Tuning reactive oxygen species at the WO₃/BN interface: a synergistic strategy for high-yield, selective photocatalytic methane-to-methanol conversion

Direct photocatalytic oxidation of methane (CH₄) into high-value liquid oxygenates such as methanol (CH₃OH) under ambient conditions offers a sustainable, solar-driven avenue for C₁ chemical valorization. However, this process faces a persistent activity-selectivity trade-off: the inert chemical nature of the symmetric C-H bond (C-H bond dissociation energy of ~439 kJ/mol) demands powerful oxidizing species for activation, yet the generated target product, CH₃OH, is substantially more reactive than CH₄, rendering it highly vulnerable to overoxidation into formaldehyde (HCHO), carbon monoxide (CO), and carbon dioxide (CO₂).

To break this classic trade-off, a research team from Southwest Petroleum University and Chengdu University has developed an advanced interfacial coupling strategy by anchoring tungsten trioxide (WO₃) nanoparticles onto two-dimensional hexagonal boron nitride (BN) nanosheets. Published in ENGINEERING Energy, their study demonstrates that the resulting WO₃/BN interface regulates charge-carrier transfer and the balance of reactive oxygen species (ROS), preferentially generating milder hydroperoxyl (•OOH) radicals while moderating hydroxyl (•OH) radical accumulation to promote highly selective methanol production under atmospheric pressure.

Key Research Highlights & Structural Insights

• Interfacial Charge Redistribution:

Interfacial electronic coupling between WO₃ and BN creates a directional charge-separation pathway. BN serves as a hole acceptor that rapidly extracts photogenerated holes, allowing photogenerated electrons to preferentially accumulate within the WO₃ domain.

• Tuning the •OOH/•OH Radical Ratio:

The electron accumulation in the WO₃ domains preferentially enhances hydroperoxyl radicals (•OOH) generation, resulting in a ~2.5-fold enhancement in Electron Paramagnetic Resonance (EPR) signals for •OOH compared to a ~1.6-fold enhancement for •OH. This elevates the relative •OOH/•OH ratio in the catalytic microenvironment.

• Synergistic Methane Activation and Product Formation:

EPR and in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) reveal that the relatively mild •OOH radicals selectively cleave the inert C-H bond of CH₄ to yield methyl intermediates (*CH₃). Concurrently, moderated levels of •OH radicals—partially stabilized by B-OH/N-H interactions on the BN surface—react with *CH₃ to yield CH₃OH while suppressing overoxidation pathways (CH₄ → *CH₃O → *CH₂OH → HCHO → CO₂).

• Superior Catalytic Performance under Ambient Pressure:

The optimized WO₃/BN-1:1 composite catalyst achieves a CH₃OH production rate of 741.6 μmol/(g·h) with a CH₃OH selectivity of 77.2% under 1 atm system pressure at 60 °C. This production rate is nearly double that of pristine WO₃ (376.5 μmol/(g·h)).

• Exceptional Structural & Chemical Stability:

Recycling tests confirmed that the WO₃/BN-1:1 catalyst maintains stable catalytic activity, crystal phase (XRD), and interfacial electronic states (XPS) across five consecutive reaction cycles without noticeable performance decay.

Article Information & Links

· Journal: ENGINEERING Energy

· Read the full article for free:  https://rdcu.be/tFHi1fukxEpa

· Cite this article: Qiu, J., Yu, W., Xu, K., Cao, Y., He, Y., Cai, D., & Zhou, Y. (2026). Regulating reactive oxygen species balance at the WO₃/BN interface for selective photooxidation of methane to methanol. ENGINEERING Energy, 20(5), 10900. https://doi.org/10.1007/s11708-026-1090-0

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