Department of Chemical Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, 02139 Cambridge, Massachusetts, United States.
ACS Nano. 2017 Jul 25;11(7):6782-6794. doi: 10.1021/acsnano.7b01632. Epub 2017 Jun 14.
Sulfur-rich molybdenum sulfides are an emerging class of inorganic coordination polymers that are predominantly utilized for their superior catalytic properties. Here we investigate surface water dependent properties of sulfur-rich MoS (x = 3/) and its interaction with water vapor. We report that MoS is a highly hygroscopic semiconductor, which can reversibly bind up to 0.9 HO molecule per Mo. The presence of surface water is found to have a profound influence on the semiconductor's properties, modulating the material's photoluminescence by over 1 order of magnitude, in transition from dry to moist ambient. Furthermore, the conductivity of a MoS-based moisture sensor is modulated in excess of 2 orders of magnitude for 30% increase in humidity. As the core application, we utilize the discovered properties of MoS to develop an electrolyteless water splitting photocatalyst that relies entirely on the hygroscopic nature of MoS as the water source. The catalyst is formulated as an ink that can be coated onto insulating substrates, such as glass, leading to efficient hydrogen and oxygen evolution from water vapor. The concept has the potential to be widely adopted for future solar fuel production.
富含硫的钼硫化物是一类新兴的无机配位聚合物，主要因其卓越的催化性能而被应用。在此，我们研究了富含硫的 MoS（x = 3/）及其与水蒸气相互作用的表面依赖性。我们发现 MoS 是一种高吸湿性半导体，每摩尔 Mo 可可逆地结合多达 0.9 个 HO 分子。表面水的存在对半导体的性质有深远的影响，在从干燥到潮湿的环境过渡时，调制材料的光致发光超过 1 个数量级。此外，基于 MoS 的湿度传感器的电导率在湿度增加 30%时可调节超过 2 个数量级。作为核心应用，我们利用 MoS 的发现性质开发了一种无电解质水分解光催化剂，该催化剂完全依赖 MoS 的吸湿性作为水的来源。该催化剂被配制成可以涂覆在绝缘基底（如玻璃）上的油墨，从而可以从水蒸气中有效地产生氢气和氧气。该概念有可能被广泛应用于未来的太阳能燃料生产。
