Atom substitution method to construct full-solar-spectrum absorption MoSeS/TiO2 nanotube arrays for highly efficient hydrogen evolution

Abstract

Two-dimensional semiconductor shows highly efficient photocatalytic H2 generation due to plasma enhancement effect. Herein, a large area layered MoSeS in conjunction with TiO2 nanotube arrays is achieved by Ti foil anodization and chemical vapor deposition processes. MoSeS/TiO2 heterojunction has been prepared by one-step and two-step atom substitution methods, we found that the one-step atomic substitution method had higher photocatalytic performance than that. The composites can greatly reduce the charge transfer resistance and accelerate the carrier transport, leading to a high photocurrent response. UV–vis absorption spectra indicated an obvious redshift, which greatly improved the utilization efficiency of visible light. Photoelectrochemical properties of the composites showed that one-step atom substituted MoSeS has the highest performance. For the MoSeS/TiO2 by one-step (ES-TNTs), the hydrogen production efficiency reaches 92.74μmolh−1cm−2, which is 11 times higher than that of pure TiO2 nanotube arrays (TNTs). Also, the photocurrent density is 1.2 mAcm−2 at a bias of 0V, which is about 6 times higher than that of pure TNTs. In comparison to the two-step atom substitution method (S-E-TNTs, E-S-TNTs), the result is that MoSeS is easy to agglomerate on the surface of TNTs, which greatly reduces the contacted area and photocurrent density.