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fff; International audience; Identifying the structure of the most active site is essential to improve the performance of supported metal catalysts. For structure-sensitive reactions, in silico design cannot be easily achieved combining the scaling relations and Brønsted–Evans–Polanyi relations, which are only built on energy-based descriptors. We used here the generalized coordination number as a structural descriptor and established that low-coordinated sites are desirable when using Co and Cu to perform the acceptor-less alcohol dehydrogenation reaction.

fff; International audience; Mo/TiO2 catalysts with atomic dispersion of molybdenum appear active and stable in the gas-phase hydrogenation of CO2. The comparison between various titania materials shows a crucial effect of the support surface structure on the methanol yield. Molybdenum supported at low coverage on rutile titania nanorods is the most active and methanol-selective system. From catalyst characterization by aberration-corrected scanning transmission electron microscopy, near-ambient pressure X-ray photoelectron spectroscopy, diffuse reflectance UV-vis spectroscopy, and temperature-programmed techniques, we suggest that the most active catalysts for methanol production involve atomically-dispersed oxomolybdate species with high reducibility and strong interaction with the rutile support.

The catalytic effect of nitrogen incorporation into Mo on hydrogenation (of –NO2 to –NH2 in nitrobenzene to aniline) and hydrogenolysis (of –CO in benzaldehyde to toluene) processes has been assessed. Bulk Mo was prepared by temperature programmed reduction of MoO3 (in H2 to 933 K) and β-Mo2N (confirmed by powder XRD) subsequently synthesised by Mo nitridation in N2/H2. Two intermediate samples (MoN-1 and MoN-2) with different Mo/N ratio were prepared by altering the duration (1 and 2 h) of the nitridation step. XPS analysis revealed a nitrogen surface enrichment (Mo/N = 2.2 → 0.9 from MoN-1 to β-Mo2N) relative to the bulk (Mo/N = 5.1 → 2.5). Incorporation of N did not affect morphology and each sample exhibited (by SEM analysis) aggregates (

This study describes the use of new ZnO/PAAH hybrid nanomaterials (PAAH = polyacrylic acid) as copper catalyst supports for the hydrogenolysis of glycerol. A study of the synthesis parameters (washing process, temperatures of synthesis and calcination) of these hybrid supports has allowed us to vary their morphology and specific surface area and ultimately the sizes and dispersion of the copper nanoparticles, and to perform a general analysis of their effects on the catalytic performance of the materials. All catalysts were synthesized by the urea deposition-precipitation method (DPU) and were fully characterized to establish a structure–activity relationship. Optimization of the synthesis and catalytic conditions allowed remarkable yields/conversions of the order of 70% for selectivities in 1,2 propanediol of 90%.

International audience; Acceptor-less alcohol dehydrogenation reaction allows the co-production of added-value carbonyl compounds and H 2 from alcohols. Focusing on supported Ru and Cu catalysts, we evaluated the support effect on the dehydrogenation of 2-octanol and 1-octanol and identified the side products as resulting from aldolisation coupling. The most active and selective catalysts were then tested on the aliphatic vicinal-diol octan-1,2-diol and the highest conversion was reached using Cu/ZrO 2 (60%) with a high selectivity (94%) towards 1-hydroxy-2-octanone.

International audience; Cobalt nanorods and cobalt nanoplatelets, prepared by the same organometallic route with two different metal precursors, were tested for the first time in the acceptor-less dehydrogenation of 2-octanol. The nature of the metal precursor determines not only nanoparticle morphology but also their surface chemistry. While cobalt nanorods showed high conversions (up to 85% after 24 h) and complete selectivity toward 2-octanone with concomitant molecular hydrogen production, cobalt nanoplatelets were practically inactive. Here, we show that this striking difference in the catalytic properties is not associated with facet-dependent differences in reactivity, but rather with different surface chemistry. The activity critically depends on the coordinating ability of the adsorbed species under catalytic reaction conditions and to a smaller degree on their concentration, as evidenced by ligand exchange experiments at room temperature as well as by direct addition of ligands in the reaction during catalysis by cobalt nanorods. This study shows that to optimize performances with unsupported metal nanocatalysts, the capping ligands should be selected by considering their ability to reversibly dissociate from the metal surface during catalysis.

SSCI-VIDE+CDFA:ECI2D+RCE:CPI:LPI:NPR; International audience; Catalysts based on molybdenum carbide or nitride nanoparticles (2–5 nm) supported on titania were prepared by wet impregnation followed by a thermal treatment under alkane (methane or ethane)/hydrogen or nitrogen/hydrogen mixture, respectively. The samples were characterized by elemental analysis, volumetric adsorption of nitrogen, X-ray diffraction, and aberration-corrected transmission electron microscopy. They were evaluated for the hydrogenation of CO2 in the 2–3 MPa and 200–300°C ranges using a gas-phase flow fixed bed reactor. CO, methane, methanol, and ethane (in fraction-decreasing order) were formed on carbides, whereas CO, methanol, and methane were formed on nitrides. The carbide and nitride phase stoichiometries were tuned by varying the preparation conditions, leading to C/Mo and N/Mo atomic ratios of 0.2–1.8 and 0.5–0.7, respectively. The carbide activity increased for lower carburizing alkane concentration and temperature, i.e., lower C/Mo ratio. Enhanced carbide performances were obtained with pure anatase titania support as compared to P25 (anatase/rutile) titania or zirconia, with a methanol selectivity up to 11% at 250°C. The nitride catalysts appeared less active but reached a methanol selectivity of 16% at 250°C.CO(2)hydrogenation

SSCI-VIDE+CDFA+MBE:NPR; International audience; Metal catalysts are essential in the production of fuels and chemicals. Nonetheless, tailoring the exposed active sites to achieve the maximal theoretical conversion is still a great challenge. In the case of structure-sensitive reactions, such as the attractive acceptor-less alcohol dehydrogenation, playing on the exposed metallic sites appears as an appealing strategy. Still, this approach requires advanced preparation protocols and is even more difficult to implement for supported non-noble metal catalysts which easily undergo sintering. Using the polyol method, we synthesized fourteen different cobalt catalysts, which consist of unsupported shaped nanoparticles stabilized by adsorbed carboxylate ligands. Their shape and the amount of ligands were characterized by combining TEM and TGA-N2 measurements. These catalysts were found to be active in the 2-octanol dehydrogenation conditionally upon an organic layer limited to 1 to 2 monolayers. Moreover, they were fully selective towards the desired ketone and H2. The active catalysts were stable, with no leaching or modification of the shape during the reaction. Periodic DFT computations predict a greater activity of the pristine open-type facet than of the compact one, but this is not confirmed experimentally with no clear correlation between the activity expressed in turnover number and the amount of a given type of site as quantified by TEM. Further modeling including the organic layer shows that the presence of ligands reduces the sensitivity to the metallic structure. Nonetheless, these ligands generate a catalytic pocket, similar to the one found in enzymes, that interacts with the alcohol substrate through H-bonding. This pocket is the most adapted to the alcohol dehydrogenation on the open-type facet, which is mainly exposed on rods. This detailed understanding paves the way to an improved design of bespoke unsupported catalysts considering simultaneously the structure and the nature of the ligand.

SSCI-VIDE+CDFA:ECI2D+CPI:SLO:MBE:NPR; International audience; The acceptor-less dehydrogenation of 2-octanol was tested over Co supported on Al2O3, C, ZnO, ZrO2 and various TiO2. The catalysts were characterized by ICP, XRD and TGA-H2. For Co/TiO2 P25, the effects of passivation, aging (storage at room temperature), and in situ activation under H2 were investigated. The catalysts have to be tested shortly after synthesis, in order to prevent deactivation. Co supported onTiO2 P25 was the most active and 69% yield of 2-octanone was obtained, using decane as a solvent. Selectivity to 2-octanone in the range of 90% to 99.9% were observed. Small amounts of C16 compounds were also formed due to aldol condensation/dehydration reactions. The catalysts exhibited higher conversion for the dehydrogenation of secondary alcohol (65-69%), in comparison to primary alcohol (2-10%). The dehydrogenation of 1,2-octanediol led principally to 1-hydroxy-2-octanone, with a selectivity of 90% and 69% for Co/TiO2 P25 and Co/TiO2 P90, respectively.

SSCI-VIDE+CDFA+ASD:NPR:CPI:MBE; International audience; Bimetallic Rh-ReOx (Re/Rh molar ratio 0.4-0.5) catalysts supported on TiO2 and ZrO2 were prepared by the successive impregnation of dried and calcined unreduced supported Rh catalysts. Their catalytic performances were evaluated in the hydrogenolysis of erythritol to butanetriols (BTO) and butanediols (BDO) in aqueous solution at 150-240 degrees C under 30-120 bar H-2. The activity depended on the nature of the support, and the highest selectivity to BTO and BDO at 80% conversion was 37 and 29 %, respectively, in the presence of 3.7 wt% Rh-3.5 wt% ReOx/ZrO2 at 200 degrees C under 120 bar. The characterization of the catalysts by CO chemisorption, TEM with energy-dispersive X-ray spectroscopy, thermogravimetric analysis with MS, and X-ray photoelectron spectroscopy suggests a different distribution and reducibility of Re species over the supported Rh nanoparticles, which depends on the support.

International audience; The aqueous-phase hydrogenolysis of xylitol into glycols over Ru/C was performed in the presence and absence of a wide range of concentrations of Ca(OH)2 to investigate the reaction pathway. Without base, epimerization and cascade decarbonylation were the predominant reactions with high selectivities to C5 and C4 alditols and light alkanes at full conversion. Glycol production was obtained by the addition of Ca(OH)2 to promote the retro-aldol reaction. It competed with reactions without base and became the main reaction for a OH−/ xylitol molar ratio Rmol(OH/xylitol) of 0.13, and high selectivities to glycols (56 %) and glycerol (16 %) were observed. However, lactate was a byproduct at up to 27 % with a high base amount (Rmol(OH/xylitol)=0.68). Bifunctional Ru/metal oxide/C catalysts (metal: Zn, Sn, Mn, Sr, W) were synthesized and were able to cleave the C−C bond into glycols without a base promoter. The 3.1 wt %Ru/MnO(4.5 %)/C catalyst was the most active (220 h−1) with reasonable selectivity to glycols (22 %) and glycerol (10 %) and a low production of lactate (

The production of cyclopentanone derivatives from 5-hydroxymethylfurfural (HMF) using non-noble metal based catalysts is reported for the first time. Five different mixed oxides containing Ni, Cu, Co, Zn and Mg phases on an Al-rich amorphous support were prepared and characterised (XRD, ICP, SEM, TEM, H2-TPR, NH3/CO2-TPD and N2 sorption). The synthesised materials resulted in well-dispersed high metal loadings in a mesoporous network, exhibiting acid/base properties. The catalytic performance was tested in a batch stirred reactor under H2 pressure (20–50 bar) in the range T = 140–180 °C. The Cu–Al2O3 and the Co–Al2O3 catalysts showed a highly selective production of 3-hydroxymethylcyclopentanone (HCPN, 86%) and 3-hydroxymethylcyclopentanol (HCPL, 94%), respectively. A plausible reaction mechanism is proposed, clarifying the role of the reduced metal phases and the acid/basic sites on the main conversion pathways. Both Cu–Al2O3 and Co–Al2O3 catalysts showed a loss of activity after the first run, which can be reversed by a regeneration treatment. The results establish an efficient catalytic route for the production of the diol HCPL (reported for the first time) and the ketone HCPN from bio-derived HMF over 3d transition metals based catalysts in an environmental friendly medium such as water.

Oxidation of aliphatic α,ω-diols is a potentially interesting route to the production of valuable α,ω-diacids or ω-hydroxy acids for various polymer synthesis. 1,4-Butanediol (BDO), 1,5-pentanediol (PDO) and 1,6-hexanediol (HDO) are particularly attractive since they may be obtained from lignocellulosic biomass. The aqueous aerobic oxidation of these diols to the corresponding diacids was investigated in water over a set of Au, Pt, Au–Pt and Au–Pd catalysts supported on zirconia at 70 °C or 90 °C under 40 bar air. The nature of the metallic catalyst influenced the distribution of products as oxidation proceeded. The longer the carbon chain linking the terminal alcohol groups, the higher the yield of the diacid. The best yields of succinic acid, glutaric acid and adipic acid reached 83, 84 and 96% from BDO, PDO and HDO, respectively, over Au–Pt/ZrO2. There was some evidence of decarbonylation of the α,ω-hydroxyaldehyde at the early stage of the reaction. The presence of the hydroxyl substituent in 1,2,6-hexanetriol significantly slowed the oxidation rates compared with HDO. Besides, oxidation of PDO or HDO was highly selective to the ω-hydroxycarboxylate in moderate alkaline medium (NaOH/diol = 2) over Au/ZrO2 (90–93%).

TiO2-supported Mo carbides “MoC/TiO2” were prepared by impregnation of Mo salt followed by temperature programmed reduction-carburization using 20% v/v C2H6/H2. Catalysts were characterized by XRD, XPS, TEM, STEM, ICP, Raman, BET, and carbon elemental analysis. The catalytic activity was evaluated for aqueous phase hydrogenation of succinic acid at 160–240 °C, and 90–150 bar of H2 in batch reactor. MoC/TiO2 is active for this reaction. The main products after 24 h are γ-butyrolactone, and more remarkably butyric acid. These intermediates are then converted to tetrahydrofuran, butanol, 1,4-butanediol and butane. The reaction conditions (temperature, pressure) do not impact the products distribution. A larger amount of butyric acid is formed when catalysts were synthesized with a higher gas hourly space velocity. The deactivation observed while recycling the catalyst was mainly attributed to a decrease in the amounts of carbidic molybdenum and carbidic carbon, as demonstrated by XPS analysis.

SSCI-VIDE+CDFA:ING+FRM:NPA:NPR:MBE; International audience; Understanding platinum (Pt) speciation on catalysts is crucial for the design of atom-efficient materials and optimized formulations. The adsorption of carbon monoxide (CO) as a probe molecule is widely used to reveal Pt dispersion and structures, yet the assignment of IR bands is not straightforward, hindering determination of the nature of the surface sites or ensemble involved. CO adsorption was studied here over a zirconia-supported Pt catalyst. Specific sites at the interface between Pt and the support were highlighted, giving rise to an unusual band around 1660 cm–1 that could be confidently assigned to a Pt2–CO bridging carbonyl interacting head-on with a support surface hydroxyl. This adduct was yet unstable in the present conditions and was converted into a linear and bridged carbonyl bound only to Pt. Such sites are potentially important for bifunctional reactions requiring both metal and acid/base properties, particularly those occurring at the metal–support perimeter. Such adducts have probably been mistaken for carbonate-type species in many past contributions and could potentially represent crucial reaction intermediates for CO oxidation and the water–gas shift reaction.

Production of linear deoxygenated C4 (butanetriols, -diols, and butanols), C5 (pentanetetraols, -triols, -diols, and pentanols), and C6 products (hexanepentaols, -tetraols, -triols, -diols, and hexanols) is achievable by hydrogenolysis of erythritol, xylitol, and sorbitol over supported-bimetallic Rh-ReOx (Re/Rh molar ratio 0.5) catalyst, respectively. After validation of the analytical methodology, the effect of some reaction parameters was studied. In addition to C O bond cleavage by hydrogenolysis, these polyols can undergo parallel reactions such as epimerization, cyclic dehydration, and C C bond cleavage. The time courses of each family of linear deoxygenated C4, C5, and C6 products confirmed that the sequence of appearance of the different categories of deoxygenated products followed a multiple sequential deoxygenation pathway. The highest selectivity to a mixture of linear deoxygenated C4, C5, and C6 products at 80% conversion was favoured under high pressure in the presence of 3.7wt.%Rh-3.5wt.%ReOx/ZrO2 catalysts (54–71% under 80 bar) at 200 °C.

International audience; We report the first synthesis of Mo2C-supported Au and Au–Pd catalysts (nominal Au/Pd = 10 and 30) obtained from colloidal nanoparticles stabilised by polyvinyl alcohol (PVA). Equivalent Au/Al2O3 and Au–Pd/Al2O3 were prepared and served as benchmarks. Residual PVA was removed by thermal treatment in N2, which was monitored by thermogravimetric analysis. The catalysts were characterised in terms of temperature-programmed reduction (TPR), BET surface area, H2 chemisorption, powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) measurements. The reduced catalysts exhibited an equivalent metal particle size range (1–8 nm) and mean size (4–5 nm). The carbide samples showed greater H2 chemisorption capacity than the Al2O3 systems where inclusion of Pd enhanced H2 uptake. XPS measurements suggest electron transfer from Al2O3 to Au while the Au binding energy for the carbide samples is close to that of the metallic Au reference. The catalysts were tested in the gas phase hydrogenation of nitrobenzene, p-chloronitrobenzene and p-nitrobenzonitrile and delivered 100% selectivity to the target amine in each case. Inclusion of Pd served to increase selective hydrogenation rates where Au–Pd/Mo2C outperformed Au–Pd/Al2O3, a response that is attributed to increased surface hydrogen.

International audience; Oxidation of alcohols is a key-reaction for the valorization of biomass compounds, and green processes are preferred to avoid the use or production of toxic compounds. In this context, unsupported nanometer-sized catalysts have emerged as very promising materials for heterogeneous catalysis. In this paper we explore the catalytic activity of unsupported cobalt nanoparticles towards the dehydrogenation of aliphatic primary and secondary alcohols under solvent-free conditions. The unsupported particles are found to be highly active for the conversion of secondary alcohol to the corresponding ketone vs. the primary alcohol. The oxidation process is following an acceptorless dehydrogenation mechanism, where the only by-product of the reaction is the highly valuable H2 molecule. DFT calculations evidence that the chemoselectivity of secondary vs. primary alcohols originates from a more favorable desorption of the ketone reaction product compared to the aldehyde. It is also found that the morphology of the particles has a strong influence on the catalyst efficiency and stability: Co nanorods can be recycled at least three times without a loss in catalytic performances.

SSCI-VIDE+CDFA+NPR:CPI:MBE; International audience; The hydrogenolysis reaction of biomass-derived xylitol to glycols and glycerol has been carried out in different water/organic solvent mixtures over a bifunctional Ru/MnO/C catalyst under alkaline-free conditions at 60 bar H2 and 200 °C. In pure water, the retro-aldol reaction takes place. However, decarbonylation and epimerization are the dominant reactions and produce C4 and C5 alditols, which limits the overall selectivity to glycols and glycerol (30%). When 90:10 vol % water/1,4-dioxane and water/2-PrOH solutions are used as solvents, the product distribution is very similar to the one in water. Meanwhile, in 90:10 vol % water/primary alcohol (ROH with R = Me, Et, nPr, nBu), the overall selectivity to glycols and glycerol is greatly enhanced (up to 70%), whereas the selectivity to C4 and C5 alditols is reduced. In a solution with a higher MeOH proportion of 20 vol %, the glycols are detected with even higher selectivity; however, some deactivation of the catalyst is observed. TGA analysis of the used catalysts shows that during the process some coke is deposited on the catalyst via a dehydrogenation step of ROH. The coke selectively inhibits the Ru sites that are active for the undesired reactions of decarbonylation and epimerization.

SSCI-VIDE+CDFA+NPR:CPI:MBE; International audience; 1,6-Hexanediol is an emerging building-block chemical, which may be derived from biomass and can produce adipic acid for the synthesis of polymers. A series of supported Pt, Bi-Pt, Au, Pd, Au-Pd, and Au-Pt catalysts were prepared and evaluated in the aerobic oxidation of 1,6-hexanediol to adipic acid in aqueous solution without the addition of a base or an acid. The influences of various molar ratios of the metals in the bimetallic systems and the support (C, ZrO2) were studied. Under the conditions used, bismuth did not promote the catalytic performance of Pt catalysts. On the other hand, formation of an alloy of Au-Pd or Au-Pt made the catalysts very effective. A yield of adipic acid of ca. 96% was achieved at 70 °C under 40 bar of air over the Au-Pt catalyst supported on zirconia with a Au/Pt molar ratio of about 1. Recycling tests revealed the possibility to use the catalyst up to 6 times without significant changes in its catalytic performance.

A series of Ru-(Mn-M)OX catalysts (M: Al, Ti, Zr, Zn) prepared by co-precipitation were investigated in the hydrogenolysis of xylitol in water to ethylene glycol, propylene glycol and glycerol at 200 &deg, C and 60 bar of H2. The catalyst promoted with Al, Ru-(Mn-Al)OX, showed superior activity (57 h&minus, 1) and a high global selectivity to glycols and glycerol of 58% at 80% xylitol conversion. In comparison, the catalyst prepared by loading Ru on (Mn-Al)OX, Ru/(Mn-Al)OX was more active (111 h&minus, 1) but less selective (37%) than Ru-(Mn-Al)OX. Characterization of these catalysts by XRD, BET, CO2-TPD, NH3-TPD and TEM showed that Ru/(Mn-Al)OX contained highly dispersed and uniformly distributed Ru particles and fewer basic sites, which favored decarbonylation, epimerization and cascade decarbonylation reactions instead of retro-aldol reactions producing glycols. The hydrothermal stability of Ru-(Mn-Al)OX was improved by decreasing the xylitol/catalyst ratio, which decreased the formation of carboxylic acids and enabled recycling of the catalyst, with a very low deactivation.

Au–Pt and Au–Pd bimetallic catalysts were prepared over various supports using different preparation methods and were compared in the base-free selective aerobic catalytic oxidation of glucose to glucaric acid. The method of preparation of the bimetallic catalysts, the support material for the Au–Pt bimetallic nanoparticles, and the metal molar ratios have a strong influence on the activity and the maximum yield of glucaric acid. The Au–Pt/ZrO2 catalyst with a molar ratio for Au/Pt = 1 provides a 50% yield of glucaric acid at complete conversion of glucose and gluconic acid at 100 °C, under 40 bar air, using a glucose/metal ratio of 80. The catalyst was stable upon sequential recycling in a batch reactor and in long-term use in a continuous reactor. The influence of possible residual impurities has been studied. Furan derivatives or lignin residues might be problematic for catalytic oxidation of glucose in hemicellulose hydrolysates.

The catalytic response of Ni on Al2O3 obtained from Ni-Al layered double hydroxides was studied for the liquid-phase hydrogenation of hydroxymethyl furfural to tetrahydrofuran-2,5-diyldimethanol (THFDM) in water. The successive calcination and reduction of the precursors caused the removal of interlayer hydroxyl and carbonate groups and the reduction of Ni(2+) to Ni(0). Four reduced mixed oxide catalysts were obtained, consisting of different amount of Ni metal contents (47-68 wt%) on an Al-rich amorphous component. The catalytic activity was linked to Ni content whereas selectivity was mainly affected by reaction temperature. THFDM was formed in a stepwise manner at low temperature (353 K) whereas 3-hydroxymethyl cyclopentanone was generated at higher temperature. Coke formation caused deactivation; however, the catalytic activity can be regenerated using heat treatment. The results establish Ni on Al2O3 as a promising catalyst for the production of THFDM in water.

Metal–Organic Frameworks (MOFs) are porous crystalline materials that have emerged as promising hosts\ud for the heterogenization of homogeneous organometallic catalysts, forming hybrid materials which\ud combine the benefits of both classes of catalysts. Herein, we report the encapsulation of the\ud organometallic cationic Lewis acidic catalyst [CpFe(CO)2(L)]+ ([Fp–L]+, Cp ¼ h5\ud -C5H5, L ¼ weakly bound\ud solvent) inside the pores of the anionic [Et4N]3[In3(BTC)4] MOF (H3BTC ¼ benzenetricarboxylic acid) via\ud a direct one-step cation exchange process. To conclusively validate this methodology, initially [Cp2Co]+\ud was used as an inert spatial probe to (i) test the stability of the selected host; (ii) monitor the\ud stoichiometry of the cation exchange process and (iii) assess pore dimensions, spatial location of the\ud cationic species and guest-accessible space by single crystal X-ray crystallography. Subsequently,\ud the quasi-isosteric [Fp–L]+ was encapsulated inside the pores via partial cation exchange to form\ud [(Fp–L)0.6(Et4N)2.4][In3(BTC)4]. The latter was rigorously characterized and benchmarked as\ud a heterogeneous catalyst in a simple Diels–Alder reaction, thus verifying the integrity and reactivity of\ud the encapsulated molecular catalyst. These results provide a platform for the development of\ud heterogeneous catalysts with chemically and spatially well-defined catalytic sites by direct exchange\ud of cationic catalysts into anionic MOFs.

International audience; b-Mo2C and b-Mo2C/Al2O3 have been synthesised via temperature programmed carburisation and employed, for the first time, as supports for gold catalysts. 1%w/w Au/Mo2C and Au/Mo2C/Al2O3 were prepared by deposition-precipitation with urea and used to promote the gas phase hydrogenation of para-chloronitrobenzene (p-CNB) and meta-dinitrobenzene (m-DNB) where 1% w/w Au/Al2O3 served as a reference catalyst. The supports and supported Au catalysts have been characterised in terms of point of zero charge, temperature programmed reduction (TPR), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) measurements. Both Mo2C and Mo2C/Al2O3 exhibited hydrogenation activity that was significantly enhanced with the incorporation of Au. XPS and elemental analysis of Mo2C/Al2O3 revealed a lesser carbidic character and the presence of free surface carbon. Moreover, preparation of Au/Mo2C/Al2O3 was accompanied by a leaching of the Mo component into solution. The carbide-based catalysts were characterised by a broader distribution of larger Au particles compared with the reference Au/Al2O3, which can be attributed to weaker Au/carbide interactions resulting in Au agglomeration during synthesis and activation. Nevertheless, the carbide systems delivered higher hydrogenation rates relative to Au/Al2O3. All the Au catalysts tested exhibited 100% selectivity to the target p-chloroaniline product in p-CNB hydrogenation. In the case of m-DNB, both nitro groups were hydrogenated to generate m-phenylenediamine as principal product for reaction over Au/Al2O3 whereas Au/Mo2C promoted the exclusive production of m-nitroaniline at low conversions. The results demonstrate a synergistic effect between Au and Mo2C that can be exploited in the cleaner production of commercially important aromatic amines.