The Integration of multiple degradation pathways in a single catalyst is a potential approach to advance the technologies of organic pollutants degradation. To integrate both heterogenized photo-Fenton reaction and Z-scheme...

Switching between the redox potential of an appropriate semiconductor heterostructure could show critical applications in selective CO2 reduction. Designing a semiconductor photocatalyst with a wavelength‐dependent response is an effective strategy for regulating the direction of electron flow and tuning the redox potential. Herein, the switching mechanism between two charge migration pathways and redox potentials in a Bi2S3/TiO2/MoS2 heterostructure by regulating the light wavelength is achieved. In situ irradiated X‐ray photoelectron spectroscopy (ISI‐XPS), electron spin resonance (ESR), photoluminescence (PL), and experimental scavenger analyses prove that the charge transport follows the S‐scheme approach under UV–vis–NIR irradiation and the heterojunction approach under vis–NIR irradiation, confirming the switchable feature of the Bi2S3/TiO2/MoS2 heterostructure. This switchable feature leads to the reduction of CO2 molecules to CH3OH and C2H5OH under UV–vis–NIR irradiation, while CH4 and CO are produced under Vis–NIR irradiation. Interestingly, the apparent quantum efficiency of the optimal composite at λ = 600 nm is 4.23%. This research work presents an opportunity to develop photocatalysts with switchable charge transport and selective CO2 reduction.

The hydrothermal dissolution-recrystallization process is a key step in the crystal structure of titania-based nanotubes and their composition. This work systematically studies the hydrothermal conditions for directly synthesizing anatase TiO2 nanotubes (ATNTs), which have not been deeply discussed elsewhere. It has been well-known that ATNTs can be synthesized by the calcination of titanate nanotubes. Herein, we found the ATNTs can be directly synthesized by optimizing the reaction temperature and time rather than calcination of titanate nanotubes, where at each temperature, there is a range of reaction times in which ATNTs can be prepared. The effect of NaOH/TiO2 ratio and starting materials was explored, and it was found that ATNTs can be prepared only if the precursor is anatase TiO2, using rutile TiO2 leads to forming titanate nanotubes. As a result, ATNTs produced directly without calcination have excellent photocatalytic CO2 reduction than titanate nanotubes and ATNTs prepared by titanate calcination.

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climate change. [1] Thus, there is an acute need to develop green technologies for converting solar energy into pure chemical energy that could reduce the greenhouse effect and alleviates the global energy crunch. [2] Photocatalytic CO 2 reduction into CO or economic hydrocarbon fuel like methane (CH 4 ), as well as photoelectrochemical water splitting into a zerocarbon emission fuel (H 2 production) are promising ways to convert and store solar energy. [2c,3] Semiconductor nanoparticles have gained interest in the fields of photocatalysis, water splitting, and energy conservation and conversion. [2b,3c,4] Among them, titanium oxide has played a significant role in efficiently mitigating air and water pollution problems due to its excellent optoelectronic properties and long-term photostability. [2c,4-7] Yet, the inappropriate large energy band gap, high electron-hole recombination, and unfavorably low solar light consumption have hindered the photoconversion efficiency of the pristine TiO 2 semiconductor. [2c,4b,8] Heterostructuring TiO 2 with an appropriate semiconductor is an operative approach to overcome its drawbacks and construct an efficient photocatalyst. [2c,4a,8] MoS 2 is an appealing semiconductor for fabricating heterostructured Regulating the transfer pathway of charge carriers in heterostructure photocatalysts is of great importance for selective CO 2 photoreduction. Herein, the charge transfer pathway and in turn the redox potential succeeded to regulate in 2D MoS 2 /1D TiO 2 heterostructure by varying the light wavelength range. Several in situ measurements and experiments confirm that charge transfer follows either an S-scheme mechanism under simulated solar irradiation or a heterojunction approach under visible light illumination, elucidating the switchable property of the MoS 2 /TiO 2 heterostructure. Replacing the simulated sunlight irradiation with the visible light illumination switches the photocatalytic CO 2 reduction product from CO to CH 4.13 CO 2 isotope labeling confirms that CO 2 is the source of carbon for CH 4 and CO products. The photo electrochemical H 2 generation further supports the switching property of MoS 2 /TiO 2 . Unlike previous studies, density functional theory calculations are used to investigate the band structure of Van der Waals MoS 2 /TiO 2 S scheme after contact, allowing to propose accurate charge transfer pathways, in which the theoretical results are well matched with the experimental results. This work opens the opportunity to develop photocatalysts with switchable charge transport and tunable redox potential for selective artificial photosynthesis.