Regulated Photocatalytic CO 2 -to-CH 3 OH Pathway by Synergetic Dual Active Sites of Interlayer

Herein, composites of nanosheets with van der Waals contacts are employed to disclose how the interlayer-microenvironment affects the product selectivity of carbon dioxide (CO 2 ) photoreduction. The concept of composites of nanosheets with dual active sites is introduced to manipulate the bonding configuration and promote the thermodynamic formation of methanol (CH 3 OH). As a prototype, the CoNi 2 S 4 –In 2 O 3 composites of nanosheets are prepared, in which high-resolution transmission electron microscopy imaging, X-ray photoelectron spectroscopy spectra, and zeta potential tests confirm the presence of van der Waals contacts rather than chemical bonding between the In 2 O 3 nanosheets and the CoNi 2 S 4 nanosheets within the composite. The fabricated CoNi 2 S 4 –In 2 O 3 composites of nanosheets exhibit the detection of the key intermediate *CH 3 O during CO 2 photoreduction through in situ Fourier transform infrared spectra, while the In 2 O 3 nanosheets and CoNi 2 S 4 nanosheets alone do not show this capability, further verified by the density functional theory calculations. Accordingly, the CoNi 2 S 4 –In 2 O 3 composites of nanosheets show the ability to produce CH 3 OH, whereas the CoNi 2 S 4 and In 2 O 3 nanosheets solely generate carbon monoxide products from CO 2 photoreduction.