C-H Activation Research Articles

Activation of CH4, NH3, and N2 by Tantalum Ions, Clusters and Their Oxides: What Can Be Learnt from Studies of Ions in the Gas Phase.

The emission control of harmful compounds and greenhouse gases and the development of alternative, sustainable fuel sources is a major focus in current research. A solution for this problem lies in the development of efficient catalytic materials. Here, gas phase model systems represent prominent examples for obtaining fundamental insights on reaction properties of prospective catalytic systems. In this work, we review results from studies of tantalum clusters and their oxides in the gas phase and discuss insights with a potential relevance for applied systems. We focus on reactions that are essential for sustainable chemistry in the future. In detail, we address the activation of methane, which may enable the transformation of a greenhouse gas to a chemical feedstock, and we discuss the activation of NH3, which may function as an alternative energy carrier whose unwanted emission needs to be curbed in future applications. Finally, we consider the activation of N2 as a third reaction, since reducing the high energy demand of ammonia synthesis still bears significant challenges. While tantalum may be an interesting catalytic material, the discussed studies may also serve as benchmark for investigations of other materials.

Mechanistic and Kinetic Analysis of Complete Methane Oxidation on a Practical PtPd/Al2O3 Catalyst

A PtPd/Al2O3 catalyst developed for the complete oxidation of methane from the ventilation air of underground coal mines is compared against a model PdO/Al2O3 catalyst. Although the PtPd/Al2O3 catalyst is substantially more active and stable than the model catalyst, the nature of active sites between the two catalysts is deemed to be fundamentally the same based on their response to different feed gas compositions and the evolution of surface CO adsorption complexes during time-resolved CO adsorption DRIFTS experiment. For both catalysts, coordinatively unsaturated Pd sites are considered the active centers for methane activation and the subsequent oxidation reaction. H2O competes with CH4 for the same active sites, resulting in severe inhibition. Additionally, the CH4 oxidation reaction also causes self-inhibition. Taking both inhibition effects into consideration, a relatively simple kinetic model is developed. The model provides a good fit of the 72 sets of kinetic data collected on the PtPd/Al2O3 catalyst under practically relevant reaction conditions with CH4 concentration in the range of 0.05–0.4%, H2O concentration of 1.0–5.0%, and reaction temperatures of 450–700 °C. Kinetic parameters based on the model suggest that the CH4 activation energy on the PtPd/Al2O3 catalyst is 96.7 kJ/mol, and the H2O adsorption energy is −31.0 kJ/mol. Both values are consistent with the parameters reported in the literature. The model can be used to develop catalyst sizing guidelines and be incorporated into the control algorithm of the catalytic system.

Enhanced electrocatalytic C[sbnd]H amination of toluene via tailored interfacial microenvironment

Electrocatalytic CH amination of hydrocarbons is a promising avenue for the synthesis of high-value CN compounds. However, efficient activation of CH bonds remains a significant challenge in electrocatalytic CN coupling. Herein, we present a novel strategy to enhance the electrocatalytic conversion of toluene to N-benzylacetamide through a Ritter–type reaction by engineering a hydrophobic electrode–electrolyte interface using polytetrafluoroethylene (PTFE)-coated carbon paper (CP). The hydrophobic CP-based electrode exhibited a superior N-benzylacetamide productivity of 1860.9 mmol m−2h−1 and a substantially higher Faradaic efficiency (FE) of 70.1 % compared to pure CP (41.5 %). Experimental results and density functional theory (DFT) calculations reveal that the PTFE coating promotes toluene adsorption and efficiently lowers the energy barrier for toluene dehydrogenation. Additionally, the hydrophobic interface effectively hinders water adsorption on the electrode, suppressing the competitive water oxidation reaction. This study underscores the crucial role of interfacial engineering in optimizing electrocatalytic CN coupling reactions for the sustainable synthesis of high-value amide compounds.

Extra-framework cations promoted zeolite-encaged cobalt catalysts towards efficient ethylbenzene dehydrogenation

The transformation of ethylbenzene to styrene through direct dehydrogenation is essential process in chemical industry, indispensable for the synthesis of polymers and plastics. Herein, faujasite zeolite encaged cobalt catalyst with potassium ion as the extraframework cations, namely K-Co@Y, is reported to be a robust catalyst for ethylbenzene direct dehydrogenation, showing ethylbenzene conversion of ∼45 % and styrene selectivity of ∼95 % simultaneously under employed conditions. The superior performance of K-Co@Y in comparison with Na-Co@Y is attributed to the effective modulation of zeolite-encaged Co2+ species by extraframework K+ ions, which increases the electron density of cobalt sites and facilitates CH bond activation. Although coke deposits cause gradual deactivation, the structural integrity of K-Co@Y can be well preserved during the dehydrogenation reaction and the performance can be full restored via a simple calcination regeneration step, making K-Co@Y an eligible catalyst for long-term running in the continuous regeneration mode. This study highlights the vital role of extraframework cations in zeolite-encaged single-site catalysts for target chemical transformations and opens up a new way to modulate the performance of zeolite catalysts.

Facile synthesis of substituted 2-styrylnaphthyridine derivatives via sp3 C-H functionalization under mild conditions and their antimicrobial activity and Electrochemical properties

Metal-free synthetic approach for the Efficient synthesis of pyrazole, imidazopyridine based substituted 2-styryl-1, 8-naphthyridines has developed via sp3 CH activation of substituted 7-methyl-1,8-naphthyridines, with various aromatic/heteroaromatic aldehydes through knoevenagel condensation under mild basic (Piperidine) conditions. Further, the synthesized titled molecules tested their absorption and emission spectra, interestingly compound 3d was found to be that inspiring emission spectra at 626 nm (red shift) with impressive stokes shift 133 nm. Moreover, some of the best resultant conjugate scaffolds (compounds 3c, 3d, 3e, and 4e) were analysed their electrochemical properties, thus, 3c, 3d, 3e, and 4e molecules respectively displaying medium to good redox potentials (compound 3e displays 0.3, -1.71 V respectively) and tested scanning rate (from 50 to 500 mV s−1) also. Furtherly, all synthsized derivatives analysed their biological activity, i.e., antifungal and antifungal. Among that, the compounds 3c, 3d, 3e, 3i, 3k, 3l, 5c, 5d and 5f respectively were established excellent inhibition zone of activity against standard drugs.

An integrated photocatalytic redox architecture for simultaneous overall conversion of CO2 and H2O toward CH4 and H2O2

Solar-driven overall conversion of CO2 and H2O into fuels and chemicals shows an ultimate strategy for carbon neutrality yet remains a huge challenge. Herein, an integrated photocatalytic redox architecture of Zn NPs/GaN Nanowires (NWs)/Si is explored for light-driven overall conversion of CO2 and H2O into CH4 and H2O2 simultaneously without any external sacrificial agents and additives. The as-designed architecture affords a benchmark CH4 activity of 189 mmol gcat−1 h−1 with a high selectivity of 93.6%, in the synchronized formation of H2O2 at a considerable rate of 25 m g−1 h−1. Moreover, a considerable turnover number of 27,280 mol CH4 per mol Zn was achieved over a long-term operation of 80 h. By operando spectroscopic characterizations, isotope experiments, and density functional theory calculations, it is unraveled that Zn sites are synergetic with GaN to drive CO2-to-CH4 conversion with a lowered energy barrier of 0.27 eV while inhibiting hydrogen evolution reaction with a relatively high energy barrier of 0.93 eV. Notably, owing to the unique surface properties of GaN, water is split into *OH and *H, followed by the formation of H2O2 because of the alleviated adsorption strength of *OH by Zn NPs. Together, the hierarchical architecture enables the achievement of high activity and high selectivity of CH4 from CO2 reduction in distilled water along with the generation of H2O2. This work provides an integrated photocatalytic redox architecture for the synchronized production of CH4 and H2O2 with the only inputs of CO2, distilled water, and light.

Incorporating Si into NiO support to facilitate oxygen activation for CH4 combustion

In this study, high-performance Pd/NiO-Si catalysts for lean methane oxidation were synthesized using the solution combustion and impregnation method. The incorporation of silicon in NiO promoted the generation of Ni2+ and strengthened the metal-support interaction. This enhanced interaction promoted the generation and movement of active oxygen species on surface, which are essential for maintaining Pd species in an active oxidized state, thereby ensuring the effective activation of CH4. The Pd/NiO-Si catalyst with an optimal amount of Si exhibited an excellent catalytic performance, achieving a T90 of 440 °C for methane oxidation under wet conditions. The elemental doping strategy in this study, which significantly enhances the production of highly active oxygen species with strong mobility, plays a crucial role in the effective utilization of precious metals such as Pd.

Self-Assembled Controllable Cu-Based Perovskite/Calcium Oxide Hybrids with Strong Interfacial Interactions for Enhanced CH4 Electrosynthesis.

Cu-based perovskite oxide catalysts show promise for CO2 electromethanation, but suffer from unsatisfactory CH4 selectivity and poor stability. Here, we report self-assembled, controllable Cu-based perovskite/calcium oxide hybrids with strongly interacting interfaces for high-performance CH4 electrosynthesis. As proof-of-concept catalysts, the La2CuO4/(CaO)x (x from 0.2 to 1.2) series has tunable CaO phase concentrations and thus controllable interface sizes. The La2CuO4 and CaO components are intimately connected at the interface, leading to strong interfacial interactions mainly manifested by marked electron transfer from Ca2+ to Cu2+. In CH4 electrosynthesis, their activity and selectivity show a volcano-type dependence on the CaO phase concentrations and are positively correlated with the interface sizes. Among them, the La2CuO4/(CaO)0.8 delivers the optimal activity and selectivity for CH4, together with good stability, much better than those of a physical-mixture counterpart and most reported Cu-based perovskite oxides. Moreover, La2CuO4/(CaO)0.8 stands out as one of the most effective Cu-based catalysts for CH4 electrosynthesis, achieving a high CH4 selectivity of 77.6% at 300 mA cm-2. Our experiments and theoretical calculations highlight the significant role of self-assembly-induced strong interfacial interactions in promoting *CO adsorption/hydrogenation, intensifying resistance to structural degradation, and consequently underpinning the achievement of such optimized performance.

Cold plasma-activated Ni-Co tandem catalysts with CN vacancies for enhancing CH4 electrocatalytic to methyl formate

The direct electrooxidation of methane (CH4OR) into high value-added liquid products has been considered an effective method to efficient and clean utilization of methane. However, this process is mainly limited by CH4 activation and subsequent intermediate regulation. Here, we report the first successful achieve methyl formate from CH4OR on Ni-Co tandem catalysts with CN vacancies prepared by H2 cold plasma. The faradaic efficiency of CH4OR into methyl formate reaches 56.7 % at 2.0 V vs. RHE with remained stability for 160 h. In situ ATR-SEIRAS and DFT calculations suggest that the CN vacancies can shift the d-band center of the active Ni sites upwards to enhance the chemisorption of CH4 over Ni atom near CN vacancy, generating the key intermediates of *CH3 and *CH2. *CH2 further overflows onto the Co atom around the same CN vacancy, providing favorable conditions for esterification reaction to obtain methyl formate. This work opens a new avenue for the development of efficient electrocatalytic systems for the clean utilization of methane and the electrosynthesis of methyl formate under ambient conditions.

Boosting Dry Reforming of Methane Over NiCo/CeO2 Catalysts Treated by Hydrogen Plasma

ABSTRACTNickel (Ni)‐based catalysts are prospective materials for dry reforming of methane (DRM) reaction, but suffer from coke formation and limited activity for CO2 conversion. To improve the reactivity of Ni‐based catalysts, a promising strategy is introducing cobalt (Co) metal. Here, we construct highly efficient NiCo sites on CeO2 support by H2 plasma, which enables the catalyst to obtain a remarkable increase in DRM reaction than the samples treated by conventional H2 reduction. H2 plasma treatment results in the formation of highly dispersed NiCo alloy nanoparticles and high‐concentration oxygen vacancy. These features create large numbers of highly active sites to boost the activation of CH4 and especially CO2 and their catalytic reactions, resulting in strong coke resistance in the DRM reaction.

Surface Restructuring of Hollow Ni@S-1 Promoted the Activation of CH4 and CO2 in Chemical Looping

Surface Restructuring of Hollow Ni@S-1 Promoted the Activation of CH₄ and CO₂ in Chemical Looping

Theoretical screening of single-atom catalysts (SACs) on Mo2TiC2O2 MXene for methane activation

Producing value-added chemicals and fuels from methane (CH4) under mild conditions efficiently utilizes this cheap and abundant feedstock, promoting economic growth, energy security, and environmental sustainability. However, the first CH bond activation is a significant challenge and requires high energy. Efficient catalysts have been sought for utilizing CH4 at low temperatures including emerging single-atom catalysts (SACs). In this work, we screened fourteen transition metals (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Pt) doped at a single oxygen vacancy in Mo2TiC2O2 (TMSA-Mo2TiC2O2 SACs) for methane activation using density functional theory (DFT) calculations. Our results reveal that methane adsorption is thermodynamically stable on all simulated TMSA-Mo2TiC2O2 SACs, with the adsorption energies (Eads) ranging from −0.92 to −0.40 eV. For the CH activation process, Ru-SAC exhibits the lowest activation barrier (Ea) of 0.22 eV. In summary, Ru-, Rh-, Co-, V-, Cr-, Ti-, and Pt-SACs demonstrate promising catalytic properties for methane activation, with Ea values below 1.0 eV and an exothermic nature. Our findings pave the way for the design and development of novel single-atom catalysts in MXene materials, applicable not only for methane activation but also for other alkane dehydrogenation processes.

Regulating Atomically-Precise Pt Sites for Boosting Light-Driven Dry Reforming of Methane.

Light-driven dry reforming of methane is a promising and mild route to convert two greenhouse gas into valuable syngas. However, developing facile strategy to atomically-precise regulate the active sites and realize balanced and stable syngas production is still challenging. Herein, we developed a spatial confinement approach to precisely control over platinum species on TiO2 surfaces, from single atoms to nanoclusters. The configuration comprising single atoms and sub-nanoclusters engenders pronounced electronic metal-support interactions, with resultant interfacial states prompting surface charge rearrangement. The unique geometric and electronic properties of these atom-cluster assemblies facilitate effective activation of CH4 and CO2, accelerating intermediate coupling and minimizing side reactions. Our catalyst exhibits an outstanding syngas generation rate of 34.41 mol gPt -1 h-1 with superior durability, displaying high apparent quantum yield of 9.1 % at 365 nm and turnover frequency of 1289 h-1. This work provides insightful understanding for exploring more multi-molecule systems at an atomic scale.

Regulating Atomically‐Precise Pt Sites for Boosting Light‐Driven Dry Reforming of Methane

AbstractLight‐driven dry reforming of methane is a promising and mild route to convert two greenhouse gas into valuable syngas. However, developing facile strategy to atomically‐precise regulate the active sites and realize balanced and stable syngas production is still challenging. Herein, we developed a spatial confinement approach to precisely control over platinum species on TiO2 surfaces, from single atoms to nanoclusters. The configuration comprising single atoms and sub‐nanoclusters engenders pronounced electronic metal‐support interactions, with resultant interfacial states prompting surface charge rearrangement. The unique geometric and electronic properties of these atom‐cluster assemblies facilitate effective activation of CH4 and CO2, accelerating intermediate coupling and minimizing side reactions. Our catalyst exhibits an outstanding syngas generation rate of 34.41 mol gPt−1 h−1 with superior durability, displaying high apparent quantum yield of 9.1 % at 365 nm and turnover frequency of 1289 h−1. This work provides insightful understanding for exploring more multi‐molecule systems at an atomic scale.

The Neolignan Honokiol and Its Synthetic Derivative Honokiol Hexafluoro Reduce Neuroinflammation and Cellular Senescence in Microglia Cells.

Microglia-mediated neuroinflammation has been linked to neurodegenerative disorders. Inflammation and aging contribute to microglial senescence. Microglial senescence promotes the development of neurodegenerative disorders, including Alzheimer's disease (AD). In this study, we investigated the anti-neuroinflammatory and anti-senescence activity of Honokiol (HNK), a polyphenolic neolignane from Magnolia officinalis Rehder & E.H Wilson, in comparison with its synthetic analogue Honokiol Hexafluoro (CH). HNK reduced the pro-inflammatory cell morphology of LPS-stimulated BV2 microglia cells and increased the expression of the anti-inflammatory cytokine IL-10 with an efficacy comparable to CH. HNK and CH were also able to attenuate the alterations in cell morphology associated with cellular senescence in BV2 cells intermittently stimulated with LPS and significantly reduce the activity and expression of the senescence marker ß-galactosidase and the expression of p21 and pERK1/2. The treatments reduced the expression of senescence-associated secretory phenotype (SASP) factors IL-1ß and NF-kB, decreased ROS production, and abolished H2AX over phosphorylation (γ-H2AX) and acetylated H3 overexpression. Senescent microglia cells showed an increased expression of the Notch ligand Jagged1 that was reduced by HNK and CH with a comparable efficacy to the Notch inhibitor DAPT. Overall, our data illustrate a protective activity of HNK and CH on neuroinflammation and cellular senescence in microglia cells involving a Notch-signaling-mediated mechanism and suggesting a potential therapeutic contribution in aging-related neurodegenerative diseases.

Isoacid supplementation influences feed sorting, chewing behaviors, and enteric methane emissions differentially in mid-lactation dairy cows depending on dietary forage level

Past studies have shown that isoacids (ISO) improve dairy cow performance, with effects varying based on dietary forage levels, leading us to speculate that ISO supplementation may also differentially affect enteric methane (CH4) emissions depending on dietary forage levels. Therefore, our primary objective was to examine the effects of ISO supplementation on enteric CH4 emissions in lactating dairy cows fed 2 forage NDF levels (FL), along with monitoring feed particle sorting and chewing behaviors to assess any potential interactions. Sixty-four (64) mid-lactation Holstein cows were utilized in a 10-wk long randomized complete block design trial. Parity, DIM, and prior milk yield (MY) for multiparous cows or genetic merit for primiparous cows were used as blocking factors. Cows were randomly assigned to 1 of 4 diets (n = 16 per diet) with a 2 × 2 factorial arrangement of treatment combinations, including 2 FL, 17 (LF) and 21% forage NDF (HF), without or with ISO supplementation (7.85 mmol/kg DM for isobutyrate and 3.44 mmol/kg DM for 2-methylbutyrate, respectively). Enteric CH4 and chewing activity (rumination and eating time) were measured using the GreenFeed system and sensor-based ear tag system, respectively. The particle size of each diet and ort from individual cows was measured using the Penn State Particle Separator, and a sorting index was calculated. A sorting index of 100 indicates no sorting, while values above or below 100 indicate sorting for or against, respectively. Data were analyzed using a mixed model including FL, ISO, and FL × ISO as fixed effects and block as a random effect (lme4 in R). Our result shows that ISO increased sorting index for long particle in LF (96.1 vs. 109; P < 0.01) but decreased it in HF (100.8 vs. 92.5; P = 0.04). In contrast, ISO did not affect the physically effective particle sorting index (P = 0.51) or intake (P = 0.27) regardless of FL. In alignment with the long particle sorting index, ISO decreased eating and chewing time in the HF but increased them in the LF diet (P < 0.01). In contrast, rumination time was comparable between FL (P = 0.70) and ISO levels (P = 0.19). In the LF diet, ISO supplementation reduced daily CH4 production (g/d) by 9% and intensity (g/kg of MY) by 18% (P < 0.01). In the HF diet, ISO supplementation led to a 10% increase in daily CH4 (P < 0.01) but did not change CH4 intensity (P = 0.17; g/kg of MY) due to improved milk production. Overall, ISO altered feed sorting, feeding behaviors and enteric CH4 emissions depending on FL.

Exploring the potential of cobalt-based catalysts in the methane dry reforming for sustainable energy applications

Cobalt-based powder catalysts with different Co loadings were synthesized via wet impregnation using MgAl2O4 spinel as support. The catalytic properties of the solids were evaluated in the dry-reforming methane at different reaction temperatures and two CH4:CO2 ratios. The catalyst with higher cobalt content (13 %) presented superior performance due to increased Co0 species availability, confirmed by XPS analysis. Besides, this catalyst displayed remarkable resistance to carbon deposition at 550 °C and CH4:CO2 1: 1 ratio. In-situ DRIFT measurements demonstrated the formation and transformation of carbonate and hydrogen carbonate species during the DRM reaction, highlighting efficient CO2 and CH4 activation on the catalyst surface. Based on this data, a structured catalyst was deposited on top of the FeCrAlloy monolith, which was active, stable, selective for H2, and resistant against on/off cycles. Compared with the powder catalyst, the structured system displayed higher catalytic activity, possibly due to higher reducibility of metal species and improved heat transfer provided by the FeCrAlloy substrate. The results highlight the potential of Co-based structured catalysts for H2 or synthesis gas production processes.

Unraveling the catalytic performance of RuO2(1 1 0) for highly-selective ethylene production from methane at low temperature: Insights from first-principles and microkinetic simulations

Despite significant progress in low-temperature methane (CH4) activation, commercial viability, specifically obtaining high yields of C1/C2 products, remains a challenge. High desorption energy (>2 eV) and overoxidation of the target products are key limitations in CH4 utilization. Herein, we employ first-principles density functional theory (DFT) and microkinetics simulations to investigate the CH4 activation and the feasibility of its conversion to ethylene (C2H4) on the RuO2 (1 1 0) surface. The CH activation and CH4 dehydrogenation processes are thoroughly investigated, with a particular focus on the diffusion of surface intermediates. The results show that the RuO2 (1 1 0) surface exhibits high reactivity in CH4 activation (Ea = 0.60 eV), with CH3 and CH2 are the predominant species, and CH2 being the most mobile intermediate on the surface. Consequently, self-coupling of CH2* species via CC coupling occurs more readily, yielding C2H4, a potential raw material for the chemical industry. More importantly, we demonstrate that the produced C2H4 can easily desorb under mild conditions due to its low desorption energy of 0.97 eV. Microkinetic simulations based on the DFT energetics indicate that CH4 activation can occur at temperatures below 200 K, and C2H4 can be desorbed at room temperature. Further, the selectivity analysis predicts that C2H4 is the major product at low temperatures (300–450 K) with 100 % selectivity, then competes with formaldehyde at intermediate temperatures in the CH4 conversion over RuO2 (1 1 0) surface. The present findings suggest that the RuO2 (1 1 0) surface is a potential catalyst for facilitating ethylene production under mild conditions.

Selectively photocatalytic oxidation of methane to methanol promoted by Charge-Polarized Zn-Ti pairs

Photocatalysis offers an intriguing route for selective oxidation of CH4 to CH3OH under mild conditions. However, owing to the ultra-high stability of CH4 and the diversity of oxidative products, the activity of CH4 oxidation and the selectivity of CH3OH are still far from satisfactory. Herein, we report a dual-cocatalyst of Au and bimetallic oxide (Zn2Ti3O8) nanoparticles (NPs) modified TiO2 nanotube (Au/Zn2Ti3O8/TiO2) for highly active and selective photocatalytic oxidation of CH4 to CH3OH with O2 at room temperature. The introduction of Zn2Ti3O8 NPs is skillfully exploited the epitaxies of ZIF-8 on the surface of protonated titanate nanotubes (H-TNTs) and the followed thermal treatment with air. During photocatalytic CH4 oxidation, 1.7 %Au/Zn2Ti3O8/TiO2-4 achieved a formation rate of liquid oxygenates of 1200 μmol·gcat.–1·h−1 with a CH3OH selectivity of 91.5 %, which were much higher than those over 1.7 %Au/TiO2 and 1.7 %Au/ZnO. Mechanism investigation confirmed the presence of the strong electron interaction between Au NPs, Zn2Ti3O8 NPs and TiO2 nanotubes in 1.7 %Au/Zn2Ti3O8/TiO2-4, which intensified the charge polarization between Zn sites and Ti sites. These charge-polarized Zn-Ti sites were not only beneficial to the adsorption and activation of CH4, but also accelerated the further transformation of CH3OOH to CH3OH, as well as inhibited the excessive oxidation of CH3OH.

Ultrathin 2D[sbnd]2D WO3-x-C3N4 heterostructure-based high-efficiency photocatalyst for selective oxidation of toluene

Photocatalytic oxidation of toluene for the organic synthesis of value-added benzaldehyde has attracted great attention in recent years. However, activation of CH bonds and selective production of benzaldehyde under mild green conditions remains a great challenge. Herein, a series of two-dimensional (2D) ultrathin heterostructure-based components (WO3-x-C3N4 nanosheets), fabricated by coupling oxygen-deficient WO3-x with amorphous C3N4 via a simple electrostatic self-assembly method, was demonstrated as high-efficiency photocatalysts to produce benzaldehyde in the presence O2 as oxidant at room temperature. Under optimal conditions, the prepared 10WCN sample (10 wt% WO3-x-C3N4) exhibited improved photocatalytic oxidation ability with a good benzaldehyde selectivity (96 %) and high benzaldehyde yield (2738.6 μmol g−1 h−1) within 6 h, which is 6.6 and 3.3 times than that of pure WO3-x (412.5 μmol g−1 h−1) and C3N4 (835.7 μmol g−1 h−1). The enhanced photocatalytic performance was due to the constructed 2D type II heterojunction and abundant oxygen vacancies (OVs), contributing to the photoinduced carriers' separation and migration efficiently. This work indicates the synergistic effect of defect metal oxides and 2D ultrathin sheet-to-sheet heterojunctions in photocatalytic hydrocarbon conversion.