Solar water splitting into H₂ and O₂ is a promising approach to provide renewable fuels. However, the presence of O₂ hampers H₂ generation and most photocatalysts show a major drop in activity in air without synthetic modification. Here, we demonstrate efficient H₂ evolution in air, simply enabled by controlling O₂ diffusion in the solvent. We show that in deep eutectic solvents (DESs), photocatalysts retain up to 97% of their H₂ evolution activity and quantum efficiency under aerobic conditions whereas in water, the same catalysts are almost entirely quenched. Solvent-induced O₂ tolerance is achieved by H₂ generation outcompeting O₂-induced quenching due to low O₂ diffusivities in DESs combined with low O₂ solubilities. Using this mechanism, we derive design rules and demonstrate that applying these rules to H₂ generation in water can enhance O₂ tolerance to >34%. The simplicity and generality of this approach paves the way for enhancing water splitting without adding complexity.

中文翻译：

---

溶剂控制的 O2 扩散可实现耐空气的太阳能制氢

太阳能水分解成H ₂和O ₂是一种提供可再生燃料的有前途的方法。然而，O ₂的存在阻碍了H _{2 的}生成，并且大多数光催化剂在没有合成改性的情况下在空气中的活性显着下降。在这里，我们展示了空气中H _{2 的}高效释放，只需通过控制溶剂中的O ₂扩散即可实现。我们表明，在深共熔溶剂 (DES) 中，光催化剂在有氧条件下保留高达 97% 的 H ₂析出活性和量子效率，而在水中，相同的催化剂几乎完全淬灭。通过 H ₂实现溶剂诱导的 O ₂耐受性由于DESs中的低O ₂扩散率与低O ₂溶解度相结合，产生的O ₂诱导的猝灭胜过O ₂诱导的淬灭。使用这种机制，我们推导出设计规则并证明将这些规则应用于水中的H ₂生成可以将 O ₂耐受性提高到 > 34%。这种方法的简单性和通用性为在不增加复杂性的情况下增强水分解铺平了道路。