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Recently, photo-thermocatalysis has been intensively motivated since it is beneficial for both relieving energy consumption and using the full solar spectrum energy. In this work, efficient photo-promoted thermocatalytic removal of VOCs has been investigated on ACo 2 O 4 (A = Ni, Cu, Fe, Mn) spinel by harvesting inexhaustible solar energy to provide thermal energy. ACo 2 O 4 was synthesized by co-precipitation method, which exhibits strong light absorption in the entire solar spectrum (200–2500 nm) and high solar heating effect, providing enough thermal energy for catalytic degradation of toluene. The photo-thermocatalytic performance of ACo 2 O 4 catalysts follows the sequence: NiCo 2 O 4 > CuCo 2 O 4 > FeCo 2 O 4 > MnCo 2 O 4 , in which NiCo 2 O 4 exhibits the highest photo-thermocatalytic activity (93% for toluene conversion and 80% for CO 2 yield) and good stability (at least for 20 h) for toluene oxidation under irradiation. And such excellent light-driven catalytic performance over NiCo 2 O 4 can be mainly explained by its strong light absorption, high photo-thermal conversion, more active oxygen species, enlarged surface area and the better OCS. Besides, a novel light-enhanced effect is revealed to considerably increase the photo-thermocatalytic activity for toluene oxidation, which is quite different from the traditional photocatalysis. By combining CO temperature-programmed reduction (CO-TPR) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS), it is revealed that the irradiation is able to enhance the mobility of active oxygen species, resulting in a significant improvement of photo-thermocatalytic activity over NiCo 2 O 4. Unlabelled Image • ACo 2 O 4 spinel exhibits the broad and strong light absorption. • Efficient solar-thermal conversion offers energy to drive toluene degradation. • Optimal NiCo 2 O 4 catalyst shows 93% of toluene conversion and 80% of mineralization. • A photo-promotion effect was found to be able to enhance the catalytic activity. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • MnO x /Cr 2 O 3 composites are prepared by using MIL-101-Cr as sacrificial template. • Strong interaction between MnO x and Cr 2 O 3 results in physicochemical properties. • As-obtained catalyst shows good stability and durability in removal of toluene. Abstract A series of MnO x /Cr 2 O 3 composites have been prepared via the combination methods of impregnation, in situ redox precipitation and pyrolysis based on MIL-101-Cr. The physicochemical properties of catalysts have been investigated by using XRD, Raman, BET, SEM, TEM, XPS, H 2 -TPD and O 2 -TPD, and their catalytic performance has been evaluated by toluene combustion. With introduction of MnO x into Cr 2 O 3 , the MnO x /Cr 2 O 3 -M exhibits the obviously enhanced catalytic activity for toluene oxidation compared to commercial Cr 2 O 3 or pure Cr 2 O 3 pyrolyzed by MIL-101-Cr. The 14.6 wt% MnO x /Cr 2 O 3 -M (named as 15Mn/Cr 2 O 3 -M) shows the highest efficiency and lowest E a values under different SV and toluene concentrations. The catalytic durability test for toluene oxidation on 15Mn/Cr 2 O 3 -M presents a solid stability, where the toluene conversion maintains at ca. 85% for at least 240 h without obvious inactivation (270 °C, 1000 ppm of toluene, 20,000 mL/(g h), with 10 vol% of water vapor) and it can also maintain at conversions of 90% and 50% for at least 50 h with higher space velocity (1000 ppm of toluene, 60,000 mL/(g h)). The good durability and tolerance of 15Mn/Cr 2 O 3 -M are probably associated with better stability for crystal structure, oxygen vacancies, and reducibility. More MnO x addition amount (25Mn/Cr 2 O 3 -M) cannot further promote catalytic performance, possibly due to excessive MnO x existed as isolated phase with lack of strong interaction between two metal oxides. The investigation of in situ DRIFTS on 15Mn/Cr 2 O 3 -M confirms that surface lattice oxygen O Latt plays a crucial role in toluene combustion and the pathway for toluene combustion is via rapid transformation to aldehydic and then benzoate species and finally form CO 2 and H 2 O. [ABSTRACT FROM AUTHOR]

Three-dimensional penetrating Pt-loaded mesoporous Cr 2 O 3 catalysts (Pt@M-Cr 2 O 3 ) were synthesized by pyrolysis of MIL-101-Cr containing pre-impregnated Pt NPs. Physicochemical properties of the samples were characterized by means of various techniques including XRD, Raman, BET, SEM, TEM, XPS and H 2 -TPR, and their catalytic activities were evaluated by toluene combustion compared with commercial Cr 2 O 3 (C-Cr 2 O 3 ). It is found that mesoporous Cr 2 O 3 (M-Cr 2 O 3 ) support with a high surface area of 77.40 m 2 /g is composed of vast Cr 2 O 3 nanocrystallites. With pre-impregnated Pt loading in MIL-101-Cr, it partly restrains the aggregation of Pt NPs during the pyrolysis of MOFs to M-Cr 2 O 3 and strengthens the interaction between Pt NPs and Cr 2 O 3 nanocrystallites. The obtained 0.82Pt@M-Cr 2 O 3 exhibits the best catalytic performance of toluene combustion, giving 120, 140 and 144 °C of T 10% , T 50% and T 90% under 1000 ppm of toluene at space velocity of 20,000 mL/(g h), respectively. The investigation of the different space velocity, the catalytic stability and the effect of water vapor on catalytic activity over 0.82Pt@M-Cr 2 O 3 have confirmed the good catalytic performance. Furthermore, the studies of in situ DRIFTS indicate toluene degradation over 0.82Pt@M-Cr 2 O 3 is via benzoate species by rapidly transforming of benzylic and aldehydic species, and then oxidized to maleic anhydride in an aromatic-ring opening reaction, finally is decayed to CO 2 and H 2 O. [ABSTRACT FROM AUTHOR]

Light driven photothermal catalysis has been carried out by converting the light energy into heat to reach the light-off temperature of the reaction. Herein we have synthesized the ternary multifunctional catalysts of polymeric carbon nitride coupled with Pt-embedded transition metal oxide (Pt-Co x /CN), for the catalytic degradation of toluene. Under the condition of space velocity of 30,000 mL/(g h) and concentration of 210 ppm, toluene conversion and CO 2 mineralization can reach 90% and 83% over Pt-Co 20 /CN, respectively. The introduction of an appropriate proportion of CoO enhances the light absorption of nanocomposites and improves the adsorption for toluene. Meanwhile, CoO promotes the proportion and mobility of adsorbed oxygen on the surface, which are conducive to the catalytic oxidation reaction according to the Mars-van Krevelen mechanism. The results also suggest that light irradiation serves as a source of heat to initiate photo-induced chemical reactions and promote photothermal catalytic oxidation by promoting the activation of lattice oxygen. [Display omitted] • Pt-Co x /CN catalysts are prepared by hydrothermal and chemical reduction method. • Introduction of appropriate CoO can effectively improve photothermal performance. • Light irradiation facilitates the activation of lattice oxygen. • Photothermocatalytic oxidation process mainly follows Mars-van Krevelen mechanism. [ABSTRACT FROM AUTHOR]

Mesoporous CeO 2 catalysts (CeO 2 -MOF) were synthesized by pyrolysis of Ce-MOF precursor (Ce-(1,3,5-benzenetricarboxylic acid) (H 2 O) 6 ). Physicochemical properties of the samples were investigated by means of various techniques including XRD, SEM, TEM, BET, Raman, XPS, H 2 -TPR, O 2 -TPD and NH 3 -TPD, and their catalytic performance were evaluated by toluene combustion compared with commercial CeO 2 (CeO 2 -C) and CeO 2 prepared by precipitation method (CeO 2 -P). The results show that CeO 2 -MOF/350 catalyst (pyrolyzed at 350 °C) presents enhanced catalytic activity for toluene oxidation with the conversion of T 10% , T 50% and T 90% at 180, 211, and 223 °C, respectively (SV = 20,000 mL/(g h), toluene concentration = 1000 ppm). Especially for high-temperature region, CeO 2 -MOF/350 catalyst displays much superior ability to rapidly reach to 100% conversion compared to CeO 2 -C and CeO 2 -P catalysts which usually result in a much broader temperature region to achieve complete conversion of toluene. The high catalytic performance of CeO 2 -MOF/350 can be reasonably ascribed to a series of better properties, such as three-dimensional penetrating mesoporous channels, larger specific surface area, smaller average grain size, higher relative percentages of Ce 3+ /Ce 4+ and O Sur /O Latt , higher oxygen storage capacity, higher oxygen vacancy concentration, better low temperature reducibility, more active oxygen species and more acid sites. Furthermore, CeO 2 -MOF/350 catalyst presented excellent resistance to H 2 O deactivation and temperature change, and in situ DRIFTs study on CeO 2 -MOF/350 catalyst suggests that toluene degradation is proceeded in consecutive steps via rapid transformation to aldehydic and benzoate species to finally form CO 2 and H 2 O. [ABSTRACT FROM AUTHOR]

A new strategy has been introduced to successfully fabricate the hydrophobic barriers of PADs by using organofluorine-modified superhydrophobic TiO 2 NPs. Superhydrophobic TiO 2 -140 NPs with high-photoactivity can be converted to hydrophilicity by self-degradation of surface organic moieties under full spectrum light irradiation. Superhydrophobic TiO 2 -RT NPs with low-photoactivity exhibits good hydrophobic stability under light irradiation. Thus, combining these features, the PADs have been designed and constructed by photo-induced fabrication of hydrophobic barriers on the surface of the paper. To demonstrate the effectiveness of the constructed PADs, colorimetric detections have been displayed for Fe 3+ and Ni 2+ ions. The synchronous multi-component detections based on the “multi-channel” PADs and the intuitive detections based on the “chemical-symbol-style” PADs are rapid and feasible. A detection range of Fe 3+ and Ni 2+ ions based on the “circle-array” PAD is applicable and reliable in 0.2–6.0 mM and 0.4–4.0 mM, respectively. Thus, these results make it to be believed that this new strategy provides an alternative way to effectively construct the PADs. [ABSTRACT FROM AUTHOR]