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As one of the most promising nonprecious metal catalysts for the oxygen reduction reaction (ORR), the structure of the active site on nitrogen-doped carbon materials is still under debate. Here, we report that the sensitivity of the ORR on the local configuration of multiple nitrogen dopants may be overlooked. Combining global structure searching with density functional theory calculations, we established the structure-activity relationship for 19 and 298 possible configurations of graphitic nitrogen-doped graphene with N content of 2 and 3%, respectively. It was revealed that the stability cannot be a screener to determine the major contributor to the activity. 77.5% of current density is contributed by the active configuration with 4.59% population on the graphene containing 3% nitrogen. It unambiguously demonstrates the configuration sensitivity of N-doped graphene for ORR and opens a new window to identifying the optimal structure of N-doped carbons for various applications.

Environmentally friendly and energy saving treatment of black liquor (BL), a massively produced waste in Kraft papermaking process, still remains a big challenge. Here, by adopting a Ni CaO Ca12Al14O33 bifunctional catalyst derived from hydrotalcite-like materials, we demonstrate the feasibility of producing high-purity H2 (∼96%) with 0.9 mol H2 mol−1 C yield via the sorption enhanced steam reforming (SESR) of BL. The SESRBL performance in terms of H2 production maintained stable for 5 cycles, but declined from the 6th cycle. XRD, Raman spectroscopy, elemental analysis and energy dispersive techniques were employed to rationalize the deactivation of the catalyst. It was revealed that gradual sintering and agglomeration of Ni and CaO and associated coking played important roles in catalyst deactivation and performance degradation of SESRBL, while deposition of Na and K from the BL might also be responsible for the declined performance. On the other hand, it was demonstrated that the SESRBL process could effectively reduce the emission of sulfur species by storing it as CaSO3. Our results highlight a promising alternative for BL treatment and H2 production, thereby being beneficial for pollution control and environment governance in the context of mitigation of climate change.

Direct ethanol fuel cell (DEFC) as a promising device for converting chemical energy to electricity has been paid ever-increasing attention. However, the slow kinetics of ethanol electrooxidation at an anode hinders the application of DEFCs. Although Pt is the best catalyst among all the pure metal catalysts, it still has a relatively poor ability to break the C C bond, is deactivated by the accumulated COad intermediates, and undergoes unwanted desired structure change over long-term operation. In recent years, the addition of other metals to form binary, ternary, and quaternary catalysts have significantly improved electroactivity and stability. Ternary catalysts can have numerous element combinations and complicated architectures and, therefore, have been the subject of considerable research. In this review, most of the reported ternary catalysts will be summarized and categorized according to their structure while discussing the essence of the role of each component.

Electrochemical reductions of CO2 (ECRR) and N2 (ENRR) can not only reduce CO2 emissions in the air but also make use of N2 and H2O, the most extensive resources on earth, to produce high value-added chemicals, which has become one of the hot research directions. In this study, the formation energy (Ef) and dissolution potential (Udiss) of 96 two-dimensional catalysts derived from different defect sites of monoclinic crystal boron nitride (BN) were calculated, and the catalysts with thermodynamic and electrochemical stability were selected. The suitable catalysts for producing HCOOH (Ga/In@N-BN), CO (Sn@BN), and CH3OH (Co@N-BN) by ECRR and NH3 (Fe@BN) by ENRR were predicated based on a selective calculation method. The results obtained can provide guidance for the design and development of new catalysts for ECRR and ENRR.

Childhood obesity is related to impaired health and to some diseases in adulthood. Overweight children and adolescents have also been shown to experience social and psychological problems such as s...

Particulate materials possessing dual functionalities have received tremendous investigations in many fields, owing to their superiority over mono-functional counterparts and their potential for process integration and intensification. This review focuses on bi-functional catalytic particles which also serve as sorbents/adsorbents or heat suppliers in the scheme of various thermo-chemical processes, enabling inherent separation or energy conservation within single-step operation. Bi-functional particles applied for integration of reaction and separation including sorption-enhanced hydrogen production and integrated capture and catalytic conversion processes are reviewed in detail, providing insights into material design and key performance indicators. On the other hand, bi-functional particles applied for integration of reaction and non-thermal radiation heating, including electrothermal and photothermal assisted heterogeneously catalyzed reactions, are also reviewed, with emphasis on the material property and energy efficiency improvement. These bi-functional particles show broad adaptability and feasibility in various reactions operated in integrated and intensified schemes, affording huge potentials for further improving productivity and efficiency in thermo-chemical processes.

Glycerol is a significant by-product of biodiesel production and a functional molecule with three hydroxyl groups. Glycerol can be transformed through different catalytic processes, among which the selective oxidation of glycerol over heterogeneous catalyst is appealing due to its environmental friendliness and the facile production of various value-added products from glycerol. Owing to the structural sensitivity of the reaction, the activity and products selectivity not only depend on the active metal sites, but also is affected by many other factors, such as the pH of the reaction system, the structure and characters of metal and support. This article provides a comprehensive review of recent developments on glycerol selective oxidation over supported noble metal catalysts. Critical attention is paid to the influence of metal-support and metal-metal interactions on the electronic and geometrical structure of catalysts and the consequent catalytic performances, which is conducive to better understanding of the reaction mechanism and more rational design of catalyst to enhance the catalytic activity and selectivity of desired products, such as 1,3-dihydroxyacetone.

Metal- and nitrogen-doped carbon materials (Me–N–C) have received intensive scientific interest as single-atom catalysts (SACs) for electro- and thermocatalytic reactions. In this work, the potenti...

The electrochemical reduction of CO2 and H2O to syngas, a widely used precursor for chemical synthesis, has attracted increased attention. However, producing syngas over a wide range of CO:H2 ratios is important for its potential application. Herein, a facile method using an anodic oxidizing zinc plate has been developed to obtain lattice-dislocated ZnO, which exhibited higher faradaic efficiencies (above 90%) of syngas than that of ZnO without lattice dislocation. Moreover, the ratio of CO to H2 can be regulated in a wide range from 0.28 to 2.11 by applying different electrolyzing potentials, which is applicable to the synthesis of various chemicals. With density functional theory calculations, we conclude that the lattice dislocation defects in ZnO promote the electroreduction of CO2. In addition, stability and electrochemical noise tests show that lattice-dislocated ZnO can withstand long-term operation due to its effective corrosion resistance.

Nowadays, hierarchically macro-/meso-/microporous 3D carbon materials have been paid more attention due to their imaginative application potential in specific electrochemistry. Here, we report a dual-template strategy using eutectic NaCl/ZnCl2 melt as airtight and swelling agent to obtain 3D mesoporous skeleton structured carbon from renewable lignin. The prepared lignin-derived biocarbon material (LN-3-1) has a high specific surface area (1289 m2 g−1), a large pore volume (2.80 cm3 g−1), and a well-connected and stable structure. LN-3-1 exhibits extremely high activity and stability in acidic medium for oxygen reduction reaction (ORR), superior to Pt/C catalyst and most non noble-metal catalysts reported in recent literatures. The prepared carbon material was used as a cathode catalyst to assemble a H2-O2 single fuel cell, and its excellent catalytic performance has been confirmed with the maximum power density of 779 mW cm−2, which is one of the highest power densities among non-metallic catalysts so far. Density functional theory (DFT) calculations indicate that the synergy of chlorine and nitrogen reconciles the intermediate adsorption energies, leading to an appropriate theoretical ORR onset potential. We develop a cost-effective and highly efficient method to prepare biocarbon catalyst for ORR in proton-exchange membrane fuel cells.

Phenol is one of the major products of bio-oil derived from biomass pyrolysis. Sorption-enhanced steam reforming of phenol (SESRP) aiming to produce high-purity H2 has been carried out over Ni–Ca–A...

The reduction of CO2 emission is crucial for the mitigation of climate change. A considerable amount of industrial CO2 can be absorbed in the form of carbonates through high-temperature sorption processes. In this regard, the efficient conversion of carbonates to value-added products will provide an economically viable method for the sustainable usage of carbon compounds. Herein, we report a promising solution involving the use of a glycerol and ethanol mixture as a hydrogen donor in the dry reforming process with CaCO3 to produce syngas. A series of metal active components, including Ni, Fe, Co, Cu, Pt, Pd, Ru, and Rh, was used to promote this reaction. Ni showed comparable performance with that of Pd, but outperformed Co, Fe, Cu, Rh, Ru, and Pt. Approximately 100% conversion of glycerol and ethanol, ∼92% selectivity of synthesis gas (H2 and CO), and a H2/CO ratio of ∼1.2 were achieved over CaCO3 containing 10 wt% Ni (10Ni–CaCO3). Meanwhile, the CO2 concentration was less than 5 vol%, indicating that most of the CO2 captured by the carbonate can be transformed into chemicals; however, they cannot simply be emitted. The CO2 released from the decomposition of CaCO3 not only adjusted the ratio of H2 to CO but also eliminated cokes to guarantee the CO2 absorption–conversion cyclic stability in the absence of steam and at high temperatures.

An efficient Ni2P–CdS photocatalyst for photocatalytic hydrogen evolution was synthesized by phosphorizing β-Ni(OH)2 nanosheet with exposed (001) facets on CdS nanorods. The obtained Ni2P–CdS composite displays an outstanding and stable photocatalytic hydrogen generation rate of 68.47 mmol g−1 h−1 in 10 vol% lactic acid under visible light irradiation, more than 17 times higher than that for pure CdS nanorods. The transient photocurrent response, EIS measurement, Mott-Schottky plots, acidic LSV measurement, and PL spectra have proved that Ni2P loading can significantly improve the separation of photo-excited electron-hole pairs in CdS nanorods and enhance the hydrogen evolution capability for CdS. These improvements are achieved by features of Ni2P such as the high capability of trapping photo-generated electrons from CdS, lifting the total Fermi level and lowering the hydrogen evolution overpotential of the composite. The results show that β-Ni(OH)2 precursor with a high exposure degree of (001) facet is contributed to the epitaxial formation of (001)-facet-exposed Ni2P co-catalyst on CdS nanorods, resulting in that the Fermi level and the hydrogen evolution overpotential of the composite can be further lifted and lowered. This study has provided a novel precursor-derived route to fabricate high-performance co-catalysts with highly exposed active facets on CdS nanorods for effective photocatalytic hydrogen evolution.

As an efficient approach to high-purity hydrogen, the sorption-enhanced steam reforming (SESR) is usually highly energy-intensive. Herein, the sorbent decarbonation was conducted in the presence of O2 to enable the exothermic reaction between CaO and cobalt oxides to form calcium cobaltate (CCO). By utilizing CCO as oxygen carrier (OC), the chemical looping methane combustion (CLMC) was employed prior to the SESR of glycerol (SESRG). The CCO was pre-reduced to generate a multi-functional material composed of metallic Co catalysts and CaO sorbent, which can significantly improve the H2 yield from SESRG. With a simple Pt-doped CCO acting as pre-catalyst, CO2 sorbent and OC, we realized 70% CH4 conversion and 96 vol.% H2 with 120% yield for 20 cycles. The promoting effects of Pt towards CH4 conversion and H2 production were rationalized by CH4-TPR, XPS, SEM and TEM. Our results demonstrate the feasibility of process integration and intensification enabled by multi-functional materials.

Nitrogen dopants on carbon materials play vital roles in metal-free carbon catalysis, while the role of pyridinic nitrogen (NP) or graphitic nitrogen (NG) is still on debate. In this work, N-doped ...

Ru has been found to be a highly efficient catalyst for producing γ-valerolactone from the hydrogenation of levulinic acid. However, the active species on Ru nanoparticles (NPs) are still unclear. ...

Me N C catalysts have received intensive scientific interest as non-noble-metal single-atom catalysts (SAC) for electrochemical- and thermocatalytic reactions. However, the lack of understanding of its properties hinders further improvement of the catalytic performance. An interesting issue is the molecular details of the reaction involving more than one reactant, since the activation of the second reactant is inevitably affected by the first one on SAC. Here, we synthesized Co N C SACs for the aerobic oxidation of benzyl alcohol (BA) to benzaldehyde. The catalyst exhibited excellent activity for this reaction, among the most active non-noble-metal catalysts. Differently from particulate metal or metal oxide catalysts, the Co N C SAC displayed “self-poisoning” due to the strong competitive adsorption of BA to O2, as revealed by kinetics experiments and density functional theory calculations. Moreover, we rationalized the poisoning effect of polar moieties, including organic solvents and aqueous solutions, on the SAC. These results shed light on the catalytic behavior of aerobic oxidation of BA on the molecular level and enable the rational design of catalytic organic synthesis over Co N C SACs.

Electrochemical conversion of carbon dioxide (CO2) into useful chemicals has attracted a lot of attention to store energy and reduce the greenhouse effect. Herein, a new electrocatalyst of carbon nanotubes coated with cadmium sulfide is reported, the faradaic efficiency (FE) of CO2 reduction reaction (CO2RR) to carbon monoxide (CO) is as high as 95%. We clearly demonstrate that sulfur vacancies (S-vacancies) are in-situ generated on the catalyst surface in CO2RR, which is evidenced by electron paramagnetic resonance spectra (EPR), in-situ differential electrochemical mass spectrometry (DEMS) and inductively-coupled plasma spectrometer (ICP). With the increase of S-vacancies, the catalytic activity of CO2RR to CO improve significantly and the charge-transfer resistance decrease. Combined with in-situ infrared absorption spectroscopy and density functional theory calculations, it can be concluded that the formation of S-vacancies changes the electron density of the catalyst surface and decreases the energy barrier for the conversion of COOH∗ to CO∗. Finally, we tried to power electrochemical reduction of CO2 with solar panel under natural light conditions, the energy conversion efficiency on CdS-CNT catalyst from solar energy to CO has been calculated, predicting a hopeful application prospect in the future.

Catalytic reduction of CO

Heteroatom doped carbon materials have been synthesized and served as catalyst supports for Pd nanoparticles (NPs). Numerous Pd-carbon catalysts can be produced via single-, dual-, and multi-doping heteroatoms into carbon supports. Therefore, it is highly desired to seek a universal descriptor, regardless of the doping types, in guiding to the design of efficient catalysts. The electronic state of Pd affected by carbon supports is crucial in catalysis, which can be described by the binding energy (BE) accurately and conveniently using X-ray photon spectroscopy. In this work, the single (dual)-doped carbon nanotubes (CNTs) with tunable doping degrees were synthesized via thermal pyrolysis of heteroatom-containing precursors, accompanied by the defluorination of fluorinated CNTs. Density functional theory results show that the charge distributions of the doped-CNTs are determined by the doping configurations. After loading Pd NPs, the charge of the support redistributes. Meanwhile, the BEs of Pd0 3d5/2 change correspondingly due to the electronic metal-carbon interaction (EMCI). Eventually, Pd NPs with different electronic states show the difference in the turnover frequency of phenol hydrogenation. Therefore, the electronic state of Pd NPs can be considered as a proper descriptor for estimating the catalytic performance and indicator for developing highly efficient catalysts.

Background The hallmark of type 1 diabetes (T1D) is an absolute lack of insulin. However, many studies showed a tendency to heterogeneity in TID. We aimed to investigate the demographic and clinical characteristics in T1D and the differences in young-onset and adult-onset patients. Methods This retrospective study was conducted among 1943 patients with clinically diagnosed T1D. Medical records on patients’ demographics, anthropometric measurements, and clinical manifestation were collected. According to the age at onset, the newly diagnosed patients were divided into the young-onset group ( Results The median age of patients at disease onset was 22 years. The median duration of patients was 3 years. The overall median glycated hemoglobin (HbA1c) value was 10.3 % [89(mmol/mol)]. The prevalence of diabetic retinopathy was 25.1 %. The overall rate of DKA at onset in the new-onset patients was 59.6 %. The frequency of overall dyslipidemia was 37.8 %. The most frequent dyslipidemia was low high-density lipoprotein-cholesterol (HDL) (29 %). The proportion of patients with anti-glutamic acid decarboxylase (GADA), insulin antibody (IAA) and islet cell antibody (ICA) were 28.1 %, 6.4 % and 21.6 %, respectively. The mean HbA1c showed a downward trend with age. Increasing or decreasing trends of overweight and obesity in this population during the period 2012 to 2018 was not found. Compared with young-onset T1D, adult-onset patients comprised better islet function (FCP: 0.4 vs. 0.3 ng/ml, P P P P = 0.006), higher proportion of obesity or overweight (24.6 % vs. 9.5 %, P = 0.002), higher frequency of GADA (33.7 % vs. 23.3 %, P = 0.025), and lower frequency of diabetic ketoacidosis at disease onset (64.5 % vs. 43.5 %, P Conclusions This population was characterized by poor overall blood glucose control, high prevalence of DKA, dyslipidemia and diabetic retinopathy, and low prevalence of islet-related antibodies, and overweight or obesity. Adult-onset patients with T1D were not uncommon and had better clinical manifestations than young-onset patients. Any findings related to body mass index (BMI) and autoantibodies should be considered strictly exploratory due to excessive missing data.

As an efficient approach to high-purity hydrogen, the sorption-enhanced steam reforming (SESR) is usually highly energy-intensive. Herein, the sorbent decarbonation was conducted in the presence of O2 to enable the exothermic reaction between CaO and cobalt oxides to form calcium cobaltate (CCO). By utilizing CCO as oxygen carrier (OC), the chemical looping methane combustion (CLMC) was employed prior to the SESR of glycerol (SESRG). The CCO was pre-reduced to generate a multi-functional material composed of metallic Co catalysts and CaO sorbent, which can significantly improve the H2 yield from SESRG. With a simple Pt-doped CCO acting as pre-catalyst, CO2 sorbent and OC, we realized 70% CH4 conversion and 96 vol.% H2 with 120% yield for 20 cycles. The promoting effects of Pt towards CH4 conversion and H2 production were rationalized by CH4-TPR, XPS, SEM and TEM. Our results demonstrate the feasibility of process integration and intensification enabled by multi-functional materials.

Background: Child and adolescent overweight is becoming more prevalent in recent decades. It is imperative to investigate the determinants of children and adolescents’ weight outcomes. Methods: Through analyzing the 2004, 2006, 2009 and 2011 waves of survey data released by China Health and Nutrition Survey (CHNS), this paper investigated the gender and rural-urban differences in terms of the ways in which parental feeding knowledge and practices affected the weight status of Chinese children and adolescents aged 6 to 17. Data were collected through random sampling strategy and logistic regression models were built to conduct analyses.Results: The results showed that feeding knowledge and practices varied by parental residence and were different among mothers and fathers. In addition, parental feeding knowledge, parental eating habits and styles, mother’s intervention on children’s food intakes and physical exercise, and the number of meals parents sharing with children showed significant effects on children and adolescents' weight status. Conclusions: As compared to fathers, mothers’ feeding practices showed more significant effects on children and adolescents’ weight status. The manner in which parental feeding practices influenced children and adolescents’ weight status also differed in rural and urban settings. These findings suggested that mothers were still “gatekeepers” of children and adolescents’ food choices and selection; their feeding practices played a more decisive role on Chinese youth’s weight status. The urban-rural differentials highlighted in this research also reminded us that the “one-fits-all” solutions to prevent youth’s obesity should be avoided.