Photocatalytic nonoxidative coupling of CH4 to multicarbon (C2+) hydrocarbons (e.g., C2H4) and H2 under ambient conditions provides a promising energy-conserving approach for utilization of carbon resource. However, as the methyl intermediates prefer to undergo self-coupling to produce ethane, it is a challenging task to control the selective conversion of CH4 to higher value-added C2H4. Herein, we adopt a synergistic catalysis strategy by integrating Pd-Zn active sites on visible light-responsive defective WO3 nanosheets for synergizing the adsorption, activation, and dehydrogenation processes in CH4 to C2H4 conversion. Benefiting from the synergy, our model catalyst achieves a remarkable C2+ compounds yield of 31.85 μmol·g-1·h-1 with an exceptionally high C2H4 selectivity of 75.3% and a stoichiometric H2 evolution. In situ spectroscopic studies reveal that the Zn sites promote the adsorption and activation of CH4 molecules to generate methyl and methoxy intermediates with the assistance of lattice oxygen, while the Pd sites facilitate the dehydrogenation of methoxy to methylene radicals for producing C2H4 and suppress overoxidation. This work demonstrates a strategy for designing efficient photocatalysts toward selective coupling of CH4 to higher value-added chemicals and highlights the importance of synergistic active sites to the synergy of key steps in catalytic reactions.

中文翻译：

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甲烷与乙烯在 Pd-Zn 协同催化位点上的高效和选择性光催化非氧化偶联。

在环境条件下，CH4 与多碳 (C2+) 烃（例如 C2H4）和 H2 的光催化非氧化偶联为利用碳资源提供了一种有前途的节能方法。然而，由于甲基中间体更倾向于自偶联生成乙烷，因此控制CH4选择性转化为附加值更高的C2H4是一项具有挑战性的任务。在此，我们采用协同催化策略，将 Pd-Zn 活性位点整合到可见光响应缺陷的 WO3 纳米片上，以协同 CH4 转化为 C2H4 的吸附、活化和脱氢过程。受益于协同作用，我们的模型催化剂实现了 31.85 μmol·g-1·h-1 的显着 C2+ 化合物产率，以及 75.3% 的极高 C2H4 选择性和化学计量的 H2 释放。原位光谱研究表明，Zn 位点促进 CH4 分子的吸附和活化，在晶格氧的帮助下生成甲基和甲氧基中间体，而 Pd 位点促进甲氧基脱氢生成亚甲基自由基，从而产生 C2H4 并抑制过氧化。这项工作展示了一种设计高效光催化剂以将 CH4 选择性偶联为更高附加值化学品的策略，并强调了协同活性位点对催化反应中关键步骤协同作用的重要性。而 Pd 位点促进甲氧基脱氢生成亚甲基自由基以产生 C2H4 并抑制过氧化。这项工作展示了一种设计高效光催化剂以将 CH4 选择性偶联为更高附加值化学品的策略，并强调了协同活性位点对催化反应中关键步骤协同作用的重要性。而 Pd 位点促进甲氧基脱氢生成亚甲基自由基以产生 C2H4 并抑制过氧化。这项工作展示了一种设计高效光催化剂以将 CH4 选择性偶联为更高附加值化学品的策略，并强调了协同活性位点对催化反应中关键步骤协同作用的重要性。