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Synergistic effects and kinetics of rGO-modified TiO2 nanocomposite on adsorption and photocatalytic degradation of humic acid
摘要： Graphene oxide was prepared using the modified Hummers method and reduced graphene oxide (rGO) - titanium dioxide (TiO2) nanocomposite was synthesised using the one-step hydrothermal treatment. The synergistic effects on adsorption and photocatalytic properties of the rGO-TiO2 nanocomposite for the humic acid removal were systematically investigated. The results of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman and infrared (IR) spectroscopy indicate that GO was partially reduced to reduced graphene oxide (rGO) in the hydrothermal synthesis process and anatase TiO2 nanoparticles uniformly grew on the surface of rGO. The photoelectron and photohole generated under visible light irradiation were effectively separated on the surface of rGO-TiO2. The rGO-TiO2 nanocomposite exhibited higher photocatalytic activity as a result of the synergistic effects of surface functional groups for adsorption and the excellent conductivity for photocatalytic reaction. The effect of rGO-TiO2 nanocomposite dosage, light intensity and system temperature on the removal of humic acid solution was investigated. The results show that the removal efficiency of humic acid increased with system temperature and light intensity. When the dosage of rGO-TiO2 nanocomposite was 1.2 g/L, the temperature, the light intensity and the pH of this system was 303 K, 4.37 Wm?2 and 7, respectively, the removal efficiency of humic acid reached 88.7% under visible light irradiation.
关键词： Synergistic effects,rGO,Humic acid,TiO2,Adsorption and photocatalysis
更新于2025-11-14 17:03:37
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Cobalt/Molybdenum Phosphides and Oxides Heterostructures Encapsulated in N-doped Carbon Nanocomposite for Overall Water Splitting in Alkaline Media
摘要： The development of designing and searching inexpensive electrocatalysts with highly activity for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is significant to enable water splitting as a future renewable energy source. Herein, we synthesis a new CoP(MoP)-CoMoO3 heterostructure coated by N-doped carbon shell (CoP(MoP)-CoMoO3@CN) via thermal decomposing and phosphatizing the CoMoO4?0.9H2O nanowires encapsulated in N-doped carbon. At 10 mA?cm?2, this CoP(MoP)-CoMoO3@CN nanocomposite exhibits superior electrocatalytic activity of low overpotentials of 296 mV for OER and 198 mV for HER in alkaline media. More importantly, we achieve a current density of 10 mA?cm?2 at 1.55 V by using this CoP(MoP)-CoMoO3@CN as both cathode and anode for overall water splitting. This promising performance could be due to the high activity of CoP(MoP)-CoMoO3 and the good conductivity of external mesoporous N-carbon shell, which makes the CoP(MoP)-CoMoO3@CN nanowires as a competitive alternative to noble metal based catalysts for water splitting.
关键词： metal phosphides,overall water splitting,synergistic effects,nanowires,N-doped Carbon
更新于2025-09-23 15:22:29
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Selfa??Assembled Ruddlesdena??Popper/Perovskite Hybrid with Latticea??Oxygen Activation as a Superior Oxygen Evolution Electrocatalyst
摘要： The oxygen evolution reaction (OER) is pivotal in multiple gas-involved energy conversion technologies, such as water splitting, rechargeable metal–air batteries, and CO2/N2 electrolysis. Emerging anion-redox chemistry provides exciting opportunities for boosting catalytic activity, and thus mastering lattice-oxygen activation of metal oxides and identifying the origins are crucial for the development of advanced catalysts. Here, a strategy to activate surface lattice-oxygen sites for OER catalysis via constructing a Ruddlesden–Popper/perovskite hybrid, which is prepared by a facile one-pot self-assembly method, is developed. As a proof-of-concept, the unique hybrid catalyst (RP/P-LSCF) consists of a dominated Ruddlesden–Popper phase LaSr3Co1.5Fe1.5O10-δ (RP-LSCF) and second perovskite phase La0.25Sr0.75Co0.5Fe0.5O3-δ (P-LSCF), displaying exceptional OER activity. The RP/P-LSCF achieves 10 mA cm?2 at a low overpotential of only 324 mV in 0.1 m KOH, surpassing the benchmark RuO2 and various state-of-the-art metal oxides ever reported for OER, while showing significantly higher activity and stability than single RP-LSCF oxide. The high catalytic performance for RP/P-LSCF is attributed to the strong metal–oxygen covalency and high oxygen-ion diffusion rate resulting from the phase mixture, which likely triggers the surface lattice-oxygen activation to participate in OER. The success of Ruddlesden–Popper/perovskite hybrid construction creates a new direction to design advanced catalysts for various energy applications.
关键词： electronic structure,lattice-oxygen activation,hybrid construction,oxygen evolution reaction,synergistic effects
更新于2025-09-23 15:19:57
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Laser-Assisted Fabrication for Metal Halide Perovskite-2D Nanoconjugates: Control on the Nanocrystal Density and Morphology
摘要： We report on a facile and rapid photo-induced process to conjugate graphene-based materials with metal-halide perovskite nanocrystals. We show that a small number of laser pulses is sufficient to decorate the 2-dimensional (2D) flakes with metal-halide nanocrystals without affecting their primary morphology. At the same time, the density of anchored nanocrystals could be finely tuned by the number of irradiation pulses. This facile and rapid room temperature method provides unique opportunities for the design and development of perovskite-2D nanoconjugates, exhibiting synergetic functionality by combining nanocrystals of different morphologies and chemical phases with various 2D materials.
关键词： graphene oxide,2D materials,photo-induced processes,laser-induced synthesis,nanoparticles,anion exchange,synergistic effects
更新于2025-09-23 15:19:57
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Glucose-assisted hydrothermal synthesis of plasmonic Bi deposited nested Bi2O2?xCO3 photocatalysts with enhanced photocatalytic activity
摘要： Crystal defects play an important role on the physical and chemical properties of semiconductors. In this work, a series of Bi/Bi2O2?xCO3 photocatalysts have been fabricated by an one-pot hydrothermal method, where glucose is used as reducing and morphological control agent. The phase structure, morphology, optical and photoelectrochemical properties of the photocatalysts are characterized by various techniques. These oxygen vacancies (OVs) have been confirmed and characterized by ESR spectroscopy and XPS spectra. The Bi/Bi2O2?xCO3 photocatalysts exhibits highest removal efficiency of Lanasol Red 5B and ciprofloxacin. The corresponding degradation rate constant for Lanasol Red 5B is about 2.28 times higher than that of Bi2O2CO3 under simulated solar irradiation, and 10.9 times under visible light irradiation, respectively. Radical scavenger experiments futher indicated that holes (h+) and hydroxyl radical (OH) are the main active species for Lanasol Red 5B degradation. This enhanced photocatalytic performance can be rationalized by the synergistic effects of Bi plasmon and OVs, resulting in, enhanced light-harvesting and electron- hole separation ability of Bi/Bi2O2?xCO3 photocatalysts.
关键词： Oxygen vacancies,Bi2O2CO3,Bi plasmon,Nested,Synergistic effects
更新于2025-09-19 17:13:59