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Photocatalytic H 2 O 2 production has gained significant attention as an environmentally friendly approach. The key is to explore efficient photocatalysts with sufficient active sites and excellent electron transfer capacity. Herein, we propose a novel approach by incorporating carbon dots (CDs) on ethylenediamine capped Zn 0.5 Cd 0.5 S, which was bridged with an interfacial amide bond. Smooth transfer of photoinduced electrons from Zn 0.5 Cd 0.5 S to carbon dots via a high-speed electron channel is afforded by interfacial amide bond. A remarkable H 2 O 2 yield with a rate of 252 μmol/h and an apparent quantum yield (AQY) of 31 % at 400 nm is achieved. Photoelectrochemical analysis and density function theory (DFT) calculation reveal CDs with abundant oxygenous functional groups as active sites, boosting activity and selectivity. This interfacial engineering strategy with the acceleration of electrons transfer and enhanced 2e- selectivity can be applied to advanced photocatalytic systems for the achievement of valuable organics, environmental purification and new energy carriers. [Display omitted] • Carbon dots bridged Zn 0.5 Cd 0.5 S with interfacial amide bond was fabricated. • Amide bond enables smooth electron transfer to O 2 reduction center of carbon dots. • A 34-fold enhancement of H 2 O 2 production was achieved. [ABSTRACT FROM AUTHOR]

Oxygen defects in Hafnium Oxide (HfO2)-based ferroelectric thin films not only are related to the cause of ferroelectricity but also affect the ferroelectric properties of the thin films. This paper, therefore, focuses on the fabrication of Zr:HfO2 thin films by RF (Radio Frequency) magnetron sputtering with Zr-doped HfO2 as the target and examines how oxygen flow impacts the oxygen vacancies and electrical properties thereof. Additionally, TiN thin-film electrodes were prepared by direct current (DC) magnetron reactive sputtering using nitrogen as the reaction gas, the influences of the substrate temperature on the film deposition rate and crystal phase structure were investigated, and the resultant thin-film electrodes with the lowest resistivity were obtained. Furthermore, the ferroelectric hysteresis loop and leakage current density of metal–insulator–metal (MIM) ferroelectric capacitors formed by annealing the 30 nm thick deposited Zr:HfO2 sandwiched between the top and bottom TiN electrodes were measured. The results demonstrate that varying oxygen flow has a considerable effect on oxygen vacancies and the Zr doping concentration of deposited Zr:HfO2 ferroelectric thin films. When the oxygen flow is set to 40 sccm (standard cubic centimeters per minute) and an external electric field strength of 2 mV/cm is applied, the remnant polarization reaches 18 μC/cm2, with a decrease in the leakage current density of 105–6 orders of magnitude. [ABSTRACT FROM AUTHOR]

We develop a new PdCu/UTCN hybrid by loading low-crystalline PdCu NPs on large-area ultrathin 2D carbon nitride (UTCN) nanosheets that exfoliated from bulk g-C 3 N 4 using a twice thermal exfoliation and repolymerization method for photocatalytic Suzuki C-C cross coupling reaction. Due to the advantages of 2D structure of the UTCN and the changes in electronic structure and surface structure of low-crystalline PdCu NPs, PdCu/UTCN shows promoted photocatalytic activity with high selectivity for Suzuki coupling reaction. The TOF value for coupling of iodobenzene with phenylboronic acid is 418.2 h−1, which is 8 and 6.2 times higher than that of previously reported Pd-g-C 3 N 4 and Pd based alloy photocatalysts under the same reaction, respectively. Morevoer, this photocatalyst shows a good functional group tolerance as well as good to excellent yield and selectivity for various substrates. This study reports for the first time the PdCu alloy supported UTCN photocatalytic material for enhanced Suzuki reaction. A new PdCu/UTCN hybrid by loading low-crystalline PdCu NPs on large-area ultrathin 2D carbon nitride (UTCN) nanosheets that exfoliated from bulk g-C 3 N 4 using a twice thermal exfoliation and repolymerization method for photocatalytic Suzuki C-C cross coupling reaction. [Display omitted] • Large-area ultrathin 2D carbon nitride nanosheets (UTCN) is successfully prepared. • PdCu/UTCN hybrid is constructed by loading low-crystalline PdCu NPs on UTCN. • PdCu/UTCN shows excellent photocatalytic activity for Suzuki coupling reaction. • UTCN has a large specific surface area and a higher charge separation efficiency. • Low-crystalline PdCu promotes charge separation, light harvesting, and reaction. [ABSTRACT FROM AUTHOR]

Sunlight-driven valorization of CO 2 into fuels is a promising solution to renewable energy storage, but the design of an integrated and efficient solar-to-chemical conversion system remains challenging. Herein, an all-solar-driven artificial photosynthetic system (APS) by tailoring photovoltaic-photoelectrochemical cell which can efficiently produce formic acid fuel from CO 2 and H 2 O with bias-free illumination is demonstrated. Guided by density functional theory (DFT) calculations, a BiOI–Bi (BOI–Bi) cathode catalyst is synthesized, which is highly selective for CO 2 to HCOOH conversion, and coupled with a single crystalline argon-treated TiO 2 (TiO 2 -Ar) photoanode, whose valence band edge is beneficial for the oxidation of H 2 O to O 2. The APS exhibits high product selectivity, robust activity and good durability. A solar-to-HCOOH selectivity of 96.5% is obtained with a HCOOH yield of 108.2 mmol g−1 h−1 under bias-free illumination of AM1.5G. The device can operate stably for at least 12 h. In particular, an apparent photon quantum efficiency of 7.5% and a solar-to-chemical conversion efficiency (η SCC) of 8.3% are recorded, rivaling all the incumbent precious-metal-free all-solar-driven components for CO 2 -to-HCOOH conversion. This study highlights the potential of BOI-Bi for CO 2 to HCOOH conversion with high selectivity and its integration into APS system to realize carbon-negative solar-to-chemical conversion with industrial relevance. • The pathways of selectively converting H C O 3 – /CO 2 -to-HCOOH is simulated. • The gain effect of VBM for potential distribution in PEC system is clarified. • The cell voltage of optimized APS meets the highest selectivity for HCOOH. • The APS exhibits a highest η S C C of 8.3% in all the precious-metal-free devices. [ABSTRACT FROM AUTHOR]

Au nanoparticles (NPs) are dispersively deposited on the explored nonpolar {100} plane of 3D porous ZnO nanosheets (NSs), parallel to the IEF direction. The SPR field parallel to the polar {001} facet, coupling with the IEF. The exciton binding energy can be decreased by the field-field coupling, leading to better charge separation, activity, and selectivity under simulated solar light illumination. • The coupling of plasmonic field and IEF promoted CO 2 photoreduction. • Conversion efficiency of solar-to-hydrocarbon was improved by one order of magnitude. • Au can result in the solar conversion of CO 2 to C 2 H 6 at an amazing selectivity. • The electron phonon decoupling enhanced the PCET process of ZnO nanosheets. • The novel pathway of photocatalytic CO 2 conversion was proposed by DFT. Molecular-level understanding of the solar-driven CO 2 conversion is of importance to design high-efficiency artificial photosynthetic systems for rebalancing the global carbon cycle. Herein, some physical insights into the surface plasmon resonance (SPR) mediated CO 2 photoreduction were demonstrated with metal (Au, Ag, and Pd)/3D porous ZnO nanosheets (NSs). Such plasmonic photocatalysts were designed elaborately to expose the polar {001} facet, based on the physical prototype of field-field coupling, in order to benefit chemical polarization and activation of the inert molecule. Among these plasmonic metals, gold was found to be not only more effective for promoting the solar-driven CO 2 conversion, but unique for producing the higher hydrocarbon, C 2 H 6. A 10-fold enhanced conversion efficiency and a quantum efficiency of 1.03% were achieved on Au/ZnO NSs at ca. 80% selectivity to hydrocarbons under solar light irradiation. The characterization results indicated that the metal-semiconductor interaction enables the electron-phonon decoupling to generate more amounts of energetic electrons in the excited ZnO NSs by a proposed pathway, called the SPR energy transfer induced interband transition that promotes the semiconductor photoexcitation, kinetically accelerating the conversion. Density functional theory calculations revealed that the field-field coupling greatly intensifies the surface polarization for adsorbates, charging negatively the C atom of CO 2 and making O C O bond bent, along with the electrophilic attack by two competitive paths, leading to the concomitance of CO and CH 4. The loading of plasmonic metal nanoparticles alters the molecular paths of CO 2 conversion by tuning thermodynamically the first dehydroxylation step, consequently the product selectivity. Especially Au plasmon, it enables the CO hydrogenation path, making CH 4 faster. [ABSTRACT FROM AUTHOR]

NO 2 sensor has attracted extensive attention due to its important application in environment monitor. Conventional NO 2 sensors based on the yttria-stabilized zirconia (YSZ) electrolyte possess fast response, high sensitivity and good stability, whereas its ionic conductivity decreases significantly at low- and intermediate-temperature, limiting the practical application in motor vehicles. In this work, a pyrochlore-phase A 2 B 2 O 7 solid electrolyte, Pr 2 Zr 2−x Ce x O 7+δ (PZC), was applied for the first time to construct the amperometric-type NO 2 sensor. Ce incorporated significantly improved the sensing performance of the PZC NO 2 sensor with NiO as the sensing electrode. The effect of Ce-doped concentration and operating temperature on the sensitivity, selectivity, stability, response and recovery characteristics were investigated in detail. The results showed that the optimal sensor based on the Pr 2 Zr 1.9 Ce 0.1 O 7+δ substrate gave high sensitivity, excellent selectivity and quick response-recovery behavior to NO 2 gas. The gas-sensing mechanism was also discussed. The PZC sensors are well established effective for sensing NO 2 at mild-temperature working window of 500–700 °C, and thus exhibit the promising application in motor vehicles. [ABSTRACT FROM AUTHOR]