查看更多>>摘要：A dual function material (DFM) comprised of 1% Ru, 10% Na2O/gamma -Al(2)O(3)was studied for combined direct air capture (DAC) of CO2 and catalytic methanation in a temperature swing operation. In the newly proposed operation, the DFM captures CO2 (400 ppm) from air at ambient conditions. The material is then heated in H-2 to a temperature sufficient for catalytic conversion of the captured CO2 to renewable natural gas. In this study, we demonstrate high CO2 adsorption capacity and rates at ambient conditions (25 ?); the adsorbed CO2 is then successfully catalytically methanated upon heating in H-2. Adsorption was also carried out in humid conditions, more closely simulating ambient air. Adsorption and methane production were greatly improved with stable initial performance. The rate of adsorption is shown to be flowrate-dependent, which is critical for future reactor design.
查看更多>>摘要：Formate synthesis by CO2 electroreduction reaction (CO2RR) has been considered as a promising strategy for mitigating the excessive CO2. Here, we synthesize Cu6Sn5 alloy on Sn foil (Cu6Sn5/Sn) and gas diffusion electrode (GDE) using laser irradiation. Cu6Sn5/Sn exhibits high formate faradaic efficiency (FEformate) of 87.2% and remains stable at 28.69 mA cm(-2) over 14 h. Further, with the help of laser drilling, the channeled Cu6Sn5/Sn used directly as GDE shows increased current density (118 mA cm(-2)) and steady FEformate (86.69%) in flow cell. Density functional theory (DFT) calculations reveal that the high performance of Cu6Sn5/Sn benefits from the appropriate binding energy of the key intermediates *OCHO. Meanwhile, COMSOL simulation results of CO2 concentration and electric field distribution combined with the results of kelvin probe force microscopy (KPFM) prove that CO2RR prefers to occur around the channels of electrode. More importantly, this laser irradiation method is also available to synthesize other alloy electrocatalysts.
查看更多>>摘要：Herein, we designed and constructed an ultrathin porous phosphorus-doped g-C3N4 nanosheet (PCN) bifunctional photocatalytic system for efficient production of H2O2 and degradation of non-steroidal anti-inflammatory drugs in aqueous environment. The phosphorus atoms introduced in g-C3N4 significantly improved the utilization of light, enhanced the adsorption capacity for O-2, and inhibited the recombination of photogenerated carriers, thereby boosting the photocatalytic performance. Consequently, the optimized PCN photocatalyst produced 285.34 mu M of H2O2 under blue LED light irradiation, which was 3.41 times that of pristine g-C3N4, and its degradation rate constant for diclofenac (0.1248 min(-1)) was 46.22 times that of the g-C3N4. Density functional theory (DFT) calculations suggested that phosphorus doping modulated the local electronic structure of gC(3)N(4), which improved the electron-hole separation and promoted the O-2 reduction reaction. This work comprehensively reveals the mechanisms of phosphorus doping on g-C3N4, while offering a promising strategy for addressing current energy demands and environmental remediation concerns.
查看更多>>摘要：Designing rational nanostructure to promote the oxygen reduction reaction (ORR) catalytic activity of microbial fuel cells (MFCs) is desirable but still remains a huge challenge. In this work, an elaborately designed strategy is proposed to deposit layered double hydroxides (LDHs) on the surface of ZIF-67 grown along nanofibers, thereby obtaining nanoflower-branch composites (CoNi-LDH@CNFs) with a rich cavity structure supported by electro-spinning nanofibers. During the pyrolysis process, the variable cobalt in ZIFs is captured by LDHs nanosheets to generate CoNi alloy. As expected, CoNi-LDH@CNFs exhibits brilliant ORR catalytic activity. The as-prepared catalyst is an outstanding cathode in MFC, with a maximum power density of 1390.37 mW/m(2), superior to Pt/C corresponding MFC (843.67 mW/m(2)). Impressively, the nanofiber-derived catalyst exhibits long-term durability in single-chamber MFCs. This work provides a new perspective for the combination of LDHs and nanofiber-derived materials, and gives promising performance in realistic MFCs applications.
查看更多>>摘要：Selective hydrogenation of aromatic ring represents an essential process for the valorization of lignin in the chemical industry but achieving this process at low temperature is still a challenge. Herein, a series of Ru-based catalysts were investigated. It is found that Ru/gamma-Al2O3 with small Ru metal particle size shows the low activity in this system. A unique and strong metal-support interaction for Ru/gamma-Al2O3 indicates that the strongly bounded Ru-O-Al sites lead to the positive charge of Ru species. In contrast, Ru/alpha-Al2O3 with well-dispersed Ru nano particles supported on alpha-Al2O3 can successfully catalyze the selective hydrogenation of lignin-derived aromatic compounds at room temperature. Ru/alpha-Al2O3 has the excellent recyclability, air stability and the highest activity. The selective hydrogenation of aromatic ring for Ru/alpha-Al2O3 results from the fast dissociation of H-2 and the high adsorption energy of aromatic ring as revealed by X-ray absorption spectra, X-ray photoelectron spectroscopy and density functional theory calculations.
查看更多>>摘要：Sustainable technologies and efficient process design in chemical synthesis are in great demand for achieving a low-carbon society. Here, a sustainable approach for producing aromatics is designed via a biomass-derived carbon-negative route. A target aromatic yield of up to 50% was achieved using an industrial aqueous oxygenate mixture as the feedstocks. Such high performance is ascribed to the Zn modified ZSM-5 zeolites, which were proved to introduce synergistic catalysis involving Lewis acid sites and Bronsted acid sites, and were essential to aromatize these oxygenates efficiently. This approach provides a promising route for converting biomass-derived complex mixtures to valuable chemicals toward the carbon-neutral goal.
查看更多>>摘要：The regulation and stabilization of the oxidation state to promote the conversion of CO2 to C2 fuel still faces many challenges. Based on the principle of charge balance, we creatively propose a co-doping strategy to adjust the surface oxidation state distribution of metallic catalysts. A TiO-based photocatalyst co-doped with Zn and N was synthesized by ammonia assisted one-step calcination method, named ZN-TC. XPS characterization shows that Zn and N adjust the valence states of adjacent Ti elements respectively, so that the surface of TiO maintains a relatively stable Ti3+/Ti2+ ratio. Under visible light irradiation, the material can catalyze CO2 into CO (324.11 mu mol.g(-1).h(-1)) and C2H6 (10.27 mu mol.g(-1).h(-1)) in the liquid phase. The selectivity of C2H6 reached 14.45%. When irradiated with near-infrared light, ZN-TC shows 100% CO selectivity because the photon energy is not enough to support the catalytic hydrogenation of CO2. Theoretical calculations and experiments proved that Zn and N elements mainly act on the B-1 band to regulate the Ti valence state. In-situ DRIFTS and in-situ Raman tests confirmed the function of oxidation state adjustment to promote the C-C coupling on the catalyst surface to produce ethoxy groups, which ultimately led to the production of C2H6.
查看更多>>摘要：Photoreforming of plastic waste is a novel approach, which can not only degrade plastic waste into valuable chemicals, but also produce high-energy-density hydrogen fuels. Here, we developed an in-situ derived carbon nitride-carbon nanotubes-NiMo hybrids via NiMo-assisted catalysis route, which works as an efficient and stable photocatalyst for plastics photoreforming. The strong pi-pi interaction between in-situ derived CNTs and CN promotes electron transfer, increases carrier lifetime and improves photocatalytic activity. The DFT calculations and single-particle PL quenching phenomenon confirmed the strong interface effect and charge transport for CN-CNTs-NM. In addition, the strong interaction between photocatalyst and ethylene glycol in plastics was observed in situ by single-particle PL. This work provides a smart strategy of utilizing in-situ derived pi-pi interaction as well as direct evidence of the charge transfer from the photocatalysts to ethylene glycol, which provides guidance for the rational design of highly efficient photocatalysts for plastics photoreforming.
查看更多>>摘要：Molecular engineering in donor-acceptor conjugated polymers is currently one of the most successful and popular strategy to prepare high performance photocatalysts for hydrogen evolution. In this contribution, we have designed and synthesized two novel conjugated polymers with tailored donor-acceptor structures based on dibenzothiophene-S,S-dioxide and thiophene derivatives, which exhibited tunable band gaps and adjustable charge separation efficiencies. As a result, PDBTSO-T showed an outstanding hydrogen evolution rate (HER) of 1.47 mmol h(-1) by DMF exfoliation under UV-vis region with Pt cocatalyst in ascorbic acid aqueous solution at 10 mg level, which is among the top performance for photocatalysis conversion reported so far. Very excitingly, when the photocatalysis tests were subjected to natural sunlight irradiation, an impressive HER of ~27 mL (107 mmol g(-1) h(-1)) was achieved after 0.5 h of illumination (12:30 pm - 13:00 pm) on a consistently sunny day under identical reaction conditions.
查看更多>>摘要：Zn-CO2 batteries hold great promise for carbon-neutral and electricity generation simultaneously, whereas the main obstacle is the development of electrocatalysts with high activity and durability towards CO(2 )reduction reaction (CRR). Herein, we design atomically dispersed Bi clusters supported on hollow carbon spheres (BiC/ HCS) for effectively reducing CO2 to formate, which shows the highest faradaic efficiency of 97 & PLUSMN; 2% at -0.6 V vs RHE, being comparable to the previously best reported values of Bi-based materials. Experimental and theoretical analyses reveal that the atomic-level Bi-x clusters not only enable high CO2 adsorption but also stabilize the key *HCOO intermediate with a low free energy barrier. Further, an assembled rechargeable Zn-CO2 battery with BiC/HCS as the cathode achieves a peak power density of 7.2 & PLUSMN; 0.5 mW cm(-2) as well as an impressive rechargeability of 200 cycles. This work provides a promising alternative for CO2 utilization and energy storage by Zn-CO(2 )batteries. Graphical Abstract Bi clusters anchored on hollow carbon spheres have developed as an excellent cathode for Zn-CO2 battery. The catalyst presents a maximal formate faradaic efficiency of 97 & PLUSMN; 2% at -0.6 V vs RHE as well as good durability. The assembled Zn-CO2 battery achieves a peak power density of 7.2 & PLUSMN; 0.5 mW cm(-2 )and energy efficiency of 68.9% (@ 3 mA cm(-2)), and a more than 200 cycle rechargeability.
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