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High conversion rate and selectivity are challenges for CO2 utilization through catalytic reverse water gas shift (RWGS) reaction. Herein, a novel mesoporous biochar (MB) supported Cu-Mo2C nano-interface was prepared by consecutive physical activation of coconut shells followed by carbothermal hydrogen reduction of bimetal. As compared with traditional carbon materials, this MB exhibited ultra-high specific surface area (2693 m2 g–1) and mesopore volume of mesopore (0.81 cm3 g–1) with a narrow distribution (2–5 nm), responsible for the high dispersion of binary Cu-Mo2C sites, CO2 adsorption and mass transfer in the reaction system. Moderate carbothermal reduction led to the sufficient reduction of Mo ion with carbon matrix of MB and dispersive growth of nano Cu-Mo2C binary sites (~ 6.1 nm) on the surface of MB. Cu+ species were formed from Cu0 via electron transfer and showed high dispersion with simultaneous boosted bimetal loading due to the strong interaction between nano Mo2C and Cu. These were advantageous to the intrinsic activity and stability of the Cu-Mo2C binary sites and their accessibility to the reactant molecules. Under the RWGS reaction conditions of 500 °C, atmospheric pressure, and 300,000 ml/g/h gas hour space velocity, the CO2 conversion rate over Cu-Mo2C/MB reached 27.74 × 10–5 molCO2/gcat/s at very low H2 partial pressure, which was more than twice that over traditional carbon supported Cu-Mo2C catalysts. In addition, this catalyst exhibited 99.08% CO selectivity and high stability for more than 50 h without a decrease in activity and selectivity. This study offers a new development strategy and a promising candidate for industrial RWGS. Highlights: Coconut shell derived ordered mesoporous biochar with ultra-high SBET and mesopore volume was fabricated. Mesoporous biochar facilitates nano Cu-Mo2C interface formation, CO2 adsorption and mass transfer. Strong interaction between Mo2C and Cu leads to electron transfer and anchoring of Cu. CO2 conversion rate over Cu-Mo2C/MB was twice that over Cu-Mo2C/traditional carbon. The catalyst exhibited 99.1% CO selectivity and high stability for more than 50 h. [ABSTRACT FROM AUTHOR]

Alkaline oxygen reduction reaction (ORR) is critical to electrochemical energy conversion technology, yet the rational breaking of thermodynamic inhibition for ORR through spin regulation remains a challenge. Herein, a Mott–Schottky catalyst consisting of Er2O3‐Co particles uniformly implanted into carbon nanofibers (Er2O3‐Co/CNF) is designed for enhancing ORR via spin‐selective coupling. The optimized Er2O3‐Co/CNF affords a high half‐wave potential (0.835 V vs reversible hydrogen electrode, RHE) and onset potential (0.989 VRHE) for the ORR surpassing individual Co/CNF and Er2O3/CNF. Theoretical calculations reveal the introduction of Er2O3 optimizes the electronic structure of Co through Er(4f)‐O(2p)‐Co(3d) gradient orbital coupling, resulting in significantly enhanced ORR performance. Through gradient orbital coupling, the induced spin‐up hole in Co 3d states endows the Er‐O‐Co unit active site with a spin‐selective coupling channel for electron transition. This favors the decrease of the energy gap in the potential‐limiting step, thus achieving a high theoretical limiting potential of 0.77 VRHE for the Er2O3‐Co. Moreover, the potential practicability of Er2O3‐Co/CNF as an air‐cathode is also demonstrated in Zn‐air batteries. This work is believed to provide, new perspectives for the design of efficient ORR electrocatalysts by engineering spin‐selective coupling induced by rare‐earth oxides. [ABSTRACT FROM AUTHOR]

An dual electronic and architectural engineering strategy is a good way to rationally design earth‐abundant and highly efficient electrocatalysts of the oxygen evolution reaction (OER) for sustainable hydrogen‐based energy devices. Here, a Ce‐doped Co9S8 core–shell nanoneedle array (Ce−Co9S8@CC) supported on a carbon cloth has been designed and developed to accelerate the sluggish kinetics of the OER. Profiting from valance alternative Ce doping, a fine core–shell structure and vertically aligned nanoneedle arrayed architecture, Ce−Co9S8@CC integrates modulated electronic structure, highly exposed active sites, and multidimensional mass diffusion channels; together, these afford a favorable catalyzed OER. Ce−Co9S8@CC exhibits remarkable performance in the OER in an alkaline medium, where the overpotential requires only 242 mV to deliver a current density of 10 mA cm−2 for the OER; this is 70 mV superior to that of Ce‐free Co9S8 catalyst and other counterparts. Good stability and impressive selectivity (nearly 100 % Faradic efficiency) are also demonstrated. When integrated into a two‐electrode OER//HER electrolyzer, the as‐prepared Ce−Co9S8@CC displays a low operation potential of 1.54 V at 10 mA cm−2 and long‐term stability, thus demonstrating great potential for economical water electrolysis. [ABSTRACT FROM AUTHOR]

AbstractThe utilization of celery seeds as seasonings and in herbal teas is widespread due to their significant nutritional and medicinal value. The determination of volatile organic compounds (VOCs) is a valuable tool for species identification and classification. Currently, there is an absence of information investigating the volatile constituents present in the cultivars of celery seeds. To analyze the varietal differences of celery seeds, VOCs were isolated using headspace solid-phase microextraction with by determination by gas chromatography-mass spectrometry. The samples underwent further comparison using multivariate statistical analysis to determine the changes in VOCs. Cluster analysis and principal component analysis were used to conduct correlation measurements on the samples. An orthogonal partial least squares discriminant analysis (OPLS-DA) model was developed to discriminate between samples and identify differential compounds. The distribution of these key compounds in these seeds was analyzed using a Sankey diagram. The samples contained 30 volatile components, mainly terpenes and esters. Correlation analysis revealed distinct variations in the VOCs. Furthermore, the utilization of the OPLS-DA model facilitated the identification of 11 differential compounds. The Sankey diagram illustrated significant disparities in the distribution patterns of these key compounds in the celery seeds. [ABSTRACT FROM AUTHOR]

AbstractDeveloping robust analytical methodologies for the discrimination of craft and industrial beer presents a significant yet formidable challenge. The identification and differentiation of products necessitate the utilization of reliable analytical methods, which are indispensable for ensuring market stability and safeguarding consumer interests. In this study, representative samples with a significant market share were selected for headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) analysis to compare the volatile substance characteristics of craft and industrial beers. The findings suggested that alcohols and esters constituted the primary volatiles. Craft beer exhibited a higher abundance of both types and concentrations compared to industrial beer. Subsequently, unsupervised and supervised chemometric techniques were employed for further analysis of the data matrix. An orthogonal partial least squares discriminant analysis (OPLS-DA) method was established to effectively discriminate between industrial and craft beers, enabling the identification of characteristic volatile markers. The untargeted GC-MS metabolomics coupled with multivariate statistical analysis holds promise for the authentication of craft and industrial beers. [ABSTRACT FROM AUTHOR]