Boosting photocatalytic CO2 conversion using strongly bonded Cu/reduced Nb2O5 nanosheets.

Green energy production is becoming increasingly important in mitigating the effects of climate change, and the photocatalytic approach could be a potential solution. However, the main barriers to its commercialization are ineffective catalysis due to recombination, poor optical absorption, and sluggish carrier migration. Here, we fabricated a two-dimensional (2D) reduced niobium oxide photocatalyst synthesized by an in situ thermal method followed by copper incorporation. Compared to its counterparts, pure Nb2O5 (0.092 mmol g-1 CO) and r-Nb2O5 (0.216 mmol g-1 CO), the strongly bonded Cu/r-Nb2O5 (0.908 mmol g-1) sample produced an exceptional amount of CO. The separation of charge carriers and efficient use of light resulted in a remarkable photocatalytic performance. The acceptor levels were created by the Cu nanophase, and the carrier trapping states were created by the oxygen vacancies. This mechanism was supported by ESR and DRIFT analyses, which showed that enough free radicals were produced. This study opens up new possibilities for developing efficient photocatalysts that will generate green fuel.

Epitaxial Growth of Flower-Like MoS2 on One-Dimensional Nickel Titanate Nanofibers: A "Sweet Spot" for Efficient Photoreduction of Carbon Dioxide.

Herein, a full spectrum-induced hybrid structure consisting of one-dimensional nickel titanate (NiTiO3) nanofibers (NFs) decorated by petal-like molybdenum disulfide (MoS2) particles was designed through a facile hydrothermal method. The key parameters for tailoring the morphology and chemical, surface, and interfacial properties of the heterostructure were identified for efficient and selective conversion of CO2 into valuable chemicals. Introducing MoS2 layers onto NiTiO3 NFs provided superior CO2 conversion with significantly higher yields. The optimized hybrid structure produced CO and CH4 yields of 130 and 55 µmol g-1 h-1, respectively, which are 3.8- and 3.6-times higher than those from pristine NiTiO3 nanofibers (34 and 15 µmol g-1 h-1, respectively) and 3.6- and 5.5-times higher than those from pristine MoS2 (37 and 10 µmol g-1 h-1, respectively). This improved performance was attributed to efficient absorption of a wider spectrum of light and efficient transfer of electrons across the heterojunction. Effective charge separation and reduced charge carrier recombination were confirmed by photoluminescence and impedance measurements. The performance may also be partly due to enhanced hydrophobicity of the hierarchical surfaces due to MoS2 growth. This strategy contributes to the rational design of perovskite-based photocatalysts for CO2 reduction.