A Co atom enhances the HER activity of monolayer MoS2 whereas a Ni atom exhibits the opposite effect on the same basal site.

Photocatalytic water splitting is attracting enormous interest for the storage of solar energy but no practical method has yet been identified. In the past decades, various systems have been developed but most of them suffer from low activities, a narrow range of absorption and poor quantum efficiencies (Q.E.) due to fast recombination of charge carriers. Here we report a dramatic suppression of electron-hole pair recombination on the surface of N-doped TiO2 based nanocatalysts under enhanced concentrations of H+ and OH−, and local electric field polarization of a MgO (111) support during photolysis of water at elevated temperatures. Thus, a broad optical absorption is seen, producing O2 and H2 in a 1:2 molar ratio with a H2 evolution rate of over 11,000 μmol g−1 h−1 without any sacrificial reagents at 270 °C. An exceptional range of Q.E. from 81.8% at 437 nm to 3.2% at 1000 nm is also reported.

There has been an intense research to develop 2-H MoS2 based catalysts to reduce or eliminate the use of Pt/C at higher metal loading for hydrogen evolution reaction (HER) in catalytic hydrolysis of water, which enables the capture of renewable energy sources as fuel and chemical. However, the study of its uncommon polymorph, 1T-MoS2 and particularly the doping effect with transition metal (TM) is rather limited due to the instability of this phase. Here we report a simple ambient temperature modification method using sonication to dope the single layer 1T-S MoS2 with various TM precursors. It is found that 1-T S MoS2 is more superior than corresponding 2H-S MoS2 and the inclusion of 3 wt% Pt or Pd can also further enhance the HER activity. STEM-EELS and XAS show the active single TM atom doping on this surface is to account for the high activity. Kinetic and DFT analyses also illustrate that the metallic nature of 1T-S MoS2 greatly facilitates the first proton reduction step from water, rendering it non-rate limiting as contrast to that of 2H-S MoS2. The inclusion of TM single doper such as Pd, despite at low loading, can offer the dramatic acceleration on the rate limiting recombination of H to H2. As a result, a bifunctional catalysis for HER over this tailored composite structure is demonstrated which outperforms most reported catalysts in this area.

Replacement of Hg with non-toxic Au based catalysts for industrial hydrochlorination of acetylene to vinyl chloride is urgently required. However Au catalysts suffer from progressive deactivation caused by auto-reduction of Au(I) and Au(III) active sites and irreversible aggregation of Au(0) inactive sites. Here we show from synchrotron X-ray absorption, STEM imaging and DFT modelling that the availability of ceria(110) surface renders Au(0)/Au(I) as active pairs. Thus, Au(0) is directly involved in the catalysis. Owing to the strong mediating properties of Ce(IV)/Ce(III) with one electron complementary redox coupling reactions, the ceria promotion to Au catalysts gives enhanced activity and stability. Total pre-reduction of Au species to inactive Au nanoparticles of Au/CeO2&AC when placed in a C2H2/HCl stream can also rapidly rejuvenate. This is dramatically achieved by re-dispersing the Au particles to Au(0) atoms and oxidising to Au(I) entities, whereas Au/AC does not recover from the deactivation.

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Vulcan carbon was pre-treated at 850 o C at a ramp rate of 5 o C/min and maintained for 24 hours under 5% H2 in Ar. Cs-Ru modified MgO and AC preparationTypically, Ru3(CO)12 was dispersed in THF for 2 hours under sonication. The mixture was then transferred to the MgO or activated carbon (AC) and allowed to sonicate at ambient

Transition metal doped chalcogenides are one of the most important classes of catalysts that have been attracting increasing attention for petrochemical and energy related chemical transformations due to their unique physiochemical properties. For practical applications, achieving maximum atom utilization by homogeneous dispersion of metals on the surface of chalcogenides is essential. Herein, we report a detailed study of a deposition method using thiourea coordinated transition metal complexes. This method allows the preparation of a library of a wide range of single atoms including both noble and non-noble transition metals (Fe, Co, Ni, Cu, Pt, Pd, Ru) with a metal loading as high as 10 wt % on various ultrathin 2D chalcogenides (MoS2, MoSe2, WS2 and WSe2). As demonstrated by the state-of-the-art characterization, the doped single transition metal atoms interact strongly with surface anions and anion vacancies in the exfoliated 2D materials, leading to high metal dispersion in the absence of agglomeration. Taking Fe on MoS2 as a benchmark, it has been found that Fe is atomically dispersed until 10 wt %, and beyond this loading, formation of coplanar Fe clusters is evident. Atomic Fe, with a high electron density at its conduction band, exhibits a superior intrinsic activity and stability in CO2 hydrogenation to CO per Fe compared to corresponding surface Fe clusters and other Fe catalysts reported for reverse water–gas-shift reactions.

There is an exciting possibility to decentralize ammonia synthesis for fertilizer production or energy storage without carbon emission from H2 obtained from renewables at small units operated at lower pressure. However, no suitable catalyst has yet been developed. Ru catalysts are known to be promoted by heavier alkali dopants. Instead of using heavy alkali metals, Li is herein shown to give the highest rate through surface polarisation despite its poorest electron donating ability. This exceptional promotion rate makes Ru–Li catalysts suitable for ammonia synthesis, which outclasses industrial Fe counterparts by at least 195 fold. Akin to enzyme catalysis, it is for the first time shown that Ru–Li catalysts hydrogenate end‐on adsorbed N2 stabilized by Li+ on Ru terrace sites to ammonia in a stepwise manner, in contrast to typical N2 dissociation on stepped sites adopted by Ru–Cs counterparts, giving new insights in activating N2 by metallic catalysts.