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Industrial‐scale reforming of methane is typically carried out with an excess of oxidant to suppress coking of the catalyst. On the other hand, many academic studies on dry reforming employ a CO2/CH4 ratio of unity to quickly observe coking which can be reduced by adding a catalyst promoter. In this work, Ni/Al2O3 catalysts were tested for dry reforming of methane (CO2/CH4=1) with additional regeneration steps to test the resistance against an oxidation treatment. Thereby, we wanted to evaluate catalyst stability for industrial relevance. The effects of three promoters, Cr, Mn and Fe, that differ in their degree of CO2 interaction, are compared. A higher iron loading on Ni/Al2O3 leads to higher stability in dry reforming with lower coke formation. However, the higher the concentration of a promoter with high CO2 affinity, the quicker the catalyst is oxidized during regeneration with CO2. Subsequent reduction of a catalyst oxidized with CO2 leads to considerable sintering in all cases. This sintering induces formation of more coke during dry reforming. On such sintered samples only highly effective promoters in large concentrations still have a noticeable effect compared to unpromoted Ni/Al2O3. [ABSTRACT FROM AUTHOR]

The development of effective catalysts for the electrocatalytic carbon dioxide reduction reaction (CO2RR) to two‐carbon (C2) products is a practical approach to solve the energy crisis and stabilize the carbon cycle of the ecosystem. The production of electrocatalytic CO2RR with copper metal shows low selectivity and mainly generates one‐carbon (C1) products, hindering its wide practical application. The use of copper (I) oxide (Cu2O) in electrocatalysis has attracted intense research attention because it can more efficiently produce C2 products with high energy density such as ethylene (C2H4) and ethane (C2H6). We use an amino‐modified Cu2O catalyst (NH2−Cu2O) for electrocatalytic CO2RR to obtain significantly increased production of the CO and C2 products. Electrochemical in‐situ infrared spectroscopy analysis was used to detect the presence of the *COOH and *CHO reaction intermediates. Density functional theory calculations showed that the amino (−NH2) modification reduces the free energy of the *CO→*CHO reaction that is the rate‐determining step in C2H4 production. Our results show that amino modification can promote the protonation of *CO and *CHO carbon‐carbon coupling to produce C2H4. Thus, amino‐modified copper‐based catalysts are promising materials for application in electrocatalytic CO2RR to multi‐carbon products. [ABSTRACT FROM AUTHOR]

This work reports on the use of gallium aminotrisphenolate compounds as catalysts for the synthesis of cyclic carbonates from epoxides and CO2. The results show that they are highly active, and more so than the corresponding aluminium congeners. The catalyst system is applicable at low and elevated temperatures across a wide substrate scope including terminal, internal, multiple and fully deuterated epoxides. Applying low catalyst loadings has allowed for a TON of 344,000 to be obtained, highlighting their stability. A DFT investigation has confirmed that the gallium catalysts have lower energetic profiles compared to the aluminium congeners. Measurement of the Lewis acidity of both the gallium and aluminium aminotrisphenolate compounds using the Gutmann‐Beckett method provides the experimental proof that the gallium compounds are more Lewis acidic than their aluminium congeners. Finally, Ab‐Initio Molecular Dynamic (AIMD) simulations have investigated and quantified the dynamic behaviour of the catalytic systems, highlighting an important increase in fluxionality in some cases which helps to explain the increase in catalytic activity. [ABSTRACT FROM AUTHOR]

The Front Cover shows an amino‐modified copper(I) oxide catalyst reduces the Gibbs free energy for electrocatalytic reduction of carbon dioxide to ethylene. The roller coasters and tracks represent the catalysts and the Gibbs free energy, respectively. In their Full Paper, H. Deng et al, illustrate that the modification of amino on copper(I) oxide promotes the hydrogenation of *CO to *CHO, which is the rate‐determining step for the formation of ethylene. This work presents an amino‐assisted carbon‐carbon coupling mechanism during electroreduction of carbon dioxide to multi‐carbon products. More information can be found in the Full Paper by H. Deng et al. [ABSTRACT FROM AUTHOR]

The synthesis of cyclic carbonate from CO2 and epoxide is one of the valid routes in line with atomic economy to achieve CO2 conversion. Combining the advantages of high activity and easy separation for heterogeneous catalytic reaction system, a series of heterogeneous catalysts poly(ionic liquid)s with high ionic density (HDPILs) were designed and synthesized. Looser structures and high ionic density were obtained by using muti‐center ionic liquids with different number of substituents as cross‐linking agents. Ply[PhSVIM]Br, the copolymerized HDPILs with six substituents on the benzene ring was optimal. The catalyst exhibited excellent catalytic performance for CO2 cycloaddition with 98 % conversion and 99 % selectivity under optimal conditions. These HDPILs have comparable catalytic activity to homogeneous catalysts and convenient product separability. Particularly, combining XPS and DFT, a structural performance relationship was revealed, the multi‐center ionic liquids used instead of the traditional crosslinking agent as the polymeric backbone can contribute to the reduction of the anion and cation binding energy (BE) and freeing of Br−, which leads to efficient catalytic activity. This study provides a novel strategy for developing a highly efficient catalysts for CO2 conversion to high value products. [ABSTRACT FROM AUTHOR]

In search of a better understanding of the structure‐property relationship of heteroleptic CuI photosensitizers, two structurally closely related complexes are investigated in detail. Although both compounds bear the same 4‐methoxyphenyl substituents at the phenanthroline moiety (i. e. at 5,6‐position in Cu1 and at 4,7‐position in Cu2), substitution at the 4,7‐position increases the attenuation coefficient in the 300–500 nm range by a factor of more than two. Even more drastic is the difference in emission lifetime (11 vs. 628 ns), which rises by a factor of almost 60 when positions 4 and 7 (i. e. Cu2) are chosen. A combination of solid‐state structural analysis, TDDFT calculations, transient absorption spectroscopy and quenching studies is then applied to elucidate the reasons for the superior photophysical properties of Cu2. Subsequently, a non‐emissive and long‐lived excited state (715 ns) has been revealed for Cu1. In a next step, both complexes were successfully used in the photocatalytic splitting of water and the reduction of CO2 to CO to test the influence of this behavior on the activity. Most importantly, Cu2 not only performs significantly better than Cu1, but also than the benchmark system and the noble‐metal‐based complex [Ir(dFppy)3]. [ABSTRACT FROM AUTHOR]

Immobilization of well‐defined homogenous (electro)catalysts onto conductive supports offers an attractive strategy for designing advanced functional materials for energy conversion. In this context, this study reports (i) the introduction of a pyrene anchoring group on a PNP−pincer IrI complex previously described as a selective catalyst for the electrodriven CO2 reduction (CO2RR) into CO in DMF/water mixtures, (ii) the comparison of its CO2RR activity in DMF/water mixtures with the ones of two pyrene‐free reference complexes, and (iii) its activity in pure water after immobilization onto carbon nanotubes (CNTs). Surprisingly, in homogeneous conditions we find HCOO−, instead of CO, as the main CO2 reduction product for the three catalysts. After immobilization on CNTs, even if non‐negligible competitive proton reduction reaction is observed in fully aqueous media, the complex is still able to drive CO2RR and produce HCOO− with a significantly lower overpotential with respect to solution studies. [ABSTRACT FROM AUTHOR]

The hydrodeoxygenation (HDO) is a fundamental step in the production of biofuels from lignin, and the catalyst type and reaction conditions can play an important role. In this work, Co nanoparticles finely dispersed in the porosity of SBA‐15 stand out a high selectivity toward deoxygenated products (63 % of methylcyclohexenes and 16 % of methylcyclohexane) in the HDO of m‐cresol (30 bar of pressure, temperature of 350 °C). The effect of co‐feeding CO and CO2, which can be present in the pyrolysis gas after transformation of carboxylic acids, was investigated. An unexpected positive effect on the stability of the catalyst was observed when CO2 was added in the feed stream. On the contrary, the presence of CO led to a strong decrease of the m‐cresol conversion. These experimental findings are supported by DFT calculations which show that the m‐cresol is much more strongly adsorbed than CO2 at the Co@SiO2 interface while the interaction energy of CO is close to the one of m‐cresol. [ABSTRACT FROM AUTHOR]

Nanostructured Cobalt‐Actinide (An=Th, U) bimetallic oxides were for the first time prepared by the epoxide addition method and electrospinning technique aiming the synthesis of aerogels and nanofibers, respectively. Tested as catalysts for the methanation of CO2 and regardless of the actinide element, the yield and selectivity towards CH4 are high (>40 and 95 %, respectively), which was explained by their physicochemical properties such as reducibility and basicity and the existence of a synergic effect between cobalt and actinide species. The aerogels present the best catalytic behavior, namely those with thorium and the catalytic activity increases with the Co/An molar ratio. Both aerogels and nanofibers also present a high resistance to deactivation for at least 75 h in the gaseous stream, which is an advantage for any catalytic application. Moreover, at 300 °C they are 2 to 4 times more active than two reference catalysts (5wt % Rh/Al2O3 and NiO/Al2O3) tested in the same conditions, which to our best knowledge is a significant result. [ABSTRACT FROM AUTHOR]

A series of dihydroxybenzene‐derived ILs was synthesised via a halide‐free, eco‐friendly methodology and fully characterized. Their activity as single component catalyst towards synthesis of cyclic organic carbonates (COCs) via CO2 insertion into terminal epoxides was evaluated, observing that methyltrioctylammonium hydroquinolate, [N1888][HYD], was the most active catalyst in the proposed optimized conditions ([N1888][HYD] 10 % mol, T=120 °C, t=6 h, p0(CO2)=2.0 MPa, 12 examples, conversion >99 %, yield up to 98 %). Interestingly, [N1888][HYD] was also an active catalyst for CO2 insertion reactions with cyclohexene oxide (CHO), observing formation of both the COC and polycarbonate product. It is proposed that for p0(CO2)≥1.0 MPa, the catalytically active species is the hemicarbonate derivative of the hydroquinolate anion, active towards epoxide ring opening via an unusual hemicarbonate‐alkoxide pathway. [ABSTRACT FROM AUTHOR]

Metal sulfides generally show high visible light photocatalytic activity, but lower selectivity in the CO2 photoreduction due to the competitive hydrogen evolution. Here, a partial hydrolysis method is reported to promote the selective photocatalytic CO2 reduction over ZnIn2S4. The ZnIn2S4 was post‐hydrolyzed in an aqueous ammonia solution to form oxide species (ZIS‐[InOx]). Detailed experiment and DFT calculation demonstrated that the post‐hydrolysis treatment facilely prohibits the recombination of photogenerated charge carriers and benefits CO2 activation. Under visible light irradiation, the ZIS‐[InOx] photocatalyst shows enhanced CO2‐to‐CO conversion activity with a CO‐evolving rate of 1771 μmol g−1 h−1, which is about 8 times higher than that over pristine ZIS and 3.5 times higher than that over bulk ZIS/In2O3. More importantly, the post hydrolysis treatment significantly prohibits the hydrogen evolution and increases the CO/H2 ratio from 0.08 over ZIS to 1.8 over ZIS‐[InOx]. This work provides a new strategy to prepare catalysts for photocatalytic CO2 reduction. [ABSTRACT FROM AUTHOR]

A series of Cu−Mn−(La)−Zr catalysts with molecular ratios of 6 : 3 : (0.35) : 1 was synthesized by sol‐gel (CMLZ−S), co‐precipitation (CML−CP, CMLZ−CP) and hydrothermal (CMLZ−H) methods, respectively. The effects of the Mn and La on the activity of catalysts were investigated. It was found that the addition of La promoted the formation of the medium basic sites. Mn acted as an electronic promotor that transfer electrons through redox reactions, causing other metals to exhibit different valence states, thus promoting the adsorption and activation of H2 and CO2. At a certain temperature, methanol selectivity decreased in the order of CMLZ−H>CMLZ−S>CMLZ−CP>CMZ−CP. The selectivity of methanol is correlated with the distribution of basic sites. For the CMLZ−H catalyst, the highest percentage of moderate basic sites facilitated the activation of CO2, resulting in the highest selectivity of methanol. The CO2 conversion was correlated with the Cu specific surface area. [ABSTRACT FROM AUTHOR]

Supported nickel nanoparticles are promising catalysts for the methanation of CO2. The role of nickel particle size on activity and selectivity in this reaction is a matter of debate. We present a study of metal particle size effects on catalytic stability, activity and selectivity, using nickel on graphitic carbon catalysts. Increasing the Ni particle size from 4 to 8 nm led to a higher catalytic activity, both per gram of nickel and normalized surface area. However, the apparent activation energy remained the same (∼105 kJ mol−1). Comparing experiments at atmospheric to 30 bar pressure demonstrates the importance of testing under industrially relevant pressures; the highest selectivity is obtained at high CO2 conversions and pressures. Finally, the selectivity was particle size‐dependent. The largest particles were not only most active but also most selective to methane. With this work we contribute to the ongoing debate about Ni particle size effects in CO2 methanation. [ABSTRACT FROM AUTHOR]

Cobalt‐lanthanide bimetallic oxide nanofibers (5Co3O4.3LnCoO3, Ln=La, Pr; 4Co3O4.Ln2O3, Ln=Sm, Gd, Dy, Yb and 2Co3O4.CeO2) were prepared by electrospinning technique and for the first time evaluated as catalysts for the hydrogenation of CO2. Depending on the lanthanide, the reaction products are different: lighter lanthanides (La, Pr, Sm and Gd) produce mainly CO and are more active to reverse water gas shift (RWGS), whereas the catalysts with Ce, Dy and Yb are more active and selective to methane. Lanthanide intrinsic properties such as ionic radii and basicity strongly correlate with the nanofibers' catalytic performance: lower lanthanide ionic radii and higher basicity favour the catalysts activity. Moreover, the bimetallic oxide nanofibers catalytic behavior also seems to point to the existence of a synergetic interaction between cobalt and lanthanide. The cobalt‐lanthanide bimetallic oxides present a high deactivation resistance for at least 60 h in the gaseous stream, which is an advantage for any catalytic application. Compared with a commercial catalyst (5wt.% Rh/Al2O3) tested in the same conditions, cobalt‐ytterbium, dysprosium and cerium bimetallic oxide nanofibers present an activity 5 to 13 times higher at 350 °C. [ABSTRACT FROM AUTHOR]

Electrocatalytic reduction of CO2 over zeolitic imidazolate frameworks (ZIFs) generally has poor activity and low CO Faradaic efficiency due to the poor contact between conductive substrate and ZIFs synthesized by ex‐situ method. Here, ZIF‐8 films on Zn foils (ZIF‐8/Zn) fabricated by in‐situ electrochemical deposition were used for CO2 electroreduction in ionic liquid‐based ternary electrolyte. Tunable morphology and thickness of ZIF‐8 film can regulate the activity of CO2 electroreduction. The ZIF‐8/Zn‐40 electrode demonstrates the highest CO Faradaic efficiency (91.8 %) with the current density of 12.6 mA cm−2 at −1.9 V vs. Ag/Ag+, which is superior to the performance of ZIF‐8/CP electrode prepared by ex‐situ method. The excellent activity of ZIF‐8/Zn‐40 electrode is mainly attributed to abundant active sites in 3D structures with largest surface area, tight and good contact between ZIF‐8 film and Zn foil, faster rate CO2 diffusion, and synergistic effect between electrode and [Bmim]PF6‐containing electrolyte. The facile synthesis of ZIF‐8/Zn electrode provides a novel technology to design efficient electrodes for CO2 electroreduction. [ABSTRACT FROM AUTHOR]

Renewable electricity‐driven reduction of CO2 into value‐added chemicals has been recognized as a promising sustainable energy conversion method to achieve carbon‐neutrality. Although Sn‐based catalysts show excellent selectivity towards CO and HCOOH in CO2 reduction, the reaction activity, i. e. current density, remains quite low (<100 mA cm−2). Herein, a hierarchical bimetallic electrocatalyst consisting of Cu foam‐supported bundle‐like structure and thin amorphous SnO layer was fabricated for efficient electroreduction of CO2 to C1 products (CO and HCOOH). The hierarchical structure ensured higher large electrochemically active surface area, while the thin amorphous SnO layer could efficiently adsorb CO2, and stabilize the *CO2− intermediate formed in the rate‐determining step, thereby boosting the reaction activity of CO2 reduction. As a result, an unprecedented partial current density of 128.6 mA cm−2 was achieved for C1 products at −1.4 V vs. RHE with a Faradaic efficiency of 79.2 % in an H‐type cell. The strategy of integrating optimized structure with active site here may be beneficial to other related energy conversion systems. [ABSTRACT FROM AUTHOR]

4065 4065 1 10/11/21 20211007 NES 211007 B The Cover Feature b highlights the successful use of gallium aminotrisphenolate compounds as catalysts for the synthesis of cyclic carbonates from CO SB 2 sb and epoxides. In their Full Paper, L. Álvarez-Miguel et al. highlight the facile synthesis of the gallium compounds, demonstrate their wide substrate scope when employed as catalysts for cyclic carbonate synthesis and compare the gallium compounds to their aluminium congeners, through both experiments and a detailed DFT study. [Extracted from the article]