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[Display omitted] • Oxygen vacancy mediated L 2-x CO catalysts were designed via cation-deficiency. • A dual-reaction-center structure was formed by oxygen vacancy and ≡Cu(II) • Methyl group in phenolic increased electron transfer between dual-reaction-center. • DFT results showed that the O V enhanced H 2 O 2 adsorption and O-O stretching. • Catalytic mechanism and DMP decomposition path were investigated. The treatment of coal pyrolysis biochemical effluent has always been a serious problem in coal chemical process. However, improving the removal capacity of wastewater based on the characteristic of coal pyrolysis wastewater (CPW) has not been well investigated. In this work, the cation deficiency of Cu-based perovskite was used to couple with ≡Cu(II) to form dual-reaction-centers catalyst, which would improve the degradation of CPW in the heterogeneous Fenton-like system. According to the characterization, the La-deficiency could induce the generation of surface oxygen vacancy (O V) on the surface of L 2 CO perovskites, which would regarded as electron-rich center. Afterwards, ≡Cu(II) and dimethylphenol (DMP) were treated as electron-poor center and electron donor to accelerate electron transfer. The experimental results indicated that the L 1.8 CO sample achieved higher degradation activity than that of bulk L 2 CO sample for DMP degradation. The hydroxyl radical (∙OH) was the main function for the catalytic degradation of DMP. Significantly, the methyl group in phenolic pollutants could benefit to transfer electron in the electron-rich/poor reaction centers. Moreover, the density functional theory (DFT) calculation revealed that the introduction of surface O V would promote H 2 O 2 adsorption and strengthen electron transfer between H 2 O 2 and L 1.8 CO sample. Meanwhile, the DMP degradation pathways were also deduced by DFT calculation and UPLC-QTOF/MS analysis. The L 1.8 CO sample showed excellent recycling performance and catalytic stability during the heterogeneous Fenton-like process. This study developed a new perspective for designing more effective heterogeneous Fenton-like materials for CPW removal. [ABSTRACT FROM AUTHOR]

Brain‐inspired (neuromorphic) computing that offers lower energy consumption and parallelism (simultaneous processing and memorizing) compared to von Neumann computing provides excellent opportunities in many computational tasks ranging from image recognition to speech processing. To accomplish neuromorphic computing, highly efficient optoelectronic synapses, which can be the building blocks of optoelectronic neuromorphic computers, are necessary. Currently, carbon nanotubes (CNTs), an attractive candidate to develop circuit‐level photonic synapses, provide weak light responses. The inferior photoresponse of CNTs increases the energy consumption of neuromorphic optoelectronic devices. Herein, a method to grow organic–inorganic halide perovskite quantum dots (PQDs) directly on multiwall CNTs (MWCNTs) to increase the photosensitivity of optoelectronic synapses is demonstrated. The new hybrid material synchronizes the high photoresponse of PQDs and the excellent electrical properties of MWCNTs to provide photonic memory under very low light intensity (125 µW cm−2). However, neat MWCNTs do not show any detectable light response at the tested light intensity, as high as 25 mW cm−2. Since the PQDs are grown directly on and in the MWCNTs, the hybrid PQD‐MWCNT provides a new direction for the future MWCNT‐based optoelectronic devices for neuromorphic computing with a potential to break the von Neumann bottleneck. [ABSTRACT FROM AUTHOR]

Hybrid perovskites have been investigated for various potential applications because of their tunable optical properties. In this paper, we report the synthesis of quantum dots (QDs) of two-dimensional (2D) Ruddlesden–Popper (RP) hybrid perovskite using a top-down approach. The QDs of the developed 2D RP perovskite exhibit high and sharp photoluminescence in the ultraviolet region. The sharp peak in the absorption spectrum and the intense photoluminescence in the ultraviolet region indicate strong quantum confinement in these particles, which is further confirmed by x-ray photoelectron spectroscopy. These QDs show superior nonlinear optical scattering and absorption properties with the optical z-scan technique and strong nonlinear absorption property with the photoacoustic z-scan technique. Evaluating the nonlinear optical properties using two complementary techniques provides a deeper understanding of the nonlinear mechanism involved in the optical limiting process. The two-photon absorption coefficient obtained by optical z-scan is 7.2 × 102 cm/GW, which is larger than that of most perovskite nanocrystals and nanosheets. Our studies, therefore, reveal a new class of material, 2D RP perovskite QDs, which show important nonlinear properties that are important for optical limiting applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • A bifunctional core–shell V O -LCO@CeO x nanoreactor was designed for H 2 O 2 activation. • Heterostructure boosted V O levels via the removal of oxygen atoms to interface. • Direct electron transfer between ≡Cu and ≡Ce achieved efficient ROS production. • The catalytic mechanism had been further confirmed through DFT calculations. Double oxygen vacancies (V O) tuned core–shell La V CuO δ @CeO x (V O -LCO@CeO x) nanoreactors with direct electron transfer (DET) structure was synthesized as an effective heterogeneous Fenton-like catalyst for the quinoline removal. The DET structure was constructed by electron-rich ≡Cu center of V O -LCO core and electron-capture center of CeO x shell for electrons supplying and consuming. This structure elevated total V O levels of catalyst through the removal of oxygen atoms in CeO 2 from attice to interface sites. Meanwhile, the ≡Ce(III) acted as reactive sites for the adsorption of hydrogen peroxide (H 2 O 2) to form surface peroxide species, and then the electron-rich ≡Cu center was further provided electrons to surface peroxide species by DET to produce hydroxyl radical. Moreover, the newly formed surface V O would also be further promote hydroxyl radical production through self-activation of H 2 O 2. This catalyst displayed excellent catalytic activity and stability. The density functional theory (DFT) results further pointed out that this structure had excellent adsorption energy, and generable electron transfer from V O -LCO to CeO x. This work provided a novel approach for the development of heterogeneous Fenton-like catalysts to degrade quinoline wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel Fe 3 O 4 -LaFeO 3 /C/GF heterojunction cathode was used for hetero-EF process. • The modified cathode showed high efficiency and stability for CPW mineralization. • A higher total density of states value was induced by Fe 3 O 4 -LaFeO 3 interface. • Possible catalytic mechanisms with Fe 3 O 4 -LaFeO 3 /C/GF cathode was studied. A bifunctional electro-Fenton (EF) cathode with Fe 3 O 4 -LaFeO 3 /C embedded graphite felt (GF) was synthesized through a hydrothermal process, which was used for in situ electrochemical formation of active oxygen species (ROS) for coal pyrolysis wastewater (CPW) removal. Experimental results illustrated that the mineralization efficiency of dimethylphenol (DMP) was achieved at 90.7 % within 150 min reaction. On the basis of quenching test and free radical detection, the ∙OH and ∙O 2 − were the detectable ROS in the hetero-EF system for DMP removal. Meanwhile, the formed oxygen vacancies (OVs) and the redox of Fe2+/Fe3+ promoted the oxygen adsorption and H 2 O 2 activation. Density functional theory (DFT) calculations further discussed that the Fe 3 O 4 -LaFeO 3 interface possessed more downward spin density of states in the conduction band, resulting in a higher total density of states (DOS) value near the Fermi level. Moreover, the Fe 3 O 4 -LaFeO 3 /C/GF cathode displayed good recyclability with low metal ion dissolution for 5 times (99.5 % DMP removal and 78.6 % TOC removal) and underlying actual CPW application potential (80.2 % of COD removal and 100 % of total phenol (Tph) removal). Overall, this work invented a novel and stable bifunctional cathode for the efficient removal of refractory CPW in the hetero-EF system. [ABSTRACT FROM AUTHOR]

Cobalt mediated perovskite oxides (Ca–Fe–Co- x) were prepared for heterogeneous Fenton-like, which exhibited excellent tetracycline (TC) degradation efficiency and wider pH suitability (3–11). Experimental results showed that Ca–Fe–Co-1.0 sample displayed the highest degradation rate could reach 80.5% under neutral conditions, and maintain at around 80% after four cycles. The analysis of degradation mechanism showed that the redox of Fe2+/Fe3+ and Co2+/Co3+ significant enhanced the activation of H 2 O 2 to superoxide radical (∙O 2 −). Meanwhile, the hydroxyl radical (∙OH) was also detected by ESR analysis. In addition, the possible degradation pathway and mechanism of TC were deduced via UPLC-QTOF/MS analysis and density functional theory (DFT) calculations. The toxicity of TC and its intermediates were also evaluated by the ECOSAR software. The Ca–Fe–Co-1.0/nanocellulose aerogel (NCA) displayed highly removal efficiency of TC wastewater in the long-term operation conduction. This study provided a feasible method to design and synthesis heterogeneous Fenton-like catalysts for antibiotic degradation. [Display omitted] • Cobalt mediated perovskite would promote H 2 O 2 decompose to superoxide radical. • DFT calculations prove that cobalt enhance the electron transfer in perovskite. • Degradation intermediates were identified, and possible pathways were proposed. • Ca–Fe–Co/NCA displayed excellent efficiency in the continuous experiments. [ABSTRACT FROM AUTHOR]

Coal pyrolysis wastewater (CPW) contained all kinds of toxic and harmful components, which would seriously threaten the natural environment and human health. However, the traditional advanced oxidation processes frequently failed to remove phenolic substances. An A 2 BO 4 -type perovskite (La 2 CuO 4) was successfully synthesized through sol-gel process and first applied in the treatment of CPW. More than 90% of 3, 5-dimethylphenol (DMP) was removed within 200 min at neutral conditions. Moreover, La 2 CuO 4 also displayed excellent catalytic activity and stability in the actual CPW treatment process. Results demonstrated that DMP was removed through the attack of ∙OH, ∙O 2 − and 1O 2 in La 2 CuO 4 /H 2 O 2 system. The La 2 CuO 4 were more favorable for H 2 O 2 activation and have a lower adsorption energy than LaFeO 3. XPS of fresh and spent La 2 CuO 4 illustrated that the decomposition of hydrogen peroxide (H 2 O 2) was mainly due to the redox cycle between surface copper and oxygen species. Moreover, the possible degradation pathway of DMP was deduced by identifying degradation products and analyzing density functional theory (DFT) calculations. This research provided a novel strategy for the development of perovskite-based catalytic materials on the treatment of practical CPW. • La 2 CuO 4 was applied to the treatment of actual CPW for the first time. • La 2 CuO 4 maintained high catalytic activity in a neutral pH environment. • The La 2 CuO 4 had a lower adsorption energy than that of LaFeO 3 by DFT calculations. • Degradation products were identified by UPLC-QTOF/MS and Fukui index. • Enhanced DMP removal mechanisms with La 2 CuO 4 was proposed. [ABSTRACT FROM AUTHOR]

Oxygen vacancies (V O) constructing in metallic compounds have been verified to enhance hydrogen peroxide (H 2 O 2) activation for pollutants treatment. However, the interactions between surface V O concentration and H 2 O 2 were still ambiguous. In this study, perovskites with different surface V O concentration were successfully prepared by a simple sol-gel process. Experimental results showed that A-site cation deficient was capable of distorting FeO 6 octahedra in Ca 1−x FeO 3-δ (x = 0, 0.1, 0.2) orthorhombic perovskites for the regulation of surface V O concentration. Afterwards, Ca 0.9 FeO 3-δ exhibited excellent catalytic activity and stability for tetracycline (TC) degradation, which was 4 times higher of catalytic enhancement than that of the raw Ca 1.0 FeO 3-δ. Moreover, up to 9, 17 and 27 times of catalytic enhancement as compared with commercial Fe 3 O 4 , ɑ-FeOOH and Fe 2 O 3 towards TC degradation. Based on electron spin resonance and free radical quenching experiments, the hydroxyl radical (∙OH) was the main active species for the catalytic degradation of TC. Meanwhile, higher or lower surface V O concentration was harmful to the production of ∙OH. Additionally, the toxicity of TC degradation by-products exhibited a decreasing trend according to the results of toxicological simulation. This work provides a new strategy for designing an efficient and promising heterogeneous Fenton-likes catalyst for environmental remediation. [Display omitted] • Perovskite with abundant surface V O was synthesized by sol-gel method. • Surface V O concentration was regulated by regulated the A-site cation deficient. • Higher or lower surface V O concentration was hamful to the activation of H 2 O 2. • Degradation intermediates were identified, and possible pathways were proposed. [ABSTRACT FROM AUTHOR]

Neuromorphic Computing: Growing Perovskite Quantum Dots on Carbon Nanotubes for Neuromorphic Optoelectronic Computing (Adv. In article number 2000535, Kaitlyn E. Crawford, Jayan Thomas, and co-workers grow perovskite quantum dots (PQDs) on multi-wall carbon nanotubes (MWCNTs) to fabricate two-terminal optoelectronic synapses. Since the PQDs are grown on each MWCNT, this new hybrid material is beneficial for future nanoscale neuromorphic computing and sensing devices. [Extracted from the article]

Perovskite Solar Cells: Predictions and Strategies Learned from Machine Learning to Develop High-Performing Perovskite Solar Cells (Adv. In article number 1901891, Jayan Thomas and co-workers use machine learning (ML) to optimize material composition and predict design strategies and performance of perovskite solar cells. Bandgap prediction, machine learning, perovskite materials, perovskite solar cells. [Extracted from the article]

Perovskite solar cells (PSCs) have recently received considerable attention due to the high energy conversion efficiency achieved within a few years of their inception. However, a machine learning (ML) approach to guide the development of high‐performing PSCs is still lacking. In this paper ML is used to optimize material composition, develop design strategies, and predict the performance of PSCs. The ML models are developed using 333 data points selected from about 2000 peer reviewed publications. These models guide the design of new perovskite materials and the development of high‐performing solar cells. Based on ML guidance, new perovskite compositions are experimentally synthesized to test the practicability of the model. The ML model also shows its ability to predict underlying physical phenomena as well as the performance of PSCs. The PSC model matches well with the theoretical prediction by the Shockley and Queisser limit, which is almost impossible for a human to find from an ensemble of data points. Moreover, strategies for developing high‐performing PSCs with different bandgaps are also derived from the model. These findings show that ML is very promising not only for predicting the performance, but also for providing a deeper understanding of the physical phenomena associated with the PSCs. [ABSTRACT FROM AUTHOR]

For the first time, Cu-based perovskite oxides were used as catalysts to treat highly toxic and refractory petroleum refining wastewater based on catalytic wet peroxide oxidation (CWPO) technology. Perovskite La 2 CuO 4 was synthesized by sol-gel method. A series of characterizations showed that the synthesized catalyst particles are tetragonal phase perovskite structure. The experimental results showed that under the conditions of catalyst dosage of 0.75 g, temperature of 100 ℃ and reaction time of 30 min, the COD removal rate was 89.58 %, the TOC removal rate was 87.38 %. The morphology and structure of the catalyst before and after the reaction proved that the catalyst has strong stability and catalytic activity. The components of raw water, Wet Air Oxidation (WAO) effluent and CWPO effluent were compared and analyzed by Gas Chromatography-Mass Spectrometry (GC-MS), and the possible mechanism and path of WAO and CWPO degradation of petroleum refining wastewater were further explored. The changes of Cu components in La 2 CuO 4 before and after CWPO reaction and the transformation of lattice oxygen and adsorbed oxygen were analyzed by X-ray Photoelectron Spectroscopy (XPS). The involvement of Cu (Ⅱ) /Cu (Ⅰ) in the activation of H 2 O 2 was speculated. Finally, the biotoxicity of raw water, WAO effluent and CWPO effluent was predicted. The results provide reference value for the application of catalyst La 2 CuO 4 in various petrochemical wastewater. [Display omitted] • La 2 CuO 4 was first used as a catalyst in the CWPO process for wastewater treatment. • The catalyst La 2 CuO 4 shows strong catalytic activity and stability. • The synthesized catalyst particles had a tetragonal phase perovskite structure. • Under the optimum condition, the COD removal rate of CWPO effluent is 89.58 %. [ABSTRACT FROM AUTHOR]

The changes of substances during catalytic pyrolysis. • The structural differences of La 0.8 M 0.2 FeO 3 (M = La, Ca, Sr, Ba) are investigated. • The differences of lignin pyrolysis catalyzed by La 0.8 M 0.2 FeO 3 are compared. • The possible mechanism of lignin pyrolysis catalyzed by perovskite is proposed. A new method named the production of aryl oxygen-containing compounds via catalytic pyrolysis of bagasse lignin (BL) over perovskites, La 0.8 M 0.2 FeO 3 (M = La, Ca, Sr, Ba) was proposed. La 0.8 M 0.2 FeO 3 (M = La, Ca, Sr, Ba) samples were synthesized by the sol-gel method (SG) and characterized by XRD, SEM, BET and XPS, and their catalytic pyrolysis performances were evaluated by the test of TG and the evaluation of the fixed bed microreactor. Under the action of perovskites, the pyrolysis of BL was promoted, the yields of gaseous and solid products decreased while the yield of liquid products increased by 10–20%; decarboxylation and decarbonylation could be inhibited, and it was conducive to the fracture of aliphatic hydrocarbon side chains on aromatic rings, as a result, the selectivity of CO 2 /CO decreased while the selectivity of hydrocarbons in gaseous products increased; the total selectivity of aryl oxygen-containing compounds increased from 56 wt.% in the liquid product obtained from pure BL pyrolysis to more than 69 wt. % in that of catalytic pyrolysis of BL. The spent catalyst was regenerated after controlled combustion of solid product — char, and it showed good structural and catalytic stabilities after 5 successful redox cycles. [ABSTRACT FROM AUTHOR]