Search

Constructing mixed dimensional materials have been regarded as an outstanding approach to maximum the advantages from materials of different dimensions. In this work, we prepared a mixed dimensional photocatalyst based on Formamidinium lead bromide (FAPbBr3 ) perovskite and 2D materials (2DMs). The aim of this work is to utilize distributions of the active sites in 2DMs, through growing FAPbBr 3 on the different position of 2DMs, the concentration of photogenerated charges is manipulated, thus conducting different reactions. A pre-treatment using HBr to increase the unsaturated bonds in MoS2 presents significant influence on the FAPbBr3 growth and its photocatalytic product. The scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) confirm that the perovskite nanoparticles were well loaded on the 2D materials. The photocatalytic process and the heterojunction arrangement are demonstrated by X-ray photoelectron spectroscopy (XPS), time-resolved photoluminescence (TRPL), electron paramagnetic resonance (EPR) and surface photovoltage microscopy (SPVM). By adjusting the weight ratios and growth of FAPbBr3 on the top of 2DMs, the optimized composite photocatalyst (with 30 wt% of FAPbBr3) exhibits remarkable photoactivity for oxidation of benzyl alcohol into benzaldehyde (30 wt% FAPbBr3@WS2 performed 75.9% conversion in 4 h, approximately 9-fold than the pure 2DMs). Meanwhile, by growing FAPbBr3 on the edge of 2DMs, benzoic acid is obtained as the product. Although longer reaction time is needed, the photocatalyst performs outstanding activity (30 wt% FAPbBr 3@MoS2 reached 84.5% conversion in 5 h).

Incident angle variation of light from the sun is a critical factor for the practical utilizations of solar energy devices. These devices typically receive the zenith of photon density under a solar elevation angle of 90&deg, and dramatic deletion of light density along with the decrease of solar elevation angle. Photonic crystals (PCs) with long range ordered arrays possess the controllable position of the photonic stop band (PSB) reliant on several factors, including incident angles, based on the Bragg&ndash, Snell law. The multiple scattering, refraction and inhibition of charge carrier recombination within the PSB suggests the potential capability for improving the efficiency of photoactive materials. In this work, we focus on the multiple scattering and refraction effects of PCs. A photoelectrode based on photonic crystal fluorine-doped tin oxide (PC FTO) film was fabricated, which allows the embedded photoactive materials (CdS nanoparticles) to benefit from the features of PCs under variable incidence, especially under lower incidence. The photoelectrode thus has enhanced overall photoelectrochemical (PEC) efficiency in different seasons, even if the increased surface area factor is deducted.

Polycyclic aromatic hydrocarbons (PAHs) in tobacco tar are regarded as a significant threat to human health. PAHs are formed due to the incomplete combustion of organics in tobacco and cigarette paper. Herein, for the first time, we extended the application of CsPbBr3 quantum dots (CsPbBr3) to the photocatalytic degradation of tobacco tar, which was collected from used cigarette filters. To optimize the photoactivity, CsPbBr3 was coupled with Bi2WO6 for the construction of a type-II photocatalyst. The photocatalytic performance of the CsPbBr3/Bi2WO6 composite was evaluated by the degradation rate of PAHs from tobacco tar under simulated solar irradiation. The results revealed that CsPbBr3/Bi2WO6 possesses a large specific surface area, outstanding absorption ability, good light absorption and rapid charge separation. As a result, in addition to good stability, the composite photocatalyst performed remarkably well in degrading PAHs (over 96% were removed in 50 mins of irradiation by AM 1.5 G). This study sheds light on promising novel applications of halide perovskite.

The mixed dimensional materials, especially 0D/2D mixed materials have been regarded as outstanding candidates for photodetector and photovoltaic devices, while have rarely been utilized for photocatalytic reactions including photosynthesis, water splitting and CO2 reduction. In this work, a mixed dimensional material composited by cubic 0D CsPbBr3 perovskite quantum dots (PQDs) and cubic 2D-PbS is prepared for reduction of CO2 to fuels. The PQDs, as light-harvesting components, are homogeneously grown on the 2D-PbS nano-substrate which is employed for electron transport. The same cubic crystal structures and rather small lattice mismatch ( Δ d / d CsPbBr 3 = 0.84 % ) between CsPbBr3 and PbS guarantee easy in-situ growth of PQDs on PbS nano-substrate and rapid electron migration. As a result, an improved photocurrent is obtained based on the combination of the advantages of 0D and 2D materials. In addition, the size of PQDs synthesized on the 2D-PbS is dramatically reduced in comparison to that synthesized in solvent, thus endowing them wider bandgap and greater potential enough for the photocatalytic reactions. This PQDs/2D-PbS mixed dimensional materials exhibit outstanding selectivity (over 99%) and activity (yield 81.6 and 52.7 μmol g−1) for reducing CO2 to CO and CH4, from which the CH4 yielded is ca. 9-fold than that of pure PQDs.