Plasmonic Metal Mediated Charge Transfer in Stacked Core–Shell Semiconductor Heterojunction for Significantly Enhanced CO₂ Photoreduction

Abstract

Construction of core–shell semiconductor heterojunctions and plasmonic metal/semiconductor heterostructures represents two promising routes to improved light harvesting and promoted charge separation, but their photocatalytic activities are respectively limited by sluggish consumption of charge carriers confined in the cores, and contradictory migration directions of plasmon‐induced hot electrons and semiconductor‐generated electrons. Herein, a semiconductor/metal/semiconductor stacked core–shell design is demonstrated to overcome these limitations and significantly boost the photoactivity in CO2 reduction. In this smart design, sandwiched Au serves as a “stone”, which “kills two birds” by inducing localized surface plasmon resonance for hot electron generation and mediating unidirectional transmission of conduction band electrons and hot electrons from TiO2 core to MoS2 shell. Meanwhile, upward band bending of TiO2 drives core‐to‐shell migration of holes through TiO2–MoS2 interface. The co‐existence of TiO2 → Au → MoS2 electron flow and TiO2 → MoS2 hole flow contributes to spatial charge separation on different locations of MoS2 outer layer for overall redox reactions. Additionally, reduction potential of photoelectrons participating in the CO2 reduction is elaborately adjusted by tuning the thickness of MoS2 shell, and thus the product selectivity is delicately regulated. This work provides fresh hints for rationally controlling the charge transfer pathways toward high‐efficiency CO2 photoreduction.

Spatially Separated Redox Cocatalysts on Ferroelectric Nanoplates for Improved Piezophotocatalytic CO2 Reduction and H2O Oxidation

“…The first protonation of CO 2 to form *COOH is the rate-limitation step for both sites of PbTiO 3 and AuCu. The free-energy change (ΔG) values for this step on Au and Cu sites of the AuCu alloy are 1.129 and 1.190 eV, respectively, significantly smaller than that on Ti sites of PbTiO 3 (2.384 eV), demonstrating that the introduction of AuCu cocatalysts substantially lowers the energy barrier of CO 2 reduction, thereby significantly promoting CO generation Figure e displays the optimized pathways of OER on PbTiO 3 {001} and MnO x surfaces.…”

“…The free-energy change (ΔG) values for this step on Au and Cu sites of the AuCu alloy are 1.129 and 1.190 eV, respectively, significantly smaller than that on Ti sites of PbTiO 3 (2.384 eV), demonstrating that the introduction of AuCu cocatalysts substantially lowers the energy barrier of CO 2 reduction, thereby significantly promoting CO generation. 57 S13), consistent with SEM characterization, and the clear contrasts in corresponding amplitude and phase images indicate its strong piezoelectric response nature (Figure 6a,b). Figure 6c shows the PFM amplitude−voltage curve and phase−voltage hysteresis loop.…”

Cu-BTC-confined synthesis of Cu-Cu2O-CuS nanojunctions embedded in a porous carbon matrix for remarkable photothermal CO2conversion

“…Similar to plasmonic Au, extra hot electrons are generated by plasmonic Cu and injected into Cu 2 O and CuS for the photocatalytic CO 2 reduction reaction despite this effect being very small. 55,56…”

Crystal phase engineering of Ru for simultaneous selective photocatalytic oxidations and H2 production

“…[1][2][3] One of the major drawbacks is the rapid photogenerated charge carrier recombination, leaving room for further improvement to maximize the photocatalytic activity. 4 The addition of noble metal nanoparticles (NPs) as cocatalyst can not only slow down the electron-hole recombination by trapping photogenerated charges, [5][6][7][8] they can also provide catalytically active sites. [9][10][11] Therefore metal NP cocatalysts are crucial in the development of improved semiconductor PCs.…”