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[Display omitted] • The dual-plasma enhanced g-C 3 N 4 /Pd/MoO 3-x heterojunction was fabricated for high-selectivity photocatalytic CO 2 reduction. • The g-C 3 N 4 /Pd/MoO 3-x composites revealed excellent near-infrared absorption ability. • The carrier separation efficiency was effectively improved under the synergistic effect of MoO 3-x and Pd nanosheets. • The g-C 3 N 4 /Pd/MoO 3-x S-scheme heterojunction displayed high photocatalytic performance and CO selectivity. • The S-scheme charge transfer mechanism was proposed based on UPS and ESR results. The localized surface plasmon resonance (LSPR) effect has shown significant progress in enhancing the efficiency of light absorption and separating photogenerated carriers. Herein, the dual-plasma enhanced 2D/2D/2D g-C 3 N 4 /Pd/MoO 3-x (CPM) S-scheme heterojunction photocatalysts were synthesized using the method of hydrothermal and electrostatic self-assembly for high-selectivity photocatalytic reduction of CO 2 to produce CO. The dual LSPR effect of MoO 3-x and ultrathin Pd nanosheets synergistically broadened the optical response range of the CPM composites and successfully improved the photocatalytic activity and near-infrared (NIR) performance. The optimized CPM-30 photocatalysts exhibited CO yields of 18.55 μmol g−1 with a selectivity of 96.3%. In addition, the CO yield reached 3.92 μmol g−1 after 4 h of NIR light photoirradiation. The electron spin resonance (ESR) and ultraviolet photoelectron spectroscopy (UPS) tests showed that the S-scheme heterojunctions were constructed by coupling g-C 3 N 4 /Pd nanosheets and MoO 3-x. This work will provide a reference for improving product selectivity through the design of two-dimensional composites and the utilization of plasma materials. [ABSTRACT FROM AUTHOR]

S-scheme heterojunction of In 2 O 3 /H 1.5 CN/2Au was prepared by hydrothermal, acidizing and calcination methods. The two-dimensional thin layer H 1.5 CN avoided the aggregation of In 2 O 3 and completed the S-scheme charge transfer with In 2 O 3. Moreover, Au not only enhanced the visible light absorption capacity of composites but also provided more active sites for CO 2 reduction. [Display omitted] • S-scheme heterojunction of In 2 O 3 /H 1.5 CN/2Au achieve CO 2 photocatalytic conversion to CO and CH 4. • The enhanced photocatalytic activity results from effective interfacial charge migration and separation and increased active sites. • The LSPR effect of Au improves the utilization of visible light. The construction of S-scheme heterojunction is of great significance for the photocatalytic reduction of CO 2. Here, we prepared two-dimensional (2D) ultra-thin g-C 3 N 4 by acidifying the carbon nitride precursor, and used In 2 O 3 to construct a S-scheme heterojunction with 2D g-C 3 N 4 , and finally In 2 O 3 /H 1.5 CN was modified with Au nanoparticles. The physicochemical properties of the prepared materials were studied by SEM/TEM, XPS, DRS, PL and photochemical test. Meantime, the S-scheme charge transfer mechanism was demonstrated by UPS and ESR. As a result, on the one hand, S-scheme heterojunction accelerated the transfer of electrons on the CB of In 2 O 3 to the VB of g-C 3 N 4 , avoided the recombination of photon-generated carrier. On the other hand, Au, as an effective cocatalyst, promoted photoinduced electron transfer and provided more active sites for CO 2 reduction and the local surface plasmon resonance phenomenon caused by Au NPs enhanced the visible light absorption capacity of the composite material. Moreover, 2D thin layer of g-C 3 N 4 played a carrier effect to disperse In 2 O 3 cube. Therefore, In 2 O 3 /H 1.5 CN/2Au had stable CO 2 reduction products, and the yields of CO/CH 4 reached 141.24/77.05 μmol/g. [ABSTRACT FROM AUTHOR]

rGO modified g-C 3 N 4 /R-CeO 2 Multi-interface contact S-scheme heterojunction photocatalyst maximizes the transfer efficiency of photogenerated electron and the CO 2 adsorption ability, thus greatly improving the CO 2 photoreduction performance. [Display omitted] • 2D-1D-2D g-C 3 N 4 /R-CeO 2 /rGO photocatalyst has been prepared for CO 2 photoreduction. • 2D-1D-2D multi-interface contact structure is of help for carrier transfer process. • π-π conjugation effect and Ce4+/Ce3+ transformation facilitate electron transmission. • In-situ FTIR and 13C isotope tracer tests analysis the CO 2 photoreduction mechanism. Construction of multi-interface contact step-scheme (S-scheme) photocatalyst is a promising pathway to achieve high-electron transfer efficiency for photocatalytic CO 2 reduction. In this paper, g-C 3 N 4 nanosheets were selected as the main photocatalyst, rod-like CeO 2 (R-CeO 2) with unique Ce4+→Ce3+ conversion property and rGO were loaded on the g-C 3 N 4 surface to construct 2D-1D-2D sandwich photocatalyst. The yields of CO and CH 4 were about 63.18 and 32.67 μmol/g after 4 h when the rGO/R-CeO 2 /g-C 3 N 4 was used as catalyst, which were about 4 and 6 times higher than that of pure CN, respectively. Cyclic experiments proved that the composite had excellent photocatalytic and material stability. Photoelectrochemical tests showed that the construction of S-scheme electron transfer model and the introduction of rGO can great enhance the electron transmission and separation of photogenerated electron-hole pairs. CO 2 adsorption test identified that the loading of R-CeO 2 and rGO obviously enhanced the CO 2 adsorption ability of pure g-C 3 N 4. Density functional theory (DFT) calculations used to analyze the electron transfer path and the formation of the build-in electric field at the semiconductor interface. In-situ FTIR and 13CO 2 element-tracer detection carried out to research the process of CO 2 photoreduction. A possible multi-interface contact S-scheme electron transfer mechanism for enhanced CO 2 photoreduction activity has been discussed. [ABSTRACT FROM AUTHOR]