Mo₂CT_x is regarded as a potential cocatalyst to substitute noble metals in photocatalytic hydrogen production owing to its good electrical conductivity and a large number of active sites. However, Mo₂CT_x-based photocatalysts by the conventional physical mixing method always display a weak coupling interface between Mo₂CT_x and photocatalysts due to the large block-layered structure of Mo₂CT_x, which results in slow photogenerated-electron transfer of photocatalysts, thereby leading to unsatisfactory hydrogen production efficiency. Considering that in situ construction and the 2D/2D structure can increase the contact area and enhance the coupling interface interaction, in this study, a strategy of constructing a 2D/2D Mo₂CT_x/g-C₃N₄ photocatalyst from pre-etched Mo₂CT_x and guanidine hydrochloride (CH₆ClN₃) through a one-step NH₄Cl-assisted calcination method is realized by the gas-expansion exfoliation of Mo₂CT_x and in situ generation of thin g-C₃N₄ nanosheets. Experimental results unveiled that the 2D/2D Mo₂CT_x/g-C₃N₄ composite photocatalyst exhibits an exceptional H₂-evolution activity (125 μmol h⁻¹ g⁻¹, AQE = 3.88%), which is almost 25 and 18 times greater than that of pure g-C₃N₄ and physically mixed Mo₂CT_x–g-C₃N₄, respectively. The enhanced photocatalytic H₂-production efficiency is attributed to the robust coupling interface between Mo₂CT_x and g-C₃N₄ in 2D/2D Mo₂CT_x/g-C₃N₄, which promotes the fast photogenerated electron transfer from g-C₃N₄ to Mo₂CT_x and achieves an optimized Gibbs free energy. This study offers a novel perspective on preparing high-efficiency 2D/2D MXene-based photocatalysts.

中文翻译：

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2D/2D Mo2CTx/g-C3N4 具有强耦合界面，通过一步 NH4Cl 辅助煅烧增强光催化产氢


Mo ₂ CT _x因其良好的导电性和大量的活性位点而被认为是光催化制氢中替代贵金属的潜在助催化剂。然而，由于Mo ₂ CT _x的大块层结构，传统物理混合方法制备的Mo ₂ CT _x基光催化剂在Mo ₂ CT _x和光催化剂之间总是表现出弱耦合界面，导致光生电子转移缓慢。光催化剂的影响，从而导致产氢效率不理想。 考虑到原位构建和2D/2D结构可以增加接触面积并增强耦合界面相互作用，在本研究中，采用预蚀刻Mo构建2D/2D Mo ₂ CT _x /gC ₃ N ₄光催化剂的策略₂ CT _x和盐酸胍(CH ₆ ClN ₃ )通过一步NH ₄ Cl辅助煅烧方法通过Mo ₂ CT _x的气体膨胀剥离和原位生成薄gC ₃ N ₄纳米片实现。实验结果表明，2D/2D Mo ₂ CT _x /gC ₃ N ₄复合光催化剂表现出优异的H ₂析出活性（125 μmol h ⁻¹ g ⁻¹ ，AQE = 3.88%），分别比纯 gC ₃ N ₄和物理混合的 Mo ₂ CT _x –gC ₃ N ₄提高了近 25 倍和 18 倍。光催化H ₂生产效率的提高归因于2D/2D Mo ₂ CT _x /gC ₃ N ₄中Mo ₂ CT _x和gC ₃ N ₄之间强大的耦合界面，这促进了gC ₃ N的快速光生电子转移₄转化为 Mo ₂ CT _x并实现优化的吉布斯自由能。这项研究为制备高效 2D/2D MXene 基光催化剂提供了新的视角。