1D/2D TiO_2/MoS_2 Hybrid Nanostructures for Enhanced Photocatalytic CO_2 Reduction

摘要

Photocatalytic reduction of CO_2 into solar fuels is recognized an attractive approach to solve the environmental and energy crisis. MoS_2, a type of 2D transition metal dichalcogenides, has attracted significant attention in photoelectronics, sensors and photo/electrocatalytic water splitting owing to its remarkable properties. Nevertheless, to date, MoS2 is barely used as (co)catalyst for CO_2 photoreduction. Herein, novel 1D/2D TiO_2/MoS_2 nanostructured hybrid with TiO_2 fibers covered by MoS_2 nanosheets by hydrothermal transformation method is fabricated. The MoS_2 sheet arrays show a lateral size of ≈80 nm and a thickness of down to 2 nm, vertically and uniformly standing upon the TiO_2 fibers. X-ray photoelectron spectroscopy (XPS) results and density functional theory (DFT) calculation imply the intimate chemical interaction between MoS_2 and TiO_2 upon hybridization, which can facilitate electron–hole separation upon photoexcitation. In addition, the hierarchical TiO_2/MoS_2 nanostructure shows enhanced optical absorption and CO_2 adsorption, therefore, a superior photocatalytic activity for reducing CO_2 into methane and methanol is achieved over the hybrid as compared to pristine TiO_2. Isotope (13C) tracer test confirms that the products are produced from the photocatalytic reduction of the CO_2 source instead of any organic contaminants. This work offers an alternative approach to rationally design and synthesize TiO_2-based photocatalysts toward highefficiency photoreduction of CO_2.