Domino Effect: Gold Electrocatalyzing Lithium Reduction to Accelerate Nitrogen Fixation.

Green production of NH , especially the Li-mediated electrochemical N reduction reaction (NRR) in non-aqueous solutions, is attracting research interest. Controversies regarding the NRR mechanism greatly impede its optimization and wide applications. To understand the electrocatalytic process, we treated Au coated carbon fibrous paper (Au/CP) as the model catalyst.

A Heterobimetallic Au -Pt Photocatalyst for Water Reduction to Hydrogen.

A supramolecular complex, [Au(C^N^C)(C≡CC H C≡C)Pt(terpy)] , has been synthesized as a photocatalyst for water reduction. This compound consists of a cyclometalated alkyne-gold(III) photosensitizer and a platinum(II) terpyridine complex bridged through a central phenylethynyl group.

An all-inorganic lead halide perovskite-based photocathode for stable water reduction.

Lead halide perovskites (LHPs) have been investigated for photoelectrochemical hydrogen generation from water splitting. However, the harsh requirements in preparing the environment, i.e.

[Emergy analysis of four typical planting modes in Karst faulted basins of Yunnan Province, China.].

Accurate evaluation of typical cropping patterns in faulted basins can provide scientific guidance for planting in the area. The planting modes of marigold, pomegranate, pomegranate+grass+sheep in Mengzi City of Yunnan Province were compared with the traditional corn planting mode. The ecological benefits and economy benefits of these rocky desertification control modes were analyzed by the method of emergy analysis.

Visible-Light-Driven Hydrogen Production and Polymerization using Triarylboron-Functionalized Iridium(III) Complexes.

The development of novel iridium(III) complexes has continued as an important area of research owing to their highly tunable photophysical properties and versatile applications. In this report, three heteroleptic dimesitylboron-containing iridium(III) complexes, [Ir(p-B-ppy) (N^N)] {p-B-ppy=2-(4-dimesitylborylphenyl)pyridine; N^N=dipyrido[3,2-a:2',3'-c]phenazine (dppz) (1), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq) (2), and 1,10-phenanthroline (phen) (3)}, were prepared and fully characterized electrochemically, photophysically, and computationally. Altering the conjugated length of the N^N ligands allowed us to tailor the photophysical properties of these complexes, especially their luminescence wavelength, which could be adjusted from λ=583 to 631 nm in CH Cl .

High light harvesting efficiency CuInS quantum dots/TiO/MoS photocatalysts for enhanced visible light photocatalytic H production.

Expanding the photoresponse range of TiO2-based photocatalysts is of great interest for photocatalytic H2 production. Herein, noble-metal-free CuInS2 quantum dots were employed as a novel inorganic dye to expand the visible light absorption of TiO2/MoS2 for solar H2 generation. The as-prepared CuInS2/TiO2/MoS2 photocatalysts exhibit broad absorption from the ultraviolet to near-infrared region.

Bandgap-tunable black phosphorus quantum dots: visible-light-active photocatalysts.

Bandgap-tunable black phosphorus quantum dots prepared by a liquid exfoliation method in a mixture solvent of N-methylpyrrolidone and oleic acid can act as efficient photocatalysts for the degradation of rhodamine B. This is the first report on solely black phosphorus capable of destroying organic pollutants under visible light irradiation.

Synthesis of Pyridinic-Rich N, S Co-doped Carbon Quantum Dots as Effective Enzyme Mimics.

N and S co-doped carbon quantum dots (N, S-CQDs) with high N- and S-doping level were synthesized by microwave solid-phase pyrolysis within 50 s. Owing to the dominant pyridinic N injection into the conjugated framework, both high enzyme mimics catalytic activity and photoluminescence quantum yield are achieved simultaneously.

Robust, double-shelled ZnGaO hollow spheres for photocatalytic reduction of CO to methane.

Robust, double-shelled ZnGaO hollow spheres were successfully fabricated by hydrothermally treating an aqueous solution containing Zn(ii), Ga(iii), and citric acid, followed by annealing at 600 °C, 700 °C, or 800 °C in air to remove the carbon species. The hollow structure is expected to trap incident photons to enhance the light absorbance. The sample annealed at 700 °C exhibited the optimized photocatalytic performance in the reduction of CO in the presence of water vapor to methane.

Metal-complex chromophores for solar hydrogen generation.

Solar H generation from water has been intensively investigated as a clean method to convert solar energy into hydrogen fuel. During the past few decades, many studies have demonstrated that metal complexes can act as efficient photoactive materials for photocatalytic H production. Here, we review the recent progress in the application of metal-complex chromophores to solar-to-H conversion, including metal-complex photosensitizers and supramolecular photocatalysts.

Evaluation of bis-cyclometalated alkynylgold(iii) sensitizers for water photoreduction to hydrogen.

Well-defined gold sensitizers for hydrogen production from water remain extremely rare despite decades of interest, and are currently limited to systems based on ruthenium, iridium or platinum complexes. This report details the synthesis and characterization of a series of neutral cyclometalated gold(iii) complexes of the type [(RC^N^CR)Au(C[triple bond, length as m-dash]C-R')] (R = H or tert-butyl group; R' = aryl groups) that have been found to be good candidates to function as harvesting materials in light-induced electron transfer reactions. We established the efficacy of systems with these gold(iii) complexes as photosensitizers (PSs) in the production of renewable hydrogen in the presence of [Co(2,2'-bipyridine)]Cl or [Rh(4,4'-di-tert-butyl-2,2'-bipyridine)](PF) as a H-evolved catalyst and triethanolamine (TEOA) as a sacrificial electron donor in acetone-water solution.

Osmium(ii) complexes for light-driven aerobic oxidation of amines to imines.

Herein, we describe the synthesis and characterization of three Os(ii) complexes (i.e., [Os(fptz)2(PPhMe2)2] (1, fptzH = 3-trifluoromethyl-5-pyridyl-1,2,4-triazole), [Os(fptz)2(CO)(L1)] (2, L1 = PPh3; 3, L1 = pyridine)) that have been successfully utilized as good photocatalysts to promote aerobic oxidative coupling of amines to imines with molecular oxygen in air as a green oxidant.

Adjusting the Crystallinity of Mesoporous Spinel CoGa2O4 for Efficient Water Oxidation.

Effective and stable electrocatalysts (ECs) are of great importance for the modification of semiconductor (SC) photoanodes, to achieve efficient photoelectrochemical (PEC) water splitting. Herein we demonstrate that the low-crystallinity mesoporous spinel CoGa2O4 oxygen evolution catalyst (OEC), exhibiting excellent bulk electrocatalytic stability and activity for oxygen-evolving reaction (OER), obviously improved water oxidization on a-Fe2O3 photoanode. Low crystallinity not only balances the stability and activity for ECs themselves but facilitates formation of adjustable Schottky junctions between ECs and SCs.

MoS2 Nanosheet-Modified CuInS2 Photocatalyst for Visible-Light-Driven Hydrogen Production from Water.

Exploiting photocatalysts respond to visible light is of huge challenge for photocatalytic H2 production. Here, we synthesize a new composite material consisting of few-layer MoS2 nanosheets grown on CuInS2 surface as an efficient photocatalyst for solar H2 generation. The photocatalytic results demonstrate that the 3 wt % MoS2 /CuInS2 photocatalyst exhibits the highest H2 generation rate of 316 μmol h(-1)  g(-1) under visible light irradiation, which is almost 28 times higher than that of CuInS2 .

Neutral nickel(II) phthalocyanine as a stable catalyst for visible-light-driven hydrogen evolution from water.

Neutral nickel(ii) phthalocyanine was found to be an efficient and stable catalyst for photocatalytic H2 evolution from water when coupled with an iridium complex as the photosensitizer and triethanolamine as the sacrificial electron donor. The result shows that the Ni-N sigma bond can enhance the stability of the catalyst.

Noble-Metal-Free Molybdenum Disulfide Cocatalyst for Photocatalytic Hydrogen Production.

Photocatalytic water splitting using powered semiconductors as photocatalysts represents a promising strategy for clean, low-cost, and environmentally friendly production of H2 utilizing solar energy. The loading of noble-metal cocatalysts on semiconductors can significantly enhance the solar-to-H2 conversion efficiency. However, the high cost and scarcity of noble metals counter their extensive utilization.

A Noble-Metal-Free Nickel(II) Polypyridyl Catalyst for Visible-Light-Driven Hydrogen Production from Water.

The complex [Ni(bpy)3](2+) (bpy=2,2'-bipyridine) is an active catalyst for visible-light-driven H2 production from water when employed with [Ir(dfppy)2 (Hdcbpy)] [dfppy=2-(3,4-difluorophenyl)pyridine, Hdcbpy=4-carboxy-2,2'-bipyridine-4'-carboxylate] as the photosensitizer and triethanolamine as the sacrificial electron donor. The highest turnover number of 520 with respect to the nickel(II) catalyst is obtained in a 8:2 acetonitrile/water solution at pH 9. The H2 -evolution system is more stable after the addition of an extra free bpy ligand, owing to faster catalyst regeneration.

Energy Transfer in a Hybrid Ir(III) Carbene-Pt(II) Acetylide Assembly for Efficient Hydrogen Production.

A new heterometallic supramolecular complex, consisting of an iridium carbene-based unit appended to a platinum terpyridine acetylide unit, representing a new Ir(III) -Pt(II) structural motif, was designed and developed to act as an active species for photocatalytic hydrogen production. The results also suggested that a light-harvesting process is essential to realize the solar-to-fuel conversion in an artificial system as illustrated in the natural photosynthetic system.

Significant enhancement in photocatalytic hydrogen evolution from water using a MoS2 nanosheet-coated ZnO heterostructure photocatalyst.

A novel MoS2 nanosheet-coated ZnO heterostructure photocatalyst was successfully synthesized via a simple hydrothermal method. Two-dimensional MoS2 nanosheets were intimately deposited onto ZnO surface to form an intimate function, which favors the charge-transfer and suppresses the recombination of the photogenerated electron-hole pairs between MoS2 and ZnO, resulting in a significantly enhanced photocatalytic activity for hydrogen evolution. The photocatalytic activities of the MoS2-ZnO composite photocatalysts with different MoS2 contents for hydrogen production were systematically evaluated.

Hydrogen photogeneration promoted by efficient electron transfer from iridium sensitizers to colloidal MoS2 catalysts.

We report the utilization of colloidal MoS2 nanoparticles (NPs) for multicomponent photocatalytic water reduction systems in cooperation with a series of cyclometalated Ir(III) sensitizers. The effects of the particle size and particle dispersion of MoS2 NPs catalyst, reaction solvent and the concentration of the components on hydrogen evolution efficiency were investigated. The MoS2 NPs exhibited higher catalytic performance than did other commonly used water reduction catalysts under identical experiment conditions.

Water reduction systems associated with homoleptic cyclometalated iridium complexes of various 2-phenylpyridines.

The photoreduction of water to hydrogen represents a promising method for generating sustainable clean fuel. The molecular processes of this photoreduction require an effective light absorber, such as the ruthenium polybipyridine complex, to collect and convert the solar energy into a usable chemical form. In the search for a highly active and stable photosensitizer (PS), iridium complexes are attractive because of their desirable photophysical characteristics.

Tricyclometalated iridium complexes as highly stable photosensitizers for light-induced hydrogen evolution.

The development of an efficient and stable artificial photosensitizer for visible-light-driven hydrogen production is highly desirable. Herein, a new series of charge-neutral, heteroleptic tricyclometalated iridium(III) complexes, [Ir(thpy)2(bt)] (1-4; thpy = 2,2'-thienylpyridine, bt = 2-phenylbenzothiazole and its derivatives), were systematically synthesized and their structural, photophysical, and electrochemical properties were established. Three solid-state structures were studied by X-ray crystallographic analysis.

Charge-neutral amidinate-containing iridium complexes capable of efficient photocatalytic water reduction.

Two new charge-neutral iridium complexes, [Ir(tfm-ppy)(2)(N,N'-diisopropyl-benzamidinate)] (1) and [Ir(tfm-ppy)(2)(N,N'-diisopropyl-4-diethylamino-3,5-dimethyl-benzamidinate)] (2) (tfm-ppy=4-trifluoromethyl-2-phenylpyridine) containing an amidinate ligand and two phenylpyridine ligands were designed and characterised. The photophysical properties, electrochemical behaviours and emission quenching properties of these species were investigated. In concert with the cobalt catalyst [Co(bpy)(3)](2+), members of this new class of iridium complexes enable the photocatalytic generation of hydrogen from mixed aqueous solutions via an oxidative quenching pathway and display long-term photostability under constant illumination over 72 h; one of these species achieved a relatively high turnover number of 1880 during this time period.

A copper(I) dye-sensitised TiO2-based system for efficient light harvesting and photoconversion of CO2 into hydrocarbon fuel.

A new copper(I) complex with the ability to bind to TiO(2) was synthesised and successfully employed as a solar cell sensitizer. Furthermore, we demonstrated that the copper(I) dye-sensitised TiO(2)-based photocatalyst exhibits impressive effectiveness for the selective photoreduction of CO(2) to CH(4) under visible light.

Impact of ligand modification on hydrogen photogeneration and light-harvesting applications using cyclometalated iridium complexes.

To explore structure-activity relationships with respect to light-harvesting behavior, a family of bis-cyclometalated iridium complexes [Ir(C^N)(2)(Hbpdc)] 2-5 (where C^N = 2-phenylbenzothiazole and its functionalized derivatives, and H(2)bpdc =2,2'-bipyridine-4,4'-dicarboxylate) was synthesized using a facile method. The photophysical and electrochemical properties of these complexes were investigated and compared to those of analogue 1 (C^N = (4-trifluoromethyl)-2-phenylbenzothiazole); they were also investigated theoretically using density functional theory. The molecular structures of complexes 2-4 were determined by X-ray crystallography, which revealed typical octahedral coordination geometry.