Cu₂O is a typical p-type semiconductor that can efficiently absorb visible light and has a high absorption coefficient due to its narrow forbidden band. Thus, it finds potential applications in solar energy conversion and photocatalysis. However, Cu₂O photocathodes suffer from a major issue of chemical stability and sluggish proton reduction for splitting water using sunlight. We present here a facile method of coating a thin MoS₂ layer onto Cu₂O to significantly improve its stability and proton reduction efficiency. MoS₂ coating on top of Cu₂O is achieved by spin coating a [Mo₃S₇(S₂CNEt₂)₃]I precursor combined with a thermal annealing process to obtain the optimal stoichiometry. MoS₂ thin films synthesized using this method show good prospects as both a protection layer and an electrocatalyst for hydrogen evolution reactions (HER) due to excellent stability and high electrocatalytic activity. The proton reduction performance of spin-coated MoS₂/FTO electrodes is studied to determine the optimal synthesis conditions using various derivatives of MoS₂ precursors. Our study suggests that the rate-limiting kinetic step of MoS₂ synthesized in this method is the desorption of adsorbed hydrogen atoms to form molecular hydrogen, and that nanocrystalline MoS₂ with copiously exposed S edges are more active for HER. Photoelectrochemical measurements demonstrate the highest activity for 3-layered (<40 nm thick) MoS₂/Cu₂O photocathode fabricated at 450 °C with a photocurrent density of ∼6.5 mA cm⁻² at −0.2 V vs. RHE. Additionally, the MoS₂ coating helps minimize the dark current of the Cu₂O photocathode.

中文翻译：

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由[Mo ₃ S ₇（S ₂ CNEt ₂）₃ ] I 合成MoS ₂，以增强Cu ₂ O光电阴极的光电化学性能和稳定性，从而有效分解太阳能†

Cu ₂ O是典型的p型半导体，由于禁带窄，因此可以有效吸收可见光并且具有高吸收系数。因此，它在太阳能转化和光催化中发现了潜在的应用。但是，Cu ₂ O光阴极存在化学稳定性和质子减少的主要问题，该质子降低了利用阳光将水分解的质子。我们在这里提出一种在Cu ₂ O上涂覆一层薄MoS ₂层的方法，以显着提高其稳定性和减少质子的效率。的MoS ₂的涂层对Cu顶部₂ O由旋涂实现[沫₃小号₇（S ₂ CNET ₂）₃ ] I前驱体与热退火工艺相结合以获得最佳化学计量。使用这种方法合成的MoS ₂薄膜由于具有出色的稳定性和高电催化活性，因此既可以作为氢析出反应（HER）的保护层又可以用作电催化剂。研究了旋涂MoS ₂ / FTO电极的质子还原性能，以确定使用MoS ₂前驱体的各种衍生物的最佳合成条件。我们的研究表明，用这种方法合成的MoS ₂的限速动力学步骤是吸附的氢原子解吸形成分子氢，而纳米晶MoS ₂S边缘大量暴露的HER对HER更为活跃。光电化学测量结果表明，在450°C下制造的3层MoS ₂ / Cu ₂ O光电阴极（厚度小于40 nm）具有最高活性，在-0.2 V相对于RHE的光电流密度为6.5 mA cm ^-2。另外，MoS ₂涂层有助于最小化Cu ₂ O光电阴极的暗电流。