查看更多>>摘要：Algae contains most of the marine biogenic S, and is the main producer of dimethylsulfide, of which oxidation products contribute - 40% acidity of the acid rain. The biogenic S of red algae mainly exists in carrageenan molecules. In this work, 89% of C and 96% of biogenic S in carrageenan was synchronically fixed into biochar to form thiophene S decorated biochar aerogel (SCA), efficiently preventing the loss of C and S elements. More importantly, the presence of thiophene S structure in SCA can "push" electrons into the antibonding orbitals of N2, and simultaneously "pull" the lone-pair electrons from N2, thus endowing the SCA super activity for nitrogen reduction reaction. Experimentally, its NH3 yield rate reaches high as 36.69 μg h~(-1) mg~(-1)_(cat), surpassing most metal-free electrocatalysts. Theoretical calculations demonstrate that the thiophene S can promote the absorption and activation of N2, and efficiently lower the energy barrier of N2 protonation.
查看更多>>摘要：This study focuses on improving photocatalytic CO2 reduction reaction (CRR) activity and modulating product selectivity. An In4SnS8/Cs3Bi2Br9-X (ISS/CBB-X) heterojunction is prepared using novel lead-free Cs3Bi2Br9 perovskite quantum dot-modified In4SnS8, which shows considerable potential as photocatalysts for CRRs under visible light. The optimised ISS/CBB photocatalyst exhibits high activity and CO selectivity with a CO yield and selectivity of 9.55 μmol g~(-1) h~(-1) and 92.9%, respectively, 3.8 and 1.5 times higher than those of pristine ISS, respectively. Moreover, the step-scheme (S-scheme) mechanism can be fully confirmed via in situ irradiated X-ray photoelectron spectroscopy, in situ electron spin resonance, femtosecond time-resolved absorption spectroscopy and density functional theory calculations. Based on in situ diffuse reflectance spectra and theoretical investigations, the ISS/CBB shows a decreased energy barrier towards CO2 reduction to CO through an adsorbed *COOH intermediate. This study contributes to the further understanding of fabricating efficient S-scheme-based photocatalysts for selective CRR.
查看更多>>摘要：Single-atom catalysts (SACs) have aroused extensive attention due to their ultrahigh activity and selectivity. However, precisely regulating and designing the coordination microenvironment of SACs to optimize the catalytic efficiency remains a great challenge. Here, a facile ionic liquid (IL) modification strategy is creatively proposed to obtain N and P dual-coordinated Fe single atoms with N unsaturated coordination on pre-designed Fe_(SAC)-'N4/C sites. The using a hydrophobic IL can alter the binding affinity of O2, maintain a higher O2 concentration at the catalyst interface, and protect Fe single atom sites from surface oxidation and methanol toxicity. Theoretical calculation indicates that this unique coordination and the N vacancy can tailor the electronic structure of the metal atoms and alter the charge distribution at the coordination structures, thus improving the oxygen reduction reaction performance. This study offers an effective approach for accurately controlling the coordination electronic structure and interface environment of SACs at room temperature.
查看更多>>摘要：In this work, smart strategies are conducted to design advanced multifunctional electrocatalysts: Co3S4/CoOx heterostructured nanosheets-assembled nanotube arrays on 3D framework integrated with single Rh atoms and subnanometer clusters. The catalyst can reach current density of 10 mA cm~(-2) at low overpotentials of 248.2, and 56.1 mV for oxygen evolution reaction, and hydrogen evolution reaction, respectively. The catalyst also shows very low potential of 1.32 V for urea oxidation reaction at 10 mA cm~(-2). A water electrolyzer that achieves current density of 10 mA cm~(-2) at small cell voltage of 1.45 V is prepared under action of the developed catalyst. We also conduct urea electrolysis assembled with the catalyst and find that the device requires a cell voltage of only 1.35 V to drive a current density of 10 mA cm~(-2), proving the great potential of our catalyst for simultaneous energy-saving H2 production and the treatment of urea-rich wastewater.
查看更多>>摘要：In-situ supply of H2 by aqueous phase reforming (APR) of methanol is promising but still challenging due to the unsatisfied activity and stability of catalyst. Herein, we prepared lanthanum nickel perovskite supporting Pt catalysts and evaluated their performance in methanol APR. A transformation from lanthanum nickel perovskite into LaCO3OH happened after APR. The characterizations results reveal that these two perovskite catalysts transformed into LaCO3OH supporting Pt and NiOx structure. We further prepared Pt-NiOx/LaCO3OH catalyst to verify it. Combining with temperature programmed surface reaction, a possible mechanism is proposed. The transformed catalyst possessed more metallic Pt sites and more abundant active OH groups, which are beneficial for methanol decomposition and CO shift, respectively. In addition, although the structure transformation happened for perovskite supporting Pt catalyst, it presented extremely excellent stability with only 7% loss of its highest rate of hydrogen production after 315 h on stream.
查看更多>>摘要：The XC-72R supported Pd catalysts exhibit low-temperature catalytic activity for CO oxidation under light irradiation. The CO conversion can reach 100% with the light irradiation of 900 mW · cm~(-2) at a catalyst temperature of 100 °C. Pd/C catalysts with different Pd loading have similar performance enhancement under light irradiation. The activation energy of 1% Pd/C catalyst remains unchanged implying that CO oxidation belongs to photothermal catalytic oxidation. The enhanced performance could be ascribed to ultrahigh surface temperature (275 °C) induced by the light irradiation of 800 mW · cm~(-2) and detected by an IR camera. That is higher than the catalyst temperature (187 °C) measured by the thermocouple. Carbon generates a higher temperature than Pd NP, causing heat transfers from carbon to Pd NP. In contrast, Pd NP produces a higher temperature than Al2O3 for Pd/Al2O3 catalyst, and heat is transferred from Pd to Al2O3. These demonstrate that the enhanced performance contributes to the photothermal effect of carbon.
查看更多>>摘要：The authors regret to misuse the data in Fig. 3c, d and Fig. 4f. The mass spectra data presented in Fig. 3c, d and the electron paramagnetic resonance test data presented in Fig. 4f are incorrect. Due to the confusion of the sample test sequence, one of the authors unintentionally misused the data for other samples. We apologize for making this mistake and it should be corrected as follows.
查看更多>>摘要：This study reports that freshly formed manganese dioxide (MnO2 is an effective photocatalyst for the abatement of micropollutants, such as nalidixic acid (NDA) and gemfibrozil (GFRZ). The freshly formed MnO2 was flower-like β-MnO2 and showed better efficiency in micropollutant abatement owing to its better adsorption capability than commercial MnO2. Electron paramagnetic resonance (EPR) spectra confirmed that reactive oxygen species (ROS), including hydroxyl radicals (HO·), superoxide radicals (O2~(·-)) and singlet oxygen (~1O2), were formed in the UV/MnO2 system. Valence band X-ray photoelectron spectroscopy (VB-XPS) spectra and UV-vis adsorption curves verified the generation of ROS via the reaction between e~- and oxygen as the sole pathway. Holes (h~+) dominated the degradation of NDA, while both ROS and h~+ were important for GFRZ abatement. Side chain cleavage, kentonization and hydroxylation took place in NDA and GFRZ degradation, while demethylation and decarboxylation also occurred during NDA degradation.
查看更多>>摘要：Antibiotics and heavy metal contaminants often coexist in wastewater but their simultaneous/synergistic removal remains a great challenge. Herein, a synergistic effect on the photocatalytic removal of antibiotics and hexavalent chromium (Cr (VI)) is realized using ultra-thin g-C3N4. The mechanism of synergistic effect is studied deeply at molecular level through experiments and theoretical calculation. Antibiotics molecules are first adsorbed on the surface of g-C3N4 by π-π interactions, and subsequently act as electron donors (hole sacrificial agents) to accelerate the separation of photo-generated electron-hole pairs and allow more electrons/holes to participate in the redox reaction. Another crucial finding is that there is a linear relationship between the electron-donating capacity and the synergistic efficiency. Detailly, the contaminant molecules with greater electron-donating capacity are more favorable to the improvement of synergistic efficiency. Our work systematically analyzes the mechanism of synergistic effect on contaminants removal and proposes reasonable methods to enhance the synergistic efficiency.
查看更多>>摘要：Exploring advanced non-noble metal-based catalysts for H2 release from chemical hydrogen storage materials is of paramount importance to boost hydrogen economy. Rationally tailoring over architecture and electronic state promises high-efficiency catalysis. Herein we present, for the first time, delicate engineer of cobalt phosphide with a unique porous, multishelled, and hollow architecture (multishelled Co-P) for dramatically promoting ammonia borane (AB) dehydrogenation. Featuring hollow porous structure and complex nanoconfined interior space, multishelled Co-P possesses abundant accessible active sites and facile mass transfer. Importantly, theoretical calculations decipher that P incorporation in Co-P can modulate electronic structure of Co sites to give promoted H2O adsorption and favorable H2O dissociation kinetics (rate-determining step), thereby facilitating AB dehydrogenation. This study provides a fundamental understanding of correlation between electronic state of Co-P and AB dehydrogenation behavior, and highlights that decent architectural engineering coupled with electronic modulation is an effective protocol to construct advanced catalytic systems.
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