitation method and tested for preferential oxidation of CO in H2-rich gases. The effect of Cu loading on the oxidation activity is investigated by producing samples with final Cu content varying between 2.5 and 10 wt%. According to the analysis results, the chemical nature of the CuO species differs in each sample depending on the Cu loading. All materials tested are highly selective towards CO oxidation up to 160 °C. The 5 wt% Cu loaded material demonstrates the optimum CO-PROX performance, which is ascribed to the formation of finely dispersed and easily reducible copper oxide nanoparticles. Stability and durability of the latter sample are assessed by performing multiple testing cycles corresponding to >100hrs on stream as well as by the separate and combined addition of CO2 and H2O in the feeding stream.