Hui Miao

As a narrow-band gap semiconductor, antimony sulfide (Sb2S3) exhibits a strong light response while being non-toxic and environmentally benign. These combined properties position it as a leading candidate for the development of low-cost and efficient photoelectrodes. However, severe recombination of photogenerated carriers on the Sb2S3 photocathode surface poses a significant challenge, which not only affects the PEC performance, but also leads to unsatisfactory long-term stability of the photoelectrode. Therefore, enhancing transportation and separation of photogenerated carriers on Sb2S3 surface is crucial for improving its photoelectrochemical (PEC) water splitting performance. To this end, constructing heterojunctions through energy band engineering represents a highly significant strategy. In this work, we used microwave solvothermal method to construct Sb2S3/SnS2 type Ⅱ heterojunction by regulating reaction parameters. On this basis, FeOOH particles were further modified by solution immersion method to form Sb2S3/SnS2/FeOOH composite photocathode. Compared to the Sb2S3 monomer, the Sb2S3/SnS2 photoelectrode exhibited a 6.14-fold enhancement in photocurrent density, reaching up to 3.07 mA/cm2 (0 VRHE). Compared with Sb2S3 monomer (5.44 %), the IPCE value of Sb2S3/SnS2 was 14.12 % (735 nm). Also, the charge injection efficiency of the Sb2S3/SnS2 increased from 6.34 % to 45.55 %. In the one-hour stability test, the photocurrent density of the Sb2S3/SnS2/FeOOH composite photocathode showed no significant attenuation and could produce 2.59 μmol/cm2 hydrogen per hour. This work opens a pathway for developing stable and efficient Sb2S3 photoelectrodes.

Antimony sulfoselenide (Sb₂(S,Se)₃), a highly promising photovoltaic material, has garnered significant attention in solar cell applications. Sb₂(S,Se)₃ exhibits anisotropic carrier transport, with carrier mobility along the [hk1] direction being significantly higher than that along the [hk0] direction. In this work, [hk1]-oriented Sb₂(S,Se)₃ nanorods were epitaxially grown on 2D Bi₂O₂S nanosheets via a one-step hydrothermal method. Subsequently, an S-scheme heterojunction was constructed by integrating In₂S₃. This heterojunction not only compensates for the weak short-wavelength light absorption of the photoanode but also suppresses carrier recombination. Achieving 6.05 mA cm^-2 at 1.23 V_RHE, the composite photoanode confirms enhanced PEC performance through efficient carrier utilization. This work develops a hydrothermal methodology to synthesize quasi-1D Sb₂(S,Se)₃ nanorods and construct 1D-2D Sb₂(S,Se)₃/In₂S₃ heterostructures.

Constructing high catalytic activity heterojunctions to compensate for the shortcomings of single catalysts has promoted the development of semiconductor catalysts in photoelectrochemical (PEC) water splitting. In this case, the 2D/2D Bi₂O₂S/CdS composite was successfully constructed by an in situ surface epitaxial growth method. At 1.23 V vs RHE, the catalytic activity of Bi₂O₂S/CdS with a 2D/2D heterojunction is the highest, and the current density of the Bi₂O₂S/CdS photoanode is 3.46 mA/cm². Compared with the Bi₂O₂S photoanode (0.59 mA/cm²), the performance has been improved by 5.86 times. In electrochemical impedance spectroscopy testing, the arc radius of 2D/2D Bi₂O₂S/CdS is smaller than that of Bi₂O₂S, indicating faster charge-transfer kinetics. The data show that the 2D/2D heterojunction with surface-surface contact successfully enhances the catalytic activity of Bi₂O₂S, greatly elevating the efficiency of charge separation and migration. This study provides a method to enhance the PEC activity in type-I heterojunction photoelectrodes, promoting the application of Bi₂O₂S-based materials in photoelectrochemistry.

Antimony selenosulfide (Sb₂(S,Se)₃) was considered to have great potential for photoelectrochemical (PEC) water splitting applications due to its excellent chemical stability, good light absorption, abundant reserves and non-toxicity. However, Sb₂(S,Se)₃ faces some limitations in the field of PEC, such as the serious recombination problem of photogenerated carriers. Therefore effectively restraining its deep-level defects is the crucial for enhancing its PEC properties. In this paper, We successfully fabricated Sb₂(S,Se)₃/CdSe S-scheme heterojunction via one-step hydrothermal method, which improves its solar absorption capacity, facilitates efficient carrier separation. And, Sb₂(S,Se)₃/CdSe S-scheme heterojunction can suppress the adverse effects of deep-level defects on the PEC performance of Sb₂(S,Se)₃. Under simulated solar irradiation, the light current density can reach 4.02 mA cm⁻² (33.5 times that of monomeric Sb₂(S,Se)₃) at 1.23 V_RHE, accompanied by low initial voltage and extremely high surface charge injection efficiency. This study is of great significance for the application of Sb₂(S,Se)₃ in the PEC field.