Photothermal CO2 hydrogenation to methanol on MoS2 with morphology and sulfur vacancies tuning

Photothermal hydrogenation of CO 2 to methanol using renewable H 2 represents a promising strategy for mitigating the greenhouse effect and the energy crisis. MoS 2 has been investigated as an effective catalyst for CO 2 hydrogenation in thermal catalysis. However, till now, the photothermal catalysis of MoS 2 for enhanced methanol synthesis has been rarely reported. In this study, we synthesized and investigated MoS 2 with a series of morphological changes from nanoflower, nanosheet to bulk structures. Characterization revealed that the nanosheet MoS 2 possesses the highest specific surface area and the most abundant active Sv sites. Performance tests indicated that under standalone thermal catalysis, the turnover frequency (TOF) for methanol synthesis follows the order: nanosheet > nano-flower > bulk for MoS 2 . However, the light-enhancement effects under photothermal catalysis exhibited a different trend with respect to morphological structure. It was discovered that bulk MoS 2 , which possesses the least specific surface area and Sv, showed the best light-enhancement effect with 102.45 % increase in methanol yield. It is hypothesized that the light-enhancement effect is more related to more exposed planar sites, which do not align linearly with specific surface area and Sv. These are evidenced by physiochemical characterizations, photoelectric response experiments and performance tests. These findings could offer important insights into future catalyst design for MoS 2 -type materials with both enhanced thermocatalytic activity and light-enhancement effect.