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Electrocatalytic CO 2 reduction reaction (CO 2 RR) to produce formate has been recognized as one of the most efficient strategies to convert CO 2 to energy-rich products and store renewable energy compared with other methods such as biological reduction, thermal catalytic reduction, and photocatalytic reduction. Developing an efficient catalyst is crucial to enhance the formate Faradaic efficiency (FE formate ) and retard the competing H 2 evolution reaction. The combination of Sn and Bi has been demonstrated to be effective in inhibiting the evolution of H 2 and the generation of CO, promoting the formation of formate. Herein, we design Bi- and Sn-anchored CeO 2 nanorods catalysts with the valence state and oxygen vacancy (V o ) concentration controllable for CO 2 RR by reduction treatment at different environments. The m-Bi 1 Sn 2 O x /CeO 2 with moderate H 2 composition reduction and suitable Sn/Bi molar ratio achieves a remarkable FE formate of 87.7% at -1.18 V vs. RHE compared with other catalysts. Additionally, the selectivity of formate was maintained over 20 h with an outstanding FE formate of above 80% in 0.5 M KHCO 3 electrolyte. The outstanding CO 2 RR performance was attributed to the highest surface Sn 2+ concentration which improves the formate selectivity. Further, the electron delocalization effect between Bi, Sn, and CeO 2 tunes electronic structure and V o concentration, promoting the CO 2 adsorption and activation as well as facilitating the formation of key intermediates HCOO* as evidenced by the in-situ Attenuated Total Reflectance-Fourier Transform Infrared measurements and Density Functional Theory calculations. This work provides an interesting measure for the rational design of efficient CO 2 RR catalysts via valence state and V o concentration control., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

In recent decades, rising anthropogenic greenhouse gas emissions (mainly CO2 and CH4 ) have increased alarm due to escalating effects of global warming. The dry carbon dioxide reforming of methane (DRM) reaction is a sustainable way to utilize these notorious greenhouse gases. This paper presents a review of recent progress in the development of nickel-based catalysts for the DRM reaction. The enviable low cost and wide availability of nickel compared with noble metals is the main reason for persistent research efforts in optimizing the synthesis of nickel-based catalysts. Important catalyst features for the rational design of a coke-resistant nickel-based nanocatalyst for the DRM reaction are also discussed. In addition, several innovative developments based on salient features for the stabilization of nickel nanocatalysts through various means (which include functionalization with precursors, synthesis by plasma treatment, stabilization/confinement on mesoporous/microporous/carbon supports, and the formation of metal oxides) are highlighted. The final part of this review covers major issues and proposed improvement strategies pertaining to the rational design of nickel-based catalysts with high activity and stability for the DRM reaction., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Vegetation responses to rising atmospheric CO2 levels can significantly affect water availability (defined as precipitation minus evapotranspiration (ET)). While this effect has long been recognized and assessed for the mean state, its influence on interannual variability, which is more closely associated with extreme events, has yet to be comprehensively quantified. In this study, our primary focus is to evaluate the impacts of ET by plant physiology (denoted as ETPhy) on the mean and interannual variability of water availability under elevated CO2 using multiple CO2 sensitivity experiments from the coupled model intercomparison project phase 6. We show that the contribution of vegetation physiological effects to the mean water availability varies among regions, while it consistently contributes to variability by about 33%. Considering CO2 physiological effects alone, ETPhy exerts a more significant influence on the mean state than on variability, particularly in humid regions. Consequently, ETPhy contributes less than 5% to the variability of water availability in humid regions under rising CO2, whereas it accounts for about 20% of the mean state. This distinction could be attributed to the different mechanisms governing the mean and variability of ETPhy. Specifically, evaporation from CO2 physiological forcing is the most critical contributor to the variability of ETPhy in most regions while showing minimal impacts on the mean state. Our findings identify the divergent effects of ETPhy on the mean state and interannual variability of water availability under elevated CO2, as important in future climate projections. Plain Language Summary: Rising atmospheric CO2 concentrations impacts on vegetation physiological processes are expected to change the evapotranspiration (ET) by plant physiology (denoted as ETPhy), allowing for altering the mean and the interannual variability of water availability (defined as precipitation minus ET). Using an ensemble of Earth system model simulations, this study reveals that the impacts of CO2 physiological effects on the mean of water availability are region‐specific, but with a nearly consistent contribution to its interannual variability. Combined with the impact of ETPhy on the mean and variability of water availability resulting from CO2 physiological forcing, ETPhy typically contributes less than 5% to the variability of water availability in humid regions under rising CO2, whereas it accounts for about 20% of the mean state. This discrepancy could arise from the different mechanisms governing the mean and variability of ETPhy. These results underscore the importance of accounting for the effects of ETPhy in response to increasing CO2 in altering the mean and the interannual variability of regional water resources. Key Points: The effects of CO2 vegetation responses contribute variably in space to mean annual water availability but uniformly to variabilityThe evapotranspiration (ET) from CO2 physiological forcing (ETPhy) shows more impacts on the mean of water availability than its variabilityThe evaporation from CO2 physiological forcing plays an important role in the variability of ETPhy but has weak effects on the mean [ABSTRACT FROM AUTHOR]

Ni@Ni embedded SiO2 yolk-shell nanocomposites with controllable specific surface area are synthesized by using a facile self-templating method via the transformation of Ni phyllosilicate (NiPhy). NiPhy is found to form initially at the interface of Ni and SiO2, stretching its branches within the whole SiO2 shell and outward onto the SiO2 surface. Upon calcination and reduction, NiPhy decomposes to smaller Ni nanoparticles within the SiO2 shell to form a Ni@Ni embedded SiO2 yolk-shell nanocomposite with high surface area, high Ni dispersion, and strong interaction between Ni and SiO2. The nanocomposite with a treatment time of 12 h exhibits stable and high CO2 and CH4 conversions of 82 and 74 %, respectively, for the CO2 reforming reaction of CH4 at 700 °C within the testing period of 50 h. This interfacial transformation method is promising for the synthesis of other Ni@NiM (M=Cu, Zn, and Mg) phyllosilicate yolk-shell nanocomposites for application as adsorbents and catalysts of other processes. [ABSTRACT FROM AUTHOR]

Ni@Ni embedded SiO2 yolk-shell nanocomposites with controllable specific surface area are synthesized by using a facile self-templating method via the transformation of Ni phyllosilicate (NiPhy). NiPhy is found to form initially at the interface of Ni and SiO2, stretching its branches within the whole SiO2 shell and outward onto the SiO2 surface. Upon calcination and reduction, NiPhy decomposes to smaller Ni nanoparticles within the SiO2 shell to form a Ni@Ni embedded SiO2 yolk-shell nanocomposite with high surface area, high Ni dispersion, and strong interaction between Ni and SiO2. The nanocomposite with a treatment time of 12 h exhibits stable and high CO2 and CH4 conversions of 82 and 74 %, respectively, for the CO2 reforming reaction of CH4 at 700 °C within the testing period of 50 h. This interfacial transformation method is promising for the synthesis of other Ni@NiM (M=Cu, Zn, and Mg) phyllosilicate yolk-shell nanocomposites for application as adsorbents and catalysts of other processes. [ABSTRACT FROM AUTHOR]

Ni@Ni-Mgphy(Ni-Mgphy = Ni–Mg phyllosilicate) core–shellcatalysts were designed by hydrothermally treating Ni@SiO2nanoparticles with magnesium nitrate salt. The porosity and basicityof the catalysts were easily tuned by forming Ni-Mgphy shell usingNi originating from Ni@SiO2during the hydrothermal treatmentprocess and Mg(NO3)2as the Ni and Mg sources,respectively. Among Ni@Ni-Mgphy core–shell catalysts synthesizedunder different hydrothermal durations, the catalyst treated for 10h achieved the best catalytic performance for CO2reformingof CH4reaction with stable CO2and CH4conversions of around 81% and 78%, respectively, within 95 h reactionduration at 700 °C. The high Ni accessibility, strong basicity,and high structural stability for Ni@Ni-Mgphy core–shell catalystwith 10 h treatment time accounted for its superb catalytic performance.This method to simultaneously tune the porosity and basicity of Ni@SiO2core–shell nanoparticles demonstrates a general wayto modify the properties of other silica based core–shell nanoparticlesthrough treating them with different metal salts. [ABSTRACT FROM AUTHOR]

CO 2 (dry) reforming of CH 4 (DRM) reaction is an attractive measure to not only mitigate the environmental problems such as global warming but also produce the syngas as feedstock for liquid fuel production. Great achievements have been made in various DRM processes such as thermally-driven DRM, plasma-assisted DRM and solar-driven DRM together with the corresponding catalyst design strategies. Herein, the merits and demerits of these three processes as well as these design strategies are compared and analyzed. We start with thermally-driven DRM which accounts for the large majority of researches being reported in the recent five years (2016–2020). Four typical measures to achieve sintering and carbon resistant catalysts including designing catalysts with strong MSI, bimetallic catalysts, layered doubled hydroxide catalysts and core shell structured catalysts are summarized. Thereafter, for plasma-assisted DRM, the effect of operating parameters to the performance of classical plasma reactors as well as the influence of different packing materials for these packed plasma reactors are analyzed. After this, for solar-driven DRM, the application and design of solar reactors are discussed for solar thermocatalysis, which is followed by the discussion of solar photocatalysis and hybrid photothermo catalysis. Finally, we propose potential challenges and research directions of these three processes to give a comprehensive understanding of DRM reaction. Image 1 • CH 4 dry reforming-DRM is attractive to mitigate global warming and produce syngas. • Sintering/carbon resistant catalyst design is imperative for thermally-driven DRM. • Catalyst design strategies featured for plasma-assisted DRM are highly desired. • Light management and solar reactor engineering are challenging for solar-driven DRM. • Understanding in situ generated reactive species during DRM reaction is vital. [ABSTRACT FROM AUTHOR]

[Display omitted] • Y-doped CeO 2 is designed for DMC synthesis from CO 2 and CH 3 OH. • A solid solution structure with abundant Y–V O –Ce sites is formed in 5% Y–CeO 2. • The activation of CO 2 is enhanced along with moderately passivating CH 3 OH adsorption. • The formation of bidentate carbonate and bridged methoxy is the key to generate DMC. • DMC yield reaches around 15 mmol⋅(g cat)−1. and methanol conversion is around 0.8%. Cerium(IV) oxide (CeO 2)-based materials are effective catalysts for the synthesis of dimethyl carbonate (DMC) from carbon dioxide (CO 2) and methanol (CH 3 OH). Herein, 5% Y–CeO 2 was synthesized by the co-precipitation method. It forms a solid solution structure, which leads to the highest concentration of oxygen vacancies. The Y–V O –Ce active site created by Y3+ doping enhances the adsorption and activation of CO 2 based on moderately passivating CH 3 OH adsorption. Consequently, 5% Y–CeO 2 exhibited the highest CH 3 OH conversion rate of 0.8% and a DMC yield of 15 mmol⋅(g cat)−1, which is 1.4 times of pure CeO 2 (reacting in a stainless-steel autoclave at 140 °C with a stirring speed of 1000 r⋅min−1 and an initial pressure of 3.0 MPa for 2 h). An adsorption test and in situ diffuse reflectance infrared Fourier transform spectroscopy showed that 5% Y–CeO 2 could effectively inhibit the formation of triple-bonded methoxy species, and promote the formation of bidentate carbonate and bridged methoxy intermediates, which is conducive to the improvement of reaction activity. [ABSTRACT FROM AUTHOR]

CH x * oxidation is one of the most vital routes to alleviate the carbon deposition problem of CO 2 reforming of methane (DRM) reaction. Whereas, little experimental evidence has been observed on NiMo catalysts where the CH x * oxidation was dominant over its dissociation reaction. Herein, to experimentally unveil the CH x * oxidation route of NiMo catalysts, we design three catalysts with different particle sizes and structures. Among them, Mo/Niphy@SiO 2 core shell catalyst demonstrated the dominant CH x * oxidation route over its dissociation based on in-situ diffuse reflectance infrared Fourier transform spectroscopy experiments. This was attributed to the confinement effect of SiO 2 and the formation of Ni–Mo alloy, inhibiting the CH x * dissociation reaction. It exhibited relatively stable CH 4 and CO 2 conversions (77 % and 75 % respectively) within 180 h. By contrast, on Mo/Niphy catalyst which has a big Ni size, CH x * was mainly dissociated to C* and oxidized to CO which further underwent a disproportion reaction to produce CO 2 and C*, leading to the severe carbon deposition and unstable DRM performance. The strategy to unveil the dominant role of CH x * oxidation via design catalysts with different sizes and structures sheds light on the study of reaction mechanism of other reactions. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • DRM and CRR are valuable for carbon neutralization and syngas production. • Catalyst design strategies are crucial to improve CO 2 utilization efficiency. • Structured catalysts design are effective in decreasing carbon deposition for DRM. • Electronic structure, size, morphology, and porosity tuning are efficient for CRR. • Mechanism understanding using in situ characterization tools is important. CO 2 conversion to produce syngas via reforming of CH 4 and electrochemical reduction reaction is attractive to achieve carbon neutralization, mitigate CO 2 related environmental problems, and provide important intermediate for value-added chemicals production. Tremendous progress has been made in the catalyst development for these two reactions, which is critical to improve the utilization efficiency of the inert CO 2. Whereas, catalyst design strategies for these two reactions have not been systematically discussed. Therefore, here, design strategies such as increasing sintering resistance, enhancing redox property, basicity, and porosity etc. for structured catalysts including core/yolk shell, perovskite and spinel catalyst for DRM are analysed. In addition, CRR catalyst design measures from both atomic-, molecular- and meso -scale for instance tuning of electronic structure, size, morphology, and porosity to increase the syngas selectivity are compared. Finally, challenges and future work of these two reactions are proposed. Some of the challenges and solutions include (1) facile large scale synthesis strategies are highly desired to design multifunctional catalysts with low mass transfer resistance in addition to silica-based and noble-metal based catalysts; (2) mechanism illustration of confinement effect, synergistic effect, and intermediate species are crucial and feasible aided with various in situ characterization techniques; (3) more stringent reaction conditions are required to boost their industrial process of these two reactions. This review is timely and useful to boost the advancement of these two reactions and promote carbon neutralization. [ABSTRACT FROM AUTHOR]

[Display omitted] • ZnZrO x /ZSM-5@t-ZrO 2 is designed for enhanced CO 2 hydrogenation to C 2 =–C 4 =. • T-ZrO 2 coating ZSM-5 is the key to improve the selectivity of C 2 =–C 4 =. • The t-ZrO 2 neutralizes the strong Brønsted acid sites of ZSM-5. • The t-ZrO 2 inhibitis excessive hydrogenation of C 2 =–C 4 =. • ZnZrO x /ZSM-5@t-ZrO 2 generated 81.1% of C 2 =–C 4 = and the byproduct CO is only 34.3%. The hydrogenation of carbon dioxide to light olefins is a direct and effective approach for achieving carbon neutrality. However, developing a tandem catalytic process involving methanol as an intermediate to achieve efficient directional conversion under mild conditions remains a challenge. Thus, we designed and constructed a bifunctional tandem catalyst, ZnZrO x /ZSM-5@n-ZrO 2 , where n represents the amorphous (am), monoclinic (m), and tetragonal (t) phases of ZrO 2. The catalyst was prepared by coating an n-ZrO 2 layer on the surface of ZSM-5 zeolite to form ZSM-5@n-ZrO 2 with a coating structure, which was then ground and mixed with ZnZrO x to obtain the ZnZrO x /ZSM-5@n-ZrO 2 tandem catalyst. At 340 °C and 2 MPa, the selectivity of the ZnZrO x /ZSM-5@t-ZrO 2 catalyst toward light olefins reached 81.1%, with the carbon monoxide (CO) byproduct constituting only 34.3%. In contrast, the selectivity of ZnZrO x /ZSM-5 catalyst toward light olefins reached only 40.5% and a CO selectivity of 56.8%. Various characterizations and experimental results indicate that the ZSM-5@t-ZrO 2 coating structure in the designed bifunctional catalyst effectively regulates the acid density and pore distribution of zeolite while inhibiting excessive hydrogenation of light olefins, ultimately achieving the desired mild transformation. [ABSTRACT FROM AUTHOR]

[Display omitted] • CO 2 electrocatalysis reduction (CO 2 RR) is efficient to boost carbon neutralization. • Bimetallic CuAg/CeO 2 -6 exhibits the highest FE CO of 84% at –1.1 V. • Electron delocalization effect tunes the electronic structure of CuAg and V o of CeO 2. • In situ ATR-SEIRAS unveils the reaction mechanism via COOH* intermediates. • This study provokes the electronic structure tuning of both metals and support via doping. CO 2 electrocatalysis reduction (CO 2 RR) is considered to be one of the most efficient methods to achieve carbon neutralization and realize renewable energy conversion. Unfortunately, at present, CO 2 electrocatalysts confront the challenges of high overpotential, low selectivity, and poor stability. Ag based electrocatalysts are considered to be the most promising catalysts for CO production via CO 2 RR on a large scale, due to their relatively higher catalytic performance and more abundant reserves compared with other noble metals. Whereas, they still suffer from high cost. In this paper, we design bimetallic CuAg/CeO 2 -6 catalysts by the simple impregnation method for CO 2 RR, exhibiting the highest FE CO of 84% at –1.1 V vs. RHE compared with other bimetallic catalysts with different Cu/Ag ratio and monometal catalysts. XPS results demonstrate the electron delocalization effect not only between Cu and Ag bimetals but also among CeO 2 support. This effect results in the electronic structure change and the formation of the highest concentration of oxygen vacancies, promoting the CO 2 adsorption and activation as well as facilitating the formation of COOH* intermediates as evidenced by the in situ ATR-SEIRAS measurements. Additionally, the highest active surface for CO 2 RR and the smallest charge resistance of CuAg/CeO 2 -6 also contributes to its good CO 2 RR performance. This work sheds light on the design of other efficient CO 2 RR catalysts through electronic structure tuning by bimetallic strategy. [ABSTRACT FROM AUTHOR]

Linde Type A (LTA) zeolite is an effective inorganic water permeable membrane material due to its inherent Na+-gated water-conducting mechanism. Although dense LTA membranes show excellent water selective permeability, the water permeability rate still needs to be improved to drive the CO 2 hydrogenation reaction towards methanol production. In this work, we prepared a water-conducting LTA membrane with well-distributed non-penetrative macroholes, resulting in a cheese-like structure that combines the advantages of micro-nanochannels for high water selective permeability and macroholes for quick water diffusion. These semi-hollow (SH)-LTA membranes with different thicknesses and number of macroholes were fabricated via a steam-assisted method by adjusting the amount of water in the precursor solution. The optimized SH-LTA membranes presented an average water permeance of 8.57 × 10−7 mol m−2 s−1 Pa−1 at 200 °C along with CH 3 OH, H 2 , and CO 2 permeances of 3.24 × 10−9, 7.92 × 10−12, and 4.32 × 10−12 mol m−2 s−1 Pa−1, respectively. The membrane stability was verified under continuous mixture gas permeation tests for 10 h between 200 and 300 °C. The dissolution-recrystallization route of the SH morphology was confirmed following comprehensive characterizations and complemented by molecular dynamics simulations to elucidate the superior water separation behavior in SH-LTA membrane in comparison with pristine LTA membrane. [Display omitted] • A unique LTA zeolite membrane was synthesized for water permeation. • Steam-assisted method to create macroholes within the microporous LTA. • Non-penetrating macroholes with highly selective water permeability. • Controllable thickness and macrohole quantity of the membrane. • Molecular dynamics simulations were employed to explain the mechanism. [ABSTRACT FROM AUTHOR]

[Display omitted] • CO 2 reforming of methane (DRM) is promising to promote carbon neutralization. • Minimize carbon deposition is critical for Ni based DRM catalysts. • Complete confinement of Ce/Ni in SiO 2 nanotubes is achieved via coating method. • Ce/Ni@SiO 2 has high sintering and carbon resistance due to high oxygen vacancy. • The synthesis method is imperative to design other bi/trimetallic confined catalysts. • In-situ DRIFTS reveals the CO 2 activation mechanisms via CeO 2 and H*. CO 2 reforming of methane (DRM) is currently one of the most promising processes to convert two green-house gases: CH 4 and CO 2 to value-added syngas, boosting CO 2 utilization and promoting carbon neutralization. However, a major challenge of inexpensive and active Ni-based catalysts for DRM reactions is their easy sintering and carbon deposition issues. Herein, a series of bimetallic Ce/Ni nanoparticles completely confined within SiO 2 nanotube (NT) catalysts were synthesized by the precipitation and coating method. Compared with Ni@SiO 2 , bimetallic xCe/Ni@SiO 2 catalysts have higher specific activities for DRM reaction. In addition, 20Ce/Ni@SiO 2 shows high and stable CH 4 and CO 2 conversions of 76.3% and 80.1%, respectively at 700 °C for 80 h. High Ni sintering resistance, high concentration of surface Ni and oxygen vacancies (V o), high carbon resistance contribute to its outstanding DRM performance. The CO 2 activation mechanisms via CeO 2 and H* was revealed via in-situ DRIFTS study. The preparation method to completely confine bimetallic nanoparticles within SiO 2 NTs sheds light on the design of other confined bi/tri-metallic catalysts with high sintering resistance to be applied in other high temperature reactions. [ABSTRACT FROM AUTHOR]

In recent decades, CO 2 utilization has become increasingly important in view of the escalating global warming phenomenon. In view of this, conversion of CO 2 to syngas via CO 2 (dry) reforming of methane (DRM) reaction has been gaining prominent research interest. This paper presents a review on the kinetic and mechanistic aspects for DRM reaction with focus on Ni based catalysts. Ni-based catalysts are commercially attractive due to the low cost and wide availability of Ni metal. Kinetic studies over the Ni based catalysts are vital in scaling up of the DRM process in order to assess its industrial viability. Many differing opinions have been formed for the rate determining steps (RDS) of the reaction kinetics. In this review, a survey of the differing RDS presented in literature based on the widely used Langmuir Hinshelwood Hougen Watson (LHHW) models for Ni-catalyzed DRM reactions are categorized and presented along with the importance of experimental techniques for justifying mechanistic formulation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mn 2 O 3 -ZnO/SAPO-34 is designed for CO 2 hydrogenation to lower olefins. • Interface synergism of Mn 2 O 3 -ZnO binary oxide helped enhance tandem reaction. • Tandem spacing between two phases is crucial to suppress by-product CO selectivity. • Lower olefins selectivity exceeds 80% and CO 2 conversion is close to 30%. The direct conversion of CO 2 hydrogenation to lower olefins via methanol as an intermediate is of great significance, but challenges still remain. Herein, we present a binary Mn 2 O 3 -ZnO oxide, which is responsible for catalytic hydrogenation of CO 2 to methanol. After combination of Mn 2 O 3 -ZnO and SAPO-34 molecular sieve, the catalytic reaction displays a markable increase. CO 2 adsorption by alkaline nature, followed by oxygen vacancy activation and synergistic hydrogenation over the binary Mn 2 O 3 -ZnO oxide are the prerequisites for the tandem reaction. However, the tandem spacing between oxide and molecular sieve plays a crucial role, because the suitable intimacy can induce enhanced methanol formation as intermediate via tandem dynamics effect, causing an apparent limitation for reverse water gas shift reaction at high temperature. The optimum mass ratio of 3:1 for two phases demonstrates that more components of binary oxide are needed to improve the rate of CO 2 hydrogenation to methanol, aiming to balance the two-step tandem reaction. Finally, under conditions of 380 ℃, 3 MPa and 3600 mL/g cat /h, 20%Mn 2 O 3 -ZnO/SAPO-34 tandem catalyst is obtained by physical ball milling after 15 min, with excellent stability, sulfur tolerance and catalytic performance with CO 2 conversion at almost 30%, lower olefins selectivity of 80.2% (propylene/ethylene = 5.6:1), and single-pass yield of 10.7%. [ABSTRACT FROM AUTHOR]