查看更多>>摘要：Constructing polymer heterojunction (PHJ) has emerged as an alternative to pursue excellent photocatalytic sterilization and contaminant degradation performance. Herein, the antibacterial carbazole unit is employed as the side chain of benzodithiophene. Besides, the main chain copolymerization strategy is adopted to tune the light absorption and exciton dissociation of these 2D donor-acceptor (D-A) conjugated polymer/g-C3N4 PHJ by introducing different A units. Specifically, copolymerizing diketopyrrolopyrrole into P-4 drastically bathochromic-shifts the light absorption of the PHJ. By contrast, introducing fluorinated benzotriazole into P9 contributes to achieve the most efficient charge separation. Surprisingly, the P7/g-C3N4 with benzodithiophene4,8-dione as the A unit reaches the balance between light absorption, charge separation efficiency, and water wettability. Consequently, the P7/g-C3N4 shows the highest photocatalytic activity with over 99.7% antibacterial rates for E. coli and S. aureus and 97.6% degradation rate for Rhodamine B under irradiation for 45 and 90 min, respectively.
查看更多>>摘要：Red phosphorus (RP) has recently attracted much attention in photocatalysis for its low cost, environmental benign and optical properties. However, its photocatalytic activity is still restricted since the low-charge carrier mobility and the high water-solubility. Herein, RP-S-12 h (Combination of RP nanosheet (NS) and bulk RP structure) was prepared by hydrothermal method. Results showed that the multiple reactive active sites, the energy level matching, the emergence of intermediate state and the internal unequal potential for RP-S-12 h ensured higher charge density and efficient carrier transport, improving the photocatalytic activity and stability, emphasizing the role of multiple interfacial effects. The optimum hydrogen evolution rate was 0.33 mmol g-1 h-1, and the quantum efficiency at 420 nm is 0.45%. In addition, RP-S-12 h could completely degrade 50 ppm MO in 12 min. This study provides a novel insight into the interface design of metal-free photocatalyst for environmental remediation.
查看更多>>摘要：Rational control of the compositions, morphologies and sizes of electrocatalyst are the key factors for achieving high performance of electrocatalytic reactions. Herein, a newly ultrathin PtRuRhCoNi high-entropy alloy nanowires (HEA-NWs) (~1.6 nm) catalyst is designed. The PtRuRhCoNi NWs/C achieved high mass activity of 7.68 A mg(PtRuRh)(-1), ultrahigh C1 selectivity of 78% for ethanol oxidation reaction. For hydrogen evolution reaction, the PtRuRhCoNi NWs/C also reached high mass activity, turnover frequency (11.99 A mg(PtRuRh)(-1), 31.9 s(-1), 0.5 M H2SO4 and 8.07 A mg(PtRuRh)(-1), 26.7 s(-1), 1 M KOH at -0.05 V vs. RHE) and stability. Theoretical calculations demonstrated that the excellent electroactivity of HEA is benefited by the self-complementary effect through strong orbital coupling, which maximized the electroactivity towards both oxidation and reduction and preferred binding of key intermediate. The design of pH-universal multifunctional catalyst by rational control of the compositions, morphologies and sizes strategy can facilitate the research of advanced catalysts.
查看更多>>摘要：NOx and VOCs are primary air pollutants and their photochemical reactions would generate secondary pollutants like O-3 with NO2 intermediate as the direct precursor. Here we apply a highly efficient In(OH)(3) photocatalyst to degrade mixed NO and C7H8 for inhibition of photochemical O-3 generation. The dual pollutants show synergistic interaction from the adsorption process to photocatalytic reaction. C7H8 and NO exhibit non-competitive adsorption and coupling reaction effects on In(OH)(3) surface. The coupling intermediate C7H7NOH would be oxidized to nitrotoluene and further decomposed into CO2 and nitrates. Meanwhile, the protons and electrons released during the oxidation of C7H8 can reduce NO to NH4+. Gibbs free energy calculation reveals that the coupling and reduction reactions are more favorable than the oxidation of NO to NO2. The new conversion path of NO on In(OH)(3) when C7H8 coexists could enable an increase of NO conversion efficiency to 100.0% and a decrease of NO2 selectivity to only 3.7%, thus highly inhibiting the formation of O-3.
Yu, Jimmy C.Wu, ChunxiaoZhu, RuixueTeoh, Wey Yang...
9页
查看更多>>摘要：We demonstrate a carefully tailored elemental red phosphorus (red P) for a record-high photocatalytic hydrogen evolution rate of 1280 mu mol g(-1 )h(-1). This performance has even surpassed some of the established compound photocatalysts. Systematic studies reveal that the bismuth-catalyzed selective growth of the preferential crystal phases of red P leads to the formation of fibrous and Hittorf's phases at distinctive sites within the same pho-tocatalyst particle of dendritic morphology: nanobranches of fibrous phase and main stems of Hittorf's phase. As each crystal phase possesses unique band energy potential, the intimate heterojunction between the two phases affords an effective built-in driving force for the efficient transportation of photoexcited charge carriers with suppressed charge trapping and recombination. The strategy in crystal phase engineering of red P as well as the understanding of its charge transportation properties in this work provides new insights into developing favorable elemental P-based materials for various photocatalytic applications.
查看更多>>摘要：Exploring excellent catalysts for oxygen reduction reaction (ORR) with a facile and cost-effective method is desirable but remains challenging. Herein, ultra-small PtCu3 nanoparticles (ca. 2.7 nm), immobilized on reduced graphene oxide (rGO), were synthesized via a novel and general strategy. Traceless protectant, NH4OH, was used to resist the aggregation of graphene oxide (GO), and the spray-freeze-drying method ensures excellent dispersion of the Pt and Cu precursors, which could not be achieved by other reported drying methods. After annealing, the nanoparticles with the highest mass loading, 52%, among reported ordered Pt-based catalysts were obtained. The PtCu3/rGO shows a remarkable electrocatalytic performance. Density functional theory calculations elucidate that PtCu3 possess a lowered energy barrier of the rate-determining step, contributing to significantly improved ORR kinetics. This strategy was extended to the synthesis of other binary- and quaternarymetallic Pt-based nanoparticles, which proved its generality and applicability towards the potential commercialization of fuel cell technologies.
查看更多>>摘要：The infeasible cost of PEMFCs can be effectively lowered by replacing Pt-based catalysts with PGM-free catalysts. Although promising advancements have been achieved recently, the practical availability of PGM-free catalysts in PEMFCs remains apprehensive, typically, owing to their low output power density. Herein, a huge breakthrough has been made for high power density PGM-free PEMFCs with a peak power density of 1.36 W cm-2 in H-2-O-2 and 0.65 W cm-2 in H2-air PEMFCs. Moreover, after iR-corrected, it delivers an affirmative current density of 62 mA cm-2 at 0.9 V in H-2-O-2 fuel cells, a breakthrough on the US Department of Energy 2025 target for PGM-free catalysts. The tremendous progress can be attributed to the rearrangement of active sites by recrystallization which significantly increases the active site density and mesoporosity of the Fe/N/C catalyst. Consequently, it cost-effectively enhances the catalytic activity and boosts its power density output.
查看更多>>摘要：Lead-free double perovskites with superior stability have been considered as promising non-toxic substitutes to their lead-contained counterparts in photocatalysis. However, the severe charge recombination greatly restricts their potential as high-performance photocatalysts. Herein, for the first time, we present a self-assembled het-erostructure of lead-free double perovskite Cs2AgBiBr6 nanocrystals (NCs) on the surface of MXene nanosheets via mutual electrostatic attraction. The presence of MXene nanosheets effectively promotes the formation of free charge carriers inCs(2)AgBiBr(6 ) NCs via reducing the exciton binding energy. Additionally, the ultrafast photo-generated electron transfer from Cs(2)AgBiBr(6 )to MXene with a timescale of 1.1 ps largely prolongs the charge carrier lifetime by two times. As a result of the efficient charge separation and electron extraction, the Cs2Ag-BiBr6/MXene heterostructures achieve a high photoelectron consumption yield of 50.6 mu mol g(-1 )h(-1) for pho-tocatalytic CO2 reduction, which surpasses most previously reported lead-free perovskite-based catalysts.
查看更多>>摘要：The sluggish oxygen evolution reaction (OER) limits the efficiency of overall water splitting, which thereby hinders hydrogen evolution reaction (HER). Here, we demonstrate a bifunctional CoNiP nanosheet integrated electrode (CoNiP-NIE) to boost HER and replace OER by 5-hydroxymethylfurfural oxidation reaction (HMFOR) to obtain high-valued 2,5-furandicarboxylic acid (FDCA). The as-developed CoNiP-NIE exhibits a constant high Faradaic efficiency more than 82% for HMFOR in a wide potential from 1.40 V to 1.70 V vs. RHE, which stand at the top level among the reported electrocatalysts. Moreover, the low overpotential for HER further indicates its high efficiency in the H2 generation. Based on the bifunctional activity of CoNiP, an electrochemical hydrogen evolution coupled with biomass oxidation device is constructed, which delivers lower voltage (1.46 V) for anode oxidation and higher evolution rate of H-2 (41.2 L h(-1) m(-2)) than water splitting (1.76 V, 16.1 L h(-1) m(-2)).
查看更多>>摘要：Hydrodesulfurization is well established in the industry while costly and environmentally unfriendly due to CO2 emissions and H2S production. An alternative, cost-effective desulfurization process remains unreported. Here, we demonstrate a desulfurization process for dibenzothiophene, one of the most well-known and recalcitrant sulfur-containing model compounds against catalytic desulfurization, under the regulation of methane instead of hydrogen over a combination of two catalysts, generating a new sulfur-containing product, CS2, as an important intermediate in organic chemistry and non-polar solvent with lower environmental impact than H2S. A catalytic mechanism is proposed and supported by extensive experimental and computational evidence. It is discovered that methane acts as a critical initiator and intensifies the direct desulfurization pathway, where two catalysts must work cooperatively and a surface sulfur transfer process is indispensable. This study explores an alternative desulfurization route with unique reaction pathways towards CS2 formation, whose practical potential is also supported by the desulfurization performance over a series of real-world crude samples.
NSTL
Elsevier