CuInS₂ Photocathodes with Atomic Gradation-Controlled (Ta,Mo)_x(O,S)_y Passivation Layers for Efficient Photoelectrochemical H₂ Production

Abstract

An atomic gradient passivation layer, (Ta,Mo) x (O,S) y , is designed to improve the charge transportation and photoelectrochemical activity of CuInS2-based photoelectrodes. We found that Mo spontaneously diffused to the a-TaO x layer during e-beam evaporation. This result indicates that the gradient profile of MoO x /TaO x is formed in the sublayer of (Ta,Mo) x (O,S) y . To understand the atomic-gradation effects of the (Ta,Mo) x (O,S) y passive layer, the composition and (photo)­electrochemical properties have been characterized in detail. When this atomic gradient-passive layer is applied to CuInS2-based photocathodes, promising photocurrent and onset potential are seen without using Pt cocatalysts. This is one of the highest activities among reported CuInS2 photocathodes, which are not combined with noble metal cocatalysts. Excellent photoelectrochemical activity of the photoelectrode can be mainly achieved by (1) the electron transient time improved due to the conductive Mo-incorporated TaO x layer and (2) the boosted electrocatalytic activity by Mo x (O,S) y formation.

Monitoring Transformations of Catalytic Active States in Photocathodes Based on MoSx Layers on CuInS2 Using In Operando Raman Spectroscopy

“…The presence of Mo, MoS x , and MoO x [10] on the as‐deposited Mo surface was confirmed, even though the film had not been annealed. Therefore, we conclude that the reactive high‐energy evaporated Mo atoms react with the S atoms of CuInS 2 during e‐beam evaporation, similar to previously reported results [6a] . However, the binding energy of the MoS x peak indicates that this MoS x phase closely resembles metallic MoS x which has good electronic, electrochemical, and HER properties [9, 11] .…”

Recyclable Copper Indium Sulfide Quantum Dots for Photocatalytic Homocoupling of Arenediazonium Tetrafluoroborates

“…It can provide photoluminescence (PL) emission ranging from the visible to the region, and have broad absorption, large light absorption coefficient, and chemical stability. 49,50 Accordingly, CuInS 2 QDs have been successfully applied in numerous fields including water splitting, 51 pollutant degradation, 52 H 2 production, 53 and CO 2 reduction, 54 biological activity. 55 However, as far as we know, there are few reports on the application of CuInS 2 QDs as a photocatalyst in organic synthesis.…”

Hydrothermal Synthesis in Gap: Conformal Deposition of Textured Hematite Thin Films for Efficient Photoelectrochemical Water Splitting

“…Solar water splitting, in which sunlight is used as the permanent energy source, has attracted considerable attention as a tool for converting photon energy into chemical energy, which is then stored in hydrogen molecules. Considerable effort has been devoted to searching for and developing suitable semiconductor materials since the first development of the photoelectrochemical (PEC) cell using a TiO 2 photoanode. − …”