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Improving the performance of thermoelectric (TE) materials and fabricating TE devices with higher conversion efficiency remains a significant challenge in materials research. The low figure of merit (ZT) value of n -type bismuth telluride has seriously hindered the development of TE devices based on bismuth telluride. Element doping and nanostructured defect introduction have commonly been employed to improve TE properties. Herein, we utilized high-pressure synthesis to fabricate n -type Bi 2 Se 0.3 Te 2.7 bulk nanomaterials and enhance their TE performance by adjusting the fabrication pressure and titanium doping concentration. Through this process, titanium effectively substituted bismuth to decrease carrier concentration and improve carrier mobility. As a result, the thermal conductivity was significantly decreased. By employing a fabrication pressure of 2.5 GPa and 10 at % Ti doping, a remarkable ZT value of 0.96 was achieved at 333 K, which was 2.8 times the undoped counterparts. These findings demonstrate a successful design methodology and fabrication process to generate n -type Bi 2 Te 3 with outstanding TE performance. This study provided valuable insights into the synthesis of high-performance TE materials and contributed to advancements in TE device technology. [ABSTRACT FROM AUTHOR]

[Display omitted] • A 2D/2D gC 3 N 4 /MoS 2 van der Waals heterojunction photocatalyst was prepared by a novel one-step method. • The type II band arrangement promotes an increase in photogenerated carrier concentration and separation of photogenerated charge carriers. • The in-situ formed heterojunction interface between gC 3 N 4 and MoS 2 boosts H 2 evolution by 3 times. Two-dimensional (2D) heterostructures have proven their efficiency in separating charges. Herein, a gC 3 N 4 /MoS 2 (CN/MoS 2) photocatalyst, in the form of 2D/2D van der Waals heterojunction with a type-II band alignment, was synthesized using a novel one-step method. The resulting in-situ formed heterojunction interface enhances electron transfer from gC 3 N 4 to MoS 2. The CN/MoS 2 photocatalyst exhibits exceptional activity in generating hydrogen from water under simulated solar light. Its hydrogen production rate was 1285 μmol/h/g, which was approximately 3 times higher compared to gC 3 N 4. This superiority is due to a significant increase in photogenerated carrier density and efficient charge separation facilitated by the type-II heterojunction. This study demonstrates a straightforward one-step approach for synthesizing 2D/2D composite photocatalysts, highlighting the effective synergy between different 2D materials in promoting hydrogen generation. [ABSTRACT FROM AUTHOR]