Synergistic optimization of triple phase junctions and oxygen vacancies over MnxCd1-xS/Ov-WO3 for boosting photocatalytic hydrogen evolution.

Strengthening the separation of photogenerated charge carriers is crucial for improving the efficiency of photocatalytic hydrogen evolution. Herein, t-Mn0.5Cd0.5S/Ov-WO3 (t-MCSW) triple-phase junctions with rich oxygen vacancies were developed using the calcination-hydrothermal method. The corresponding morphology and structure of the samples were examined by XRD, TEM and XPS. The formation of the S-scheme heterostructure in t-MCSW has also been confirmed with in situ XPS, work function analysis and free radical capture tests. The experimental results demonstrate that t-MCSW-7 exhibited optimal activity (194.2 mmol g-1 h-1), which was about 4 times higher than that of the individual Mn0.5Cd0.5S (t-MCS, 48.8 mmol g-1 h-1). The apparent quantum yield of t-MCSW-7 is 29.14% at 420 nm, and the material exhibits excellent stability after seven cycles of photocatalytic reaction. The excellent photocatalytic activity of t-MCSW-7 is attributed to more efficient separation of charge carriers by triple-phase junctions connected by homojunctions and heterojunctions. Moreover, the existence of oxygen vacancies broadens absorption spectra and accelerates surface charge transfer. The synergistic effect of phase junctions and oxygen vacancies leads to an enhancement of hydrogen evolution activity. This work provides a new idea for preparing efficient photocatalysts.

Green synthesis of 3D core-shell SnS2/SnS-Cd0.5Zn0.5S multi-heterojunction for efficient photocatalytic H2 evolution.

Low charge carrier separation efficiency is one of the key factors restricting photocatalytic hydrogen evolution performance. It is an effective strategy to build heterojunctions to steer charge migration. Herein, a series of x-SnS2/SnS-Cd0.5Zn0.5S (x-SS-CZS) nanosphere composites with varying mass ratios of SnS2/SnS (SS) were prepared through in situ hydrothermal synthesis. Moreover, XRD, TEM, and XPS were used to characterize the 3D core-shell SS-CZS multi-heterojunction composite. The 5-SS-CZS heterojunction composite with 5 wt% content of SS exhibits a remarkable hydrogen evolution rate of 168.85 mmol g-1 h-1, which is 5.4 times higher than that of pristine twin CZS (31.08 mmol g-1 h-1) and 1.9 times higher than that of 5-SnS2-CZS (88.21 mmol g-1 h-1). Furthermore, the composite catalyst showed excellent photostability after four cycles of reactions under visible light illumination. The apparent quantum yield at λ = 420 nm could reach up to 24.78%. The excellent hydrogen evolution performance of 5-SS-CZS nanospheres is ascribed to the following factors: (1) a core-shell catalyst with broad spectral absorption improves light utilization efficiency, (2) hybrid material with large surface area provides more active sites and shows the highest H2 activity, (3) a multi-heterojunction composite extends the lifetime of photoinduced carriers and accelerates charge separation and migration, and (4) SS as a hole trapping agent enhances the photocatalytic stability performance. This work proposes a possible photocatalytic mechanism, while also providing a novel approach for the synthesis of highly active and stable photocatalysts.

Enhancing Triplet-Triplet Annihilation Upconversion of Pyrene Derivatives for Photoredox Catalysis via Molecular Engineering.

Triplet-triplet annihilation upconversion (TTA-UC) has the potential to enhance photoredox catalysis yield. It includes a sensitizer and an annihilator. Efficient and stable annihilators are essential for photoredox catalysis, yet only a few examples are reported. Herein, we designed four novel pyrene annihilators (1, 2, 3 and 4) via introducing aryl-alkynyl groups onto pyrene to systematically modulate their singlet and triplet energies. Coupled with platinum octaethylporphyrin (PtOEP), the TTA-UC efficiency is enhanced gradually as the number of aryl-alkynyl group increases. When combining 4 with palladium tetraphenyl-tetrabenzoporphyrin (PdTPTBP), we achieved the highest red-to-green upconversion efficiency (22.4±0.3 %) (out of a 50 % maximum) so far. Then, this pair was used to activate photooxidation of aryl boronic acid under red light (630 nm), which achieved a great improved reaction yield compared to that activated by green light directly. The results not only provide a design strategy for efficient annihilators, but also show the advantage of applying TTA-UC into improving the photoredox catalysis yield.

S-vacancy-assisted fast charge transport and oriented ReS2 growth in twin crystal ZnxCd1-xS: an atomic-level heterostructure for dual-functional photocatalytic conversion.

The achievement of dual-functional photocatalytic technology requires a photocatalyst with accelerated charge flow and purposeful active-site arrangement. In this study, we developed an oriented embedding strategy to induce ReS2 growth at the S vacancy in twin-crystal Zn0.5Cd0.5S solid solution (Sv-ZCS), obtaining an atomic-level heterostructure (ReS2/Sv-ZCS). The electronic structure calculations demonstrate that the charge density of the Zn atom around the S vacancy is higher than for other Zn atoms and the introduced S vacancy establishes a high-speed channel for electron transport via formed Zn-S-Re bonds at the interface between ReS2 and Sv-ZCS. Photogenerated electrons and holes gathered on Re atoms and Sv-ZCS, respectively, which achieves spatial charge separation and separated arrangement for redox sites. As a result, the optimized ReS2/Sv-ZCS heterostructure possesses high efficiency of electron injection (2.6-fold) and charge separation (8.44-fold), as well as excellent conductivity capability (20.16-fold). The photocatalytic performance of the ReS2/Sv-ZCS composite exhibits highly improved dual-functional activity with simultaneous H2 evolution and selective oxidation of benzyl alcohol. The reaction rate of benzaldehyde and H2 evolution reaches 125 mmol gcat-1 h-1 and 159 mmol gcat-1 h-1, which is the highest efficiency achieved so far for simultaneous coproduction of H2 fuel and organic chemicals on ReS2-based composites. This work enriches the application of ReS2-modified composites in a dual-functional photoredox system and also gives insight into the role of defects in electronic structure modification and activity improvement.

Cofacial porphyrin organic cages. Metals regulating excitation electron transfer and CO2 reduction electrocatalytic properties.

Herein, we introduce a comprehensive study of the photophysical behaviors and CO2 reduction electrocatalytic properties of a series of cofacial porphyrin organic cages (CPOC-M, M = H2, Co(ii), Ni(ii), Cu(ii), Zn(ii)), which are constructed by the covalent-bonded self-assembly of 5,10,15,20-tetrakis(4-formylphenyl)porphyrin (TFPP) and chiral (2-aminocyclohexyl)-1,4,5,8-naphthalenetetraformyl diimide (ANDI), followed by post-synthetic metalation. Electronic coupling between the TFPP donor and naphthalene-1,4 : 5,8-bis(dicarboximide) (NDI) acceptor in the metal-free cage is revealed to be very weak by UV-vis spectroscopic, electrochemical, and theoretical investigations. Photoexcitation of CPOC-H2, as well as its post-synthetic Zn and Co counterparts, leads to fast energy transfer from the triplet state porphyrin to the NDI unit according to the femtosecond transient absorption spectroscopic results. In addition, CPOC-Co enables much better electrocatalytic activity for CO2 reduction reaction than the other metallic CPOC-M (M = Ni(ii), Cu(ii), Zn(ii)) and monomeric porphyrin cobalt compartment, supplying a partial current density of 18.0 mA cm-2 at -0.90 V with 90% faradaic efficiency of CO.

Mechanical milling processed highly luminescent Cs-Pb-Br perovskite emitters.

We report well-dispersed highly emitting perovskite emitters synthesized via the surfactant-assisted ball-milling method. Both the emitting peaks and the colour purity of the synthesized perovskite emitters can be effectively tuned through additive functionalization and precursor engineering.

Polarized Tunneling Transistor for Ultrafast Memory.

In today's information age, high performance nonvolatile memory devices have become extremely important. Despite their potential, existing devices suffer from limitations, such as low operation speed, low memory capacity, short retention time, and a complex preparation process. To overcome these limitations, advanced memory designs are required to improve speed, memory capacity, and retention time and reduce the number of preparation steps. Here, we present a nonvolatile floating-gate-like memory device based on a transistor that uses the polarization effect of ferroelectric material PZT (Pb[Zr0.2Ti0.8]O3) for regulating tunneling electrons for charging and discharging the MoS2 channel layer. The transistor is defined as a polarized tunneling transistor (PTT) and does not require a tunnel layer or a floating-gate layer. The PTT demonstrates an ultrafast programming/erasing speed of 25/20 ns and a response time of 120/105 ns, which is comparable to the ultrafast flash memories based on van der Waals heterostructures. Additionally, the PTT has a high extinction ratio of 104, a long retention time of 10 years, and a simple fabrication process. Our research provides future guidelines for the development of the next generation of ultrafast nonvolatile memory devices.

A facile strategy to prepare FeNx decorated PtFe intermetallic with excellent acidic oxygen reduction reaction activity and stability.

The construction of low-Pt-content intermetallic on carbon supports has been verified as a promising method to promote the activity of the oxygen reduction reaction (ORR). In this study, we have developed a simple and effective strategy to obtain a well-designed CNT-PtFe-PPy precursor. This precursor contains modulated Pt- and Fe-based content dispersed in polypyrrole (PPy) chain segments, which are in-situ generated on the templates of carbon nanotubes (CNTs). Subsequent pyrolysis of the CNT-PtFe-PPy precursor produces a CNT-PtFe@FeNC catalyst, which contains both Fe-Nx and PtFe intermetallic active sites. Due to the highly efficient dispersion of active species, the CNT-PtFe@FeNC electrocatalyst displays a 9.5 times higher specific activity (SA) and 8.5 times higher mass activity (MA) than those of a commercial Pt/C catalyst in a 0.1 M HClO4 solution. Additionally, these results, combined with excellent durability (the SA and MA maintained 94 % and 91 % of initial activity after a 10-k cycle accelerated durability test), represent among the best performance achieved so far for Pt-based ORR electrocatalysts. Furthermore, density functional theory (DFT) calculations revealed that the presence of Fe-N4 species reduces the adsorption energy between the PtFe intermetallic compound and OH*, accelerating the ORR process.

Atomically Dispersed Ni-N4 Sites Assist Pt3 Ni Nanocages with Pt Skin to Synergistically Enhance Oxygen Reduction Activity and Stability.

Currently, the rarity and high cost of platinum (Pt)-based electrocatalysts seriously limit their commercial application in fuel cells cathode. Decorating Pt with atomically dispersed metal-nitrogen sites possibly offers an effective pathway to synergy tailor their catalytic activity and stability. Here active and stable oxygen reduction reaction (ORR) electrocatalysts (Pt3 Ni@Ni-N4 -C) by in situ loading Pt3 Ni nanocages with Pt skin on single-atom nickel-nitrogen (Ni-N4 ) embedded carbon supports are designed and constructed. The Pt3 Ni@Ni-N4 -C exhibits excellent mass activity (MA) of 1.92 A mgPt -1 and specific activity of 2.65 mA cmPt -2 , together with superior durability of 10 mV decay in half-wave potential and only 2.1% loss in MA after 30 000 cycles. Theoretical calculations demonstrate that Ni-N4 sites significant redistribute of electrons and make them transfer from both the adjacent carbon and Pt atoms to the Ni-N4 . The resultant electron accumulation region successfully anchored Pt3 Ni, that not only improves structural stability of the Pt3 Ni, but importantly makes the surface Pt more positive to weaken the adsorption of *OH to enhance ORR activity. This strategy lays the groundwork for the development of super effective and durable Pt-based ORR catalysts.

Antialcohol and Hepatoprotective Effects of Tamarind Shell Extract on Ethanol-Induced Damage to HepG2 Cells and Animal Models.

Alcohol liver disease (ALD) is one of the leading outcomes of acute and chronic liver injury. Accumulative evidence has confirmed that oxidative stress is involved in the development of ALD. In this study, we used chick embryos to establish ALD model to study the hepatoprotective effects of tamarind shell exttract (TSE). Chick embryos received 25% ethanol (75 µL) and TSE (250, 500, 750 µg/egg/75 µL) from embryonic development day (EDD) 5.5. Both ethanol and TSE were administrated every two days until EDD15. Ethanol-exposed zebrafish and HepG2 cell model were also employed. The results suggested that TSE effectively reversed the pathological changes, liver dysfunction and ethanol-metabolic enzyme disorder in ethanol-treated chick embryo liver, zebrafish and HepG2 cells. TSE suppressed the excessive reactive oxygen species (ROS) in zebrafish and HepG2 cells, as well as rebuilt the irrupted mitochondrial membrane potential. Meanwhile, the declined antioxidative activity of glutathione peroxidase (GPx) and superoxide dismutase (SOD), together with the content of total glutathione (T-GSH) were recovered by TSE. Moreover, TSE upregulated nuclear factor erythroid 2-related factor 2 (NRF2) and heme oxyense-1 (HO-1) expression in protein and mRNA level. All the phenomena suggested that TSE attenuated ALD through activating NRF2 to repress the oxidative stress induced by ethanol.

Potential of Tamarind Shell Extract against Oxidative Stress In Vivo and In Vitro.

Tamarind shell is rich in flavonoids and exhibits good biological activities. In this study, we aimed to analyze the chemical composition of tamarind shell extract (TSE), and to investigate antioxidant capacity of TSE in vitro and in vivo. The tamarind shells were extracted with 95% ethanol refluxing extraction, and chemical constituents were determined by ultra-performance chromatography-electrospray tandem mass spectrometry (UPLC-MS/MS). The free radical scavenging activity of TSE in vitro was evaluated using the oxygen radical absorbance capacity (ORAC) method. The antioxidative effects of TSE were further assessed in 2,2-azobis (2-amidinopropane) dihydrochloride (AAPH)-stimulated ADTC5 cells and tert-butyl hydroperoxide (t-BHP)-exposed zebrafish. A total of eight flavonoids were detected in TSE, including (+)-catechin, taxifolin, myricetin, eriodictyol, luteolin, morin, apigenin, and naringenin, with the contents of 5.287, 8.419, 4.042, 6.583, 3.421, 4.651, 0.2027, and 0.6234 mg/g, respectively. The ORAC assay revealed TSE and these flavonoids had strong free radical scavenging activity in vitro. In addition, TSE significantly decreased the ROS and MDA levels but restored the SOD activity in AAPH-treated ATDC5 cells and t-BHP-exposed zebrafish. The flavonoids also showed excellent antioxidative activities against oxidative damage in ATDC5 cells and zebrafish. Overall, the study suggests the free radical scavenging capacity and antioxidant potential of TSE and its primary flavonoids in vitro and in vivo and will provide a theoretical basis for the development and utilization of tamarind shell.

Low-loading Pt nanoparticles combined with the atomically dispersed FeN4 sites supported by FeSA-N-C for improved activity and stability towards oxygen reduction reaction/hydrogen evolution reaction in acid and alkaline media.

Reducing the loading of Pt precious metal is the promising pathway to positively promote the large-scale application for fuel cells and water electrolysis. In this work, a composite bifunctional electrocatalyst (named Pt@FeSA-N-C) consisting of the atomically dispersed FeN4 active sites and Pt nanoparticles (NPs) is successfully prepared for oxygen reduction reaction (ORR) and hydrogen evolution reactions (HER). In the process of synthesizing precursor of Pt(OH)4-Fe-Ppy@CNFs, the Fe-Ppy@CNFs was firstly prepared where the highly dispersed Fe3+ ions were pre-anchored into polypyrrole (PPy) matrixes through in-situ polymerization on the surface of cellulose nanofibers (CNFs) and then Pt(OH)4 nano-particles were deposited on Fe-Ppy@CNFs through adjusting the pH of the solution by urea hydrolysis to obtain the Pt(OH)4-Fe-Ppy@CNFs. Compared with the commercial 20 wt.% Pt/C, the obtained Pt@FeSA-N-C possesses 5.5 wt.% low Pt loading. The strong synergistic effect of dual active sites between Pt NPs and FeN4 on one-dimensional (1D) FeSA-N-C support with a large surface area ensures effectively exposure of Fe and especial Pt active sites in the Pt@FeSA-N-C. Both ORR and HER activities of the Pt@FeSA-N-C were greatly improved in acid and alkaline media, even outperforming the commercial 20 wt.% Pt/C. Furthermore, the Pt@FeSA-N-C shows an unordinary stability, with no obvious decrease in the current density after 5000 and 1000 cycles of accelerated durability tests (ADTs) for ORR and HER processes, respectively. This work highlights a preparation strategy for the synergistic effect between low-loading Pt precious metal and non-precious metals in electrocatalytic system.

Facilitating the Carrier Transport Kinetics at the CsPbBr3/Carbon Interface through SbX3 (X = Cl, Br, I) Passivation.

The nonradiative carrier recombination at the perovskite/carrier selective layer (CSL) interface was accounted for the inferior power conversion efficiency (PCE) of perovskite solar cells (PSCs), especially rigid all-inorganic perovskite (CsPbI3 and CsPbBr3). In this study, targeting the poor interface, we introduce SbX3 (X = Cl, Br, I) surface passivation at the CsPbBr3/carbon interface. Smoothed compressive strain, reduced defect density, and enhanced energy-level alignment were achieved simultaneously, facilitating carrier extraction at the selective interface. With the simple aqueous solution-based two-step process, the PCE of our SbI3 passivated carbon-based CsPbBr3 PSCs has increased from 7.81% (without passivation) to 9.69%, a ∼25% enhancement. Specifically, Voc (1.657 V) of the SbI3-passivated cells was much higher than that of the control ones (1.488 V), confirming the ameliorated interface. Finally, our unencapsulated SbI3 passivated devices maintain 90% of their initial PCEs while left in the air for 30 days with a relative humidity of 60%. To conclude, we present an interfacial carrier extraction-enhanced strategy for preparing high-performance and stable CsPbBr3-based PSCs.

A Combination of "Push Effect" Strategy with "Triple-Phase-Boundary Engineering" on Iron Porphyrin-Based MOFs: Enhanced Selectivity and Activity for Oxygen Reduction.

Herein, the "push effect" strategy combined with "triple-phase-boundary" (TPB) engineering was innovatively employed to target the single Fe-N4 sites in an iron porphyrin-based metal-organic framework, with axially coordinated 4-octylpyridine groups on Fe-N4 (named as PCN-224 (Fe)-1). The amphiphilic 4-octylpyridine groups donate sufficient electrons toward Fe-N4 by the Fe-N(pyridine) coordination bond and simultaneously provide effective TBP reactive sites by the hydrophobic octyl terminals, resulting in enhanced ORR activity of the PCN-224 (Fe)-1 in hydrophobic octyl terminals, with an E1/2 of 0.81 V and complete 4-electron selectivity. Furthermore, TPB engineering is utilized to construct the PCN-224 (Fe)-1-based Zn-air battery with a maximum power density of 98 mW cm-2, demonstrating great practical application potential for molecule-based ORR catalysts. Meanwhile, the "push effect" mechanism on ORR is revealed by electron paramagnetic resonance, in situ UV-vis spectroelectrochemical analysis, and density functional theory.

Singlet Fission in Colloidal Nanoparticles of Amphipathic Diketopyrrolopyrrole Derivatives: Probing the Role of the Charge Transfer State.

To evaluate the role of the charge transfer (CT) state in the singlet fission (SF) process, we prepared three 3,6-bis(thiophen-2-yl)diketopyrrolopyrrole (TDPP) derivatives with zero (Ph2TDPP), one (Ph2TDPP-COOH), and two (Ph2TDPP-(COOH)2) carboxylic groups, respectively. Their colloidal nanoparticles were also prepared by a simple precipitation method. The SF dynamics and mechanism in these colloid nanoparticles were investigated by using steady-state/transient absorption and fluorescence spectroscopy. Steady-state absorption spectra reveal that the strength of the CT resonance interactions between the adjacent DPP units is increased gradually from Ph2TDPP to Ph2TDPP-COOH and then to Ph2TDPP-(COOH)2. Fluorescence and transient absorption spectra demonstrate that SF is proceeded via a CT-assisted superexchange mechanism in these three nanoparticles. Furthermore, SF rate and yield are enhanced gradually with the increase of the number of the carboxylic group, which may be attributed to the enhancement of the CT coupling strength. The result of this work not only provides a better understanding of the SF mechanism especially for the role of the CT state but also gives some new insights for the design of efficient SF materials based on DPP derivatives.

Effects of the Separation Distance between Two Triplet States Produced from Intramolecular Singlet Fission on the Two-Electron-Transfer Process.

To harvest two triplet excitons of singlet fission (SF) via a two-electron transfer efficiently, the revelation of the key factors that influence the two-electron-transfer process is necessary. Here, by using steady-state and transient absorption/fluorescence spectroscopy, we investigated the two-electron-transfer process from the two triplet excitons of intramolecular SF (iSF) in a series of tetracene oligomers (dimer, trimer, and tetramer) with 7,7,8,8-tetracyanoquinodimethane (TCNQ) as an electron acceptor in solution. Quantitative two-electron transfer could be conducted for the trimer and tetramer, and the rate for the tetramer is faster than that for the trimer. However, the maximum efficiency of the two-electron transfer in the dimer is relatively low (∼47%). The calculation result of the free energy change (ΔG) of the second-electron transfer for these three compounds (-0.024, -0.061, and -0.074 eV for the dimer, trimer, and tetramer, respectively) is consistent with the experimental observation. The much closer ΔG value to zero for the dimer should be responsible for its low efficiency of the two-electron transfer. Different ΔG values for these three oligomers are attributed to the different Coulomb repulsive energies between the two positive charges generated after the two-electron transfer that is caused by their various intertriplet distances. This result reveals for the first time the important effect of the Coulomb repulsive energy, which depends on the intertriplet distance, on the two-electron transfer process from the two triplet excitons of iSF.

Improved Perovskite/Carbon Interface through Hot-Pressing: A Case Study for CsPbBr3-Based Perovskite Solar Cells.

Due to the low cost and printable nature of the carbon paste, carbon-based perovskite solar cells (PSCs) are attractive for real application. However, the poor contact at the perovskite/carbon interface obviously hinders the achievable fill factor of the carbon-based PSCs. In this work, we introduce a pressure-assisted method to improve the contact at the perovskite/carbon interface. Via modulating the applied pressure, the power conversion efficiency of CsPbBr3 PSCs (small area) can be improved from the initial 7.40% to 7.95% (pressing) and 8.34% (hot-pressing). A more remarkable feature is that the hot-pressing process boosted the performance from 5.1% (normal) to 6.9% (hot-pressing assisted) of large-scale (0.5 cm2) devices, a more than 30% enhancement. Finally, the hot-pressing method introduced in this work shows great prospects for improving the efficiency of carbon-based PSCs, especially large-scale PSCs.

Cyclo(-Phe-Phe) alleviates chick embryo liver injury via activating the Nrf2 pathway.

Excessive reactive oxygen species (ROS) accumulation is involved in the pathogenesis of liver fibrosis and damage, specifically in the developing embryo that is extremely sensitive to oxidative stress. Herein, a liver injury model in chick embryo was established by using 2,2-azobis (2-amidinopropane) dihydrochloride (AAPH), which was used to investigate the effect of cyclo(-Phe-Phe) (CPP), a natural dipeptide found in foods and beverages. The results showed that CPP significantly alleviated AAPH-induced liver pathological damage, hepatic dysfunction and inhibited the excessive production of ROS in both chick embryo liver and HepG2 cells. Additionally, CPP increased the antioxidative activity of glutathione peroxidase (GPx) and superoxide dismutase (SOD), as well as elevated the level of glutathione (GSH), suggesting that CPP combating liver injury probably depends on its antioxidant capability. Mechanistically, CPP upregulated the mRNA and protein expression of heme oxyense-1 (HO-1) and NADPH quinone oxidoreductase 1 (NQO1) in vivo and in vitro, along with promoting the translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) while inhibiting its degradation through binding with Kelch-like ECH-associated protein 1 (Keap1). In conclusion, this study proposes a potential peptide drug for the treatment of hepatic damage induced by oxidative stress and also unravels its mechanism of action.

A perylenediimide modified SiO2@TiO2 yolk-shell light-responsive nanozyme: Improved peroxidase-like activity for H2O2 and sarcosine sensing.

Although light-responsive nanozyme have been widely used in colorimetric sensing, some limitations such as poor catalytic activity, low detection efficiency, and unclear structure-activity relationships remain unresolved. Herein, we prepared an excellent light-responsive peroxidase (POD) mimic, perylenediimide (PDI-OH) modified SiO2 @TiO2 yolk-shell spheres (SiO2 @TiO2/PDI-OH), based on DFT-assisted design. The experiment and DFT calculation revealed that the enhanced POD-like activity was mainly attributed to a suitable built-in electric field among adjacent PDI-OH molecules on the surface of the SiO2 @TiO2 and the unique yolk-shell structure with more reaction sites of SiO2 @TiO2. Consequently, the highly selective and ultrasensitive detection of H2O2 is achieved with a detection limit (LOD) of 7.6 × 10-8M. Further, the selective detection of sarcosine with LOD of 1.2 × 10-7 M was also achieved by introducing sarcosine oxidase (SOx). This colorimetric assay is successfully applied to selectively detect H2O2 and sarcosine levels in real samples. Controlled response time, anti-interference, and the robustness of the developed colorimetric sensor are the key advantages. And the present work firstly clarifies the effect of PDIs substituents on the POD-like activity of light-responsive nanozymes and provided new guidelines to develop high-performance nanozymes for hazardous substances detection.

Embedding SnO2 Thin Shell Protected Ag Nanowires in SnO2 ETL to Enhance the Performance of Perovskite Solar Cells.

The energy level mismatching between SnO2 and perovskite and the nonradiative recombination at SnO2-perovskite interface severely degrade the extraction of carriers, reducing the power conversion efficiency (PCE) and stability of planar perovskite solar cells (PSCs) based on SnO2 electron transfer layer (ETL). In the present work, a reinforced SnO2 ETL was successfully developed by embedding SnO2 thin shell protected Ag nanowires (Ag/SnO2 NWs) in traditional planar SnO2 film, which was proved to not only lower the conduction band of SnO2 to adjust the energy level matching, but also significantly reduce the interfacial carrier recombination. Moreover, Ag/SnO2 NWs improved the electrical conductivity of SnO2 ETL, and effectively promoted carrier transport. Benefiting from the use of Ag/SnO2 NWs, our newly designed PSC achieved a significantly increased champion PCE of 19.78%, which is 7% higher than the traditional PSC without Ag/SnO2 NWs embedding, indicating its great application potential in PSCs.