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Single-atom cobalt (Co–N–C) catalyst has been proposed as a superior catalyst, but the symmetrical Co–N4 structure shows unfavorable energetics, leading to much debate on its chemical nature responsible for its high activity.

Defective ultrathin Bi5O7I nanotubes are designed by the combination of structure and defect engineering strategies to achieve highly active, selective, and stable performance for electrocatalytic reduction of CO2 to formate.

The energy-conversion storage systems serve as crucial roles for solving the intermittent of sustainable energy. But, the materials in the battery systems mainly come from complex chemical process, accompanying with the inevitable serious pollutions and high energy-consumption. Natural mineral resources display various merits, such as unique architecture, adsorption capability and rich active sites, which have captured numerous attentions with remarkable advancements. Recently, the minerals compounds, containing 1D structure (halloysites, attapulgites, sepiolite), 2D structure (montmorillonite, vermiculite, molybdenite) and 3D structure (diatomite, pyrites), have been applied in plenty of fields. Aiming at their energy-storage applications, the significant utilizations in electrodes, separators, electrolyte and metal-protection were detailedly reviewed in lithium-ions battery, lithium-sulfur battery, solid-state battery and so on. However, it should be acknowledged that, the simple minerals hardly meet the demand of energy-storage systems, due to their inferior conductivity and less active substances. Thus, series of modified manners are applied for the evolution of phase (from silicate mineral to Si), the incorporating with carbon/polymer and the tailoring of surface traits, which were in-depth discussed as following. The work was expected to summarize the traits about mineral compounds from different architectures, whilst offering significant guidelines for exploring mineral-based materials in energy-storage systems.

Fuel cell reactors can be tailored to simultaneously cogenerate value-added chemicals and electrical energy while releasing negligible CO2 emissions or other pollution; moreover, some of these reactors can even “breathe in” poisonous gas as feedstock. Such clean cogeneration favorably offsets the fast depletion of fossil fuel resources and eases growing environmental concerns. These unique reactors inherit advantages from fuel cells: a high energy conversion efficiency and high selectivity. Compared with similar energy conversion devices with sandwich structures, fuel cell reactors have successfully “hit three birds with one stone” by generating power, producing chemicals, and maintaining eco-friendliness. In this review, we provide a systematic summary on the state of the art regarding fuel cell reactors and key components, as well as the typical cogeneration reactions accomplished in these reactors. Most strategies fall short in reaching a win–win situation that meets production demand while concurrently addressing environmental issues. The use of fuel cells (FCs) as reactors to simultaneously produce value-added chemicals and electrical power without environmental pollution has emerged as a promising direction. The FC reactor has been well recognized due to its “one stone hitting three birds” merit, namely, efficient chemical production, electrical power generation, and environmental friendliness. Fuel cell reactors for cogeneration provide multidisciplinary perspectives on clean chemical production, effective energy utilization, and even pollutant treatment, with far-reaching implications for the wider scientific community and society. The scope of this review focuses on unique reactors that can convert low-value reactants and/or industrial wastes to value-added chemicals while simultaneously cogenerating electrical power in an environmentally friendly manner. Graphical Abstract A schematic diagram for the concept of fuel cell reactors for cogeneration of electrical energy and value-added chemicals

Durable and stable removal of 2,4-dichlorophenpl (2,4-DCP) by CuO

Electrochemical reduction of CO2 to carbon-neutral fuels is a promising strategy for renewable energy conversion and storage. However, developing earth-abundant and cost-effective electrocatalysts ...

The renewable-energy-powered electrochemical CO2 reduction reaction (CO2RR) provides an attractive strategy to simultaneously address the energy storage and environmental issues through the synthes...

Highly active and stable bifunctional materials for the oxygen evolution/reduction reaction (OER/ORR) are critical for developing high-performance metal–air batteries and fuel cells. This study demonstrates the significantly enhanced electrocatalytic activity of a Ruddlesden–Popper (RP) perovskite (Aₙ₊₁BₙO₃ₙ₊₁, n = 3) as a bifunctional material [i.e., RP-LaSr₃(Co₀.₅Fe₀.₅)₃O₁₀−δ] for oxygen electrocatalysis via an optimal doping strategy. The improved performance mainly benefits from the enhanced oxygen vacancies, the facile oxygen release and incorporation abilities, the synergistic interplay of Co and Fe together with the increased amounts of adsorbed OH⁻/O₂, and the highly oxidative O₂²⁻/O⁻. The more positive onset potential (Eonset) and the highest half wave potential (E₁/₂) of RP-LaSr₃(Co₀.₅Fe₀.₅)₃O₁₀−δ imply a better ORR activity relative to those of the benchmark Ba₀.₅Sr₀.₅Co₀.₈Fe₀.₂O₂.₅₉ (BSCF) and the widely referred cubic perovskite (La₀.₆Sr₀.₄)₀.₉₅Co₀.₂Fe₀.₈O₃−δ (CP-LSCF). Furthermore, this material enables the electrochemical reduction of O2 by 4e⁻ to OH⁻ with an impressive stability. More importantly, RP-LaSr₃Co₁.₅Fe₁.₅O₁₀−δ shows a largely narrowed potential gap (ΔE) and achieves its minimum value of 0.91 V, remarkably smaller than those of CP-LSCF (₁.₀₁ V), BSCF (₁.₀₄ V), and most of the state-of-the-art bifunctional materials. This study paves an attractive way to accurately fabricate RP-type perovskites as highly efficient and stable materials for bifunctional oxygen electrocatalysis.

Electrochemical CO

Chemical functionalization of metal sulfides by adsorption of specially designed ligands is of primary importance in efficiently manipulating the physicochemical properties of the target surface. D...

Bi2 O3 nanosheets were grown on a conductive multiple channel carbon matrix (MCCM) for CO2 RR. The obtained electrocatalyst shows a desirable partial current density of ca. 17.7 mA cm-2 at a moderate overpotential, and it is highly selective towards HCOOH formation with Faradaic efficiency approaching 90 % in a wide potential window and its maximum value of 93.8 % at -1.256 V. It also exhibits a maximum energy efficiency of 55.3 % at an overpotential of 0.846 V and long-term stability of 12 h with negligible degradation. The superior performance is attributed to the synergistic contribution of the interwoven MCCM and the hierarchical Bi2 O3 nanosheets, where the MCCM provides an accelerated electron transfer, increased CO2 adsorption, and a high ratio of pyrrolic-N and pyridinic-N, while ultrathin Bi2 O3 nanosheets offer abundant active sites, lowered contact resistance and work function as well as a shortened diffusion pathway for electrolyte.

Tunable In(OH)3-coupled Cu2O-derived hybrid catalysts are facilely synthesized to boost the selectivity and efficiency of the electrochemical CO2 reduction reaction (CO2RR). The maximum faradaic ef...

To reduce the amount of greenhouse gas emissions and remedy related environmental damage, the research on carbon capture and storage (CCS) is gaining momentum and so is the search for a more effective way to control corrosion of pipeline steel used to transport impure supercritical (SC) CO2. Herein, we prepared an electroless high-phosphorus Ni-P coating and, for the first time, systematically explored the underlying mechanism of the interfacial process in applying Ni-P coating to protect pipeline steel that transports impure SC CO2. It is found that, benefiting from the formation of a protective surface film, Ni-P coating significantly mitigates the corrosion effects from SC CO2 and impurities (e.g., O2 and NO2), especially the synergistic effect of impurities. Concurrently, it effectively avoids the localized corrosion resulting from nonuniform adsorption of the aqueous phase. Although O2 and NO2 can degrade the coating through boosting water precipitation, deteriorating the water chemistry, and reducing the surface film protectiveness, the corrosion inhibition efficiency of Ni-P coating is invariably higher than 80%, independent of the varying causticity of SC CO2 streams, demonstrating that the coating has a superior stability toward corrosion attack. The as-prepared Ni-P coating undoubtedly holds great potential as an alternative for corrosion control of CO2 transport pipeline in the CCS industry. This work provides a new, feasible method to ensure the safe and efficient operation of CCS.

The electrochemical reduction reaction of CO2 (CO2RR) is an attractive strategy for achieving carbon-neutral sustainability while the highly active and selective reaction for formate formation remains challenging. In addition, the thermodynamic inertness of CO2 usually leads to a high energy barrier for CO2RR, resulting in a preference for the competitive hydrogen evolution reaction. It is known that CO2RR is a proton-coupled electron transfer (PCET) process and the complicated multi-electron transfer steps occur on the catalyst surface. Therefore, improving the charge transfer ability is considered as an effective approach to maximizing the electrocatalytic activity and selectivity for CO2RR. Interface engineering has been proven as an effective method to prompt charge transfer by constructing interfaces within the catalysts that is widely used in many electrochemical reactions. The introduced interfaces would benefit the electronic interaction at the interface and assist the electron redistribution, thus optimizing the electronic structure and boosting the interfacial charge transfer. Herein, we report the heterostructure of Bi2S3-Bi2O3 nanosheets (BS-BO NSs) with substantial interfaces for the efficient CO2-to-formate conversion. The rapid-interfacial charge transfer induced by the abundant interfaces not only optimizes electronic structure, but also accelerates the kinetics of CO2RR and improves the electrocatalytic activity and selectivity. Compared with the separate Bi2O3 and Bi2S3 electrocatalysts, BS-BO NSs shows desirable selectivity to formate with a maximum Faradaic efficiency of 93.8 % at a moderate potential. The CO2RR performance is further boosted by using a flow cell system. The high selectivity with large current density makes BS-BO NSs a promising candidate for the practical application of CO2RR in the formate formation.

Electrochemical reduction of CO2 to CO is an attractive approach for the sustainable carbon cycle. However, the activity and selectivity of the CO2 reduction reaction (CO2RR) are often limited by the competitive hydrogen evolution reaction (HER) in aqueous media. In this work, in-situ generated hydroxides were introduced by the synthesis of rhombohedral CdCO3 crystals (i-CdCO3) under electrochemical CO2RR conditions. The generated hydroxides contribute to an increased local pH at the electrode/electrolyte interface, thereby effectively inhibiting HER. As a result, the obtained i-CdCO3 exhibits remarkably higher CO Faradaic efficiency (over 90%) in a broad potential range, where a near 100% selectivity is achieved, as compared to a pre-synthesized CdCO3 with similar morphology. Moreover, i-CdCO3 delivers a large current density of − 24.8 mA mg−1 at − 1.26 V, together with a good stability of 36 h with negligible degradation, further demonstrating its superiority for efficient CO2RR. This study proposes a promising design strategy to boost the selectivity of CO2RR systems through in-situ producing hydroxides near the electrode to suppress the unfavorable HER.

Electrochemical reduction of CO

Electrochemical technology attracts much research interest for the treatment of metal complexes, but most electrocatalysts are incapable of effectively degrading metal complexes, which generally have highly stable cages with five or six rings coordinating with metal ions. To address this, a bridging agent linking the catalysts and metal complexes can lower the energy barrier, and thus holds much promise to facilitate the removal of such pollutants. In this study, 1-pyrenesulfonic acid (PSA) functionalization of acidic nitrogen-doped graphene (ANG) is successfully synthesized and found to effectively remove metal complexes through electrochemical membrane filtration. Results indicate that PSA, interacting with Cu-EDTA via the strong ion exchange of super acidic sulfonic (−SO3H) groups, acts as a conductive “bridge” connecting the electrocatalyst and metal complexes to overcome the challenge with penetrating the “cage” structure of metal complexes. The pyrrolic nitrogen of ANG is found to be the active sites in the electrochemical process, with the intrinsic electrochemical activity realized by the bridging agent, namely, PSA. This study highlights the importance of compounds with sulfonyl groups in circumventing the stable “cage” of the metal complexes, and thereby paves the way for effective degradation of such pollutants. Ministry of Education (MOE) This work was supported by the Singapore GSK (GlaxoSmithKline) – EDB (Economic Development Board, Singapore) Trust Fund and Singapore Ministry of Education Tier 1 Grant (2019-T1-002-065).

CO2 reduction reaction (CO2RR) is one of the most promising approaches to alleviating greenhouse gas effect and simultaneously producing value-added chemicals and has been widely studied in recent years. To this end, a composite of indium species on CuO (InOx@CuO) was facilely synthesized for CO2RR, and it is found that the selectivity of the target product could be accurately tuned through incorporating post-transition species with Cu-based materials; the desirable Faraday efficiencies of over 90%, with a maximum value of 97.8%, toward CO formation were achieved in a wide potential window from −0.3 to −0.7 V. Moreover, a high CO partial current density of 7.2 mA cm−2 and a long-term stability of 50 h with negligible degradation were obtained over InOx@CuO. More importantly, CO starts to be observed at an ultralow potential of −0.196 V, further confirming the excellence of InOx@CuO for CO2RR toward CO formation. The results demonstrate that the achieved superiority derives from the essential In species on CuO, which not only introduces more active sites, but also better stabilizes the key intermediates, accelerates electron transfer and increases CO2 adsorption.

Electrochemical CO2 reduction reaction (CO2RR) to value-added chemicals at low cost is highly attractive in mitigating the environmental issues caused by excessive greenhouse gases emission. In this work, Ag2O-derived Ag nanoparticles (OD-Ag NPs) with the optimized subsurface oxygen were obtained through steering the reducing current density (ire) upon in situ Galvano-statically reducing Ag2O NPs to metallic Ag, and it is found that the OD-Ag NPs thus obtained exhibit high catalytic activity and selectivity towards CO production. Specifically, the OD-Ag NPs derived from an intermediate ire of ‒1 mA•cm‒2 achieve the high Faradaic efficiencies (FECO) of over 90% in a wide potential window over 450 mV, whereas either smaller (‒0.1 mA•cm‒2) or larger (‒10 mA•cm‒2) ire reduces the overall CO2RR performance. This suggests that tuning the ire to change the subsurface oxygen of oxide-derived catalysts is beneficial to improve their selectivity. Theoretical DFT calculations and analysis rationalize the experimental observation, and reveal that the outstanding performance of the OD-Ag NPs benefits from the suitable concentration of subsurface oxygen which not only enhances the adsorption of intermediate *COOH, but also optimizes the free energy of the reaction pathways.

The water content limit of 1500 ppmv is obtained in supercritical CO2 streams containing 200 ppmv O2, 200 ppmv SO2 and 200 ppmv H2S at 10 MPa and 50 °C. Concurrently, the thermodynamic calculation suggests that impurities change the corrosion process through promoting the water precipitation and changing the water chemistry characteristics. When the water content is below 1500 ppmv, the corrosion effect of impurity interactions dominates the corrosion process of X65 steel. Whereas upon increasing the water content over 1500 ppmv, the corrosion effects from impurity interactions and individual impurity jointly control the corrosion process of X65 steel.

Electrochemical reduction of CO2 (CO2RR) holds the potential to battle the greenhouse effect through the synthesis of carbon-neutral fuels. The high efficiency of noble metal catalysts for CO2RR is, therefore, highly desirable to reduce the quantities of noble metals. We herein synthesized 5-fold twinned Ag nanowires (NWs) with diameters less than 25 (D-25) and 100 nm (D-100) through a facile bromide-mediated polyol method and subsequently, investigated their structure-driven enhanced catalytic activity for CO2RR. Compared with D-100 Ag NWs and Ag nanoparticles (NPs), D-25 Ag NWs possess remarkably enhanced current density ( j ) , together with significantly increased Faraday efficiencies (FEs) and energy efficiencies (EEs) over a broad potential range and achieve their maximum values of 99.3% and 61.3%, respectively. More importantly, a quite low onset overpotential (η) to initiate CO2RR and a stability with negligible degradation of over 24 h were obtained, further verifying the superior performance of D-25 Ag NWs for CO2RR. Density functional theory (DFT) calculations reveal that the improved catalytic activity over the ultrathin 5-fold twinned Ag NWs originates from the increased ratio of the catalytically active sites contributed by both diameter and length effects, and the special 5-fold twinned nanostructure completely enclosed by energetically favorable facets for CO2RR.

This study investigates the ethane conversion in solid oxide fuel cell (SOFC) reactors, comprising a nanosized Co–Cr2O3 nanocomposite anode catalyst, a proton-conducting BaCe0.8Y0.15Nd0.05O3−δ (BCYN) electrolyte, and a porous Pt cathode, for the purpose of cogenerating value-added ethylene with high selectivity and electrical power. The Co–Cr2O3 nanocomposite anode catalyst is achieved by reducing the Co2CrO4 precursor particles of about 5 nm, by a citrate–nitrate combustion method at an elevated temperature, whereas the BCYN dense membrane is obtained by sintering the BYCN precursor powders at 1400 °C for 10 h. The protonic SOFC reactor cogenerates a maximum power density of 173 mW·cm–2 and an ethylene yield of 32% at a selectivity of 91.6% at 700 °C. More importantly, no detectable acetylene and carbon dioxide (CO2) emission are formed, suggesting the superior electrocatalytic activity and dehydrogenation activity of the Co–Cr2O3 nanocomposite for the cogeneration of ethylene and electricity.

Electroreduction of CO2 holds the promise for the utilization of CO2 and the storage of intermittent renewable energy. The development of efficient catalysts for effectively converting CO2 to fuels has never been more imperative. Herein, we successfully synthesized Ag2S nanowires (NWs) dominating at the facet of (121) using a modified facile one-step method and utilized them as a catalyst for electrochemical CO2 reduction reaction (CO2RR). Ag2S NWs in ionic liquid (IL) possess a partial current density of 12.37 mA cm–2, ∼14- and ∼17.5-fold higher than those of Ag2S NWs and bulk Ag in KHCO3, respectively. Moreover, it shows significantly higher selectivity with a value of 92.0% at the overpotential (η) of −0.754 V. More importantly, the CO formation begins at a low η of 54 mV. The good performance originates from not only the presence of [EMIM–CO2]+ complexes but also the specific facet contribution. The partial density of states (PDOS) and work functions reveal that the d band center of the surface Ag ato...

Froth flotation has been widely used to separate sulfide minerals from sulfide ores, where the oxygen reduction reaction (ORR) plays a significant role as the cathodic reaction. However, the intrinsic ORR mechanism over sulfide minerals and its effect on the flotation performance remain unclear. Herein, we explored the intrinsic ORR mechanism over metal sulfides through density functional theory (DFT) calculations along with the computational hydrogen electrode (CHE) model. Our results revealed that pyrite (FeS2) and chalcopyrite (CuFeS2) exhibited similar ORR behavior to that over platinum (Pt) but not galena (PbS) and sphalerite (ZnS). The relative computational overpotentials for the ORR were completely consistent with the experimental trend in the order of Pt < FeS2 < CuFeS2 < PbS < ZnS and linearly correlate with the oxygen binding energies. We thus conclude that the distinct ORR behaviors originate from the different oxygen binding strengths which are determined by the underlying electronic structure. More importantly, we demonstrated that the DFT calculated bulk centroids of the occupied S 3p band for metal sulfides strongly correlate with the experimentally measured rest potential of the counter sulfide minerals in xanthate solution, and consequently we established the descriptor–activity relationship. Using this relationship, we present that the mechanism underlying the mixed potential model regarding the xanthate–sulfide mineral interaction is essentially governed by the relative dominating role of the compositional metallic cation to the anionic sulfur in terms of the electronic structure around the Fermi level, which favors the formation of dixanthogen and metal-xanthate, respectively.

In situ exsolution of Co nanoparticles on perovskite framework has been successfully synthesized by firing the porous precursor SrMo0.8Co0.1Fe0.1O3-δ (SMCFO) in reducing flow at 850 °C. A structure transformation (from mixed to pure cubic phase) and the growth of Co nanoparticles are observed in H2 atmosphere. This leads to an increase in the oxygen vacancy content, which is beneficial to the electrical conduction and catalytic activity towards the oxidations of H2 and C2H6. Moreover, this material exhibits good redox reversibility under the condition of multiple reduction and re-oxidation cycles, as confirmed by the thermogravimetric analysis (TGA) measurements. A protonic fuel cell (PFC) built with this newly developed material shows a comparable electrocatalytic activity in both C2H6 and H2 atmospheres while a considerably high power density of 377 mW cm−2 is achieved in H2 and 268 mW cm−2 in C2H6 at 750 °C. In addition, C2H4 yield in the cell with Co-SMCFO as anode is considerably improved (11.9%–37.8% at 650–750 °C) with respect to the widely used chromium oxide. The good electrochemical performance, the improved C2H6 partial dehydrogenation ability and the negligible carbon formation in the Co-SMCFO anode are the strong indications that the SMCFO is a promising catalyst for the cogeneration of C2H4 and electricity, and can also be potentially utilized in the PFC directly fueled with hydrocarbon.

Electrochemical CO2 reduction reaction (CO2 RR) is a promising approach to convert CO2 to carbon-neutral fuels using external electric powers. Here, the Bi2 S3 -Bi2 O3 nanosheets possessing substantial interface being exposed between the connection of Bi2 S3 and Bi2 O3 are prepared and subsequently demonstrate to improve CO2 RR performance. The electrocatalyst shows formate Faradaic efficiency (FE) of over 90% in a wide potential window. A high partial current density of about 200 mA cm-2 at -1.1 V and an ultralow onset potential with formate FE of 90% are achieved in a flow cell. The excellent electrocatalytic activity is attributed to the fast-interfacial charge transfer induced by the electronic interaction at the interface, the increased number of active sites, and the improved CO2 adsorption ability. These collectively contribute to the faster reaction kinetics and improved selectivity and consequently, guarantee the superb CO2 RR performance. This study provides an appealing strategy for the rational design of electrocatalysts to enhance catalytic performance by improving the charge transfer ability through constructing a functional heterostructure, which enables interface engineering toward more efficient CO2 RR.

The intensive pursuit of cost-effective electrocatalysts capable of enabling highly efficient and stable water splitting comprised of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), is quite imperative but challenging. Herein, a 3-dimensional (3D) hierarchical architecture consisted of copper nitride (Cu3N) and Co-Ni carbonate hydroxides (CoNiCHs) on copper foam (CF) was synthesized, and the Cu3N@CoNiCHs@CF requires quite small overpotentials (ηs) of 182 and 155 mV to afford current density (j10) of 10 mA cm−2 for HER and OER, respectively. More importantly, it requires a comparably low potential of 1.58 V to deliver j10 upon driving overall water splitting due to an optimal integration of the 3D hierarchical configuration and the desirable interface interplay of Cu3N and CoNiCHs, outperforming those of noble metals and most of the benchmarking bifunctional electrocatalysts. This study paves an attractive way to better unraveling the interface interplay over hierarchical architectures with very promising electrocatalytic activity.

To accelerate the kinetics of oxygen evolution reaction (OER) on H2O oxidation regarding the energy conversion and storage approaches, the discovery and design of desirable cost-effective and highly efficient electrocatalysts is of prime importance. This study demonstrates a novel layered perovskite via Co-doping strategy, i.e. LaSr3Co1.5Fe1.5O10-δ, which possesses significantly higher electrocatalytic activity, considerably lower overpotential and Tafel slope, remarkably higher mass activity (MA) and specific activity (SA) together with a better long-term stability than the undoped parent perovskite, the state-of-the-art IrO2 and the most active Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) under harsh OER cycling conditions in alkaline solution. These merits mainly originate from the presence of partial oxidation of surface Co3+ to Co4+ in LaSr3Co1.5Fe1.5O10-δ, an appropriate possible structure-dependent position of O p-band centre to the Fermi level and an increased amount of highly oxidative oxygen species O22-/O- in conjunction with a strong OH- adsorption and O2 desorption abilities. These findings not only improve the electrocatalytic activities of the layered perovskite family via optimal doping but also highlight the potential application of LaSr3Co1.5Fe1.5O10-δ as an earth-abundant, cost-effective, highly active and durable electrocatalyst for OER in energy conversion and storage technologies.

Sunlight-driven hydrogen production from water splitting, assisted with the commonly used Pt/TiO 2 catalyst, is a promising way to store clean and renewable energy. However, the photocatalytic activity of Pt/TiO 2 is limited owing to the agglomeration of Pt atoms. Herein, we successfully synthesized a Pt/TiO 2 catalyst, where Pt is atomically and selectively dispersed on the (1 0 1) facets of nanosized TiO 2 single crystals. A remarkably higher photocatalytic activity for H 2 evolution together with a considerable stability was observed as compared to commonly used Pt/TiO 2 . This study demonstrates a promising way to achieve atomically dispersed highly-active catalyst for water splitting.

Electrochemical reduction of CO2 (CO2RR) provides great potential for intermittent renewable energy storage. This study demonstrates a predominant shape-dependent electrocatalytic reduction of CO2 to CO on triangular silver nanoplates (Tri-Ag-NPs) in 0.1 M KHCO3. Compared with similarly sized Ag nanoparticles (SS-Ag-NPs) and bulk Ag, Tri-Ag-NPs exhibited an enhanced current density and significantly improved Faradaic efficiency (96.8%) and energy efficiency (61.7%), together with a considerable durability (7 days). Additionally, CO starts to be observed at an ultralow overpotential of 96 mV, further confirming the superiority of Tri-Ag-NPs as a catalyst for CO2RR toward CO formation. Density functional theory calculations reveal that the significantly enhanced electrocatalytic activity and selectivity at lowered overpotential originate from the shape-controlled structure. This not only provides the optimum edge-to-corner ratio but also dominates at the facet of Ag(100) where it requires lower energy to in...

To effectively reduce and utilize the atmospheric CO2, electrochemical conversion of CO2 into CO using an efficient and stable cathode in a high temperature solid oxide electrolyzer has attracted extensive interest. A composite cathode based on lanthanum nickelate potentially opens up the possibility for CO2 electrolysis. Herein, we developed a new Ni-doped La(Sr)FeO3−δ material, which has been firstly fabricated as a cathode for CO2 electrolysis in a solid oxide electrolysis cell (SOEC). The ultra-low total polarization resistance, together with an impressive current density of 1.21 A cm−2 at a potential of 1.55 V and 850 °C, demonstrates the superior electrocatalytic activity of La0.6Sr0.4Fe0.8Ni0.2O3−δ (LSFN) for stably and effectively promoting the cathodic kinetics for the CO2 electrolytic reaction. Moreover, an ultra-high Faraday efficiency of ∼99.7% was achieved at an applied potential of 1.0 V (vs. OCV) and 850 °C. The comparable cell performance for CO2 electrolysis benefits from the extension of the reactive sites due to the improved mixed ionic and electronic conductivity and accelerated adsorption and diffusion of the adsorbed active species, resulted from the high oxygen vacancy introduced on the LSFN backbone surface. Besides the comparable electrochemical performance, the excellent redox reversibility between the reduction and re-oxidation as well as considerable coking tolerance towards CO-enriched gas reveals that this newly prepared La(Sr)Fe(Ni) is a potential cathode material for SOEC, particularly for a direct carbon-abundant cell.

Bi

Tunable In(OH)

To reduce the amount of greenhouse gas emissions and remedy related environmental damage, the research on carbon capture and storage (CCS) is gaining momentum and so is the search for a more effective way to control corrosion of pipeline steel used to transport impure supercritical (SC) CO

Electrochemical reduction of CO

Electrochemical reduction of CO2 could mitigate environmental problems originating from CO2 emission. Although grain boundaries (GBs) have been tailored to tune binding energies of reaction intermediates and consequently accelerate the CO2 reduction reaction (CO2 RR), it is challenging to exclusively clarify the correlation between GBs and enhanced reactivity in nanostructured materials with small dimension (

The massive emission of carbon dioxide (CO2), the major portion of greenhouse gases, has negatively affected our ecosystem. Developing new technologies to effectively reduce CO2 emission or convert CO2 to useful products has never been more imperative. In response to this challenge, we herein developed novel in situ exsolved Fe–Ni alloy nanospheres uniformly socketed on an oxygen-deficient perovskite [La(Sr)Fe(Ni)] as a highly stable and efficient catalyst for the effective conversion of CO2 to carbon monoxide (CO) in a high-temperature solid oxide electrolysis cell (HT-SOEC). The symmetry between the reduction and reoxidation cycles of this catalyst indicates its good redox reversibility. The cathodic reaction kinetics for CO2 electrolysis is significantly improved with a polarization resistance as low as 0.272 Ω cm2. In addition, a remarkably enhanced current density of 1.78 A cm–2, along with a high Faraday efficiency (∼98.8%), was achieved at 1.6 V and 850 °C. Moreover, the potentiostatic stability te...

This study investigates the oxidation behavior of several stainless steels and nickel-based superalloys exposed to supercritical water at 800 °C for 12 h. Characterization of the resulting oxide layers were conducted using weight change measurements, X-ray diffraction, scanning/transmission electron microscopy, and energy dispersive spectroscopy. Although the exposure time is only 12 h, the thickness of the oxide layers formed was as high as 1 μm, comprising different spinel structures. The influence of alloying elements such as Al, Nb, Mo, Mn and Ti on the corrosion behavior is investigated and possible corrosion mechanisms for each candidate alloy are discussed.