A facile synthesis protocol is highlighted for catalytic MoS2, whose conformal thin film modification on Cu2O photocathode greatly enhances its photocurrent, reduces photo-corrosion and improves photostability.

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Irradiation at 460 nm of [Mo 3 (μ 3 -S)(μ 2 -S 2 ) 3 (S 2 CNR 2 ) 3 ]I ([2a]I, R = Me; [2b]I, R = Et; [2c]I, R = i Bu; [2d]I, R = CH 2 C 6 H 5 ) in a mixed aqueous−polar organic medium with [Ru(bipy) 3 ] 2+ as photosensitizer and Et 3 N as electron donor leads to H 2 evolution. Maximum activity (300 turnovers, 3 h) is found with R = i Bu in 1:9 H 2 O:MeCN; diminished activity is attributed to deterioration of [Ru(bipy) 3 ] 2+ . Monitoring of the photolysis mixture by mass spectrometry suggests transformation of [Mo 3 (μ 3 -S)(μ 2 -S 2 ) 3 (S 2 CNR 2 ) 3 ] + to [Mo 3 (μ 3 -S)(μ 2 -S) 3 (S 2 CNR 2 ) 3 ] + via extrusion of sulfur on a time scale of minutes without accumulation of the intermediate [Mo 3 S 6 (S 2 CNR 2 ) 3 ] + or [Mo 3 S 5 (S 2 CNR 2 ) 3 ] + species. Deliberate preparation of [Mo 3 S 4 (S 2 CNEt 2 ) 3 ] + ([3] + ) and treatment with Et 2 NCS 2 1− yields [Mo 3 S 4 (S 2 CNEt 2 ) 4 ] ( 4), where the fourth dithiocarbamate ligand bridges one edge of the Mo 3 triangle. Photolysis of 4 leads to H 2 evolution but at ∼25% the level observed for [Mo 3 S 7 (S 2 CNEt 2 ) 3 ] + . Early time monitoring of the photolyses shows that [Mo 3 S 4 (S 2 CNEt 2 ) 4 ] evolves H 2 immediately and at constant rate, while [Mo 3 S 7 (S 2 CNEt 2 ) 3 ] + shows a distinctive incubation prior to a more rapid H 2 evolution rate. This observation implies the operation of catalysts of different identity in the two cases.

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The crystal structure of tetra­iso­butyl­thiuram di­sulfide reveals a −85.81 (1)° C—S—C—S torsion angle and multiple intra- and inter­molecular S⋯C—H close contacts.

Hydrogen evolution reaction (HER) activities of self-assembled monolayers (SAMs) of [Mo3S7(S2CNMe2)3] and several other MoSx molecular clusters are presented on planer Au electrode. Our study suggests that such Mo-S clusters are unstable under HER reaction conditions of a strongly acidic electrolyte. The [Mo3S7(S2CNEt2)3]I monolayer prepared from DMF showed greater stability among all the studied precursors. The X-ray photoelectron spectroscopy (XPS) analysis on a monolayer of [Mo3S7(S2CNMe2)3]I in THF assembled on Au/ITO suggested sulfur-rich composition with S:Mo ratio of 2.278. The Mo-S monolayer clusters resulting from [Mo3S7(S2CNMe2)3]I in THF showed a Tafel slope of 75.74 mV dec−1 and required a lower overpotential of 410 mV to reach a high HER catalytic current density of 100 mA cm−2 compared to the other studied precursors. Surface coverage of the Mo-S clusters on the Au surface was confirmed by cyclic voltammetry (CV) curves from K3Fe(CN)6 and anodization of Au surface. Further, the rotating ring-disk electrode (RRDE) measurements were performed for the monolayer of [Mo3S7(S2CNMe2)3]I prepared in THF to study its reaction kinetics. The HER catalytic activity of such monolayer Mo-S clusters can further be improved by controlling the sulfur vacancy.

Platinum@hexaniobate nanopeapods (Pt@HNB NPPs) are a nanocomposite photocatalyst that was selectively engineered to increase the efficiency of hydrogen production from visible light photolysis. Pt@HNB NPPs consist of linear arrays of high surface area Pt nanocubes encapsulated within scrolled sheets of the semiconductor H x K 4−x Nb 6 O 17 and were synthesized in high yield via a facile one-pot microwave heating method that is fast, reproducible, and more easily scalable than multi-step approaches required by many other state-of-the-art catalysts. The Pt@HNB NPPs' unique 3D architecture enables physical separation of the Pt catalysts from competing surface reactions, promoting electron efficient delivery to the isolated reduction environment along directed charge transport pathways that kinetically prohibit recombination reactions. Pt@HNB NPPs' catalytic activity was assessed in direct comparison to representative state-of-the-art Pt/semiconductor nanocomposites (extPt-HNB NScs) and unsupported Pt nanocubes. Photolysis under similar conditions exhibited superior H 2 production by the Pt@HNB NPPs, which exceeded other catalyst H 2 yields (μmol) by a factor of 10. Turnover number and apparent quantum yield values showed similar dramatic increases over the other catalysts. Overall, the results clearly demonstrate that Pt@HNB NPPs represent a unique, intricate nanoarchitecture among state-of-the-art heterogeneous catalysts, offering obvious benefits as a new architectural pathway toward efficient, versatile, and scalable hydrogen energy production. Potential factors behind the Pt@HNB NPPs' superior performance are discussed below, as are the impacts of systematic variation of photolysis parameters and the use of a non-aqueous reductive quenching photosystem.

The title compound, [Mo3(C31H46NS2)3S7]I, crystallizes on a threefold rotational axis in P31c (space group No. 159). The [Mo3S7(S2CN(CH2C6H3-3,5- t Bu2)2)3]+ cations are arrayed in sheets in the ab plane with interligand hydrophobic interactions between tert-butyl groups guiding the packing arrangement. These cations form stacks parallel to the c axis with a separating distance of 10.9815 (6) Å (the c axis length) between the Mo3 centroids. On the underside of the cluster, opposite the μ3-S2− ligand, the iodide counteranion forms close contacts of 3.166 (2) Å with the sulfur atoms of the μ2-S2 2− ligands. These contacts are less than the sum of the van der Waals radii of the atoms (1.8 and 2.1 Å for S and I, respectively), thus indicating an appreciable degree of covalency to the [Mo3S7(S2CN(CH2C6H3-3,5- t Bu2)2)3]+...I− interactions.