Single-atom metal catalysts offer a promising way to utilize precious noble metal elements more effectively, provided that they are catalytically active and sufficiently stable. Herein, we report a synthetic strategy for Pt single-atom catalysts with outstanding stability in several reactions under demanding conditions. The Pt atoms are firmly anchored in the internal surface of mesoporous Al2O3, likely stabilized by coordinatively unsaturated pentahedral Al3+ centres. The catalyst keeps its structural integrity and excellent performance for the selective hydrogenation of 1,3-butadiene after exposure to a reductive atmosphere at 200 °C for 24 h. Compared to commercial Pt nanoparticle catalyst on Al2O3 and control samples, this system exhibits significantly enhanced stability and performance for n-hexane hydro-reforming at 550 °C for 48 h, although agglomeration of Pt single-atoms into clusters is observed after reaction. In CO oxidation, the Pt single-atom identity was fully maintained after 60 cycles between 100 and 400 °C over a one-month period.

This review provides a comprehensive overview of nickel based bimetallic catalysts for energy and environmental applications.

In coordination chemistry, catalytically active metal complexes in a zero- or low-valent state often adopt four-coordinate square-planar or tetrahedral geometry. By applying this principle, we have developed a stable Pt1 single-atom catalyst with a high Pt loading (close to 1 wt %) on phosphomolybdic acid(PMA)-modified active carbon. This was achieved by anchoring Pt on the four-fold hollow sites on PMA. Each Pt atom is stabilized by four oxygen atoms in a distorted square-planar geometry, with Pt slightly protruding from the oxygen planar surface. Pt is positively charged, absorbs hydrogen easily, and exhibits excellent performance in the hydrogenation of nitrobenzene and cyclohexanone. It is likely that the system described here can be extended to a number of stable SACs with superior catalytic activities.

In this paper, NiRu, NiRh, and NiPd catalysts were synthesized and evaluated in the hydrogenolysis of lignin C− O bonds, which is proved to be superior over single-component catalysts. The optimized NiRu catalyst contains 85% Ni and 15% Ru, composed of Ni surface-enriched, Ru−Ni atomically mixed, ultrasmall nanoparticles. The Ni 85 Ru 15 catalyst showed high activity under low temperature (100 °C), low H 2 pressure (1 bar) in β-O-4 type C−O bond hydrogenolysis. It also exhibited significantly higher activity over Ni and Ru catalysts in the direct conversion of lignin into monomeric aromatic chemicals. Mechanistic investigation indicates that the synergistic effect of NiRu can be attributed to three factors: (1) increased fraction of surface atoms (compared with Ni), (2) enhanced H 2 and substrate activation (compared with Ni), and (3) inhibited benzene ring hydrogenation (compared with Ru). Similarly, NiRh and NiPd catalysts were more active and selective than their singlecomponent counterparts in the hydrogenolysis of lignin model compounds and real lignin.

This review provides critical analysis on various downstream processes to convert lignin derived feedstock into fuels, chemicals and materials.

A highly efficient, stable NiAu catalyst that exhibits unprecedented low temperature activity in lignin hydrogenolysis was for the first time developed, leading to the formation of 14 wt% aromatic monomers from organosolv lignin at 170 °C in pure water.

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Funneling and functionalization of am ixture of lignin-derived monomers into as ingle high-value chemical is fascinating.R eported herein is at hree-step strategy for the production of terephthalic acid (TPA) from lignin-derived monomer mixtures,i nw hichr edundant, non-uniform substitutes such as methoxy groups are removed and the desired carboxyg roups are introduced. This strategy begins with the hydro-treatment of corn-stover-derived lignin oil over as upported molybdenum catalyst to selectively remove methoxy groups.T he generated 4-alkylphenols are converted into 4alkylbenzoic acids by carbonylation with carbon monoxide. The Co-Mn-Br catalyst then oxidizes various alkylchains into carboxyg roups,transforming the 4-alkylbenzoic acid mixture into asingle product:TPA.F or this route,the overall yields of TPAb ased on lignin content of corn stover could reach 15.5 wt %, and importantly,TPA with greater than 99 %purity was obtained simply by first decanting the reaction mixture and then washing the solid product with water.