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The adsorption of acetaldehyde over carbide-derived carbon (CDC) modified with nitric acid, hydrogen peroxide, or air was investigated. The physicochemical properties of the original and modified CDCs were characterized by N 2 adsorption, Fourier transform infrared spectrometer, temperature programmed desorption and X-ray photoelectron spectroscopy. It was observed that the oxidation modification, especially the nitric acid treatment, could significantly enhance the adsorption performance of CDC for acetaldehyde. The increase of acidic oxygen-containing groups like carboxylic acids and anhydrides in the modified CDCs results in the increase of adsorption performance. The density functional theory calculations and in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy show that these acidic oxygen-containing groups display strong hydrogen bonding interactions with acetaldehyde molecule, leading to the enhanced adsorption performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Depressurization followed CO 2 -N 2 injection for CH 4 recovery and CO 2 sequestration. • Effect of MH dissociation ratio on subsequently mixed hydrate formation. • CH 4 hydrate re-formation and dissociation occurred depending on CH 4 hydrate left. • CO 2 hydrate formation depended on the CH 4 left in both gas phase and hydrate phase. • Increasing CH 4 production decreased the CO 2 sequestration and hydrate restoration. Natural gas hydrates (NGHs) buried below the seafloor are globally abundant, energy-dense, and essential to the world's future energy mix. The combination of depressurization and CO 2 -N 2 injection processes for NGHs recovery has been identified as an environmental method to harvest energy, CO 2 sequestration, and to maintain the mechanical stability of sediment. In this regime, partial CH 4 was produced by depressurization followed by CO 2 -N 2 injection to form CH 4 -CO 2 -N 2 mixed hydrate (Mix-H). In this study, a series experiments were designed to examine the key factors in the depressurization process (i.e. bottom hole pressure BHP and CH 4 production ratio) on the subsequent processes of Mix-H formation, CO 2 sequestration and hydrate restoration. It was observed that Mix-H formation occurred in all cases, but the final amount of Mix-H were all lower than the initial amount of MH before depressurization. Particularly, the formation of CO 2 /N 2 hydrate in Mix-H is positively correlated with the amount of remaining CH 4 in the combined phases of gas and hydrate after depressurization. The formation of CH 4 hydrate in Mix-H during the reformation process occurred in five cases when MH dissociation ratio (D MH) reaches above 45.1 % during depressurization. MH was only observed to dissociate continuously after CO 2 /N 2 injection when D MH is low at 30.8 %, which indicates possible "CH 4 -CO 2 replacement reaction". Overall, increasing CH 4 production at the same BHP decreases the CO 2 sequestration and hydrate restoration. We first verified the feasibility of the combination method for synergistic CH 4 recovery and CO 2 sequestration in marine conditions. The experimental results provide possible guidance on the optimal design of the coupled processes and shed light on the relationship between CH 4 recovery and CO 2 sequestration that need to be wholistically balanced. [ABSTRACT FROM AUTHOR]

• A detailed review on metal/oxide heterointerface delivered by exsolution. • A comprehensive comparison among various strategies constructing metal/oxide heterointerface. • The mechanism understanding, control factor, and current advances of exsolution in heterocatalysis. • The enhancement factor, current challenges and future research directions of exsolution. The heterointerface consisting of metallic nanoparticles dispersed on oxide support represents one of the most important footstones for plenty of matured and emergent chemical reactions. Such kind of catalytic platforms were conventionally prepared by gas-based or liquid-based deposition methods, which suffer from the long-standing challenges of poor metal-oxide adhesion and durability. Alternatively, the emergence of solid-based exsolution strategy shows promising opportunities to deliver uniformly distributed metal nanoparticles with high activity, robustness, reproducibility and tunable functionality. With this regard, in this review, we will summarize the state-of-the-art understanding of the mechanistic insight, control parameters, and most recent advances of this practical strategy in heterocatalysis. We also quantitively analyze the enhancement factor resulting from exsolution manipulation in recent years and point out its unresolved challenges and future perspective. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrogen-rich syngas was produced through plasma-catalytic biogas reforming. • Ni-based bimetallic catalysts were evaluated in the plasma-catalytic biogas reforming. • The maximum conversion of CO 2 and CH 4 (29.8% and 49.1%) was achieved. • The highest hydrogen yield of 18.7% was obtained at 60 W. • 10Ni3Co showed the best reaction performance compared to other catalysts. Biogas reforming to syngas is an attractive route for the efficient utilization of biogas. In this work, plasma-catalytic dry reforming of biogas into value-added fuels and chemicals over Ni-based bimetallic catalysts was achieved using dielectric barrier discharge (DBD). The coupling DBD with 10Ni3Co exhibited the best reaction performance, reflected by the highest gas conversion, main gas product yield and selectivity, and fuel production efficiency (FPE). This hybrid process also favored the suppression of carbon deposition on the catalyst surface and the reduction of energy cost for both gas conversion and product formation. The maximum CO 2 and CH 4 conversion (29.8% and 49.1%) was obtained when the discharge power was 60 W, while a low discharge power (30 W) led to the highest FPE of 12.3%. By using Ni-based catalysts, we were able to tune the product distribution, favoring the generation of C 3 -C 4 hydrocarbons and syngas while reducing the production of C 2 hydrocarbons, with 10Ni3Co providing the most favorable results. Compared to other spent catalysts, the lowest carbon deposition (2.9%) was detected on the spent 10Ni3Co after 150 min of plasma reforming. Catalyst characterizations and density functional theory (DFT) calculations showed that the 10Ni3Co catalyst was superior due to a combination of factors such as a higher specific surface area, improved capability to adsorb CO 2 , strong interactions between the metals and the support, enhanced reducibility and the formation of a Ni-Co alloy. Furthermore, a simplified kinetics model was developed to better understand the effects of Ni-based bimetallic catalysts on the overall energy constant for the conversion of reactants in plasma-catalytic reforming of biogas. [ABSTRACT FROM AUTHOR]

• A Cu based perovskite photocatalyst toward CO 2 conversion was fabricated by consecutive in-situ exsolution/redispersion strategy. • The uniformly dispersed Cu site and modified band structure is beneficial for enhancing light absorption and photocatalytic activity. Excessive exploitation and depletion of fossil fuels have led to the escalation of CO 2 emissions, which are responsible for global climate deterioration. Cu-based solid catalysts can transform CO 2 into various hydrocarbons via a sustainable photocatalytic pathway. Herein, we fabricated a Cu-decorated LaFeO 3 photocatalyst using a sequential in situ exsolution (in H 2)/redispersion (in N 2) strategy. The dispersion of Cu was significantly enhanced (∼3 times), i.e., from 13.8 % (exsolved) to 41.4 % (redispersed). The combined theoretical and experimental results confirmed the successful formation of uniformly dispersed Cu active sites for efficient CO 2 adsorption and photocatalytic conversion. The enhancement of light absorption and manipulation of the band structure were also collectively achieved, offering an optimized catalyst involving superior CO and CH 4 production compared to its counterparts. In addition, photocatalytic water splitting was significantly suppressed, suggesting high selectivity of the photocatalytic pathway. This study offers a new perspective on the design principle of photocatalysts for selective CO 2 conversion. [ABSTRACT FROM AUTHOR]

[Display omitted] • A systematic study was conducted on the dual-catalyst CFP of poplar sawdust. • Totally 18 catalysts belonging to three types were tested as first-layered catalysts. • Effects of the 18 first-layered catalysts on the bio-oil production were evaluated. • Synergistic effects between the dual-layered catalysts were studied and compared. • Porous materials + ZSM-5 provided the highest bio-oil yield and quality. Dual-catalyst catalytic fast pyrolysis (CFP) technology is effective in converting biomass waste into hydrocarbon-rich bio-oils. However, systematic studies on dual-catalyst biomass CFP are limited, especially with respect to the best-performed dual catalyst design. In this context, dual-catalyst CFP of poplar sawdust was conducted with 18 in-situ first-layered catalysts, including 6 inorganic salts (NaCl, KCl, MgCl 2 , ZnCl 2 , K 3 PO 4 , and K 2 HPO 4), 7 metal oxides (SiO 2 , Al 2 O 3 , CaO, MgO, ZnO, Fe 2 O 3 , and CuO), and 5 porous materials (SBA-15, MCM-41, Y zeolite, Beta zeolite, and SAPO-34), while the ZSM-5 zeolite was fixed as an ex-situ second-layered catalyst. The effects of the 18 first-layered catalysts on bio-oil production were investigated and compared. Applying the porous materials as the first-layered catalysts increased the bio-oil yields compared to the inorganic salts and metal oxides. In particular, mesoporous SBA-15 combined with ZSM-5 led to the highest bio-oil yield of 19.4 wt% and a satisfactory hydrocarbon selectivity of 30.5 area%. The synergistic effects of the dual-layered catalysts were also studied. The first-layered catalysts cracked the primary biomass volatiles into smaller oxygenates, while the second-layered ZSM-5 deoxidized these molecules to hydrocarbons. In addition, the porous materials exhibited better synergy with ZSM-5 by simultaneously deoxygenating all the oxygenate types. The dual catalysts configured by Beta + ZSM-5 converted the most oxygenates into hydrocarbons, and the hydrocarbon selectivity (41.4 area%) was twice that in the blank experiment (Thermal/ZSM-5). Therefore, combining the porous materials and ZSM-5 delivers a promising catalyst for dual-catalyst biomass CFP. [ABSTRACT FROM AUTHOR]

Highlights: [•] The removal of 4-CP and TOC improves as input power increases. [•] 4-Chlorocatechol is the dominating hydroxylated intermediate. [•] Most of the chlorine atoms are released from the removed 4-CP to form Cl−. [•] Yields of ring-opening and ring-containing products take up less than 50% and 1%. [•] Both short-living and long-living plasma species contribute to 4-CP degradation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Feasibility of CH 4 recovery and CO 2 storage by gas injection at marine condition. • CH 4 hydrate co-growth and dissociation occurred depending on the gas composition. • High CO 2 composition is beneficial for co-growth of mixed hydrate. • Continuous CH 4 hydrate dissociation was observed with high N 2 composition. CH 4 hydrate have been considered as the future clean energy resource. Recovery of CH 4 from natural gas hydrates by CO 2 replacement is a promising method for energy harvest and CO 2 sequestration. Field production tests have proved the feasibility of gas production by CO 2 replacement in the permafrost region. However, most of the hydrate reservoirs are located at marine conditions where pressure and temperature conditions are not favorable for the replacement process. In this work, we identified a possible marine condition, where mixed hydrates could potentially form. We investigated the technical feasibility of CH 4 recovery by a depressurization process followed by the injection of CO 2 -N 2 gas. To quantify the dynamic behavior of mixed hydrates formation and dissociation, we developed a numerical method to estimate the phase partitioning during the replacement process. The effects of mixed gas compositions in the reactor on the replacement efficiency were investigated. Our experimental results showed that rapid co-growth of mixed hydrates occurs when the injected gas composed of a lower N 2 concentration (<25.2%). On the other hand, continuous CH 4 hydrate dissociation was observed when the injected gas was composed of a higher N 2 concentration (28.5%). During the prolonged replacement stage, the amount of CH 4 hydrate decreased and the amount of CO 2 -N 2 hydrates increased only slightly, which indicated that possible replacement occurred but at a very localized level. The results proved the technical feasibility of CH 4 production by gas injection at marine conditions, but the compositions of the mixture gas injected need to be well controlled. [ABSTRACT FROM AUTHOR]

• A Fe/Mn doped cobaltate catalyst was studied experimentally and theoretically. • Binary-dopant intensifies the involvement of lattice oxygen for OER. • The configurational entropy effect may determine the unique property of material. Lattice oxygen-mediated mechanism (LOM) on perovskite oxides for oxygen evolution reaction (OER) process has revealed kinetic superiority over conventional adsorbate evolution mechanism (AEM). However, feasibly enhancing the participation of lattice oxygen is still challenging. Here we designed a perovskite cobaltate (La 0.6 Sr 0.4 Co 0.8 Fe 0.1 Mn 0.1 O 3-δ , LSCFM) nanofiber, and discovered that the co-incorporation of Fe/Mn elements significantly intensifies the involvement of lattice oxygen for OER. Compared with its mono-dopant (Fe or Mn only) counterparts, the LSCFM gives rise to higher surface oxygen vacancies (V o) concentration and faster oxygen ion diffusion coefficient, endowing a small overpotential of 343 mV at 10 mA cm−2 and low Tafel slope of 63 mV dec−1. The strongest pH-dependent activity and metal–oxygen covalency are further unveiled on LSCFM by experimental and theoretical approaches, evidencing that the promoted OER kinetics on LSCFM predominantly stems from the formation of reactive lattice oxygen site. [ABSTRACT FROM AUTHOR]

• The B-site cations in perovskite is manipulated to facilitate water splitting. • The decoration of CoS 2 and oxygen deficiency enhance the catalytic activity. • The evolution of reactive sites was studied by experiments and DFT calculation. The family of perovskite oxides is a promising class of catalysts for diverse energy conversion processes including water splitting. In this work, a facile two-step manipulation (in-situ exsolution and post-sulfurization) strategy was proposed and applied to LaCo 0.2 Fe 0.8 O 3 (LCF) perovskite parent, through which, the electronic state, spatial immersion and intrinsic activity of B-site cobalt (Co) were stepwise tuned at nanoscale proximity accordingly (i.e., lattice Co ions → segregated Co0 → embedded CoS 2). Impressively, the as-prepared catalyst (S-LCF) obtains an emergent oxygen deficient microstructure seamlessly pinned with uniformly distributed CoS 2 nanoparticles (NPs), which demonstrates enhanced performance toward both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), and shows good stability in overall water splitting. The density functional theory (DFT) calculations illustrate the optimized metal-oxygen covalency and hydrogen adsorption Gibbs free energy (ΔG H*) on S-LCF, which further buttresses the prominence of our B-site cation engineering tactics. [ABSTRACT FROM AUTHOR]