Engineering Cobalt Oxide with Coexisting Cobalt Defects and Oxygen Vacancies for Enhanced Catalytic Oxidation of Toluene

Abstract

Most research studies reported that oxygen vacancies on transition metal oxides are crucial for improving the catalytic oxidation activities. However, few studies investigated the coexistence effect of metal defects and oxygen vacancies on the performances and mechanisms of catalysts. Herein, we present a facile approach for synthesizing a Co3–x O4–y catalyst with both cobalt defects and oxygen vacancies simultaneously, exhibiting significant thermo-/photothermo-catalytic performance for toluene oxidation (300 ppm, GHSV = 72,000 mL g–1 h–1) with over 90% toluene conversion in 10 min of light illumination (with a corresponding light-to-heat conversion temperature of ∼180 °C). Furthermore, the synchrotron radiation X-ray absorption spectroscopy, O2 temperature-programmed desorption, and density functional theory calculations demonstrate that cobalt defects are conducive to the formation of oxygen vacancies. In situ DRIFTS studies reveal that the as-formed surface-reactive oxygen species can be replenished continuously during the reaction progress, and the coexisting oxygen vacancies can accelerate the conversion of intermediates, thereby promoting the toluene degradation.

Tuning the Micro-coordination Environment of Al in Dealumination Y Zeolite to Enhance Electron Transfer at the Cu–Mn Oxides Interface for Highly Efficient Catalytic Ozonation of Toluene at Low Temperatures

“…O 2 -TPD can characterize the change of adsorbed oxygen (below 300 °C), surface lattice oxygen (300–550 °C), and bulk phase lattice oxygen (over 550 °C) in the material . Unlike lattice oxygen, which can only be activated at high temperature, the nature of the adsorbed oxygen may determine the ability of the catalyst to decompose ozone at low temperature . As shown in Figure a, the peak positions of Mn/Y and Mn/DY representing adsorbed oxygen are close, which implies that the extra-framework octahedrally coordinated aluminum species in zeolite do not contribute much to the activity of adsorbed oxygen.…”

“…41 Unlike lattice oxygen, which can only be activated at high temperature, the nature of the adsorbed oxygen may determine the ability of the catalyst to decompose ozone at low temperature. 42 As shown in Figure 4a, the peak positions of Mn/Y and Mn/DY representing adsorbed oxygen are close, which implies that the extra-framework octahedrally coordinated aluminum species in zeolite do not contribute much to the activity of adsorbed oxygen. Surprisingly, Cu-doping caused the adsorbed oxygen of Cu−Mn/Y to be more inert, while the activity of adsorbed oxygen was significantly improved and exceeded that of two single Mn catalysts when Cu was incorporated into Mn/DY.…”

High-Efficiency Electrochemical Nitrate Reduction to Ammonia on a Co3O4 Nanoarray Catalyst with Cobalt Vacancies

“…The main characteristic peaks of v Co -Co 3 O 4 /CC (Figure a) also match well with the spinel Co 3 O 4 phase, and it suggests that the etching process does not change the crystal phase of v Co -Co 3 O 4 /CC. Furthermore, the locally enlarged XRD patterns of v Co -Co 3 O 4 /CC and pristine Co 3 O 4 /CC (Figure S1c) also exhibit a small shift, suggesting that the Co vacancies lead to a shrink in interplanar spacing . The scanning electron microscopy (SEM) images of Al-Co 3 O 4 /CC in Figure S1d exhibit the smooth nanosheet structure.…”

Electrocatalytic Degradation of Levofloxacin Wastewater by Ni Single-Atom-Kernelled Ru Nanocluster Particles

“…Electronic copy available at: https://ssrn.com/abstract=4289772 P r e p r i n t n o t p e e r r e v i e w e d 15 with unique Ni single-atom-kernelled Ru nanocluster particles in the structure, the Ru-Ni/CNT electrode has high electrochemical stability potential window, large oxygen evolution potential value, small charge transfer resistance, and more surface oxygen content. This together benefits the Ru-Ni/CNT electrode to generate sufficient reactive oxygen species (ROS) in the electrocatalytic reaction, and thereby promoting the degradation of LVX [29,[44][45][46] This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=4289772 P r e p r i n t n o t p e e r r e v i e w e d 16 quenching experiments using the electrodes (Fig.…”