2D/2D CsPbBr₃/BiOCl Heterojunction with an S-Scheme Charge Transfer for Boosting the Photocatalytic Conversion of CO₂

Abstract

The rational design of a two-dimensional (2D)/2D "face-to-face" heterojunction photocatalyst is crucial for the mediation of interfacial charge transfer/separation. Herein, a unique 2D/2D step-scheme (S-scheme) photocatalyst of CsPbBr 3 /BiOCl is constructed by the self-assembly of CsPbBr 3 and BiOCl nanosheets (NSs). Profiting from the effective interface contact and appropriate band structures between CsPbBr 3 and BiOCl NSs, a valid S-scheme heterojunction of CsPbBr 3 /BiOCl is established. Density functional theory (DFT) calculations and a series of characterization techniques including X-ray photoelectron spectra (XPS), photoassisted Kelvin probe force microscopy (KPFM), and electron spin resonance (ESR) systematically corroborate the S-scheme charge-transfer mechanism between CsPbBr 3 and BiOCl. The formation of an S-scheme heterojunction endows the photocatalyst with boosted charge separation and retainment of the highest redox ability. As a result, the obtained 2D/2D CsPbBr 3 /BiOCl S-scheme photocatalyst shows much superior CO 2 -reduction performance to single CsPbBr 3 and BiOCl. This investigation provides new insights into the construction of novel S-scheme heterojunctions based on 2D/2D photocatalytic systems.

Ni3B as p-Block Element-Modulated Cocatalyst for Efficient Photocatalytic CO2 Reduction

“…The C dl values of Ni 3 B and TiO 2 are, respectively, 28.86 and 14.37 μF cm –2 , while the optimized Ni 3 B/TiO 2 had an improved C dl value of 34.19 μF cm –2 , indicating that the introduction of Ni 3 B can provide a larger electrochemically active surface area and more active sites, which greatly improve the activity of photocatalytic CO 2 reduction . The mechanism of interfacial electron transfer in semiconductor heterojunctions can be further studied by calculating the work function (Φ), which is derived from the difference between the vacuum energy level ( E V ) and the Fermi energy level ( E F ) of the semiconductor by DFT calculations. − As shown in Figure , the work functions of TiO 2 (101) and Ni 3 B­(102) surfaces are, respectively, calculated as 6.93 and 5.14 eV, indicating that the Fermi energy level of Ni 3 B is much lower than that of TiO 2 , which leads to the transfer of electrons excited in TiO 2 to the surface of Ni 3 B under the interfacial electric field when they are in close contact, which remains consistent with the analysis of XPS results. , …”

An insight into the photo-generation of H2 and a carbon fuel additive from biomass-derived ethanol: boosting the bio-chemical economy

“…Of note, from XPS analysis we confirmed the formation of the UCN/Nb 2 O 5 -(2) and Pt/UCN/Nb 2 O 5 -(2) heterostructures and, based on the changes in binding energies, we could say that positive changes in binding energy correspond to lower electron density, while negative changes in binding energy correspond to higher electron density. 41,42 Therefore, the observed positive shifts in the C 1s and N 1s spectra of UCN/Nb 2 O 5 -(2) and Pt/UCN/Nb 2 O 5 -(2), along with the negative shifts in the Nb 3d spectra of UCN/Nb 2 O 5 -(2) and Pt/UCN/Nb 2 O 5 -(2) compared with UCN, firmly underpinned the electron transfer from UCN to Nb 2 O 5 in the heterostructure. This was further validated by EPR analysis and is discussed in the section on mechanistic studies.…”

Computational Design of a Strain-Induced 2D/2D g-C3N4/ZnO S-Scheme Heterostructured Photocatalyst for Water Splitting

“…However, its relatively large band gap of 3.3 eV − inhibits visible-light utilization. , In this regard, combining g-C 3 N 4 with ZnO could benefit the photocatalytic performance since low-band gap g-C 3 N 4 could produce excited charge carriers and transfer to catalytically more reactive ZnO. In particular, it has been reported that the g-C 3 N 4 /ZnO heterostructure exhibits significantly enhanced photocatalytic performance for hydrogen production and dye degradation under visible-light irradiation. , A computational study reported that strain-induced g-C 3 N 4 /ZnO heterostructures offer suitable band edge positions and improved electron–hole separation. , …”