查看更多>>摘要：Glucose isomerization into fructose is a key process in industry for biomass valorization to produce value-added biofuels and biochemicals. Herein, considering the essential role of Lewis acid-base sites in proton transfer during glucose isomerization and hydrogen evolution process, a bifunctional polymeric red carbon nitride (PRCN) is rationally designed and fabricated by the salt-template-induced carbon incorporation strategy. The incorporation of carbon and potassium in the PRCN leads to the transient redistribution of photogenerated charges, acting as the electron-enriched Lewis base site and acid site for the deprotonation of O2-H and activation of aldehyde group of glucose, respectively. Besides, the interfacial Schottky junction boosts H2 production under visible light irradiation. This work demonstrates the feasibility of biomass photorefinery with H2 and value-added chemicals co-production under mild condition.
查看更多>>摘要：To effectively utilize glycerol as a fuel for electrochemical fuel cells, it is necessary to optimize catalysts for effective C-C bond cleavage and complete oxidation of reaction intermediates to achieve maximum efficiency. The current work showed that the synergistic interactions of platinum (Pt) with transition metal carbide (TMC) substrates, such as tungsten carbide (WC) and tantalum carbide (TaC), fulfilled these criteria. The TMC-supported Pt catalysts showed higher activity and selectivity for complete glycerol oxidation than commercial 10 wt% Pt/C. In-situ FTIR analysis revealed that 5 wt% Pt/WC was the most effective catalyst among those tested for complete glycerol oxidation at 0.9 V vs RHE. In-situ X-ray absorption fine structure characterization and density functional theory calculations provided additional insight into the synergistic interactions for glycerol oxidation over Pt/TMC catalysts.
查看更多>>摘要：Industrial water electrolysis requires highly-active and ampere-current-bearing oxygen evolution reaction (OER) catalysts, but achieving such a large operating current density at low overpotentials in available OER catalysts still remains a grand challenge. Herein, we present a new type of high-valence metal modified selenospinels (Mn-CuCo2Se4) as large-current-density OER catalysts. The optimal Mn-CuCo2Se4 exhibits prominent OER activity with overpotentials of 293 and 345 mV to achieve 500 and 1000 mA cm~(-2), respectively, and displays large mass activity, high turnover frequency and robust stability in alkaline media. Using in situ X-ray absorption spectroscopies, we observe that a surface active layer of oxyhydroxide-like phase with contracted Co-Co distance was evolved during the OER, which is responsible for the highly-active large-current-density activity. This work may open a new arena for the screening of large-current-density OER catalysts based on the wide variety of spinels compounds.
查看更多>>摘要：Electrocatalytic nitrogen reduction reaction (NRR) is an appealing strategy for green ammonia synthesis. Despite tremendous efforts, current NRR performances of most catalysis systems remain far below the targets for practical applications. Herein, a highly active and selective NRR catalysis system is reported by using an Rh single-atom catalyst in water-in-salt electrolytes (WISE). The developed single-atomic Rh on MnO2 (Rh1/MnO2) catalyst in 9 m K2SO4 presents a superior NH3 yield of 271.8 μg h~(-1) mg~(-1) and Faradaic efficiency of 73.3%, far exceeding that in dilute electrolyte and representing one of the best NRR performances on record. Multiple operando XAS, in situ FTIR/Raman spectroscopic characterizations together with the theoretical calculations unravel that WISE enables Rh1/MnO2 to exhibit suppressed H2 evolution, increased N2 enrichment on catalyst surface, and enhanced N2 activation/hydrogenation on active Rh sites.
查看更多>>摘要：Herein, we developed a novel hydrated electron induced approach by simply adding alcohols (0.2 %～0.5 %) as catalysts to enhance the decomposition of perfluorooctanoic acid (PFOA). Different from previous studies, in which high concentration of hydrated electron source materials are generally required, the hydrated electron in this study was generated from UV photolysis of water molecules. Our results clearly demonstrated that the addition of alcohols could not only protect hydrated electron from quenching by hydroxyl radical, but also improve the dispersion of PFOA in solution, thus resulting in higher hydrated electron yield and utilization efficiency. Furthermore, owing to the quenching of proton and oxygen by the generated alcohol radical, the UV/H2O/alcohol system exhibited adaptability to different environmental variables, i.e., solution pH and reaction atmosphere. Therefore, the newly developed UV/H2O/alcohol system shows promising potential for treatment of PFOA-containing wastewater and investigator derived waste, as alcohol is usually used as the desorption agent.
查看更多>>摘要：Photocatalytic persulfate (PS)-based oxidation processes have showed excellent performance in pollutant removal. However, the focus is usually on the activation of PS induced by the photogenerated carriers or co-catalysis with catalyst itself. The mechanism of PS alone enhanced by visible light (Vis) to remove pollutants that don't absorb Vis is still not clear. Here, the degradation kinetics and differences of sulfonamides via PS enhanced by Vis (Vis/PS) was studied without catalysts. Furthermore, only PS can be enhanced by Vis to degrade sulfamerazine (SMZ) selected as model comparing with peroxymonosulfate and H2O2. Results verified that the interaction between pollutants and PS was critical for enhanced absorption of Vis and generation of active species. Singlet oxygen and electron transfer mediated self-degradation contributed mainly to SMZ removal. The Vis/PS system involved radical and contaminants-dependent nonradical pathways. Therefore, this study will provide new insight into the degradation of pollutants by photoactivated PS, especially Vis.
查看更多>>摘要：Herein, we developed a novel and simple strategy to construct Pt-decorated TiO2/β-Ni(OH)2 nanosheet arrays that steadily deliver large current densities in alkaline electrolyte. It is of great interest to find that the versatile role of few-layered Ti3C2 endows the unique growth mechanism of Pt/TiO2/β-Ni(OH)2. It is worth noting that the interconnected array electrode exhibits noticeable hydrogen evolution reaction (HER) performance, achieving ultralow overpotentials of 107, 145 and 184 mV at high current densities of 500, 1000 and 1500 mA cm~(-2), respectively, which outperforms most reported HER electrocatalysts. It requires only 1.95 V to drive 1000 mA cm~(-2) towards full water electrolysis along with considerable stability. It is demonstrated for the first time that the synergistic effect of Pt and TiO2/Ni(OH)2 the enhanced HER performance. This work reports a robust nanoarray support for Pt electrocatalyst to break through its intrinsic barrier in alkaline HER and under large current density.
查看更多>>摘要：Water splitting into H2 via artificial photosynthesis represents an appealing strategy for converting solar energy into fuels. However, commonly used photosensitizers are severely limited by precious metal with narrow visible utilization range. Herein, a library of organic photosensitizers was developed by engineering Bodipy with anthryl and aromatic aldehyde (B-1 - B-6) for enhancing intersystem crossing and extending absorption range. Their absorption can cover over 80% visible regions. Impressively, B-3 can absorb λ > 600 nm visible light to efficiently sensitize nickel-catalyst to produce over 150 μL H2. This performance was much higher than that with noble-metal photosensitizer Ru(bpy)_3~(2+) (bpy = 2,2'-bipyridine), representing a breakthrough in developing noble-metal-free photocatalytic systems with long-wavelength excitation. Systematical investigations reveal that B-3 with λ > 600 nm light absorption, long-lived triplet state and superior photochemical stability greatly boost H2 evolution. This work opens an avenue to construct efficient and sustainable catalytic systems by developing organic photosensitizers with long-wavelength excitation.
查看更多>>摘要：Here, we report a collectively exhaustive CoPi-NPC (cobalt phosphate moieties incorporated into the N, P- doped carbon) nanosheets for oxygen reduction reaction (ORR) and rechargeable zinc-air battery (ZAB) applications. The unprecedented CoPi-NPC nanosheets were synthesized from the cobalt-diethyl dithiocarbamate coordination complex by using room-temperature crystallization and carbonization processes. The fabricated nanosheets catalyze the critical ORR via a four-electron transfer through an associative reaction pathway in which the O-O bond cleavage can be recognized as the rate-determining step, offering high positive onset (～0.925 V vs. RHE) and the half-wave potentials (E_(1/2) = ～0.796 V vs. RHE). The assembled ZAB based on porous CoPi-NPC-900 air cathode delivered the maximum power density of ～186 mW cm~(-2), and large specific capacity of ～729 mAh g~(-1). Hence, this study opens up a new avenue to exploit various efficient non-precious electrocatalysts through different transition metal-diethyl dithiocarbamate coordination complexes.
查看更多>>摘要：Methane oxidation to value-added chemicals under mild conditions remained a research challenge and has attracted continuous attention, owing to fundamental interest and practical significance. Herein we report fundamental study of electrochemical methane oxidation reaction (CH4OR) on iron-nickel hydroxide (Fe-Ni-OH) nanosheets with controlled composition. The Fe-Ni-OH catalysts exhibit interesting CH4OR activity towards ethanol production in the Ni(II)→Ni(III) transition potential range and show a strong composition effect on the activity property, with a 9.09 mmol/gcataiysfh ethanol formation rate, 87 % faradaic efficiency, and 0.26 s~(-1) turnover frequency achieved using Fe3Ni7(OH)_x at 1.46 V vs. RHE. Density functional theory simulations and in situ infrared characterizations suggest Ni~IIIOOH as the active site and plausible CH4OR pathways, with the reaction barriers being altered with Fe-Ni-OH composition that agrees with the experimental observations. We believe this study provides new insights into CH4OR electrocatalysis mechanisms and offers theoretical guidance in discovering advanced catalyst materials for effective methane conversion.
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