---
title: Enhancing Photocatalytic Hydrogen Evolution Using a Novel Heterojunction
description: Discover how Timegated® Raman Spectroscopy was utilized to study a novel heterojunction that enhances photocatalytic hydrogen evolution through efficient charge transfer and long-term stability for solar-to-fuel conversion.
---

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# [Enhancing Photocatalytic Hydrogen Evolution Using a Novel Heterojunction](https://www.timegate.com/resources/news/timegated-raman-spectroscopy-for-enhancing-photocatalytic-hydrogen-evolution-using-a-novel-heterojunction)

 Written by [Timegate](https://www.timegate.com/resources/news/author/timegate) | 27.3.2025 12:00

A research paper titled *Interfacial linkage modulated amorphous molybdenum sulfide/bismuth halide perovskite heterojunction for enhanced visible-light-driven photocatalytic hydrogen evolution* has been published in the Applied Catalysis B: Environment and Energy <https://www.sciencedirect.com/journal/applied-catalysis-b-environment-and-energy>by researchers He Zhao, Rossella Greco, Rafal Sliz, Olli Pitkänen, Krisztian Kordas, and Satu Ojala.

This research article focuses on enhancing photocatalytic hydrogen evolution using a novel heterojunction. The study introduces a strategy to tailor the interface of hybrid tri(dimethylammonium) hexaiodobismuthate (DMA3BiI6) and amorphous molybdenum sulfide (a-MoSx) heterojunctions. The key innovation lies in creating an interfacial Mo–S–Bi linkage, which promotes efficient charge transfer. The resulting heterostructures demonstrate improved visible-light-driven photocatalytic hydrogen evolution, achieving a high hydrogen evolution rate and quantum efficiency. The authors conduct detailed physicochemical characterization and photoelectrochemical experiments to elucidate the charge transfer mechanisms and demonstrate long-term stability. Ultimately, the findings suggest a promising approach to improve the photocatalytic performance of bismuth halide perovskite-based systems for solar-to-fuel conversion.

The **[Timegate PicoRaman instrument](https://www.timegate.com/products-and-services/products/picoraman-m3) **using **[Timegated® Technology](https://www.timegate.com/about-us/technology) **was utilized to analyze the structure of amorphous molybdenum sulfide (a-MoSx). This analysis revealed several vibration bands, with peaks at 380 and 403 cm-1 corresponding to the vibrational modes of a particular form of molybdenum sulfide (2H-MoS2). These modes were broadened in a-MoSx, indicating defects such as sulfur vacancies. Additional peaks related to the distorted lattice of a-MoSx were also identified. The shift of one peak to a lower value suggested a weakening of molybdenum-sulfur bonds due to sulfur vacancies, further supported by another broad peak, leading to the conclusion that a-MoSx consists of disordered 2H-MoS2 with sulfur vacancies. Based on the analysis of the Raman spectra, it was presumed that the a-MoSx consists of disordered 2 H–MoS2 with S vacancies. 

Read more from the open-access article [here](https://doi.org/10.1016/j.apcatb.2024.124454).

### ***Abstract***

Photocatalytic hydrogen evolution is a promising approach for direct solar-to-fuel conversion. Although significant research efforts have been put on the development of lead-free metal halide perovskites to reach excellent optoelectronic properties, their rational design for efficient heterojunction photocatalytic systems still poses challenges. Here, we report a new strategy to tailor the interface of hybrid tri(dimethylammonium) hexaiodobismuthate (DMA3BiI6) and amorphous molybdenum sulfide (a-MoS*x*) heterojunctions. Specifically, a-MoS*x* was prepared with abundant apical S2– or bridging S22– ligands to allow coupling with DMA3BiI6 via an interfacial Mo–S–Bi linkage. The as-obtained heterostructures were found to show an improved visible-light-driven photocatalytic hydrogen evolution in hydroiodic acid splitting under mild conditions reaching a superior hydrogen evolution rate of around 750 µmol g−1 h−1 and an apparent quantum efficiency (AQE) of 13.0 % at 420 nm. The high activity was kept after a long-term performance test for 3 days.

[Contact us](https://www.timegate.com/contact-us) for more information on [Timegated® Technology](https://www.timegate.com/about-us/technology) for Environmental and Energy applications.

 

 

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