查看更多>>摘要：Developing a high-performance photocatalyst with an efficient charge transfer pathway and reasonable active sites for photocatalytic NO removal is a formidable challenge. Herein, a novel Z-scheme molecular cobalt phthalocyanine(CoPc)/Bi2WO6 photothermal-assisted photocatalyst was elaborately designed. The interfacial Co-O-W bond and built-in electric field(BIEF) between Bi2WO6 and CoPc promote a cascade Z-scheme charge transfer system from Bi2WO6 to CoPc, thereby facilitating the charge separation and retaining high redox potential. Meanwhile, the Co-N4(II) sites of CoPc can capture more photoexcited electrons migrating from Z-scheme of the CoPc/Bi2WO6 composite, which facilitates the electron transfer to O2 for the generation of ·O2~-. Moreover, the photothermal effect of CoPc can further improve the O2 activation efficiency. Consequently, the obtained photocatalysts exhibit superior photocatalytic activity for NO removal (74.9%) and lower generation of toxic NO2 (<6 ppb) by-products compared with pristine Bi2WO6. This work offers a new idea for constructing high-efficiency NO photo-oxidation systems.
查看更多>>摘要：Artificial photosynthesis offers a promising strategy for converting solar energy into environmental-friendly H2O2. Herein, robust photocatalytic H2O2 production through dioxygen reduction is achieved, reaching a high H2O2 yield of 873 μmol L~(-1) h~(-1). The photocatalyst was prepared by in-situ chemical vapor deposition of N, S co-doped graphene on TiO2 nanofibers. Thanks to the intimate interface with large area and Schottky junction, the H2O2 yield of the composite can be increased by eight times than that of pristine TiO2- Experimental results and density functional theory calculations clarify that the strong synergistic effect between the doped N and S atoms provides abundant active sites to facilitate the electron transfer, promote the adsorption of O2 molecules, and restrain the decomposition of formed H2O2 by suppressing H2O2 adsorption. This work not only provides a novel approach to build close contact between photocatalyst and co-catalyst, but also develops a highly efficient photocatalyst for H2O2 production.
查看更多>>摘要：In this study, the integrated core-double-shell structures of C@MnO@TiO2 (abbreviation CMT) composites have been rationally designed and fabricated utilizing of carbon spheres as frameworks and reducing agents, which were introduced a TiO2 outer shell on MnO2 @C nanospheres by sol-gel coating and subsequent in-situ calcination reduction process. Owing to the well-defined structures, the as-prepared CMT composites can efficiently convert full-light into heat energy, achieve the rapid adsorption and enrichment of toluene and motivate the synergistic effects of photocatalysis of TiO2 and full-light driven thermalcatalysis of MnOx @C, resulting in the significantly enhanced photothermal catalytic performance of toluene oxidation upon UV-Vis TR irradiation of Xe lamp. Furthermore, the strategy on changing the molar ratio of Mn/Ti among CMT composites can not only act as important role in the control of the coating thickness of outer layer TiO2, surface morphologies and physicochemical properties within a certain range, but also yield opportunities to adjust photothermal synergistic effects between ternary components among CMT composites. Compared with other CMT composites, CMT-3 samples with a suitable Mn/Ti molar ratio of 0.4 exhibited much higher photothermal catalytic activity including a high toluene removal efficiency and CO2 production rate (99.1 % within 90 min and 102.5 μmol.g~(-1).min~(-1), respectively), which were attributed to its optimized coating thickness of outer layer TiO2, and the optimal distribution ratio of surface oxygen species (O_(ads)/O_(latt)/O_(wat)) and electronic valence of Mn species (Mn~(2+)/Mn~(3+)/Mn~(4+)). The possible mechanism for photothermal catalytic oxidation of toluene over CMT composites was also discussed in terms of the special core-double-shell structure, matching electronic band levels and photothermal synergistic effects.
查看更多>>摘要：Selective hydrodeoxygenation (HDO) of 5-hydroxymethylfurfural to 2,5-dimethylfuran is of great importance. We reveal a simple pathway for green and efficient HDO using readily available copper with in-situ hydrogen generation. A highly dispersed Cu/PBSAC catalyst consisting of small metallic Cu nanoparticles carries out isopropyl alcohol (IPA) dehydrogenation and subsequent HDO of HMF. Density functional theory calculations reveal that the dehydrogenation of IPA is more favorable on Cu(211) with a lower energy barrier of-0.6 eV. This facet exists in a higher ratio on nanosized catalysts. Batch reactions using Cu/PBSAC at 190 °C exhibited 91.9% HMF conversion and 71.7% DMF selectivity in 6 hr, and > 96% DMF yield in 10 hr. The mechanical strength of the carbon support is ideal for continuous processing for increased productivity; we demonstrate a > 90% DMF yield at 1/WHSV of 2.4 hr. The process demonstrated here can be integrated with upstream HMF separation utilizing carbon adsorbents.
查看更多>>摘要：We present the design and synthesis of a new covalent triazine framework with high content of N atoms bearing triazine and phenanthroline moieties. This material displays interesting luminescence phenomena and enhanced photoredox activity as a consequence of synergistic combination of both N-containing aromatic fragments. As catalytic application, the reduction of a variety of brominated and challenging chlorinated aromatic structures, including persistent organic pollutants such as polybrominated diphenyl ethers, has been performed under light irradiation and room temperature conditions. These chemical transformations follow a photoredox mechanism involving the formation of aryl radicals, that were trapped with different radical acceptors in order to afford the formation of new C-C, C-B and C-P bonds.
查看更多>>摘要：We achieved efficient hot hole collection via interfacing plasmonic CuS nanoplatelets with a suitable p-type semiconductor for the first time. The approach we applied was to rationally select a semiconductor (herein, BiOCl) such that it has a suitable band structure to prevent the hole loss from CuS in the dark, while allowing the hot hole injection from the plasmon-excited CuS under illumination. The resultant, efficient hot hole injection was then verified by our systematic measurements along with theoretical modelling. We showed that the transversal mode dominates the hot hole generation and has a greater contribution to photocatalysis than the longitudinal mode. We then elaborated on an optimal CuS/BiOCl composite configuration allowing for efficient hot hole collection in near-infrared photocatalysis. This work demonstrates the feasibility of harvesting hot holes from plasmonic semiconductors and opens a new route for the rational design of broadband and cost-effective plasmonic photocatalysts.
查看更多>>摘要：In this work, a Z-scheme Bi2S3-Bi2WO6 (BS-BWO) heterojunction with interfacial Bi-S bonds was constructed by in-situ growing B12S3 nannrods on Bi2WO6 nanosheets. The obtained BS-BWO heterojunction exhibited significantly enhanced piezocatalytic performance on carbamazepine (CBZ) degradation with an apparent rate constant of 0.087 min~(-1). Density functional theory (DFT) calculations together with experimental characterizations illustrated that the boosted piezocatalytic performance of BS-BWO could be ascribed to the Z-scheme charge transfer through the formed Bi-S bonds, which increased the charge transfer/separation efficiency and maintained the strong redox ability of photogenerated electrons/holes. Moreover, the increased piezoelectric potential of BS-BWO, as supported by COMSOL simulation, also contributed to the enhanced piezocatalytic performance. This study sheds light on the design and development of promising piezocatalysts for environmental remediation.
查看更多>>摘要：This work aimed at exploring the effect of optimal overpotential discrepancy between two-electron oxygen reduction reaction (OP_(2eORR)) and metal reduction reaction (OP_(MRR)) of the cathode on electro-Fenton (EF) system performance, and proposing strategy to eliminate overpotential discrepancy. Therefore, series of vanadium-doped chitosan carbon aerogel (xCCA-V) cathodes were fabricated by controlling graphitization degree. With carbonized temperature of 900 °C, the OP_(2eORR) of the 900CCA-V was -0.5 V vs. SCE, the same with the OP for vanadium reduction reaction (OP_(VRR)). This identical OP of the 900CCA-V endowed excellent EF performance, with ciprofloxacin removal of 98.1%, and TOC removal significantly increased by 41.8% compared with Ferrum-doped CCA (900CCA-Fe). Density functional theory calculation revealed efficient active sites for H2O2 adsorption on the 900CCA-V surface. Degradation pathways of ciprofloxacin and intermediates toxicity were determined. This work provides inspiration for developing strategy for overpotential regulation and design novel and efficient cathodes for enhancing EF performance.
查看更多>>摘要：Designing low-cost, high-efficiency hydrogen evolution reaction (HER) catalysts to break the bottleneck of current electrocatalytic water splitting processes remains a formidable challenge. Here, we report a strong metal-support interaction (SMSI) effect constructed with ruthenium nanorods (Ru NRs) loaded in porous titanium nitride (TiN) nanosheet assembled hollow tube (labeled as Ru NRs/TiN). Ru NRs/TiN exhibits outstanding HER performance in 1.0 M KOH solution, requiring an overpotential of only 25 mV to achieve a current density of 10 mA cm~(-2), and demonstrates ultra-high mass activity (20 times than that of Pt/C) and superior turnover frequency values with respect to most Ru-based catalysts. Density functional theory calculations show that the SMSI can induce a notable charge redistribution at the Ru-TiN interface and enhance the HER activity of the catalyst. Moreover, the catalyst exhibits excellent stability (10,000 cycles without decay) due to the SMSI effect between the Ru species and the TiN support. Our work has broadened the range of support options for Ru-based catalysts for HER, and provided new insights into the SMSI engineering.
查看更多>>摘要：Although various alloys have been extensively explored to enhance catalyst activity and stability in oxygen reduction, degradation of performance due to long-term operation has plagued the crowd. Here, we develop a catalyst synthesis strategy based on the coexistence of monoatomic Fe and Pt-based clusters/alloys on NC/TiOx. Fe/PtCo-NC/TiOx exhibits a half-wave potential of 0.948 V and mass activity of 3.69 A mg_(Pt)~(-1) at 0.9 V, the latter being approximately 32.1 times higher than that of 20% Pt/C (0.115 A mg_(Pt)~(-1)). Additionally, it also shows maximum power densities of 952.2 mW cm~(-2) and 215.8 mW cm~(-2) in the H2/O2 fuel cell and Zn-air battery, respectively. The combination of illumination and calcination promotes the electron transfer between Pt and TiOx, thus enhancing the catalytic activity and stability. We also explore the approach and mechanism of using illumination to suppress catalyst performance degradation. The intermittent irradiation inhibits the dissolution of Pt to facilitate the Fe/PtCo-NC/TiOx durability beyond that of most reported metal catalysts, with a half-wave potential degradation of only 14 mV after 30,000 cycles. The ingenious use of illumination provides a simple and feasible strategy for the sustainable utilization of catalysts.
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