Low-temperature Reduction Research Articles

On the formation of dendritic iron from alkaline electrochemical reduction of iron oxide prepared for metal fuel applications

Low-temperature electrochemical reduction (electroreduction) of iron oxides is a promising alternative to the conventional methods for iron production due to its CO2-free operation and relatively low energy consumption. In this work, we demonstrate a novel approach for electrochemical iron production by promoting the formation of dendritic structures during iron electrodeposition, which facilitates the easy harvesting of deposits in powder form. Experiments were conducted using a single pair of parallel plate electrodes, immersed in a mixture of hematite (Fe2O3) powder and aqueous alkaline (NaOH) slurry. The effects of current density, Fe2O3 mass fraction, temperature, and powder size on current efficiency and deposit morphology are investigated. A large quantity of dendritic iron structures is observed when experiments are carried out without stirring and/or applying heat from a heating plate. This condition suggests temperature and (ion/species) concentration gradients in the system. The dendrites are mainly deposited on the cathode's sides, corners, and edges. Different deposits and dendritic structures (compact layer deposit, moss-like deposit, deposit with whisker-like dendrites, and deposit with crystal-like dendrites) are observed as operating conditions change. Overall, a cathodic deposition of metallic iron with a high Faradaic efficiency (≥90 %) is successfully accomplished. The present findings provide new insights into the production of electrolytic iron powder and its future use as a carbon neutral and sustainable fuel/energy carrier.

Non-noble metal Cu modification ZnIn2S4 driving efficient production H2 under visible light

Copper species have been extensively researched as effective cocatalysts for hydrogen evolution because of their inexpensive nature when compared to Pt. In this work, we have successfully loaded Cu nanoparticles highly dispersed on the surface of ZnIn2S4 (ZIS) by an always simple low-temperature vacuum reduction method, which significantly improved the separation efficiency of photogenerated carriers. According to the transient photocurrent (TPR) and PL results, when the mass fraction of Cu is 0.6%, the maximum photocurrent density is approximately 0.55 μA/cm2, which is 2.75 times that of ZIS. And the separation efficiency of the photogenerated carriers is the fastest at this point. Simultaneously, under visible light and with a Cu loading of 0.6% in the Cu/ZnIn2S4 (Cu/ZIS) composite material, the efficiency of hydrogen production is 6.56 times greater than that of pure ZIS, ultimately achieving an optimal value of 4.66 mmol/g/h. This study provides a new method for the preparation of photocatalysts with a high efficiency of electron-hole separation.

An environment-friendly strategy for recovery of α-PbO from spent lead paste: Based on the thermochemical reduction of PbO2 with ammonium sulfate

During the process of recycling lead from waste lead-acid batteries, how to minimize the wastage of chemical reagents and prevent secondary pollution is a significant research subject. In this study, a method for preparing α-PbO based on low-temperature thermochemical reduction of PbO2 was proposed. Using (NH4)2SO4 as the roasting agent, the purity of PbSO4 in spent lead paste was improved by reducing PbO2 at low temperatures. The thermochemical mechanism revealed that the thermochemical process consists of three different stages of (NH4)2SO4 decomposition and PbO2 reduction. The purity of PbSO4 in spent lead paste could be increased to 98.43 % by controlling the thermal reaction conditions (M (SO42−: TPb) molar ratio of 1:1, roasting temperature, and time of 340 °C and 1.5 h, respectively). Then, the desulfurization of PbSO4 with (NH4)2CO3 obtained PbCO3, and α-PbO with a purity of 96.87 %-98.57 % could be obtained by pyrolysis of PbCO3. Finally, 95.63 % of NH4+, 97.34 % of SO42−, and 77.71 % of CO32− could also be recovered for the regeneration of (NH4)2SO4 and (NH4)2CO3. This study provides a feasible technology for green recycling of spent lead paste.

Spontaneous formation of Au-Co interface via a Low-Temperature reduction process

Eutectic alloys manufactured by metallurgical methods are widely used in many industrial applications due to their special properties provided by the multi-phase eutectic microstructure. Previous studies introduced the preparation of metals and alloys through the chemical reduction of metal complex salts. We employed this technique to prepare the equiatomic composition in the binary eutectic system Au-Co through a low-temperature solid-gas phase reduction of two precursors: the bi-metallic complex salt [Co(NH3)6][AuCl4]Cl2, and an equimolar mixture of H[AuCl4] and pre-reduced cobalt. Complete reduction at 350 °C resulted in the formation of a close-to-equilibrium two-phase composition of fcc gold and hcp cobalt. The structure of the fully reduced metallic materials was composed of interconnected cobalt ligaments and bi-metallic Au-Co (gold-cobalt) particles. Specifically, these spontaneously formed particles featured fcc cobalt islands interfacing with fcc gold at a specific orientation relationship. Under heating, the fully reduced Au-Co products underwent melting that corresponds to the equilibrium eutectic melting point at 996.5 °C. These results imply that spontaneous lattice self-adjustment can occur in multi-component eutectic-type systems at low temperatures directly in the solid state. This may ease the technologies of joining such as epitaxial growth, additive manufacturing, and powder metallurgy.

Revealing the effect of framework acidity on the catalytic combustion of vinyl chloride over zeolite-based catalysts

The study explored the effect of different types of acid sites on the catalytic combustion of vinyl chloride over zeolite-based catalysts. MFI-type zeolites were synthesized using impregnation method and loaded with the noble metal Ru. Results indicated that the Ru/Sn-MFI catalysts possessed only Lewis acid sites, the Ru/Al-MFI catalysts were primarily governed by Brønsted acid sites, and the Ru/Si-MFI catalysts had no acid sites. The Ru/Sn-MFI catalyst containing Lewis acid sites demonstrated increased catalytic activity, with a T90 of up to 306 °C, and efficiently prevented the formation of chlorinated by-products. In contrast, the Ru-Si/MFI catalyst exhibited inferior catalytic activity. While a significant amount of chlorinated by-products was generated on the Ru/Al-MFI catalyst. The substantial amount of Lewis acid sites on the surface of Ru/Sn-MFI catalyst facilitated the activation of C-Cl bonds and the cleavage of C–C bonds. Furthermore, the Ru/Sn-MFI catalysts had improved low-temperature reducibility and oxygen mobility, which contributed to the deep oxidation of vinyl chloride.

Establishing efficient toluene elimination over cobalt-manganese bimetallic oxides via constructing strong Co–Mn interaction

Doping proves to be an efficacious method of establishing intermetallic interactions for enhancing toluene oxidation performance of bimetallic oxides. However, conventional bimetallic oxide catalysts are yet to overcome their inadequacy in establishing intermetallic interactions. In this work, the dispersion of Mn–Co bimetallic sites was improved by hydrolytic co-precipitation, strengthening the intermetallic interactions which improved the structural and physicochemical properties of the catalysts, thus significantly enhancing its catalytic behavior. MnCo–H catalysts fabricated by the hydrolytic co-precipitation method showed promising catalytic performance (T50 = 223 °C, T90 = 229 °C), robust stability (at least 100 h) and impressive water resistance (under 10 vol.% of water) for toluene elimination. Hydrolytic co-precipitation has been found to improve dispersion of MnCo elements and to enhance interaction between Co and Mn ions (Mn4+ + Co2+ = Mn3+ + Co3+), resulting in a lower reduction temperature (215 °C) and a weaker Mn–O bond strength, creating more lattice defects and oxygen vacancies, which are responsible for superior catalytic properties of MnCo–H samples. Furthermore, in situ DRIFTs showed that gaseous toluene molecules adsorbed on the surface of MnCo–H were continuously oxidized to benzyl alcohol → benzaldehyde → benzoate, followed by a ring-opening reaction with surface-activated oxygen to convert to maleic anhydride as the final intermediate, which further generates water and carbon dioxide. It was also revealed that the ring-opening reaction for the conversion of benzoic acid to maleic anhydride is the rate-controlling step. This study reveals that optimizing active sites and improving reactive oxygen species by altering the dispersion of bimetals to enhance bimetallic interactions is an effective strategy for the improvement of catalytic behavior, while the hydrolytic co-precipitation method fits well with this corollary.

Enhancing the Precipitant and Calcination Process of Manganese-Iron Oxide Catalyst for Low-Temperature NH3-SCR

Catalysts containing manganese as the primary active component have emerged as promising candidates for ultra-low temperature NH3-SCR applications. To enhance the catalytic activity of these catalysts, a series of Mn-FeOX catalysts were prepared using the co-precipitation method. This study focuses on investigating the appropriate calcination process for catalyst preparation using different precipitants, namely NaOH, NH3-H2O and Na2CO3. The results revealed that catalysts prepared with Na2CO3 as the preferred precipitant and calcined at 330∘C exhibited exceptional NOx removal efficiency, exceeding 90% at a temperature of 60∘C and GHSV [Formula: see text] 30,000[Formula: see text]h[Formula: see text], which demonstrated this catalyst’s remarkable low-temperature reduction capability. Detailed characterization demonstrated that the MnOX catalysts synthesized through this process possessed an amorphous structure, superior pore structure and the highest Fe[Formula: see text] content. These findings offer valuable insights for optimizing the preparation conditions of Mn-FeOX catalysts in ultra-low temperature denitrification applications.

Engineering lattice oxygen mobility and optimizing reaction pathway via tuning Cu-Co interactions for efficient elimination of volatile organic compounds: A metal–organic framework template approach

Incorporating a secondary metal into individual cobalt oxides has been viewed as an efficacious approach in creating intermetallic interactions. Nonetheless, the processes involved in the construction of intermetallic interactions, as well as the underlying mechanisms that contribute to catalytic activity, remain largely elusive in current scientific understanding. In this work, a range of Cu-Co bimetallic oxides were synthesized through various preparation methods, employing MOFs as templates. Notably, the hydrothermally-synthesized Cu/Co-HT catalyst exhibited impressive catalytic qualities for toluene combustion, with T50 = 229 °C and T90 = 239 °C, alongside exceptional stability and moisture resistance (under 10 vol. % of water) for at least 100 h. The optimal catalyst Cu/Co-HT is attributed to the stronger Cu-Co interaction, which leading to larger specific surface area and weaker Co-O bond strength. And it also affects the chemical properties, such as get more Co3+ and lattice oxygen species by a redox (Co2++Cu2+→Co3++Cu+), better electron transfer performance and low-temperature reducibility. In addition, the reaction mechanism of toluene over the surface of Cu/Co-HT was also revealed by in-situ DRIFTS. It was observed that the bimetallic catalyst, characterized by robust Cu-Co interactions, optimized the reaction pathway for toluene oxidation compared to pure Co3O4. This facilitation led to the direct conversion of benzyl alcohol into benzoate and carboxylate, thereby bypassing the intermediate step involving benzaldehyde, which enhancing the reaction speed, yielding a long-term stable and efficient operational performance. This study reveals that optimize the physicochemical properties of catalytic by enhancing bimetallic interactions is an effective strategy for improving catalytic behavior.

Area-selective atomic layer deposition of palladium

We report area-selective deposition of palladium using sequential area-blocking and area-activation ALD processes. Thermal atomic layer deposition (ALD) of palladium is investigated at 100 °C using palladium (II) hexafluoroacetylacetonate and hydrogen. Palladium deposition does not proceed at such a low temperature unless catalytic sites are present to dissociate hydrogen during Pd film nucleation and before sufficient Pd has accumulated to serve as the catalyst for hydrogen dissociation. Ultrathin (<2 nm) nickel metal surfaces served as the initial catalytic sites and are prepared via low temperature (100 °C) reduction of NiO ALD films using a H-atom doser operating at 3 × 10−5 Torr. The Ni0 films are shown to seed the ALD of Pd, demonstrating a route to Pd ALD by area activation. Blanket NiO films are used to study Pd ALD growth and patterned NiO films, formed by area-blocking ALD, are used to demonstrate a bottom-up approach to patterned Pd films.

MOF-derived FeOx with highly dispersed active sites as an efficient catalyst for enchaning catalytic oxidation of VOCs

Highly efficient and stable catalysts serve as the crucial factor in VOCs catalytic oxidation technology. Iron-based materials are recognized as potential VOCs catalysts due to their cost-effectiveness and non-toxic nature. However, the limited catalytic performance of traditional iron oxide catalysts hinders their further industrial applications. A series of FeOx catalysts were synthesized via pyrolysis of Fe-based MOFs with diverse morphologies for toluene catalytic oxidation. Characterization results demonstrated that the FeOx-100 catalyst performed optimal characteristics, including the abundant specific surface area and smaller crystallite size, which offered highly dispersed active sites and defects for toluene oxidation. The catalytic activity of FeOx-100 was improved by adjusting the precursors and pyrolysis conditions, achieving a 50% toluene conversion at 223 °C and 90% conversion at 249 °C. The redox abilities of FeOx catalysts were carefully evaluated to assess their impact on catalytic activity. The results confirmed that FeOx-100 exhibited superior low-temperature reducibility, remarkable presence of surface active oxygen and lattice oxygen species, jointly facilitating the toluene oxidation performance at lower temperatures. The results of in situ DRIFTS provided evidence supporting a degradation pathway for toluene, likely proceeding as follows: toluene→ benzaldehyde→ benzoate→ anhydride → …→ CO2 and H2O.

Recovery and reuse of spent lithium-ion batteries as catalysts for low-temperature NH3-SCR

The wide application of lithium-ion batteries (LIBs) for electric vehicles forebodes the decommissioning tide of spent LIBs. Therefore, recycling valuable element from spent LIBs are becoming urgent to minimize the impact on the environment and supply chain of battery manufacturers. In this work, we propose to extract valuable elements from the cathode materials of spent ternary lithium-ion batteries and synthesize NiCoMnOx catalysts for low-temperature NH3 selective catalyst reduction (NH3-SCR) reactions. The oxalic acid is used as a precipitant and reducing agent and prepared as NiCoMnOx catalyst by hydrothermal process and heat treatment. The as-prepared catalyst presents a porous fluffy foam structure with abundant oxygen defects, ensuring sufficient catalytic active sites. As a result, the NiCoMnOx catalyst exhibits optimal catalytic activity with over 90% NOx conversion in the temperature range of 110 ∼ 230 °C, which is wider than the temperature range of 155 ∼ 210 °C for the catalysts prepared from metal salts. Meanwhile, the NiCoMnOx catalyst also shows better catalytic stability and resistance to H2O and SO2. This work provides a promising strategy to recycle spent LIBs to low-temperature NH3-SCR catalysts.

Efficient electromagnetic wave absorption of polypyrrole/low-reduction graphene oxide composites through dielectric properties modulation

Graphene oxide (GO) is widely used in electromagnetic microwave absorption (EMA) materials due to its abundant oxygen-containing functional groups and defects. Its conductivity, surface functional groups and defect density can be modified by controlling reduction degree to modulate its electromagnetic properties. However, the thermal reduction temperature needed is often too high, exceeding the Curie temperature of magnetic materials, which makes further compounding difficult. Polypyrrole (PPy), as a conductive polymer with high electrical conductivity, is widely used in EMA field and can help regulate the dielectric properties of materials. In this paper, a series of PPy/GO composites with different ratios and reduction degrees were prepared by in situ polymerization and thermal reduction, and their EMA properties were investigated. At a loading amount of 7.5 wt%, the maximum reflection loss of PPy/rGO composites can reach −66.64 dB, and the effective absorption bandwidth can reach 6.74 GHz with a reduction temperature of only 400 °C. Furthermore, the unreduced sample also has excellent absorption performance, which has a wide range of applications for future one-step compositing with magnetic materials in low reduction temperature.

Construction of Pd/Mn3O4 heterojunction catalyst for efficient photothermal synergetic catalytic propane total oxidation

Photothermal synergistic low-temperature catalytic volatile organic compounds (VOCs) degradation has an advantage on energy efficiency and reduction of carbon emissions. Herein, an impregnation-pyrolysis-oxidation strategy was adopted to synthesize Pd/Mn3O4 heterojunction catalyst. Under photothermal synergistic conditions, 0.60Pd/Mn3O4 catalyst exhibited an excellent activity for propane total oxidation, with a T90 value of 219.1 ℃, which was 115.3 ℃ lower than that of Mn3O4. Enhancement effect of the heterojunction structure on photothermal synergy was detected by various characterization techniques and density functional theory calculation. The presence of Pd species enhanced the low-temperature reducibility of Mn3O4. Meanwhile, O2 molecules were more easily activated at the Pd sites and overflow to the surface of Mn3O4 for reaction. Besides, the formation of p-n junction between Pd species and Mn3O4 in heterojunction structure promoted the charge separation and the migration of carriers, and boosted the generation of oxygen free radical, resulting in a significant improvement in photothermal catalytic activity. Overall, this study provided new strategy and deep insight for constructing heterojunction to enhance photothermal catalytic performance of VOC elimination.

Photon energy dependence of graphene oxide reduction by soft X-ray irradiation and atomic hydrogen annealing

The effects of soft X-ray irradiation and atomic hydrogen annealing on the reduction of graphene oxide (GO) to obtain graphene were investigated. To clarify the interaction between soft X-rays and GO, soft X-rays of 300 eV and 550 eV were used for C 1s and O 1s inner-shell electron excitation, respectively at the NewSUBARU synchrotron radiation facility. Low-temperature reduction of the GO film was achieved by using soft X-ray at temperatures below 150 °C at 300 eV, and 60 °C at 550 eV. O-related peaks in X-ray photoelectron spectroscopy, such as the C–O–C peak, were smaller at 550 eV than those at 300 eV. This result indicates that excitation of the core–shell electrons of O enhances the reduction of GO. Soft X-rays preferentially break C–C and C–O bonds at 300 and 550 eV, respectively.

Graphene Based Mesoporous Manganese-Cerium Oxides Catalysts: Preparation and Low-temperature Catalytic Reduction of NO

Graphene Based Mesoporous Manganese-Cerium Oxides Catalysts: Preparation and Low-temperature Catalytic Reduction of NO

Low-temperature vapor reduction of graphene oxide electrodes for vertical organic field-effect transistors

Vertical organic field-effect transistors based on a low-temperature-prepared reduced graphene oxide electrode.

Catalytic combustion of toluene over cerium modified CuMn/Al2O3/cordierite monolithic catalyst

Catalytic combustion is an effective approach to remove volatile organic compounds, in which the development of highly active and durable catalyst is extremely crucial. Herein, a series of CuMnCex/Al2O3/cordierite monolithic catalysts were synthesized by using the ultrasonic-assisted impregnation method. The physicochemical properties were comprehensively characterized via the BET, XRD, SEM, EDX, H2-TPR, O2-TPD, XPS and EPR techniques. The results showed that the catalytic activity of CuMnCex/Al2O3/Cor for toluene combustion was strongly affected by the Ce content. The CuMnCe2/Al2O3/Cor monolithic catalyst showed the best catalytic activity with toluene conversion of 90% at 263 °C under toluene concentration of 1 g/L and space velocity of 78000 mL/(g·h). Meanwhile, the well-dispersed CeO2 in the CuMn matrix not only improved the content of oxygen vacancies and the mobility of oxygen species, but also enhanced the low-temperature reducibility of the catalyst. Moreover, the CuMnCe2/Al2O3/Cor monolithic catalyst exhibited an excellent stability in the long-term test and cycle ability test.

Efficient catalyst regeneration through solvent-based wax extraction for Co/Al2O3 Fischer-Tropsch catalysts

The regeneration of Fischer-Tropsch (FT) catalysts plays a crucial role in sustaining their catalytic activity and longevity in sustainable production processes. This research investigates the effectiveness of various solvents, including n-hexane, n-heptane, toluene, xylene, and the liquid fraction of FT products (LF-FT), for catalyst regeneration and extracting wax from the 15 wt%Co/Al2O3 catalyst. Toluene, with a unique combination of key parameters such as polarity, solubility, boiling point, aromatic structure, and chemical interactions, exhibited the highest wax removal efficiency of 90.6%. However, due to its 41 °C lower boiling point compared to toluene and very similar wax removal efficiency, n-hexane appears as a more energy-efficient and cost-effective option for this process. The regenerated catalysts showed comparable characteristics, including the textural properties (surface area, pore size, and pore volume), crystallinity, and reducibility, to fresh catalysts. The slightly lower reduction temperature in the regenerated catalyst indicates a higher possibility for the formation of cobalt active sites during the catalyst reduction process with hydrogen, leading to an increased potential for higher catalytic activity. The LF-FT, comprising paraffins, iso-paraffins, olefins, napthenes, and aromatics, provided a unique combination of aliphatic and aromatic moieties, enhancing the solubility of both polar and nonpolar components in FT wax and improving the wax removal efficiency to 91.5%. The higher boiling point and operating temperature of the LF-FT also contributed to its better performance. Efficient separation of hydrocarbons from solvents allowed for solvent reusability in subsequent FT wax removal cycles, making it advantageous for large-scale applications.

Intercalation Reaction Mechanism of Fluoride-Ions in (Ca, Sr)FeO2 Cathodes with Infinite Layer Structure for All-Solid-State Fluoride-Ion Batteries

Fluoride ion batteries, which use fluoride ions as carriers, are attracting attention as the next generation of storage batteries because of their theoretical high energy density. Conventional research has focused on metal/metal fluorides such as Cu/CuF2 as cathode materials.[1] However, these cathodes have disadvantages of the power density and cyclability due to the rapid decrease in electronic conductivity and large volume change during fluorination and defluorination. To solve these problems, cathode materials that utilize topotactic fluoride ion intercalation reactions, similar to electrode materials applied in lithium-ion secondary batteries, are being developed[2]. However, these materials have the disadvantage of relatively small capacity, compared to metal/metal fluorides.In this study, we focused on SrFeO2and Ca-doped SrFeO2 cathodes with infinite layer structure as new high-capacity intercalation cathodes, and evaluated its electrochemical properties and clarified the charge compensation mechanism.Ca1-xSrxFeO2 (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) was synthesized by a low-temperature reduction method using CaH2. Ca1-xSrxFeO2/La0.9Ba0.1F2.9/vapor grown carbon fiber (VGCF) was used as the composite cathode, La0.9Ba0.1F2.9 as the electrolyte and Pb/PbF2/ La0.9Ba0.1F2.9/VGCF as the composite anode to construct the electrochemical cell of the piezoelectric material. Charge-discharge measurements were carried out in the cut-off voltage range of -1.5 to 3.0 V at 140°C. X-ray absorption spectroscopy (XAS) measurements of Fe K-edge, O K-edge, and F K-edge and resonant inelastic X-ray scattering (RIXS) measurements of O K-edge were performed on the samples after charging and discharging.All the Ca1-xSrxFeO2 (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) cathode showed voltage plateaus around -0.5 V and 1.5 V during charging, and the maximum discharge capacity (580 mAh g-1) was obtained when x = 0.8, and the cathodes could be repeatedly charged and discharged. XAS of the Fe K-edge revealed that Fe compensated for the charge in the flat potential region around -0.5 V. XAS and RIXS measurements of the O K-edge revealed that the charge compensation was carried out by the formation of O2 molecules (oxidation of oxide ions), as which is observed in lithium-excess metal oxide on charge process[4], in the voltage plateau around 1.5 V. Using inexpensive Ca and Fe, we succeeded in developing an intercalation cathode material that significantly exceeds the capacity of conventional lithium-ion battery cathodes.

Enhanced low-temperature H2-selective catalytic reduction performance and selectivity of Pt/ZSM-5–TiO2 washcoated monolithic catalysts for NOx reduction

Hydrogen-selective catalytic reduction (H2-SCR) is a promising technology for reducing nitrogen oxide (NOx) emissions at low temperatures, but the selectivity of this process is limited by the generation of N2O. To achieve enhanced denitrification (deNOx) performance, H2-SCR catalysts with mixed zeolite and TiO2 supports washcoated on monolithic cordierite were developed. The catalyst support, active metal type and content, and monolithic cordierite cell density significantly influenced the H2-SCR performance. The xPt/TiO2 catalysts (where x is the metal content, wt.%) achieved >90% NOx conversion 135–180 °C, whereas the xPd/TiO2 catalysts exhibited poor H2-SCR activity, with <30% NOx conversion. In contrast to 0.5Pt/TiO2, the 0.5Pt/zeolite catalysts achieved high NOx conversion at 140–150 °C (91% at 140 °C for 0.5Pt/ZSM-5 > 89% at 140 °C for 0.5Pt/BETA >85% at 150 °C for 0.5Pt/SSZ-13), suggesting that zeolite supports significantly promote H2-SCR activity at low reaction temperatures. For the 0.5Pt/ZSM-5 washcoated monolithic catalyst, increasing the cell density from 400 to 900 cpsi significantly improved the NOx conversion from 52% to 90% at 100 °C owing to the increased geometric surface area and open frontal area of monolithic cordierite. For catalyst with mixed supports (0.5Pt/yZSM-5zTiO2) changing the ZSM-5/TiO2 ratio (y:z) from 25:75 to 90:10 increased the low-temperature NOx conversion from 39% to 89% at 100 °C, indicating that the deNOx characteristics can be tuned. With NO as the reactant, the 0.5Pt/90Z10T catalyst produced the lowest N2O share (8–17%) within the temperature window of maximum NOx conversion, resulting in an increased N2 share (83–88%). Thus, the synergetic effect of mixed ZSM-5/TiO2 catalyst supports can enhance low-temperature NOx conversion and mitigate N2O formation.