CO Temperature-programmed Reduction Research Articles

Imparting Chemiresistor with Humidity-Independent Sensitivity toward Trace-Level Formaldehyde via Substitutional Doping Platinum Single Atom.

The modification of metal oxides with noble metals is one of the most effective means of improving gas-sensing performance of chemiresistors, but it is often accompanied by unintended side effects such as sensor resistance increases up to unmeasurable levels. Herein, a carbonization-oxidation method is demonstrated using ultrasonic spray pyrolysis technique to realize platinum (Pt) single atom (SA) substitutional doping into SnO2 (named PtSA-SnO2). The substitutional doping strategy can obviously enhance gas-sensing properties, and meanwhile decrease sensor resistance by two orders of magnitude (decreased from ≈850 to ≈2 MΩ), which are attributed to the tuning of band gap and fermi-level position, efficient single atom catalysis, and the raising of adsorption capability of formaldehyde, as validated by the state-of-the-art characterizations, such as spherical aberration-corrected scanning transmission electron microscopy (Cs-corrected STEM), in situ diffuse reflectance infrared Fourier transformed spectra (in situ DRIFT), CO temperature-programmed reduction (CO-TPR), and theoretical calculations. As a proof of concept, the developed PtSA-SnO2 sensor shows humidity-independent (30-70% relative humidity) gas-sensing performance in the selective detection of formaldehyde with high response, distinguishable selectivity (8< Sformaldehyde/Sinterferant <14), and ultra-low detection limit (10 ppb). This work presents a generalized and facile method to design high-performance metal oxides for chemical sensing of volatile organic compounds (VOCs).

Boosting hydrogen production by reducible oxygen species over Ni/MTixOy catalysts for the steam reforming of liquefied oil from Saccharina japonica

Hydrogen is a sustainable energy resource. However, H2 is mainly produced by steam reforming of fossil fuels, emitting greenhouse gases. H2 production from macroalgae is a promising alternative to fossil fuels because of the carbon neutrality of the marine biomass. In this study, we investigated the steam reforming of liquefied oil derived from Saccharina japonica over metal titanate-based Ni catalysts (Ni/K2TixOy, Ni/CaTiO3, Ni/SrTiO3, and Ni/BaTiO3). CO temperature-programmed reduction (CO-TPR), and O2 temperature-programmed desorption (O2-TPD) characterizations showed that the reducibility of lattice oxygen on metal titanates depended on metal cation species and was much higher than on the inert Al2O3. SrTiO3 exhibited the highest reducible oxygen content among the metal titanates.Catalytic evaluations showed that Ni/MTixOy catalysts exhibited higher H2 selectivity and catalytic stability than Ni/Al2O3. Ni/Al2O3 exhibited an H2/CO ratio of 1.1, while other Ni/MTixOy catalysts exhibited higher values (2.3–4.4); especially, Ni/SrTiO3 showed the highest H2 selectivity (55.8%) and H2/CO ratio (4.4). The H2 selectivity could be correlated with the amount of reactive lattice oxygen, as quantified by CO-TPR and O2-TPD. Furthermore, reactive oxygen species inhibited coke deposition on Ni/MTixOy catalysts. Overall, the Ni/MTixOy catalysts exhibited a high potential for H2 production by the steam reforming of bio-oil from macroalgae.

Mechanism of high- and low-valence doping on adsorbed oxygen of SnO2-based gas sensors and a strategy to combine the advantages of both dopants

The effect of high- and low-valence doping on adsorbed oxygen has been studied and intensely discussed for decades, in which the high-valence dopant can provide more electrons for ionosorbed oxygen species while low-valence dopant can provide more adsorption sites. In this work, this effect is observed directly by Quasi in-situ X-ray photoelectron spectroscopy and CO temperature-programmed reduction, and rationalized by density functional theory calculations. It is found that the oxygen vacancies can be easier to generate on Co-doped SnO2 surface, but the decrease in surface electron concentration actually reduces the amount of adsorbed oxygen at working temperature while Sb-doped SnO2 is more conducive to oxygen adsorption but the enormous electron concentration makes the resistance variation caused by the surface reactions insignificant. In order to combine the advantages of both dopants, Sb-doped SnO2@Co-doped SnO2 core-shell structure are designed and prepared. The synergism of the core and shell can enhance sensing reactions on the surface while efficiently converting the surface reactions into a resistance change. On the one hand, the electron diffusion from the electron-rich core to the shell provides the electrons required for oxygen adsorption, which ensures sufficient surface reactions. On the other hand, a potential barrier is formed between the core and shell which can regulate electron transport between adjacent cores, thereby effectively converting the surface reaction into a resistance change.

One step citric acid-assisted synthesis of Mn-Ce mixed oxides and their application to diesel soot combustion

Mn-Ce catalysts were prepared by a one-step synthesis method using citric acid, and were characterized by X-ray diffraction, CO temperature-programmed reduction, laser Raman spectroscopy and X-ray photoelectron spectroscopy. These catalysts were applied to the catalytic combustion of diesel soot in the presence of nitric oxide. A remarkable influence of the ratio of precursors and the method of synthesis on the physicochemical properties and subsequent catalytic activity was evidenced. The mixed oxides had higher activities than the individual ones, showing a synergistic effect whereby the catalyst with Mn/(Mn + Ce) = 0.1 had the lowest temperature of the maximum combustion rate.Mechanical mixtures of oxides were also prepared in order to better understand the synergistic effect observed. The main TPO peak was located at a similar temperature for both methods of synthesis. However, the TPO profiles of the catalysts synthesized by mechanical mixing had a shoulder at around 420 °C, which was more evident for catalysts prepared with lower Mn contents. This fact could be related to the coexistence of different MnOx species, as demonstrated by XRD, which exhibited different catalytic performances on oxidation reactions. The formation of a solid solution between Mn and Ce oxides for a ratio of Mn/(Mn + Ce) < 0.25 was observed, which enhanced the Ce4+ ↔ Ce3+ redox process. It was observed that both the coexistence of Mn2O3 and Mn3O4 at high concentrations and the formation of a solid solution strongly favored the oxidation of diesel soot, obtaining lower values of maximum combustion rate temperature.

Preparation and Evaluation of Iron-Based Catalysts from Corncob for NO Reduction

ABSTRACT This paper presents a one-step method that significantly simplifies the biomass carbonization preparation with Fe0 as active catalyst. The catalyst activity was compared to that of the catalyst prepared by a two-step method using a fixed-bed reactor for NO removal. The effects of temperature on catalyst preparation and that of SO2 on catalyst activity were also studied. The active species and surface structures of the catalysts were determined using X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis-mass spectrometry (TGA-MS), and CO temperature-programmed reduction (CO-TPR), respectively. Fe0 and Fe3C were the active catalytic species during NO removal. The catalysts prepared by the one-step method had a higher NO removal ability than that of the catalyst prepared by the two-step method. This was attributed to the small particle sizes of Fe0 and Fe3C as well as their high selectivity and anti-sintering characteristics. The catalyst prepared at 800°C exhibited the highest catalytic activity because of the special morphology. Catalyst deactivation was caused by oxidation of low-valence iron to Fe3O4 by NO, which was accompanied by agglomeration and sintering. Low SO2 concentrations affected the catalyst activity during NO removal.

Experimental and theoretical insights into the mechanism of spinel CoFe2O4 reduction in CO chemical looping combustion

The reaction mechanism of CoFe2O4 with CO during chemical looping combustion (CLC) was studied via thermogravimetric analysis (TGA) experiments and density functional theory (DFT) calculations. The CO temperature-programmed reduction revealed that the reduction of CoFe2O4 is a one-step reaction process. CoFe2O4 can be directly reduced into the Co-Fe alloy. The existence of Co evidently improves the reactivity of CoFe2O4 as compared to Fe2O3. Two types of reaction kinetics are involved in the isothermal reduction of CoFe2O4. DFT calculations were performed to study the adsorption and oxidation of CO on two terminated surfaces (surface A and surface B) of CoFe2O4 (110). The results indicated that CO preferentially chemisorbs at Co/Fe–O bridge sites on surface A and at Co/Fe atop sites on surface B. CO oxidation on surface A was more thermodynamically and kinetically favorable than that on surface B. Furthermore, the oxygen vacancy formation on surface B needs more energy consumption than that on surface A. The different reactivity between surface A and surface B may be responsible for the two reaction rate peaks observed in isothermal experiments. The synergistic effect of Co and Fe atoms on the reactivity of CoFe2O4 can be mainly ascribed to the oxygen atoms in different Co/Fe coordination environments. These results can provide fundamental insights for further improving the performance of spinel CoFe2O4 oxygen carrier.

The effects of dopant on catalytic activity of Pd/mesoporous alumina for toluene oxidation

A series of mesoporous alumina (MA) doped with acidic (Ti, W) or alkaline earth (Ba, Mg) elements were prepared. They were used as the supports for Pd catalysts. These catalysts were characterized by N2 sorption, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, infrared spectroscopy of CO adsorption and temperature-programmed reduction. Complete oxidation of toluene on these catalysts was tested in a fixed-bed micro-reactor. The results of in situ IR of CO adsorption indicated that the doping of basic element was beneficial for the dispersion of PdO particles, while the doping of acid element suppressed the dispersion of PdO particles. The binding energy of Pd in Pd/Ba-MA shifted to high energy, indicating that the interaction between PdO and support was enhanced. The results of H2-TPR showed that the reducibility of PdO doped with alkaline element was stronger than those of catalysts doped with acidic element. The doping of basic elements promoted the dispersion of PdO particles, changed the electronic state of Pd and enhanced the reducibility of PdO, which led to its high activity. The catalysts doped with the basic elements had higher activities than those doped with acidic elements, among which the Pd/Ba-MA catalyst had the highest activity among all catalysts.

Turning poison into medicine: NH3 or urea treatment leads to improved Pd-based three-way catalysts

Contrary to the stereotype that exposure to NH3 or urea should be strictly avoided when preparing three-way catalysts using Pd due to Pd2+-NH3 coordination, remarkable catalytic activity improvement was realized with careful NH3 or urea treatment towards the oxides support or Pd precursor. And with the help of a newly designed facile CO temperature-programmed reduction (TPR) method, developed to replace traditional H2-TPR, it was found that the catalytic activity is closely related with the catalyst reducibility and total oxygen storage capacity (OSC, represented by the integrated area of a CO-TPR curve), thus showing the potential of this CO-TPR method for screening candidate catalysts. When applying the most effective “Urea-PP” technology during monolith converter preparation, this method could no longer show its advantage, unless an outer layer was coated to protect the highly active but also highly sensitive inner layer.

Simultaneous introduction of K+ and Rb+ into OMS-2 tunnels as an available strategy for substantially increasing the catalytic activity for benzene elimination

OMS-2 is one of the most promising catalysts for carcinogenic benzene elimination, and single-type alkali metals are typically introduced into the OMS-2 tunnels to modify its catalytic activity. Here, we reported a novel approach for significantly increasing the catalytic activity of OMS-2 via the simultaneous introduction of K+ and Rb+ into the tunnels. The catalytic results demonstrated that K+ and Rb+ codoped OMS-2 showed catalytic activity for benzene oxidation that exceeded those of K+ and Rb+ single-doped OMS-2, as evidenced by enormous decreases (△T50 = 106 °C and △T90 > 132 °C) in catalytic temperatures T50 and T90 (which correspond to benzene conversion percentages of 50% and 90%, respectively). The origin of the effect of K+ and Rb+ codoping on the catalytic activity of OMS-2 was experimentally and theoretically investigated via 18O2 isotope labeling, CO temperature-programmed reduction, and density functional theory calculation. The higher catalytic activity of K+ and Rb+ codoped OMS-2 was attributed to its higher lattice oxygen activity as well as its higher oxygen vacancy defect concentrations compared to the single-doped OMS-2 cases.

Enhanced catalytic activity of OMS-2 for carcinogenic benzene elimination by tuning Sr2+ contents in the tunnels

Cryptomelane-type manganese oxides (OMS-2) have been intensively investigated for application in the catalytic oxidation of carcinogenic benzene, and doping metal ions in the OMS-2 tunnels are widely used for modifying its catalytic activity. In this study, we reported a novel strategy of enhancing catalytic activity of OMS-2 for carcinogenic benzene elimination by tuning Sr2+ concentration in the tunnels. The catalytic activity result revealed that an obvious decrease (△T50 = 27 °C and △T90 = 37 °C) in T50 and T90 (corresponding to benzene conversions at 50 % and 90 %, respectively; initial benzene concentration was 2000 mg m−3; contact time was 1.5 s) had been observed by increasing the Sr2+ concentration in the OMS-2 tunnels. The origin of Sr2+ doping effect on catalytic activity was theoretically and experimentally investigated by CO temperature-programmed reduction, 18O2 isotope labeling, and density functional theory calculations. The result confirmed that increasing Sr2+ concentration in the tunnels not only promoted the lattice oxygen activity, but also facilitated the generation of more oxygen vacancy defects, thus considerably improving the catalytic activity of OMS-2.

SmMn2O5 catalysts modified with silver for soot oxidation: Dispersion of silver and distortion of mullite

The mullite SmMn2O5 (SMO) was modified with silver for soot oxidation by two methods, i.e. sol-gel (Ag/SMO-sg) and impregnation (Ag/SMO-im). The catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma atomic emission spectrometry (ICP-AES), H2-O2 titration, H2 temperature-programmed reduction (H2-TPR), CO temperature-programmed reduction (CO-TPR), soot temperature-programmed reduction (soot-TPR), O2 temperature-programmed desorption (O2-TPD), cycled H2 temperature-programmed reduction (cycled H2-TPR), NO temperature-programmed oxidation (NO-TPO) and soot temperature-programmed oxidation (soot-TPO). Metallic silver nanoparticles were observed in the mullite matrix for both the catalysts. For Ag/SMO-sg, the possible incorporation of silver into the mullite crystal cell and strong electronic interaction between the highly dispersed metal and the support increase the Mn4+/Mn3+ ratio and create more structural defects in the mullite, resulting in boosted NO oxidation and thereby NO2-assisted soot combustion. The introduction of Ag can promote the generation/regeneration of active oxygen, which accelerates the ignition of soot in O2 at low temperatures. Therefore, the sol-gel-synthesized Ag/SmMn2O5 is highly promising for application in diesel particulate filters.

The remarkable effect of alkali earth metal ion on the catalytic activity of OMS-2 for benzene oxidation

Cryptomelane-type octahedral molecular sieve (OMS-2) is one of the most promising catalysts for VOCs oxidation, and introduction of metal ions in OMS-2 tunnel is widely used for tailoring its catalytic activity. Here, different types of alkali earth metal ions with the same X/Mn atomic ratio of approximately 0.012 (X represents Mg2+, Ca2+, and Sr2+) were successfully introduced into OMS-2 tunnel by a one-step redox reaction. The catalytic test showed that introducing alkali earth metal ions into tunnels had a considerable effect on the catalytic performance of OMS-2 for benzene oxidation. The Sr2+ doped OMS-2 catalyst exhibited the better catalytic activity compared with those of Mg-OMS-2 and Ca-OMS-2 samples, and was also superior to a commercial 0.5% Pt/Al2O3 catalyst, as evidenced by its low reaction temperatures of T50 = 200 °C and T90 = 223 °C (corresponding to benzene conversions at 50% and 90%, respectively). The origin of the considerable effect of alkali earth metal doping on the catalytic activity of OMS-2 catalysts was experimentally and theoretically investigated by an 18O2 isotopic labeling experiment, CO temperature-programmed reduction, O2 temperature-programmed oxidation, and density functional theory calculations. The greatest catalytic activity of Sr-OMS-2 compared with those of Mg-OMS-2 and Ca-OMS-2 samples was attributed to its highest lattice oxygen activity as well as its largest surface area. By introducing alkali earth metal ions into the OMS-2 tunnel, we developed a low-cost and highly efficient catalyst that could be used as alternative to noble metal catalysts.

Silicon nitride as a new support for copper catalyst to produce acrolein via selective oxidation of propene with very low CO2 release

To obtain thermally stable copper-based catalysts with excellent catalytic performance in the selective propene (C3H6) oxidation reaction, amorphous silicon nitride (Si3N4) was selected to anchor active copper species using a deposition–precipitation approach followed by air calcination at different temperatures. We found that the thermal treatment temperature remarkably modified the reactivity of the copper catalyst, and the 800 °C-calcined 10 wt% Cu/Si3N4 showed superior catalytic activity with 24.0% propene conversion and 86.2% acrolein selectivity at 325 °C, featuring a turnover frequency as high as 80.6 h−1. With the help of transmission electron microscopy, X-ray absorption fine structure, and in situ X-ray diffraction, we have identified that the larger Cu2O species account for the highly efficient formation of acrolein at 325 °C. From the CO temperature-programmed reduction results, we have confirmed that the presence of surface copper hydroxyls (Cu–OH) was closely related to the acrolein selectivity, since they favored CO2 generation at the beginning of the reaction. Furthermore, surface copper hydroxyls can be effectively tuned by optimizing the air calcination temperature and thus improve the catalytic activity.

Ce ion substitution position effect on catalytic activity of OMS-2 for benzene oxidation

Ce ions incorporated OMS-2 samples with Ce ions located at tunnel and framework were prepared and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption/ desorption, inductively coupled plasma (ICP), and X-ray photoelectron spectroscopy (XPS). The effect of Ce ions substitution position on lattice oxygen activity of OMS-2 was investigated by density functional theory (DFT) calculations and CO temperature-programmed reduction (CO-TPR). The result showed that Ce ions located at the OMS-2 tunnel promoted the lattice oxygen activity of OMS-2, however, Ce ion located at the framework of OMS-2 to substitute Mn ion decreased the lattice oxygen activity. The enhancement of catalytic activity of OMS-2 with Ce ion located at tunnel compared to OMS-2 with Ce ion located at framework is attributed to its greater lattice oxygen activity, thus considerably improving the catalytic activity for benzene oxidation.

Photothermocatalytic performance of ACo2O4 type spinel with light-enhanced mobilizable active oxygen species for toluene oxidation

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 ACo2O4 (A = Ni, Cu, Fe, Mn) spinel by harvesting inexhaustible solar energy to provide thermal energy. ACo2O4 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 ACo2O4 catalysts follows the sequence: NiCo2O4 > CuCo2O4 > FeCo2O4 > MnCo2O4, in which NiCo2O4 exhibits the highest photo-thermocatalytic activity (93% for toluene conversion and 80% for CO2 yield) and good stability (at least for 20 h) for toluene oxidation under irradiation. And such excellent light-driven catalytic performance over NiCo2O4 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 NiCo2O4.

Zirconium Doped Precipitated Fe-Based Catalyst for Fischer–Tropsch Synthesis to Light Olefins at Industrially Relevant Conditions

Direct conversion of synthesis gas to light olefins (ethylene, propylene, and butylenes) over Fe–Zr co-precipitated catalysts was investigated in a continuous-flow fixed-bed reactor at industrially relevant conditions. The effect of incorporation of zirconium on the textural properties, surface physicochemical properties, and reduction/carburization ability of Fe-based multi-component catalysts were examined by N2 adsorption–desorption, X-ray diffraction, transmission electron microscope, H2 temperature-programmed reduction (H2-TPR), CO temperature-programmed reduction, and X-ray photoelectron spectroscopy. The results indicated that the addition of less zirconium can promote the dispersion of iron oxide particles and increase the specific surface area of catalyst, leads to a higher Fischer–Tropsch synthesis activity. However, excessive addition of the zirconium promoter will cover the surface active sites and suppress the reduction and carburization of catalyst, which lead to lower activity. Meanwhile, the catalytic stability was destroyed by the addition of less Zr. The charge transfer between Fe and other promoter was redistributed by Zr, which disturbed the original Fe–Mg interaction. When the content of Zr further increased, the stability was improved again by a new formed Fe–Zr interaction. The zirconium promoter can effectively inhibit the chain growth probability and hydrogenation ability, resulting in the improvement of light olefins selectivity.

Tuning Pt-CeO2 interactions by high-temperature vapor-phase synthesis for improved reducibility of lattice oxygen

In this work, we compare the CO oxidation performance of Pt single atom catalysts (SACs) prepared via two methods: (1) conventional wet chemical synthesis (strong electrostatic adsorption–SEA) with calcination at 350 °C in air; and (2) high temperature vapor phase synthesis (atom trapping–AT) with calcination in air at 800 °C leading to ionic Pt being trapped on the CeO2 in a thermally stable form. As-synthesized, both SACs are inactive for low temperature (<150 °C) CO oxidation. After treatment in CO at 275 °C, both catalysts show enhanced reactivity. Despite similar Pt metal particle size, the AT catalyst is significantly more active, with onset of CO oxidation near room temperature. A combination of near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) and CO temperature-programmed reduction (CO-TPR) shows that the high reactivity at low temperatures can be related to the improved reducibility of lattice oxygen on the CeO2 support.

Catalytic Performance of Ce0.6Y0.4O2-Supported Platinum Catalyst for Low-Temperature Water-Gas Shift Reaction.

In this study, Pt/Ce0.6Y0.4O2 catalyst was prepared using a citric sol–gel method and was used as a catalyst for a water–gas shift (WGS) reaction. Compared to 1 wt % Pt/CeO2 and Pt/Y2O3 catalysts, the Pt/Ce0.6Y0.4O2 catalyst showed a much higher WGS catalytic activity. At 250 °C, the conversion of carbon monoxide was 86.35% at a weight hourly space velocity of 30 000 cm3 gcat–1 h–1. The physicochemical properties of the catalysts were investigated via X-ray diffraction, transmission electron microscopy, chemisorption, H2 and CO temperature-programmed reduction, and in situ diffuse reflection infrared Fourier transform spectroscopy. These results confirmed that the catalytic activity did not depend on the dispersion and particle size of platinum. The high reducibility of the Ce0.6Y0.4O2 support plays a crucial role in improving the activity of the Pt/Ce0.6Y0.4O2 catalyst, and this improvement can also be explained by the reduction in CO adsorption strength.

Comparison of oxide, sulfide, carbide and nitride Ni-W catalysts supported USY-Al2O3 for ring opening of decalin

The bimetallic Ni-W oxide catalyst supported on USY- Al2O3 has been prepared and converted into Ni-W sulfide, carbide and nitride catalysts. These four types of catalysts have been characterized by surface area measurements, pulsed CO chemisorption, thermogravimetric analysis, X-ray diffraction, temperature-programmed reduction and pyridine infrared spectroscopy. The initial decalin reaction activity of the catalysts decreases in the order of carbide catalyst>oxide catalyst>sulfide catalyst>>nitride catalysts. The catalysts deactivation decreases in the order of: sulfide catalyst>carbide catalyst>>nitride catalyst>oxide catalyst. The initial ring-opening activity decreases in the order of carbide catalyst>oxide catalyst ∼sulfide catalyst>>nitride catalyst. The catalyst activity has relation with the metal sites, the amount of the strong Brönsted acid sites and the surface area on the catalyst. Besides these, the catalyst deactivation also has the close relation with the coke produced on the catalyst during the reaction.

UV-Visible-Infrared Light Driven Thermocatalysis for Environmental Purification on Ramsdellite MnO2 Hollow Spheres Considerably Promoted by a Novel Photoactivation.

Novel ramsdellite MnO2 hollow spheres consisting of closely stacked nanosheets (R-MnO2-HS) were synthesized by a facile method. The R-MnO2-HS sample was characterized with SEM, XRD, TEM, BET, XPS, diffusive reflectance UV-vis-IR absorption, etc. Remarkably, R-MnO2-HS exhibits highly efficient catalytic activity for the purification of benzene (a carcinogenic air pollutant) under the full solar spectrum or visible-infrared irradiation, even under the infrared irradiation. Its catalytic activity (initial CO2 production rate) under the full solar spectrum irradiation is as high as 210.5 times higher than TiO2(P25), a well-known benchmark photocatalyst for environmental cleanup. The excellent catalytic activity of R-MnO2-HS is ascribed to its efficient thermocatalytic activity and its efficient photothermal conversion in the whole solar spectrum region, resulting in high efficient solar light driven thermocatalysis. Very interestingly, a novel photoactivation, which is completely different from the well-known photoactivation induced by photoexcited electrons and holes on TiO2, considerably enhances the solar light driven thermocatalysis. By use of CO temperature-programmed reduction (CO-TPR) under solar light irradiation and in the dark together with density function theory (DFT) calculations, the origin of the novel photoactivation was revealed: The lattice oxygen activity plays a crucial role in the thermocatalysis on MnO2. The solar light irradiation significantly promotes the lattice oxygen activity of R-MnO2-HS, consequently resulting in a considerable enhancement in the thermocatalytic activity.