Catalytic Cycling Research Articles

Rich-N highly branched COF loaded with imidazolyl ionic liquids for highly efficient catalysis of CO2 conversion under atmospheric pressure

The highly loaded ionic active centers and carbon dioxide (CO2) affinity sites play pivotal roles in catalyzing the gas-solid-liquid three-phase reaction in CO2 cycloaddition. In this study, a kind of rich-N highly branched Covalent organic framework loaded with imidazolyl ionic liquids (DhaTat-COF-IL) was synthesized through a nucleophilic substitution reaction, which bridged the highly loaded imidazolyl ionic liquids (Im-IL) active centers (20.72 %) and strong CO2-philic sites, efficiently promoting the in-situ of CO2 conversion at catalyst interface. The rich-N highly branched Covalent organic framework (DhaTat-COF) benefits from its abundant CO2-philic groups (imine and triazine groups) and microporous properties, exhibiting excellent CO2 enrichment capacity, designed as a porous crystalline material for anchoring high active Im-IL. The resultant DhaTat-COF-IL achieved a quantitative yield of 95 % (selectivity > 99 %) in converting epichlorohydrin (ECH) under ambient pressure at 80 ℃, with a turnover frequency (TOF) value reaching 1582 h⁻¹ at 120 ℃. Additionally, yields of ≥ 94 % were obtained for various terminal-substituted epoxides. Density Functional Theory (DFT) analysis reveals a synergistic effect between −CH and Br− in the DhaTat-COF-IL during catalytic cycling. This work provides valuable insights into the targeted design and performance optimization of Im-IL-grafted COF-based catalysts, emphasizing high efficiency and sustainability in CO₂ conversion.

Co-adsorbate-mediated nitrogen electroreduction on two-dimensional W@BC4N single-atom catalyst: Insight from first-principles

Co-adsorbed intermediates ubiquitous on catalyst surface play an important role in mediating the reaction pathway. Herein, we systematically explore the co-adsorbate (*N2 and *H)-mediated nitrogen electroreduction reaction (NRR) on graphene-like W@BC4N single-atom catalyst (SAC) using density-functional theory (DFT) calculation and ab-initio molecular dynamics (AIMD) simulation. The results reveal that the multiple NRR pathways dependent on adsorption mode of *N2 can cross over with one another. The proton-coupled electron transfer (PCET) in NRR is likely to couple with the intermolecular hydrogen-transfer. With three *N2 and two *H as spectators, NRR can proceed via a mixed consecutive-enzymatic mechanism, where the 6th PCET, *NH2 + (H+ + e-) → *NH3, is the potential-limiting step with UL = -0.72 V, larger than those (UL = -0.47 V, UL = -0.52 V and UL = -0.67 V) absence of the co-adsorbed *N2. Nonetheless, the co-adsorbed *N2 can facilitate the desorption of *NH3, beneficial to catalytic cycling. Given the steric hindrance of the co-adsorbed NHx intermediates, hydrazine (N2H4) is most likely to be produced during NRR. With W single-atom site working synergistically with the adjacent B site, W@BC4N has demonstrated the high promise for driving NRR.

A porous media catalyst for waste polyethylene pyrolysis in a continuous feeding reactor

This study investigated the catalytic pyrolysis of waste polyethylene (PE) using a ZSM-5/Al2O3 porous media catalyst in a continuous feeding mode. The findings revealed that the porous media catalyst with 100 mm height and 40 PPI (pore per inch) pore size had the supreme catalytic performance, which could obtain the highest pyrolysis oil yield and the light fraction (<C12) and aromatics in the oil, and improve the catalytic stability of the porous media catalyst. The optimal operating conditions were the pyrolysis temperature of 460 °C, the carrier gas velocity of 65 mL/min, and the plastic feeding rate of 25 g/h, of which the light fraction and aromatics in the oil were up to 95.25 % and 97.33 %. Moreover, the catalytic cycling performance of the porous media catalyst was thoroughly investigated. The catalytic activity declined and the catalyst deactivation rate decreased after multiple regeneration cycles. This study presents a comprehensive investigation of waste PE catalytic cracking using the porous media catalyst in continuous feeding mode, which can provide insightful guidance on the industrialization of plastic waste valorization.

Construction of plasmonic Z-scheme PGDY@MIL(Fe/Cu) photocatalyst via pore-confined growth of nano-elliptical graphdiyne for efficient photo-Fenton degradation of dinotefuran

Constructing abundant interfaces in composite catalysts to promote their synergistic effects is the key, though a tough challenge for enhancing photo-Fenton catalysts performance. Herein, a pore-confinement strategy is proposed to construct plasmonic Z-scheme PGDY@MIL(Fe/Cu) for ultra-fast removal dinotefuran. Graphdiyne was grown on Cu sites of MIL(Fe/Cu) and formed nano-elliptical graphdiyne (PGDY) nanosheets within the confinement of pores, while the C-Cu interfacial channels were constructed to promote electron transfer in the catalytic process. Upon illumination, PGDY strongly coupled with the incident light and localized surface plasmon resonance (LSPR) could be excited, thus enhancing light absorption efficiency of PGDY@MIL(Fe/Cu) at 375–600 nm and inducing numerous hot electrons. These unique properties accelerated separation efficiency of PGDY@MIL(Fe/Cu) for photogenerated carriers, which boosted the generation rate of active radicals and Fe3+/Fe2+ and Cu2+/Cu+ cycling rates during photo-Fenton catalysis. Finally, PGDY@MIL(Fe/Cu) exhibited excellent catalytic degradation kinetics (99.1 % within 40 min), mineralization efficiency (98 % within 2 h), and catalytic cycling stability for dinotefuran (DNT) compared to the reported advanced catalyst.

MgMnxOy-GAC particle electrode for effective peroxone oxidation: High salinity organic wastewater treatment with synergistic electrocatalytic ozonation

A three-dimensional electro-peroxone (3D-EP) system achieved efficient degradation of high salinity organic wastewater and showed significant implications for potential application. Herein, an MgMn-granule-activated carbon (GAC) particle electrode was developed through impregnation calcination and applied in multipollutant removal. The integration of electrolysis, ozone application, and MgMn-GAC in the 3D-EP system manifested strong synergy, leading to successful elimination of all phenol within 30 min due to ample hydroxyl radical production. The energy consumption of MgMn-GAC was 1.86 kWh·m−3 and the specific energy consumption was 0.033 kWh·g−1 COD, exhibiting high electrical energy utilization efficiency under low applied current and low O3 exposure conditions. After six consecutive reaction experiments, COD removal reached 95.6 %, demonstrating remarkable catalytic activity and cycling stability. The study findings indicate that this material could be used as a low-cost particle electrode for practical wastewater treatment.

Sulfur doped Co3O4 catalyst for efficient and stable oxygen evolution reaction at high current density

The development of oxygen evolution reaction (OER) electrocatalysts with excellent stability at high current density is key to achieving efficient hydrogen production, and spinel Co3O4 is a promising alternative material, yet its application to high current density remains challenging. Here, we employ doping engineering to apply Co3O4 modified by S to the OER. The doping of S optimizes the electronic environment of Co and generates richer oxygen defects, leading to excellent catalytic performance and cycling stability at high current density. The best performing S–Co3O4-45@NF catalyst that required 265 mV to achieve 10 mA/cm2. Furthermore, it exhibits outstanding cycling durability at 10, 200 and 1200 mA/cm2 as well as excellent mass transfer performance in multi-step current tests. The present work provides ideas for the development of low-cost and efficient transition metal-based electrocatalysts at high current density.

Significant reductions of urban daytime ozone by extremely high concentration NOX from ship’s emissions: A case study

In this paper, a four nested Weather Research and Forecasting-Community Multiscale Air Quality (WRF-CMAQ) model was applied to analyze ozone (O3) concentration reductions under the influence of extremely high NOx concentrations emitted from ships at the Hankou Jiangtan (HJ) station adjacent to the Yangtze River in Wuhan, China. By adding NO emissions along the waterway for the sensitivity experiments, the model successfully reproduced two cases of high NOx concentrations on April 9 and April 28, 2020, and one case of persistent and extremely high NOx concentrations on the night of May 3, 2020. During daytime, strong photochemical reactions generated new O3, while the high concentration NOx from ship emissions continuously reduced O3 through catalytic cycling. This led to the O3 concentrations at the HJ station being consistently lower than the surrounding stations in the afternoon, with the high NOx plume dropping O3 concentrations by 51 ppb in 1 h, and NO2 concentrations up to 110 ppb. The presence of large amounts of fresh NO (up to 265 ppb) in the ship emission plumes rapidly reduces O3 concentrations through titration reactions during night, resulting in a wide area of low O3 concentrations (2–4 ppb) over a long period of time. This study demonstrates that the pollution and impact of emissions from ships traveling in waterways on the atmosphere of the surrounding area cannot be ignored.

Improved Structural Description of Different γ-Al2O3 Materials Using Disordered δ5-Al2O3 Phase via X-ray Pair Distribution Function Analysis

Extensive research has been conducted in the past on the crystallographic characteristics of γ-Al2O3 support materials due to their advantageous properties in heterogeneous catalysis. While their structure is most commonly described as spinel, their intrinsic disorder and nanostructure have prompted alternative models involving tetragonal space groups, supercells, or occupancy of non-spinel positions. X-ray pair distribution function (PDF) analysis has further postulated the existence of short-range order domains with structural remnants from boehmite precursors from which γ-Al2O3 is commonly prepared via calcination. In this PDF study, we now show that a recently theoretically found monoclinic δ5-Al2O3 phase is, in fact, best suited for describing the structure of different commercial Al2O3 supports, as well as a self-prepared and an industrial Ni/Al2O3 methanation catalyst. Furthermore, in situ experiments under catalytic cycling in the methanation reaction demonstrate that the nanoscale structure of this δ5 phase is preserved during cycling, pointing towards the high stability of the therein-represented disorder. A complete description of the disordered Al2O3 support structure is crucial in the field of heterogeneous catalysis in order to distinguish disorder within the bulk support from additional interfacial restructuring processes such as surface oxidation or spinel formation due to nanoparticle–support interactions during catalytic cycling in in situ scattering experiments.

Fast and efficient reduction of nitroaromatic compounds with copper oxides supported nitrogen-sulfur Co-doped porous carbon material derived metal-organic framework

The expansion of heteroatom-doped carbons with metal-organic frameworks (MOFs) as precursors under heat treatment has attracted extensive attention for the betterment of the catalytic attributes of carbon-based catalysts. After simply pyrolyzing metal-organic framework (MOF) mixed with thiourea (CH4N2S) particles, N and S-doped porous carbon substrates with favorable structural and compositional properties are obtained. The as-synthesized material, which is named CuxO@CNS-400 acts as a heterogeneous catalyst in the reduction reaction of nitro-aromatic compounds, which has superior performance with high activity. The morphology, structure, and physicochemical properties of CuxO@NSC-400 were successfully synthesized and characterized using XRD, TEM, TGA, FE-SEM, EDX, FT-IR, and Raman. In particular, CuxO@CNS-400, obtained by pyrolysis at 400 °C, demonstrates excellent catalytic efficiency of 98 % and high catalytic cycling stability for rapid and highly efficient nitro aromatics reduction.

Protector-free, non-plasmonic silver quantum clusters by femtosecond pulse laser irradiation: in situ binding on nanocellulose filaments for improved catalytic activity and cycling performance.

This study introduces a new, facile method to synthesize silver clusters from aqueous silver ion solution by using high intensity femtosecond pulse laser irradiation. The particles obtained in the absence of reducing or capping agents are 1-17 nm in size and presented quantum properties, as characterized by fluorescence, but did not exhibit plasmon signals, which is not a common characteristic of conventional silver nanoparticles. In a further development, small silver quantum clusters (∼1 nm) were bound in situ to wet-spun filaments of cellulose nanofibrils by pulsed laser irradiation. The obtained hybrid filaments as well as free silver quantum clusters revealed a catalytic activity remarkably higher than that of free gold quantum clusters; moreover, the hybrid filaments were found to show improved stability and cycling performance for silver-based catalysis. The present results indicate the potential of femtosecond laser irradiation to generate clusters as well as hybrid systems with excellent performance and reactivity.

Monolith floatable dual-function solar photothermal evaporator: efficient clean water regeneration synergizing with pollutant degradation.

Meeting the growing demands of attaining clean water regeneration from wastewater and simultaneous pollutant degradation has been highly sought after. In this study, nanometric CuFe2O4 and plasmonic Cu were in situ confined into graphitic porous carbon nanofibers (CNF) through electrospinning and controlled graphitization, which were integrated onto a melamine sponge (S-FeCu/CNF) as a monolithic evaporator via a calcium ion-triggered network crosslinking method using sodium alginate (SA). This monolithic evaporator serves a dual purpose: harnessing solar-driven photothermal energy for water regeneration and facilitating synchronous contaminant mineralization through advanced oxidation processes (AOPs). The metal-modified FeCu/CNF graphitic porous carbon exhibited an enhanced light absorption property (≥95%) and was further securely anchored on the sponge by a calcium ion-triggered SA crosslinking technique, thereby efficiently restraining salt deposition. The FeCu/CNF evaporator demonstrated a solar-vapor conversion efficiency of 105.85% with an evaporation rate of 1.61 kg m-2 h-1 under one sun irradiation. The evaporation rate of the monolithic S-FeCu/CNF evaporator is close to 1.76 kg m-2 h-1, and an evaporation rate of 1.54 kg m-2 h-1 can be achieved even in 20% NaCl solution, with resistance to salt deposition and cycling stability. Synchronously, the monolithic D-S-FeCu/CNF evaporator also acts as a heterogeneous catalyst to activate peroxymonosulfate (PMS) and trigger rapid pollutant degradation, which also shows excellent catalytic cycling stability, producing clean water that satisfies the World Health Organization (WHO) standards. This work provides a potentially valuable solution for addressing desalination and wastewater treatment.

Leading edge stabilisation of vertical boundary layer diffusion flames

The leading edge stability of vertical boundary layer diffusion flames established over a 3D-printed porous gas burner is revealed through Planar Laser-Induced Fluorescence imaging of the OH radical (OH-PLIF). Flame stability is studied by premixing methane and ethylene with increasing volume fractions of bromotrifluoromethane (CF3Br/Halon-1301) to increase the characteristic chemical timescale. Blow-off occurs at 15.7% and 37.3% CF3Br addition for methane and ethylene respectively, which are remarkably large limits compared to other flame configurations. As CF3Br is added, the flame stand-off distance increases and the reaction zone broadens, thereby increasing the flame length. This accelerates the buoyancy-induced flow ahead of the leading edge, promoting O2 entrainment into the flame anchor. Consequently, the radical scavenging effects on the flame anchor reactivity are dampened, resulting in the flame re-anchoring slightly downstream along the plate. Towards extinction, the flame shortens dramatically due to efficient catalytic cycling and radiative quenching at the flame tip resulting from the brominated species and excessive soot formation. This reduces the O2 mass flux into the kinetically dampened flame anchor resulting in blow-off extinction. Therefore, blow-off is controlled by both the leading edge reactivity and trailing edge length. Methane is shown to be considerably more sensitive compared to ethylene to CF3Br owing to its larger flame speed. These results demonstrate that fire-induced buoyancy greatly increases blow-off limits when using chemically active or inert agents in vertical wall fire configurations.

Mechanistic Insights into Myofibrillar Protein Oxidation by Fenton Chemistry Regulated by Gallic Acid.

Gallic acid (GA, 3,4,5-trihydroxybenzoic acid) is a widely used natural food additive of interest to food chemistry researchers, especially regarding its effects on myofibrillar protein (MP) oxidation. However, existing studies regarding MP oxidation by GA-combined with Fenton reagents are inconsistent, and the detailed mechanisms have not been fully elucidated. This work validated hydroxyl radical (HO·) as the primary oxidant for MP carbonylation; in addition, it revealed three functions of GA in the Fenton oxidation of MP. By coordination with Fe(III), GA reduces Fe(III) to generate Fe(II), which is the critical reagent for HO· generation; meanwhile, the coordination improves the availability and reactivity of Fe(III) under weakly acidic and near-neutral pH, i.e., pH 4-6. Second, the intermediates formed during GA oxidation, including semiquinone and quinone, promoted Fenton reactivity by accelerating Fe catalytic cycling. Finally, GA can scavenge HO· radicals, thus exhibiting a certain degree of antioxidant property. All three functions contribute to MP oxidation as observed in GA-containing meat.

Magnetically recyclable 1 T-2 H MoS2/Fe3O4 hybrids with photothermal-promoted photo-Fenton catalytic performance

The transition metal sulfide MoS2 has attracted great interest from the scientific community as an excellent co-catalyst for promoting Fe2+/Fe3+ cycling in advanced oxidation processes to enhance the efficiency of H2O2 decomposition. A photothermal-enhanced photo-Fenton pollutant degradation strategy was proposed. Hybrids of magnetically recyclable Fe3O4 fabricated 1 T-2 H MoS2 (1 T-2 H MoS2 @Fe3O4) with excellent photothermal conversion efficiency were fabricated to overcome the limitations of relatively low catalytic activity and cycling stability in Fenton reaction. XRD, Raman, TEM and hysteresis loop were employed to evaluate the heterogeneous phase 1 T-2 H MoS2 nanoflowers as well as the magnetic property. The 1 T-2 H MoS2 @Fe3O4 hybrids with excellent photothermal conversion efficiency not only enhance the reaction temperature of the Fenton reaction occurring on the material surface, but also demonstrate an effective interfacial photothermal water evaporation efficiency. Due to the synergistic effect of photocatalysis and photo-Fenton catalytic reaction, a quick degradation of simulated pollution were achieved in 5 mins with 98.3% degradation, which could be further improved to 99% due to the photothermal promoting reaction. The 1 T-2 H MoS2 @Fe3O4 hybrids exhibit good magnetic recyclability, cyclic stability and photothermal performance, which endow it a wide potential application in the field of environmental remediation and the field of water evaporation at the photothermal interface, etc.

Magnetic gold catalysts obtained by sequential preparation for highly efficient catalytic reduction of nitroaromatics

Noble metal catalysts have received considerable interests owing to their glamorous properties and applications in heterogeneous catalysis. In this work, the magnetic Au nanoparticles catalysts were successful fabricated via sequential preparation strategy at room temperature. 4-nitrophenol was chosen as the model molecule to evaluate the catalytic reduction activity for the preparation of amines from their corresponding nitroaromatics. The results showed that the catalytic reaction related with 4-nitrophenol could be achieved in 3 min, and the catalyst could be easily reused at least 15 cycles without significant reduction in activity when the as-prepared Fe3O4@CB6@Au0.4% nanoparticles acted as the catalyst. It revealed that the as-prepared catalyst exhibited outstanding catalytic performance and cycling stability. The SEM and TEM images demonstrated that the Au species presented in composite system in the form of highly dispersed Au0 nanoparticles, playing a crucial role in the catalytic process. Therefore, the Au nanoparticles combined with Fe3O4@CB6 prepared by the sequential preparation strategy had excellent catalytic reduction properties for nitroaromatics, and the method could open a new way for the design of other highly dispersed nanometallic materials.

Ultrafine Gold Nanoparticles Anchored on Pyridine‐Inner‐Functionalized Hollow Porous Organic Nanospheres for Highly Efficient Heterogeneous Catalysis

AbstractThe development of metal nanoparticles (MNPs) loaded on porous materials with high efficiency and stability is significant importance for heterogeneous catalysis. Herein, ultrafine Au NPs are prepared and anchored on hollow porous organic nanospheres (Au@HPONs) with polylactide‐b‐poly(4‐vinylpyridine)‐b‐polystyrene (PLA‐b‐P4VP‐b‐PS) triblock copolymers as precursors and pyridine as the coordination group. In this strategy, pyridine functional groups can coordinate with the Au NPs and uniformly disperse them in the carrier. Due to its hollow porous structure, high specific surface area, and physicochemical stability, the obtained Au@HPONs nanocomposite shows excellent catalytic performance and cycling ability for the oxidation of benzyl alcohol and the reduction of 4‐nitrophenol.

High-Density NiCu Bimetallic Phosphide Nanosheet Clusters Constructed by Cu-Induced Effect Boost Total Urea Hydrolysis for Hydrogen Production.

The development of urea electrolysis technologies toward energy-saving hydrogen production can alleviate the environmental issues caused by urea-rich wastewater. In the current practices, the development of high-performance electrocatalysts in urea electrolysis remains critical. In this work, the NiCu-P/NF catalyst is prepared by anchoring Ni/Cu bimetallic phosphide nanosheets onto Ni foam (NF). In the experiments, the micron-sized elemental Cu polyhedron is first anchored on the surface of the NF substrate to provide more space for the growth of bimetallic nanosheets. Meanwhile, the Cu element adjusted the electron distribution within the composite and formed Ni/P orbital vacancies, which in turn accelerated the kinetic process. As a result, the optimal NiCu-P/NF sample exhibits excellent catalytic activity and cycling stability in a hybrid electrolysis system for the urea oxidation reaction (UOR) and hydrogen evolution reaction (HER). Further, the alkaline urea-containing electrolyzer is assembled with NiCu-P/NF as two electrodes reached a current density of 50 mA cm-2 with a low driving potential of 1.422 V, which outperforms the typical commercial noble metal electrolyzer (RuO2||Pt/C). Those findings suggest the feasibility of the substrate regulation strategy to increase the growth density of active species in preparation of an efficient bifunctional electrocatalyst for cracking the urea-containing wastewater.

A recyclable stereoauxiliary aminocatalyzed strategy for one-pot synthesis of indolizine-2-carbaldehydes

Indolizine-carbaldehydes with the easily modifiable carbaldehyde group are important synthetic targets as versatile precursors for distinct indolizines. However, the efficient one-pot construction of trisubstituted indolizine-2-carbaldehydes represents a long-standing challenge. Herein, we report an unprecedented recyclable stereoauxiliary aminocatalytic approach via aminosugars derived from biomass, which enable the efficient one-pot synthesis of desired trisubstituted indolizine-2-carbaldehydes via [3+2] annulations of acyl pyridines and α,β-unsaturated aldehyde. Compared to the steric shielding effect from α-anomer, a stereoauxiliary effect favored by β-anomer of D-glucosamine is supported by control experiments. Furthermore, polymeric chitosan containing predominantly β-D-anhydroglucosamine units also shows excellent catalytic performance in aqueous solutions for the conversion of various substrates, large-scale synthesis and catalytic cycling experiments. Thus, our approach advances the existing methodologies by providing a rich library of indolizine-2-aldehydes. In addition, it delivers an efficient protocol for a set of late-stage diversification and targeted modifications of bioactive molecules or drugs, as showcased with 1,2,3-trisubstituted indolizine-2-carbaldehydes.

Robust cellulose fiber/fibrous sepiolite coated RuO2-CoP aerogel as monolithic catalyst for hydrogen generation via NaBH4 hydrolysis

Commercial carriers have been used to prepare monolithic NaBH4 hydrolytic catalysts, but the fixed structure and material limit the application scope and design freedom. Herein, the RuO2-CoP catalyst is coated on the surface of fibrous sepiolite (RuO2-CoP@aSep) by in-situ deposition, annealing in air and phosphating, which is constructed into the aerogel with cellulose nanofiber (CNF) and polyvinyl alcohol (PVA) by freeze drying process. The hydrogen generation rate (HGR) of RuO2-CoP@aSep increases from 3655 to 10713mLmin-1gcatalyst-1 by adjusting the mass ratio of cobalt to ruthenium in RuO2-CoP. Moreover, the optimized composite aerogel can get HGR (5268mLmin-1gcatalyst-1) by regulating its formulation, and the catalytic activity and mass loss rate of the aerogel maintains 76.6 and 0.92 % after five cycles of testing. The synergistic interaction between Ru and Co species, micro-nano porous structure, and structural coupling provide good catalytic activity and cycling performance, and show great potential in the design of controllable NaBH4 hydrolyzed monolithic catalysts.

High-efficiency palladium/halloysite nanotubes catalyst for toluene catalytic oxidation: Characterization, performance and reaction mechanism

In this study, the halloysite treated with nitric acid was designed as a functionalized support material for favoring surface availability and dispersion of nanometric palladium (Pd) nanoparticles. The prepared supported catalysts were characterized by X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), H2 temperature-programmed reduction (H2-TPR), and O2 temperature-programmed desorption (O2-TPD). The catalytic performance and reaction mechanism of toluene oxidation were evaluated and proposed. Scanning and transmission electron microscopy images showed that 4–5 nm diameter Pd nanoparticles were uniformly dispersed on the external and edge surfaces of the A-Hal nanotubes and no obvious aggregations observed. The Pd nanoparticles were mainly present in the zero-valent state. The ratio of metallic Pd to Pd oxide species and adsorbed (Oads) to lattice (Olatt) presented a maximum value of 2.54 and 23.0, respectively, when the Pd loading was 0.5%. The prepared support catalysts exhibited a satisfactory catalytic performance and cycling stability for toluene conversion. Among the analyzed samples, the 0.5% Pd/A-Hal catalyst exhibited the highest catalytic activity for toluene oxidation, stability, and water resistance. Toluene conversions of 50% and 90% were obtained at 167 and 185 °C, respectively. In situ diffuse reflection Fourier transform spectroscopy measurements confirmed the intermediates generated during toluene oxidation and revealed that toluene oxidation occurred via the benzyl alcohol → benzaldehyde → benzoic acid → maleic anhydride reaction pathway over the obtained catalysts. These results were attributed to the high content of metal Pd species, abundant Oads species, and low-temperature reducibility. These results indicate that Hal support catalysts are promising materials for application in environmental protection.