3D/2D Heterojunction Fabricated from RuS₂ Nanospheres Encapsulated in Polymeric Carbon Nitride Nanosheets for Selective Photocatalytic CO₂ Reduction to CO

Abstract

Micro/nanostructure control of heterostructures is still a challenge for achieving high efficiency and selectivity of photocatalytic CO 2 conversion. In this work, a new three-dimensiona/two-dimensional (3D/2D) heterostructure is fabricated by encapsulating RuS 2 nanospheres in the interlayer of mesoporous polymeric carbon nitride (PCN) nanosheets based on an in situ growth and polymerization strategy. The unique microstructure of the obtained 3D/2D RuS 2 / PCN heterojunction can effectively improve the transfer and separation efficiency of photogenerated charge carriers, reduce the mass transfer resistance of CO 2 toward active sites, and provide a confined reaction space, thus propelling the photocatalytic CO 2 reduction to CO with high selectivity. The CO yield over the optimal 5%-RuS 2 / PCN sample reaches 4.2 and 2.8 times as high as that of single PCN and RuS 2 within 4 h, respectively. Furthermore, the plausible charge transfer mechanism and CO 2 reduction path are revealed by time-dependent in situ Fourier transform infrared (FT-IR) spectra combined with photophysical, electrochemical, and photoelectrochemical techniques and density functional theory (DFT) calculations. This work develops the microstructural engineering design strategy of PCN-based heterojunctions for selective photocatalytic CO 2 fuel conversion.

RuS2@CN-x with exposed (200) facet as a high-performance photocatalyst for selective C–C bond cleavage of biomass coupling with H–O bond cleavage of water to co-produce chemicals and H2

“…50,51 The discovery of Ru-S bonds further proves the successful preparation of RuS 2 @CN-2. 41 To further study the optical properties of CN and RuS 2 @CN-2, ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) was investigated. As compared with CN, the RuS 2 @CN-2 showed a red-shift in the visible light absorption range, indicating that RuS 2 @CN-2 has stronger light capture capability.…”

“…37 In addition to the above metal sulfides, RuS 2 is a semiconductor with a narrow band gap, high conductivity, and hydrogen adsorption free energy similar to Pt. 38–41 Furthermore, RuS 2 has been reported to form photocatalysts with TiO 2 , SiO 2 42 and other materials. 43 For instance, Maheu et al compounded RuS 2 and TiO 2 to obtain RuS 2 /TiO 2 and its photocatalytic activity gradually enhanced with increasing RuS 2 content.…”

Modulating the coordination microenvironment of uranyl compounds to enhance photocatalytic CO2 reduction

“…S6†). 37–40 In addition to the photoelectrochemical characterization, we also analyzed the crystal face index of UCu1 and UCu2 and found that the exposed crystal surfaces in UCu1 are mainly (110) and (1̄10), while the exposed crystal surfaces in UCu2 are mainly (100) (Fig. S7†).…”

Cu-doped mesoporous SnO2 nanoparticles with rich grain boundaries and oxygen vacancies for photocatalytic CO2-to-CO conversion

“…After the photocatalytic CO 2 reduction reaction, three transmittance peaks of intermediate products are detected on the sample Cu(2)–SnO 2 , including adsorbed/activated CO 2 * (1200–1300 cm −1 ), formate *COOH (1400–1500 cm −1 ), and bidentate bicarbonate b-HCO 3 − (1600–1650 cm −1 ). 23,35,36 The obvious transmittance peaks suggest that the adsorbed sample Cu(2)–SnO 2 can be effectively activated, and the appearance of the *COOH peak suggests that CO 2 reduction follows a *COOH pathway, which also explains the reason of the high selectivity of CO.…”