H₂O₂ is widely used as an oxidant for photocatalytic methane conversion to value-added chemicals over oxide-based photocatalysts under mild conditions, but suffers from low utilization efficiencies. Herein, we report that O₂ is an efficient molecular additive to enhance the utilization efficiency of H₂O₂ by suppressing H₂O₂ adsorption on oxides and consequent photogenerated holes-mediated H₂O₂ dissociation into O₂. In photocatalytic methane conversion over an anatase TiO₂ nanocrystals predominantly enclosed by the {001} facets (denoted as TiO₂{001})-C₃N₄ composite photocatalyst at room temperature and ambient pressure, O₂ additive significantly enhances the utilization efficiency of H₂O₂ up to 93.3%, giving formic acid and liquid-phase oxygenates selectivities respectively of 69.8% and 97% and a formic acid yield of 486 μmol_HCOOH·g_catalyst⁻¹·h⁻¹. Efficient charge separation within TiO₂{001}-C₃N₄ heterojunctions, photogenerated holes-mediated activation of CH₄ into ·CH₃ radicals on TiO₂{001} and photogenerated electrons-mediated activation of H₂O₂ into ·OOH radicals on C₃N₄, and preferential dissociative adsorption of methanol on TiO₂{001} are responsible for the active and selective photocatalytic conversion of methane to formic acid over TiO₂{001}-C₃N₄ composite photocatalyst.

H ₂ O ₂被广泛用作氧化剂，用于在温和条件下将甲烷光催化转化为高附加值化学品，而不是基于氧化物的光催化剂，但存在利用效率低的问题。在此，我们报道了O ₂是一种有效的分子添加剂，通过抑制H ₂ O ₂在氧化物上的吸附以及随后的光生空穴介导的H ₂ O ₂解离为O ₂来提高H ₂ O ₂的利用效率。在主要被 {001} 晶面包围的锐钛矿 TiO _{2纳米晶体（表示为 TiO2} {001})-C ₃ N ₄复合光催化剂在室温和常压下，O _{2添加剂显着提高了H 2} O ₂的利用率高达93.3%，甲酸和液相含氧化合物的选择性分别为69.8%和 97% 和 486 μmol _HCOOH ·g_催化剂^-1 ·h ^-1的甲酸产率。_{TiO 2} {001}-C ₃ N ₄异质结内的有效电荷分离，光生空穴介导的 CH _{4活化为 TiO 2}上的·CH ₃自由基{001} 和光生电子介导的 H ₂ O _{2在 C 3} N ₄上活化成·OOH 自由基，以及甲醇在 TiO ₂ {001}上的优先解离吸附是甲烷活性和选择性光催化转化为甲酸的原因TiO ₂ {001}-C ₃ N ₄复合光催化剂。