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The activated carbon treated at different temperatures was performed as a catalyst for the oxidation of glycerol to glycolic acid. Heat treatment at suitable temperature could promote the enrichment of ester and carboxyl functional groups with strong electronegativity, which serves as the efficient active site for the glycerol oxidation. Therefore, the optimal AC-400 catalyst with more ester and carboxyl groups shows excellent catalytic activity (0.0039 mol/g Cat /h) and GLYOA selectivity (53.2%). [Display omitted] • The efficient oxidation of glycerol to glycolic acid was realized over heat treated activated carbon. • Heat treatment tuned the composition and electronic structure of oxygen-containing functional groups. • The ester and carboxyl functional groups with strong electronegativity enhanced the adsorption and activation of glycerol. Exploring efficient and cheap catalyst for the selective oxidation of glycerol to valuable carboxylic acids is a critical and complicated challenge. Herein, we innovatively realized the efficient oxidation of glycerol to glycolic acid over metal-free catalyst under mild conditions via carbon material defect engineering. Multiple characterizations revealed that the stepwise functionalization of active carbon caused by simple high temperature control is adopted to fine-tune the composition and electronic structure of oxygen-containing functional groups. Specifically, the abundant ester and carboxyl functional groups exhibit stronger electronegativity than the hydroxyl group, and this enhanced electronic coupling effect strengthens the adsorption of glycerol, thus improving the catalytic activity. Kinetic analysis and density functional theory calculations demonstrated that the oxygen-containing functional groups (mainly ester and carboxyl) could promote the C–H bond activation of RCH 2 O* intermediate and once C–C bond cleavage of glyceric acid, ensuring the high selectivity of glycolic acid (53.2% over AC-400 catalyst). We anticipate that this work could sheds some light on the application and design of more new type of carbon-based metal-free catalysts in the aqueous phase oxidation of various polyols. [ABSTRACT FROM AUTHOR]

We report the unique nanoscale alkaline earth metals doped Pt/M−MCM−41 (70) (M = Mg, Ca, Sr and Ba) catalysts for the selective oxidation of glycerol in base-free medium. Strong basic sites generated by alkaline earth metal oxides (especially MgO and CaO) could induce the strong electronic transfer ability, the modified reduction properties of Pt and abundant surface oxygen vacancies. Reaction kinetics demonstrated that the addition of alkaline earth metal oxide (e.g. CaO) could promote the activation of primary hydroxyl group and C-H bond, resulting in the excellent catalytic performance. • Basic strength-dependent catalytic performance for glycerol oxidation was investigated. • Alkaline earth metals changed the structural properties of the Pt/MCM-41 catalyst. • The promotion role of alkaline earth metal on the reaction mechanism was elucidated. • Record TOF values for the base-free oxidation of glucose and xylose were obtained. Fundamental understanding of basic site of supported metal catalysts is highly desirable for aqueous phase oxidation of alcohols without adding extra alkali. Herein, nanoscale alkaline earth metals doped Pt/M−MCM−41 catalysts (M = Mg, Ca, Sr and Ba) were prepared for the aqueous phase oxidation of glycerol to glyceric acid in base-free medium. By establishing the correlation between basic active site and catalytic performance, it is found that catalytic activity increases almost linearly with the strength of basic sites, and excessively strong basic sites are not conducive to the improvement of glyceric acid selectivity. Multi-characterizations revealed that strong basic sites generated by alkaline earth metal oxides (especially MgO and CaO) could induce the enhanced electronic transfer ability, the modified reduction properties of Pt and abundant surface oxygen vacancies in the Pt/M−MCM−41 catalysts. Moreover, reaction kinetics demonstrated that the addition of alkaline earth metal oxides (e.g. CaO) could promote the activation of primary hydroxyl group and C-H bond, resulting in the excellent catalytic performance. In addition, as the representative of the optimal solid base catalysts, the Pt/Ca-MCM-41 (70) catalyst also exhibits record high turnover frequency (TOF) values for the oxidation of glucose (9623.0 h−1) and xylose (4561.0 h−1) to corresponding carboxylic acids. [ABSTRACT FROM AUTHOR]

Several typical pristine Pt/C and Au/C catalysts were investigated for glycerol oxidation to various C 1 -C 3 ketone/acid products via experiments, kinetics analysis, and DFT calculations. The higher metallic state and increased d electrons of Pt/C promote strong adsorption of OH– and enhance oxygen activation, leading to higher selectivity towards lactic acid by facilitating dehydration of C-OH in glyceraldehyde and promoting timely desorption of lactic acid species. Conversely, Au/C exhibits enhanced oxidative cleavage of the C-C bond in glyceric acid leading to increased production of glycolic acid products. Expanding to bimetallic catalysts, it was observed that catalysts with higher Au content exhibit enhanced selectivity towards the oxidation of glyceric acid to glycolic acid, while those with a higher Pt ratio demonstrate increased selectivity for the oxidation of glycerol to lactic acid. [Display omitted] • Several typical pristine Pt/C and Au/C catalysts were investigated for glycerol oxidation via kinetics analysis and DFT calculations. • Pt could facilitate dehydration of C-OH in glyceraldehyde and Au tends to strengthen oxidative cleavage of C-C bond in glyceric acid. • Higher Au content is beneficial to increase selectivity of glycolic acid, whereas higher Pt ratio enhances the selectivity of lactic acid. Fundamental understanding of heterogeneously catalytic aerobic oxidation of polyol is highly desirable for sustainable and efficient chemical synthesis. Herein, based on the purpose of exploring the selectivity of various carboxylic acids on Pt-Au catalysts with different ratios, we conducted a comprehensive investigation into the reaction pathways of glycerol oxidation over pristine Pt/C and Au/C catalysts via experiments, kinetics analysis and DFT calculations. Structural characterizations revealed that Pt/C exhibits a higher metallic state and more d electrons, thus tending to strongly adsorb OH– and promote oxygen activation. Conversely, the weak oxygen activation of Au/C could be attributed to fewer cationic high valence state and d electrons. Furthermore, the Langmuir-Hinshelwood kinetic model and DFT calculations indicate both catalysts exhibit obvious differences in product distribution. Specifically, Pt demonstrated higher selectivity towards lactic acid by facilitating dehydration of C-OH in glyceraldehyde and promoting timely desorption of lactic acid species. In contrast, Au displayed more glycolic acid products caused by strengthening oxidative cleavage of C-C bond in glyceric acid. Expanding to bimetallic catalysts, it was observed that catalysts with higher Au content exhibit enhanced selectivity towards the oxidation of glyceric acid to glycolic acid, while those with a higher Pt ratio demonstrate increased selectivity for the oxidation of glycerol to lactic acid. These findings provide valuable insights for guiding the design and optimization of this catalytic process to achieve targeted product generation. [ABSTRACT FROM AUTHOR]

This study proposed a super thermal integrated process for CO 2 capture by using internal thermal integration to reduce the total energy efficiency loss of the power plant. [Display omitted] • Super thermal integrated adsorption carbon capture process (STILT) is proposed. • The detailed modeling steps for the novel STILT process are carried out. • The compared analysis of energy efficiency and capture costs are calculated. • The novel process shows superior techno-economic-environment performance. The heat-integrated solid adsorbent process exhibits the potential to become an energy-saving method for CO 2 capture. Here, a super thermal integrated process (STILT) for CO 2 capture is proposed based on our experimental data. The novel process strengthened the process of internal thermal integration and significantly improved the total energy efficiency. This study further takes the commercial MEA process as the benchmark for the multi-dimensional assessment (considering the techno-economic-environment). When CO 2 products are compressed to 110 bar, the energy efficiency of the STILT process and MEA process is 53.45 % and 48.8 %, and the energy consumption is 1.5 MJ/kgCO 2 and 3.41 MJ/kgCO 2. Without CO 2 compression, the energy efficiencies of the STILT process and MEA process are 55.3% and 50.61%. The energy consumptions are 0.82 MJ/kgCO 2 and 2.63 MJ/kgCO 2. Due to the combination of internal thermal integration and enhanced CO 2 circulation capacity, the capture costs of the STILT process are 25.8–34.94 €·t−1 CO 2 , which significantly outweigh the MEA process (43.3–55.07 €·t−1 CO 2). This exhibits the superior techno-economic-environment advantages of the STILT process. This study harbors tremendous referential significance for the design and scale-up of the industrial CO 2 capture process. [ABSTRACT FROM AUTHOR]

This study proposed a synergistic catalysis effect of micro-mesoscopic channel for enhanced methyl oleate catalytic cracking to BTX inside the hierarchical ZSM-5 zeolites via molecular simulation. Such synergistic catalysis effect could increase the BTX yield by enhancing the adsorption of the reaction substrate, facilitating the transfer of the as-formed C 3 H 6 and C 4 H 8 from mesopore into micropore and accelerating the rapid diffusion of BTX to mesopore. [Display omitted] • Synergistic catalysis effect of micro-mesoscopic channel for enhanced methyl oleate catalytic cracking to BTX is proposed. • Microporous and hierarchical ZSM-5 zeolite models have been constructed that are consistent with the experimental properties. • Pioneering study of the adsorption properties of long-chain molecules inside hierarchical zeolite. • Channel dependence to produce BTX inside two zeolites is systematically discussed. The hierarchical ZSM-5 zeolite exhibits superior catalytic performance for methyl oleate catalytic cracking to BTX, while the promotion mechanism at the molecular level is still unclear. Herein, the adsorption and diffusion behaviors of reaction species in hierarchical ZSM-5 zeolite, including methyl oleate, C 3 H 6 , C 4 H 8 and BTX, were theoretically investigated by Monte Carlo combined with Molecular Dynamics simulation. It is found that the introduction of mesopores exposes the strong adsorption sites (Brønsted acid) without a confinement effect, thereby promoting the adsorption and cracking of methyl oleate. Moreover, the as-formed C 3 H 6 and C 4 H 8 rapidly transfer from mesopore into micropore, enhancing the aromatization reaction to form BTX. Finally, thanks to the adjacent mesopore providing sufficient space for molecule rotation, the desired BTX products easily desorbs from the micropore. Such synergistic catalysis effect of micro-mesoscopic channel increases the BTX yield by decreasing the diffusion coefficient of C 3 H 6 and C 4 H 8 from 13.2 × 10-9 m2/s on the traditional to 6.4 × 10-9 m2/s on the hierarchical ZSM-5. We anticipate that this work could enrich our understanding of the microcosmic mechanism of hierarchical zeolites for prolific aromatics. [ABSTRACT FROM AUTHOR]

• A assessment framework of methanol production integrated with a hybrid hydrogen strategy is established. • To comprehensively utilize hydrogen, "balance points" are proposed and defined. • The detailed techno-economic-environment performance are calculated. • The novel hybrid hydrogen supply strategy shows superior performance. A techno-economic-environment assessment framework of methanol production from coal integrated with a hybrid hydrogen supply strategy is established, gathering an insightful perspective of its broad sustainability and providing an effectually hybrid green, blue, and gray hydrogen supply plan to evaluate its performance. Process simulation and life-cycle analysis indicate that coal to methanol integrated with reverse water gas shift using coal to hydrogen (CTM-RWGS-CTH) and CTM-RWGS with water electrolysis using wind energy process show relatively independent excellent technical and environmental performance, respectively. To comprehensively utilize hydrogen energy to realize process integration and intensification, "balance points" are proposed and defined. Moreover, eleven possible hybrid hydrogen supply modes are developed and analyzed. Results show that the quaternary H 2 supply strategy exhibits enormous economic advantages, 0.051 $/kg methanol. The "balance point" in the quaternary H 2 supply strategy is CTM-RWGS-CTH 13%, CTM-RWGS H 2 from CTH without carbon capture, utilization and storage 37%, CTM-RWGS H 2 from byproduct gas to hydrogen 16%, and CTM-RWGS H 2 from water electrolysis using wind energy process 34%. Our hybrid hydrogen supply strategy embraces the full potential role of emerging CTM-RWGS processes to achieve low-carbon consumption and cleaner production, which should prevail over purely unitary hydrogen resources. [ABSTRACT FROM AUTHOR]

[Display omitted] For the explosive and strongly exothermic direct propene epoxidation with H 2 and O 2 to synthesize propylene oxide, maintaining uniform gas flow and moderate reaction in the packed bed reactor is of prime industrial and scientific significance. Herein, randomly packed beds of spherical particles were simulated with resolved particle 3D computational fluid dynamics (CFD) under industrial conditions. Effect of particle size (i.e., 6, 8 and 10 mm) on performance of gas-phase propene epoxidation was numerically simulated. The fluid flow and temperature fields were fully coupled to the species and reaction distribution, including reactions in the particles and on catalyst surface. Based on the results of velocity, pressure drop, temperature and species distribution, heat transfer together with catalytic performance inside the fixed bed reactor, it is found that PPD-6 (Packed Particle Diameter 6 mm) model has a more uniform flow distribution, higher thermal conductivity and a lower temperature compared with PPD-8 and PPD-10. In addition, as packed particle diameter increases, the heat transfer capacity reduces and the temperature rise increases. As a result, the maximum hot spot temperature for the PPD-6 model is about 3 and 8 K lower than PPD-8 and PPD-10 model, respectively. In addition, the PPD-6 model has a more uniform reaction rate within the particles compared with the PPD-8 and PPD-10 models due to short diffusion path and high mass transfer capacity. Therefore, the PPD-6 model shows superior safety together with optimum conversion and selectivity. This work harbors tremendous referential significance to the design and scale-up of industrial reactors for propene epoxidation. [ABSTRACT FROM AUTHOR]

This work reports a strategy of replacing the traditional oxygen evolution reaction with hydrazine oxidation reaction for hydrogen production in acidic media. The as-prepared PtCo alloy electrocatalyst can not only remarkably reduce the energy input for hydrogen production with an outstanding stability, but also efficiently decontaminate hydrazine effluent with a hydrazine removal efficiency up to 100%. [Display omitted] • A proton exchange membrane hydrazine electrolyzer (PEMHE) design was developed for hydrogen production in acidic media. • PtCo alloy electrocatalysts can reduce the energy input for hydrazine assisted water splitting with an outstanding stability of over 3000 h in acidic media. • Proton exchange membrane hydrazine electrolyzer can achieve the mass hydrogen production under 100 mA cm−2 for at least 60 h. • Proton exchange membrane hydrazine electrolyzer can decontaminate hydrazine sewage with removal efficiency up to 100%. The application of proton exchange membrane water electrolyzer (PEMWE) technology has long been limited by the excessive energy consumption and poor catalyst durability because of the harsh corrosive and oxidative conditions that are related to the anodic oxygen evolution reaction (OER) in acidic electrolytes. Herein, we circumvent this challenge by adopting alternative hydrazine oxidation reaction (HzOR) as the anodic half-reaction, integrated with the cathodic hydrogen evolution reaction (HER) for sustainable hydrogen production. To this end, we further developed a PtCo alloy nanosheets electrocatalyst that can efficiently catalyze both the HzOR and HER with ultralow potentials. Specifically, the overall hydrazine splitting driven by the PtCo alloy requires only 0.28 V at 10 mA cm−2 along with outstanding stability of more than 3000 h. We further proposed a PEM hydrazine electrolyzer (PEMHE) design to promote the practical application. The device can not only produce hydrogen with a high yield rate of 1.87 mmol h−1 cm−2 at a practical current density of 100 mA cm−2 with a long durability of 60 h, but also effectively decontaminate hydrazine sewage with the hydrazine removal efficiency up to 100%. Our work provides a new solution to simultaneous mass hydrogen fuel production and hydrazine hazard removal from acidic waste water at minimized energy consumption. [ABSTRACT FROM AUTHOR]