Thermal Catalytic Oxidation Research Articles

Effect of metal on corona discharge plasma in a honeycomb catalyst and optimization of the critical parameters for ethylene removal

This work focused on the factors affecting the effective generation of corona discharge plasma in a honeycomb catalyst reactor. Pd, Co, and Ag were used as the active metal catalysts to investigate the plasma formation and decomposition of ethylene. Unlike the Ag-coated honeycomb catalyst, which resulted in excessive arcing, the Co-coated honeycomb monolith was able to generate stable plasma, but the discharge power was insufficient to decompose ethylene at an acceptable level. The incorporation of a small amount of Pd with Co significantly enhanced the discharge power and the ethylene removal performance. The catalytic activity of the prepared catalyst for the removal of ethylene was evaluated using plasma catalytic oxidation and thermal catalytic oxidation. ANOVA was used to assess the effect of single process factors and their relationships in the plasma process. All the process factors such as specific energy input (SEI), ethylene concentration, and flow rate were found to affect the ethylene conversion, CO2 selectivity, and energy efficiency (EE). Under the optimal conditions, i.e., an SEI of 80 J/L, an ethylene concentration of 20 ppm, and a flow rate of 20 L/min, the ethylene conversion was 85 %, CO2 selectivity was 70 %, and EE was 0.86 g/kW h.

Insights into Chlorobenzene Catalytic Oxidation over Noble Metal Loading {001}-TiO2: The Role of NaBH4 and Subnanometer Ru Undergoing Stable Ru0↔Ru4+ Circulation.

Catalytic combustion of ubiquitous chlorinated volatile organic compounds (CVOCs) encounters bottlenecks regarding catalyst deactivation by chlorine poisoning and generation of toxic polychlorinated byproducts. Herein, Ru, Pd, and Rh were loaded on {001}-TiO2 for thermal catalytic oxidation of chlorobenzene (CB), with Ru/{001}-TiO2 representing superior reactivity, CO2 selectivity, and stability in the 1000 min on-stream test. Interestingly, both acid sites and reactive active oxygen species (ROS) were remarkably promoted via adding NaBH4. But merely enhancing these active sites of the catalyst in CVOC treatment is insufficient. Continuous deep oxidation of CB with effective Cl desorption is also a core issue successfully tackled through the steady Ru0↔Ru4+ circulation. This circulation was facilitated by the observed higher subnanometer Ru dispersion on {001}-TiO2 than the other two noble metals that was supported by single atom stability DFT calculation. Nearly 88 degradation products in off-gas were detected, with Ru/{001}-TiO2 producing the lowest polychlorinated benzene byproducts. An effective and sustainable CB degradation mechanism boosted by the cooperation of NaBH4 enhanced active sites and Ru circulation was proposed accordingly. Insights gained from this study open a new avenue to the rational design of promising catalysts for the treatment of CVOCs.

The current status of research on the catalytic oxidation of formaldehyde

ABSTRACT Formaldehyde (HCHO), which is one of the common pollutants in indoor environment and industrial processes, can cause adverse effects on human health. The thermal catalytic oxidation technology is regarded as the most promising approach due to its easy handling and environmental friendliness. This article reviews the current status of the catalytic oxidation of HCHO over noble metal and transition metal oxide catalysts. The general feature and the reaction mechanism of the catalytic oxidation of HCHO are summarized first. Based on the discussion of the reaction mechanism, the influence of some factors (catalyst preparation process, catalyst support, promoter and morphology) on the activity of the catalyst have been addressed. The structure of the catalysts has been elucidated and correlated with the reaction mechanism as well as the catalytic performance. Finally, the perspectives for the catalytic oxidation of HCHO in future research are presented. Hopefully, this review can shed light on the design of more active catalysts for HCHO oxidation to realize their practical application.

Efficient Photothermal Elimination of Formaldehyde under Visible Light at Room Temperature by a MnOx-Modified Multi-Porous Carbon Sphere.

Volatile organic compounds (VOCs) exert a serious impact on the environment and human health. The development of new technologies for the elimination of VOCs, especially those from non-industrial emission sources, such as indoor air pollution and other low-concentration VOCs exhaust gases, is essential for improving environmental quality and human health. In this study, a monolithic photothermocatalyst was prepared by stabilizing manganese oxide on multi-porous carbon spheres to facilitate the elimination of formaldehyde (HCHO). This catalyst exhibited excellent photothermal synergistic performance. Therefore, by harvesting only visible light, the catalyst could spontaneously heat up its surface to achieve a thermal catalytic oxidation state suitable for eliminating HCHO. We found that the surface temperature of the catalyst could reach to up 93.8 °C under visible light, achieving an 87.5% HCHO removal efficiency when the initial concentration of HCHO was 160 ppm. The microporous structure on the surface of the carbon spheres not only increased the specific surface area and loading capacity of manganese oxide but also increased their photothermal efficiency, allowing them to reach a temperature high enough for MnOx to overcome the activation energy required for HCHO oxidation. The relevant catalyst characteristics were analyzed using XRD, measurement of BET surface area, scanning electron microscopy, HR-TEM, XPS, and DRS. Results obtained from a cyclic performance test indicated high stability and potential application of the MnOx-modified multi-porous carbon sphere.

The performance analysis of the photo-thermal driven synergetic catalytic PV-Trombe wall

PV-Trombe wall is a popular system because it meets needs of heating and electricity, while the utilization on recovered thermal energy is limited. The thermal catalytic oxidation (TCO) is an advanced air purification technology under thermal effect. The recent research shows a photo-thermal synergetic catalytic effect is existed in TCO process. Thus, a novel photo-thermal driven synergetic catalytic PV-Trombe (PTC-PV-Trombe) wall that can meet electricity, heating, formaldehyde removal is proposed. Here, the catalytic performance and reaction kinetics over MnOx-CeO2 were investigated and the novel catalytic mechanism was investigated based on experimental works. Then, based on established models, the comprehensive performance of proposed wall was investigated. Main results are: (1) The UV radiation further improve the removal of formaldehyde, and the reaction activation energy decreases from 31.087 kJ/mol to 29.997 kJ/mol (2) A hybrid catalytic mechanism including TCO and photoactivation is proposed. (3) With PV coverage of 0.5, compared with TC-PV-Trombe wall, PTC-PV-Trombe wall has similar thermal efficiency, while a little decrease of 0.012 in the electrical efficiency because of the electrical consumption of UV-LEDs, the total generated clean air is 189.9 m3/(m2•day), with the increase by 28.2%. (4) For every PV coverage, a photo-thermal synergetic catalytic effect is existed.

Promotion Mechanism of CaSO4 and Au in the Plasma-Assisted Catalytic Oxidation of Diesel Particulate Matter.

Plasma-assisted catalysis has been demonstrated to be an innovative technology for eliminating diesel particulate matter (DPM) efficiently at low temperature (≤200 °C). Moreover, past studies have demonstrated that CaSO4, which exists in small concentrations (<2%) in DPM and is toxic in thermal catalytic oxidation processes, actually enhances DPM oxidation during plasma-assisted catalytic processes. However, the role CaSO4 plays in this promotion of DPM oxidation still remains unclear. The present study addresses this issue by investigating the underlying mechanisms of DPM oxidation during plasma-assisted catalytic processes using graphitic carbon as a surrogate DPM material in conjunction with CaSO4- and Au-impregnated γ-Al2O3 catalysts. The results of mass spectrometry and in situ diffuse reflectance infrared Fourier transform spectroscopy, which employs an in situ cell with a small dielectric barrier discharge space over the catalyst bed, demonstrate that CaSO4 can save and release O atoms contributing to graphite oxidation via the −S=O units of CaSO4 through a reversible surface reaction (−S=O + O → −S(−O)2). The results are employed to propose a formal mechanism of graphite oxidation catalyzed by CaSO4 and Au. These findings both improve our understanding of the plasma-assisted catalytic oxidation mechanisms of DPM and support the development of efficient plasma-assisted catalysts.

Cr doped Mn3O4 thermal catalytic isopropanol degradation at low-temperature and catalytic mechanism research

Thermal catalytic oxidation is an important method for organic gaseous compounds degradation, which has been researched intensively. Here, Cr-doped Mn3O4 thermal catalyst with high-performance was synthesized by using a facile calcination method. Cr-doped Mn3O4 exhibited a large specific surface area, narrow band gap, and abundant oxygen vacancies. Cr-doped Mn3O4 presented an enhanced thermal catalytic activity for isopropanol degradation compared to pristine Mn3O4 at 80–200 °C. The enhanced performance could be attributed to the following three points. The large specific surface area could provide more active sites in the catalytic reaction and conducive to the thermal catalytic reaction. The narrow band gap might reduce the excitation energy of carriers and decrease the initial reaction temperature. The existence of oxygen vacancy could realize the efficient separation of carriers and further improve the thermal catalytic activity. After 25 h of thermal catalytic reaction, the activity of Cr-doped Mn3O4 did not decrease significantly, proving its good physicochemical stability. This work provided a research idea for the construction of efficient thermal catalysts in the field of air purification.

Activity origin of boron doped carbon cluster for thermal catalytic oxidation: Coupling effects of dopants and edges

Catalytic oxidation plays important roles in energy conversion and environment protection. Boron-doped crystalline carbocatalyst has been demonstrated effective; however, the application potential of boron-doped amorphous carbocatalyst remains to be explored. For amorphous carbon material, finite-sized carbon clusters are the basic structural units, which exhibit unique activity due to edge and size effect. Herein, using sulfur dioxide (SO2) and carbon monoxide (CO) oxidation as probe thermal-catalysis reactions, we found the distribution and reactivity of active sites in boron-doped carbon clusters are simultaneously determined by dopants and edges. According to comparisons of oxygen (O2) chemisorption energy at different sites of symmetric and non-symmetric carbon cluster, the most active site is found to be the edge carbon atom with high electron donation ability, which can be accurately identified by electrophilic Fukui function. More importantly, the reactivity of boron-doped cluster is simultaneously influenced by doping configuration and the type of edge, based on which -O-B-O- configuration embedded into K-region edge (isolated carbon–carbon double bonds that do not belong to Clar sextet) is predicted to exhibit the highest reactivity among various boron doping configurations. This work clarifies unique activity origin of heteroatom-doped amorphous carbon materials, providing new insights into designing high-performance carbocatalysts.

Light-promoted activation of oxygen and carbon monoxide for low-temperature catalytic oxidation

Molecular oxygen (O 2 ) activation is a critical step in the low-temperature catalytic oxidation of carbon monoxide (CO). Photocatalysis is a facile way to activate O 2 to superoxide radicals under mild conditions. Photothermal catalysis, which integrates the photocatalysis of semiconductors and the thermocatalysis of noble metals, has arisen as an appealing strategy to achieve low-temperature catalytic oxidation. Here, we report that Pd/PdO/CeO 2 shows that the temperature of 90% CO conversion dropped by 30°C–50°C under irradiation. The apparent activation energy reduces from 64.6 kJ ⋅ mol −1 to 44.6 kJ ⋅ mol −1 . Pd/PdO/TiO 2 and Pd/PdO/Al 2 O 3 are prepared and compared to understand the underlying mechanism. The results reveal that photocatalysis is vital in lowering the apparent activation energy besides the photothermal effect. The photo-generated electrons promote O 2 activation to generate the superoxide anion. The hole can activate the adsorbed CO on the PdO. These active species are beneficial for lowering the CO oxidation temperature. • Pd/PdO/CeO 2 nanowires deposited and annealed in the reaction gas environment • Conversion temperature drops 30°C–50°C under full-spectrum light irradiation • Photocatalytic oxidation provides significant contribution in addition to photothermal effect Here, Dong et al. show photo-assisted thermal catalytic oxidation of CO based on Pd/PdO/CeO 2 . The 90% conversion temperature can be effectively reduced by photocatalytic, Pd plasmonic, and photothermal effects. Photogenerated electrons and holes promote the activation of molecular O 2 and CO to lower the activation energy.

Efficiently photothermal conversion in a MnOx-based monolithic photothermocatalyst for gaseous formaldehyde elimination

Volatile organic compound (VOC) pollution has a serious impact on human and urgently needs to be controlled through the development of new methods and catalytic materials. Compared with traditional thermal catalytic oxidation, the synergistic photothermocatalysis is regarded as a green and environmentally friendly strategy for organic compound pollutant removal, which can promote spontaneous heating of the surface of catalysts to achieve thermal catalytic reaction conditions via harvesting light irradiation. In this paper, a monolithic photothermocatalyst was synthesized through coating graphene oxide (GO) and MnOx in turn on a commercially available melamine sponge, where the GO mainly acted as a photothermal conversion layer to heat the catalytically active MnOx. This monolithic catalyst presented excellent photo-induced activity for formaldehyde elimination under ambient conditions (∼ 90% degradation ratio in 20 min for ∼160 ppm initial concentration formaldehyde), and meanwhile possessed a high catalytic durability for multiple cycles. The kinetic study demonstrated that this photothermocatalytic process followed a pseudo-second-order kinetics. Finally, we proposed a possible formaldehyde degradation pathway based on in situ DRIFTS examination.

Non-thermal plasma in honeycomb catalyst for the high-throughput removal of dilute styrene from air

This study focused on the removal of styrene using a metal-coated monolith (MCM) catalyst integrated with non-thermal plasma. The MCM catalyst was prepared by depositing a ZSM-5 support impregnated with a combination of three metals (Co, Pd, La) on a practical-scale honeycomb monolith. A comparative study with a commercial metal-coated monolith (CMCM) of the same dimensions was conducted to evaluate the effectiveness of the MCM with respect to styrene removal. The plasma discharge in the monolith was characterized by measuring the voltage and current waveforms and optical emission spectroscopy (OES). The electric power of the plasma discharge largely depended on the metal loading, flow rate, and humidity of the feed gas. The removal efficiency of styrene (inlet concentration: 20 parts per million, volumetric (ppm)) was examined using both plasma catalytic oxidation (PCO) and thermal catalytic oxidation (TCO), to enable the effect of plasma to be clearly assessed. PCO with the MCM catalyst achieved styrene removal efficiency of nearly 100% at a specific energy input (SEI) of 40 J/L, whereas the CMCM catalyst achieved 92% removal for identical SEI. In comparison, TCO with the MCM and CMCM catalysts required high temperatures of 420 °C and 480 °C, respectively, for the complete removal of styrene. In addition, the CO2 selectivity of the MCM catalyst was higher at 83% compared with 75% for the CMCM at SEI of 40 J/L. The optimal silica binder content for the deposition of a robust washcoat layer was found to be approximately 5%.

Pt–Pd bimetallic nanoparticles anchored on uniform mesoporous MnO2 sphere as an advanced nanocatalyst for highly efficient toluene oxidation

Improving catalytic performance is a yet still challenge in thermal catalytic oxidation. Herein, uniform mesoporous MnO2 nanosphere-supported bimetallic Pt–Pd nanoparticles were successfully fabricated via a SiO2 template strategy for the total catalytic degradation of volatile organic compounds at low temperature. The introduction of mesopores into the MnO2 support induces a large specific surface area and pore size, thus providing numerous accessible active sites and enhanced diffusion properties. Moreover, the addition of a secondary noble metal can adjust the Oads/Olatt molar ratios, resulting in high catalytic activity. Among them, the catalyst having a Pt/Pd molar ratio of 7:3 exhibits optimized catalytic activity at a weight hourly space velocity of 36,000 mL g−1 h−1, reaching 100% toluene oxidation at 175 °C with a lower activation energy (57.0 kJ mol−1) than the corresponding monometallic Pt or non-Pt-based catalysts (93.8 kJ mol−1 and 214.2 kJ mol−1). Our findings demonstrate that the uniform mesoporous MnO2 nanosphere-supported bimetallic Pt–Pd nanoparticles catalyst is an effective candidate for application in elimination of toluene.

New tetradentate Schiff base Cu(II) complexes: synthesis, physicochemical, chromotropism, fluorescence, thermal, and selective catalytic oxidation

Three neutral Cu(II)/ƞ4-NNNO Schiff base complexes (1-3) were prepared from the (E)-4-nitro-2-(((2-(piperazin-1-yl)ethyl)imino)methyl)phenol, tetradentate Schiff base (SB) ligand, and the corresponding copper(II) salts. The new SB and its complexes were fully characterized by CHN-EA, standard spectroscopic, thermal, and fluorescence analyses. The formation of the complexes was monitored by EDX, FT-IR, and UV-Vis. The chromotropism studies of the complexes reflected remarkable findings, in which bathochromic solvato- and thermochromism shifts were detected. The turn-off-on halochromism phenomena were observed in the acidic and basic medium. On the other hand, the fluorescence of the free SB ligand was turned off via complexation to the Cu(II) center. In the presence of H2O2 as green oxidant and under mild oxidation catalytic condition, the three complexes successfully catalyzed the formation benzaldehyde from benzyl alcohol.

The Opportunities and Challenges for NH3 Oxidation with 100% Conversion and Selectivity

The selective catalytic oxidation of ammonia (SCO) to N2 seems to be the most promising technology to remove NH3. Compared with electrocatalytic and photocatalytic ammonia oxidation technology, the thermal catalytic oxidation ammonia technology was sufficient to support large-scale commercial and industrial applications. The NH3-SCO reaction was strongly obeyed the reaction routes of imide, hydrazinium-type and iSCR mechanism. Further, in situ (electron paramagnetic resonance) EPR spectroscopy combined with DFT calculation could provide a foundation for the design and construction of highly efficient ammonia oxidation catalyst. Finally, important ideas for NH3-SCO should be given the 100% N2 selectivity and higher NH3 conversion at lowest temperature. If Ag single-atoms were inserted in the tunnels of zeolites or MOF to result in single Ag atoms anchored at the tunnel, this single-atom Ag particles exhibited super NH3 conversion, N2 selectivity and hydrothermal durability at low temperatures.

The performance analysis on a novel purified pv-trombe wall for electricity, space heating, formaldehyde degradation and bacteria in activation

On the one hand, PV-Trombe wall is a combined solar system that meets dual functions of space heating and electricity output, but the utilization on the recovered solar heat by PV-Trombe wall is very limited. On the other hand, thermal catalytic oxidation and thermal sterilization are two advanced air purification technologies and both they have huge application potential with solar heat. Therefore, a novel purified PV-Trombe wall for electricity, space heating, formaldehyde degradation and bacteria inactivation was proposed. Firstly, the system thermal and mass transfer model was established and verified by experimental data. Secondly, the comprehensive performance with the PV coverage ratio of 0 was analyzed. Finally, the effect of PV coverage ratio on the system performance was investigated. Accordingly, the main results were: ① Under PV coverage ratio of 0, the average daily air thermal efficiency and formaldehyde single-pass ratio were 0. 46 and 0. 35, respectively. Meanwhile, the total generated volume of clean air by formaldehyde degradation was 93. 4 m3 . Five kinds of bacteria were fully thermal inactivated for several hours. Accordingly, the total generated volume of clean air were 188. 3, 173. 0, 201. 4, 189. 9 and 200. 2 m3 for E. coli, L. monocytogenes, L. plantarum, S. Senftenberg and S. cerevisiae, respectively. ② The PV coverage ratio played a different role on the system comprehensive performances. For specific performances, the PV coverage ratio only had a positive influence on electrical performance and had negative effect on other performances such as thermal, formaldehyde degradation and bacteria inactivation performances. However, considering the system comprehensive performances, the electrical energy was the additional product and the low PV coverage ratio was suggested. ③ The works could provide possible support to the prevention and control of COVID-19. © 2021, Editorial Department of Journal of University of Science and Technology of China. All rights reserved.

Electrochemical and thermal catalytic studies of Co based molybdenum oxide nanomaterials for C[sbnd]H bond activation

Electrocatalytic and thermal catalytic oxidation of toluene has been investigated by designing a series of Co2-xMoxO3 (NA1-NA6). Synthesized nanomaterials were characterized by Powder X-Ray Diffraction, Scanning Electron Microscopy, and Energy-dispersive X-Ray Spectroscopy. Thermal catalytic oxidation of toluene at 150 °C characterized by Gas Chromatography-Mass Spectrometry. Specifically, 19% benzene, 11% benzyl alcohol, and 6% benzoic acid were detected by GC–MS analysis of thermal catalytic oxidation of toluene by NA3. Electrocatalytic activity of the nanomaterials to oxidize water and toluene was studied by Cyclic Voltammetry and Linear Sweep Voltammetry. The peak currents during anodic and cathodic scan depicted that the synthesized materials were actively redox in nature. The onset potential for the electrocatalytic oxidation of toluene in NA3 and NA4 was observed. Samples from electrocatalytic activity were analyzed by High-Performance Liquid Chromatography which gives efficient oxidation of toluene into respective products.

Thermal, electrical and purification performance of a novel thermal-catalytic CdTe double-layer breathing window in winter

CdTe PV cell is one perfect candidate for window application because of its good daylighting performance, low-temperature coefficient and excellent electrical performance under weak light. In addition, thermal catalytic oxidation is an thermal driven air purification technology and the thermal energy can be easily obtained from PV window systems. Therefore, a novel thermal-catalytic CdTe double-layer breathing window was proposed. Firstly, the electrical, thermal and daylighting performances of proposed window were investigated experimentally. Secondly, the removal of formaldehyde was investigated using the verified coupled formaldehyde mass transfer and thermal-catalytic reaction kinetic model. Finally, the evolution of indoor formaldehyde concentration considering formaldehyde release source was calculated. Main results were: (1) The thermal and electrical efficiencies were respectively 0.297 and 0.0715, which were closed to the reported results. Also, the proposed window had better daylighting uniformity compared with conventional window. (2) The total generated clean air was 25.7 m3/(m2•day), with the equivalent formaldehyde degradation efficiency of 0.010 based on purification performances of various air purifiers in market. (3) The comprehensive thermal efficiency was 0.518, with increase of 9.28% considering the contribution from formaldehyde removal. (4) The proposed window could make the indoor concentration approach to standard concentration under most working conditions.

Enhanced moisture resistance of Cu/Ce catalysts for CO oxidation via Plasma−Catalyst interactions

Copper/cerium bimetallic catalyst is an efficient material for the removal of carbon monoxide, while the rapid deactivation under moisture-rich conditions in the conventional thermal-catalysis limited its wide application. Here, we investigated the plasma-assisted catalytic oxidation of CO over Cu/Ce oxides supported on γ-Alumina in comparison with the conventional thermal catalytic oxidation. The TOF values of the Cu/Ce catalysts showed that the plasma catalysis was the better catalytic system for CO oxidation (2.96 s−1 for thermal catalysis, 5.13 s−1 for plasma catalysis). Importantly, the energy barriers for plasma catalysis were much lower than that for thermal catalysis, especially under moisture-rich conditions (e.g. 130.3 kJ/mol versus 246.1 kJ/mol under 9.8 vol% water vapor). The loss of activity caused by water was reversible for the plasma process, but not for the thermal process. The Cu/Ce catalyst remained good stability within 60 h in the presence of 6.1% water for plasma oxidation, while the thermal catalytic activity declines gradually. Also, water could inhibit the formation of gas byproducts (O3 and NOx). The promoting role of plasma could be mainly ascribed to the enhanced strength of oxygen mobility and plasma-assisted decomposition of surface carbonate in the presence of water, as revealed by the in-situ NTP-TPR, XPS, and the ex-situ DRIFTS analyses.

Toluene oxidation process and proper mechanism over Co3O4 nanotubes: Investigation through in-situ DRIFTS combined with PTR-TOF-MS and quasi in-situ XPS

Improving catalytic efficiency is a yet still challenge in thermal catalytic oxidation. One of the key issues is to understand its catalytic oxidation mechanism. Here, a series of Co3O4 samples were prepared by solvothermal method. The characterization records showed that nanotubular Co3O4-NTs-2 for its rough surface, low temperature reducibility, abundance of Co3+ ions and surface adsorption oxygen species, thus exhibited high efficiency (T90 = 240℃, Ea = 67.42 kJ/mol) in catalytic oxidation of toluene. In-situ DRIFTS combined PTR-TOF-MS were applied to investigate the reaction process of toluene oxidation. These results revealed that the catalytic oxidation of toluene followed the listed way: toluene → benzyl alcohol → benzaldehyde → benzoate → benzene → phenol → benzoquinone → maleic anhydride and other ring opening by-products like ethanol, acetaldehyde, acetic acid, acetone etc., then ultimately mineralized to CO2 and H2O. Furthermore, the results of quasi in-situ XPS in C7H8/N2, toluene conversion in O2-free evaluation and UV–vis-DRS analysis further confirmed that surface lattice oxygen played an important role in toluene oxidation, and gas-phase oxygen facilitated the reaction. The combination of a series of instruments provided a promising means for further understanding the oxidation mechanism of toluene.

Effective low‐temperature catalytic abatement of benzene over porous Mn‐Ni composite oxides synthesized via the oxalate route

AbstractBACKGROUNDBenzene (C6H6) is a typical kind of volatile organic compound (VOC) which can exert great harm to both human health and the environment, and, thus, which needs to be eliminated before its emission. In this work, porous manganese–nickel (Mn‐Ni) composite oxide catalysts were synthesized through the oxalate route and applied to thermal catalytic oxidation of C6H6. By means of activity tests and relative physico‐chemical characterizations, the factors affecting the activity of those Mn‐Ni composite oxides were explored.RESULTSNitrogen (N2)‐adsorption/desorption and X‐ray photoelectron spectroscopy (XPS) measurements indicated that the Brunauer–Elmett–Teller (BET) surface area and the content of surface‐adsorbed oxygen species were increased due to the addition of Ni into Mn oxide (MnOx). Meanwhile, the oxygen mobility and reducibility also were improved in the Mn‐Ni composite oxides. Accordingly, compared with MnOx, the Mn‐Ni catalysts showed higher activity for thermal catalytic oxidation of C6H6. Moreover, porous Mn‐Ni composite oxides with a Mn:Ni molar ratio of 4:1 (Mn4Ni1) displayed the best catalytic activity. Further investigation indicated that the excellent catalytic performance of Mn4Ni1 composite oxides could be ascribed mainly to the larger BET surface area and the richer content of surface‐adsorbed oxygen species, as well as stronger oxygen mobility and better reducibility compared with other Mn‐Ni catalysts.CONCLUSIONSThe Mn4Ni1 composite oxides showed a lowest T90 value of 172 °C (C6H6 concentration 200 ppm, WHSV 60 000 mL g−1 h−1) among all of the obtained Mn‐Ni composite oxides. Moreover, it also exhibited favourable catalytic stability at 210 °C in the presence or absence of moisture. © 2019 Society of Chemical Industry