Suppressed Non-Radiative Recombination in Formamidinium Lead Triiodide under Electric Activation.

The high carrier lifetime of metal halide perovskite (MHP) materials is closely related to the microscopic crystallographic structure. However, the detailed correlation between the lattice structure and carrier dynamics remains unclear. In this work, we found a correlation between lattice strain and open-circuit voltage () of MHP under electric activation.

Insight into the Rate-Determining Step in Photocatalytic Z-Scheme Overall Water Splitting by Employing A Series of Perovskite RTaON (R = Pr, Nd, Sm, and Gd) as Model Photocatalysts.

Photocatalysis is an intricate process that involves a multitude of physical and chemical factors operating across diverse temporal and spatial scales. Identifying the dominant factors that influence photocatalyst performance is one of the central challenges in the field. Here, we synthesized a series of perovskite RTaON semiconductors with different A-site rare earth atoms (R = Pr, Nd, Sm, and Gd) as model photocatalysts to discuss the influence of the A-site modulation on their local structures as well as both physical and chemical properties and to get insight into the rate-determining step in photocatalytic Z-scheme overall water splitting (OWS).

Diastereo-divergent synthesis of chiral hindered ethers via a synergistic calcium(II)/gold(I) catalyzed cascade hydration/1,4-addition reaction.

Hindered ethers are ubiquitous in natural products and bioactive molecules. However, developing an efficient method for the stereocontrolled synthesis of all stereoisomers of chiral hindered ethers is highly desirable but challenging. Here we show a strategy that utilizes in situ-generated water as a nucleophile in an asymmetric cascade reaction involving two highly reactive intermediates, 3-furyl methyl cations and ortho-quinone methides (o-QMs), to synthesize chiral hindered ethers.

Development of a novel BaBiVO photocatalyst with dual functions of both water oxidation and proton reduction performance.

To overcome the limitation of photocatalysts with dual functionality of water oxidation and proton reduction, we proposed a novel bismuth-based BaBiVO (BBVO) photocatalyst, which can simultaneously drive the proton reduction reaction under UV light and water oxidation reaction under visible light. After doping with sulfur through an vulcanization strategy, the light absorption and charge separation efficiencies of the sulfur-doped BBVO were significantly improved, thus boosting its oxygen evolution activity (64 μmol h) by more than 16 times compared with independent BBVO. The experimental results demonstrate that BBVO can be employed as a very promising bismuth-based photocatalyst for solar energy conversion.

Asymmetric Sites on the ZnZrO Catalyst for Promoting Formate Formation and Transformation in CO Hydrogenation.

The role of formate species for CO hydrogenation is still under debate. Although formate has been frequently observed and commonly proposed as the possible intermediate, there is no definite evidence for the reaction of formate species for methanol production. Here, formate formation and conversion over the ZnZrO solid solution catalyst are investigated by in situ/operando diffuse reflectance infrared Fourier transform spectroscopy-mass spectroscopy (DRIFTS-MS) coupled with density functional theory (DFT) calculations.

Suppressing non-radiative recombination in metal halide perovskite solar cells by synergistic effect of ferroelasticity.

The low fraction of non-radiative recombination established the foundation of metal halide perovskite solar cells. However, the origin of low non-radiative recombination in metal halide perovskite materials is still not well-understood. Herein, we find that the non-radiative recombination in twinning-tetragonal phase methylammonium lead halide (MAPbICl) is apparently suppressed by applying an electric field, which leads to a remarkable increase of the open-circuit voltage from 1.

Flux-assisted synthesis of tungsten-doped layered perovskite oxychloride with promoted visible-light-responsive O evolution performance.

Here, we successfully prepared BaBiTaOCl a simple one-step molten salt method and adjusted its crystal morphology and structure, based on which the O-evolving activity was significantly improved. In addition, W doping promotes the charge separation efficiency, lowers the energy barrier for water oxidation reaction, and thus improves the activity. Finally, the optimized W-doped sample after molten salt treatment shows the best O production activity (55 μmol h) without loading any cocatalyst, which is 6 times higher than that of pristine BaBiTaOCl and 2 times higher than that of the undoped BaBiTaOCl treated with molten salt, respectively.

Layered β-ZrNBr Nitro-Halide as Multifunctional Photocatalyst for Water Splitting and CO Reduction.

Developing mixed-anion semiconductors for solar fuel production has inspired extensive interest, but the nitrohalide-based photocatalyst is still in shortage. Here we report a layered nitro-halide β-ZrNBr with a narrow band gap of ca. 2.

Switching between classical/nonclassical crystallization pathways of TS-1 zeolite: implication on titanium distribution and catalysis.

In the MFI zeolite crystallization process, the classical crystallization mechanism based upon the addition of silica species is often concomitant with the nonclassical route that is characteristic of the attachment of silica nanoparticle precursors. However, the factors that govern the preferences for each mechanism remain unclear. In this work, we present the impact of switching between these two crystallization pathways on the active sites and the resulting catalytic performance of the titanosilicate TS-1 zeolite.

Pyrochlore-structural NdTaON photocatalyst with an absorption edge of over 600 nm for Z-scheme overall water splitting.

A pyrochlore-structural oxynitride NdTaON with a visible light absorption edge of 620 nm was explored for photocatalytic water splitting. Dual functions of NdTaON were confirmed by proton reduction and water oxidation half-reactions through separately loading Pt or CoO as a cocatalyst in the presence of the corresponding sacrificial reagent. Finally, the platinum modified sample (Pt/NdTaON) was prepared and employed as the H-evolving photocatalyst to fabricate an effective photocatalytic Z-scheme overall water splitting together with PtO/WO as the O-evolving photocatalyst and IO/I as shuttle ions under visible light irradiation.

Water-Stable Nickel Metal-Organic Framework Nanobelts for Cocatalyst-Free Photocatalytic Water Splitting to Produce Hydrogen.

Development of water-stable metal-organic frameworks (MOFs) for promising visible-light-driven photocatalytic water splitting is highly desirable but still challenging. Here we report a novel p-type nickel-based MOF single crystal (Ni-TBAPy-SC) and its exfoliated nanobelts (Ni-TBAPy-NB) that can bear a wide range of pH environment in aqueous solution. Both experimental and theoretical results indicate a feasible electron transfer from the HTBAPy ligand (light-harvesting center) to the Ni-O cluster node (catalytic center), on which water splitting to produce hydrogen can be efficiently driven free of cocatalyst.

Catalytic production of low-carbon footprint sustainable natural gas.

Natural gas is one of the foremost basic energy sources on earth. Although biological process appears as promising valorization routes to transfer biomass to sustainable methane, the recalcitrance of lignocellulosic biomass is the major limitation for the production of mixing gas to meet the natural gas composition of pipeline transportation. Here we develop a catalytic-drive approach to directly transfer solid biomass to bio-natural gas which can be suitable for the current infrastructure.

Mechanistic Studies on Photocatalytic Overall Water Splitting over GaO-Based Photocatalysts by MS-FTIR Spectroscopy.

Photocatalytic water splitting on semiconductor photocatalysts is one of the most important physichemical processes, but its surface reaction mechanisms are not fully understood. Based upon the ATR-FTIR investigations combining with the mass spectroscopy (MS) analysis, a direct hydroxyl radical formation mechanism that is different from those observed for other semiconductor photocatalysts is proposed. This study provides the insight into overall water splitting mechanism on GaO-based photocatalysts at a molecular level, and it helps one to further understand the photocatalysis on semiconductor photocatalysts.

Titanosilicate zeolite precursors for highly efficient oxidation reactions.

Titanosilicate zeolites are catalysts of interest in the field of fine chemicals. However, the generation and accessibility of active sites in titanosilicate materials for catalyzing reactions with large molecules is still a challenge. Herein, we prepared titanosilicate zeolite precursors with open zeolitic structures, tunable pore sizes, and controllable Si/Ti ratios through a hydrothermal crystallization strategy by using quaternary ammonium templates.

Synthesis of Aluminophosphate Molecular Sieves in Alkaline Media.

Unlike conventional aluminosilicate zeolites synthesized in alkaline media, aluminophosphate molecular sieves (AlPOs) have always been prepared under acidic conditions in the past three decades; this has been regarded as one of essential factors for synthesis, except for the case of silica-substituted analogues (SAPOs). For the first time, we demonstrate herein a simple and generalized route for synthesizing various types of aluminophosphate molecular sieves in alkaline media. A series of aluminophosphate sieves and their analogues have been prepared with different quaternary ammonium cations as structure-directing agents in this manner.

Stereostructural Elucidation of Glucose Phosphorylation by Raman Optical Activity.

Phosphorylation of glucose is the prime step in sugar metabolism and energy storage. Two key glucose phosphates are involved, that is, glucose 6-phosphate (G6P) and α-glucose 1-phosphate (αG1P). The chiral conformation of glucose, G6P, and αG1P plays an essential role in enzyme-mediated conversions.

Sustainable Synthesis of Pure Silica Zeolites from a Combined Strategy of Zeolite Seeding and Alcohol Filling.

Currently, the synthesis of pure silica zeolites always requires the presence of organic structure-directing agents (OSDAs), which direct the assembly pathway and ultimately fill the pore space. A sustainable route is now reported for synthesizing pure silica zeolites in the absence of OSDAs from a combined strategy of zeolite seeding and alcohol filling, where the zeolite seeds direct crystallization of zeolite crystals from amorphous silica, while the alcohol is served as pore filling in the zeolites. Very importantly, the alcohol could be fully washed out from zeolite pores by water at room temperature, which completely avoids calcination at high temperature for removal of OSDAs in the synthesis of pure silica zeolites.

A highly selective and stable ZnO-ZrO solid solution catalyst for CO hydrogenation to methanol.

Although methanol synthesis via CO hydrogenation has been industrialized, CO hydrogenation to methanol still confronts great obstacles of low methanol selectivity and poor stability, particularly for supported metal catalysts under industrial conditions. We report a binary metal oxide, ZnO-ZrO solid solution catalyst, which can achieve methanol selectivity of up to 86 to 91% with CO single-pass conversion of more than 10% under reaction conditions of 5.0 MPa, 24,000 ml/(g hour), H/CO = 3:1 to 4:1, 320° to 315°C.

A Short-Wavelength Raman Optical Activity Spectrometer with Laser Source at 457 nm for the Characterization of Chiral Molecules.

Developing a high-sensitivity Raman optical activity (ROA) spectrometer has been regarded as one of the great challenges in chiral science and technology. Herein, we report our recent progress on the development of a short-wavelength ROA (sw-ROA) spectrometer with the excitation line at 457 nm, which shows obviously improved signal-to-noise (S/N) ratio compared with the currently available 532 nm ROA spectrometer. This could be ascribed to the fifth-power of frequency dependence for ROA intensity together with the potential advantage of avoiding fluorescence for most molecules.

Roles of adsorption sites in electron transfer from CdS quantum dots to molecular catalyst cobaloxime studied by time-resolved spectroscopy.

Electron transfer from CdS quantum dots (QDs) to cobaloxime (Co(dmgH)2pyCl) is demonstrated by transient absorption spectroscopy (TAS), and further confirmed using photoluminescence (PL) techniques. The analysis of the PL quenching results offers a novel way to understand the roles of the surface adsorption sites of CdS QDs in the performance of charge transfer in the CdS QDs-cobaloxime hybrid system. Two types of quenching dynamics reveal that there are two different adsorption modes of cobaloxime on the CdS QD surface.

Dual Extraction of Photogenerated Electrons and Holes from a Ferroelectric Sr0.5Ba0.5Nb2O6 Semiconductor.

The separation of photogenerated charges is a critical factor in photocatalysis. Recently, anomalous photovoltaic (APV) field effects (Voc ∼ 10(3) V/cm) in ferroelectrics, with their strong driving force for charge separation, have attracted much attention in photocatalysis and photoelectrocatalysis. However, it is still unknown whether photogenerated electrons and holes can be simultaneously extracted by the strong driving force toward the surface of ferroelectrics and can become available for surface reactions.

Insights of the Crystallization Process of Molecular Sieve AlPO4-5 Prepared by Solvent-Free Synthesis.

Crystallization of AlPO4-5 with AFI structure under solvent-free conditions has been investigated. Attention was mainly focused on the characterization of the intermediate phases formed at the early stages during the crystallization. The development in the long-range ordering of the solid phases as a function of crystallization time was monitored by XRD, SEM, IR, UV-Raman, and MAS NMR techniques.

Reevaluation of the stability of G-quadruplex structures under crowding conditions.

To evaluate the stability of G-quadruplex structures comprehensively, parallel (type I), antiparallel (type II), and hybrid (type III) G-quadruplexes in the presence of monovalent and divalent cations were assessed by UV-melting technique under dilute and crowded conditions. In the presence of monovalent cations, the stability of G-quadruplexes was increased by the presence of molecular crowding agents. Surprisingly, crowding agents stabilized parallel G-quadruplex, but had no effect on stability or destabilized antiparallel or hybrid G-quadruplex structures in the presence of divalent cations.

Photo-induced H2 production from a CH3OH-H2O solution at insulator surface.

In a conventional photocatalytic or photochemical process, either a photocatalyst or a molecule is excited by irradiation light that has energy greater than the forbidden band (i.e., the band gap) of the semiconductor or the transition energy of an excited state of the molecule, respectively, for a reaction to occur.