Green and facile recycling of bauxite residue to biochar-supported iron-based composite material for hydrothermal liquefaction of municipal solid waste.

Industrial and municipal wastes remain significant sources of air, soil, and water pollution, thus causing adverse climate and health impacts. EU faces challenges in developing green recycling processes and reducing GHG emissions. Innovation in green catalysis is a key driver toward the fulfilment of these goals. This study demonstrated a single-step "Green Recycling" route by which different wastes e.g., industrial and bioorganic wastes are treated to produce biochar/Fe(0) (BC-Fe(0)) material. Typically, three different biomass namely organic fraction of municipal solid waste (biopulp), wheat straw (WS), and microalgae (MA) were used as green reducing agents for reducing bauxite residue (BR). Among all biomass, the high reduction potential of amino acids present in biopulp facilitated the synthesis of BC-Fe(0). BC-Fe(0) material acted as an effective catalyst for HTL of biopulp as the results showed the highest bio-crude yield (44 wt%) at 300 °C for 30 min with 10 wt% BC-Fe(0) loading (containing 2.5 wt% Fe). Furthermore, BC-Fe(0) also assisted in-situ hydrogenation and deoxygenation of chemical compounds present in the bio-liquid product, therefore bio-crude exhibited a higher H/C ratio (1.73) and lower oxygen contents (9.78 wt%) in comparison to bio-crude obtained without catalyst. However, Raw BR and reduced BR (RED) as catalysts showed no significant effect on the yield and oxygen content of bio-crude, which confirms the high catalytic activity of Fe(0) containing BC-Fe(0). Therefore, this study demonstrates the greener path for the one-step valorization of industrial and organic wastes, as an alternative to existing chemical and high temperature-based waste recycling and catalyst synthesis technologies.

Optimizing monosaccharide production from liquid hot water pretreatment and enzymatic hydrolysis of grass-clover press cake.

In the present study, clover-grass press cake was treated by liquid hot water at temperatures of 180-200 °C for a reaction time of 5-10 min. Evaluation of pretreatments was based on the monosaccharide yield after enzymatic hydrolysis of the pretreated slurry and solid fraction, respectively. Extraction of up to 48% hemicellulose and 4% cellulose was observed during pretreatment. The optimal pretreatment conditions were identified as 190 °C and 10 min resulting in monosaccharide yields of 90% and 73% of the theoretical maximum by slurry and solid conversion, respectively. At optimal conditions, the C6 monosaccharide yield (83-90%) was fairly equal compared to the C5 monosaccharide yield (56-89%), which increased by slurry conversion due to near-complete monomerization of soluble xylo-oligosaccharides. In this study, we showed that clover-grass press cake possesses considerable potential as feedstock for production of fermentable sugars in a biorefinery context.

Facile synthesis of N-doped graphene supported porous cobalt molybdenum oxynitride nanodendrites for the oxygen reduction reaction.

Exploring an inexpensive, active and stable electrocatalyst as an alternative to expensive Pt for the oxygen reduction reaction (ORR), porous Co-Mo-ON alloy nanodendrites supported on nitrogen-doped graphene (Co-Mo-ON/NG) have been synthesized by a two-step solid state heating method. The Co-Mo-ON/NG nanodendrites offer high ORR activity and superior electrochemical stability both in acidic and alkaline media. This superiority is due to the synergistic effect of NG, enhanced catalytic efficiency by Mo, highly active intrinsic surface area and exposure of catalytic facets of nanodendritic morphology towards the ORR. The Co-Mo-ON/NG nanodendrites show a 4e- ORR process with 0.710 V and 0.915 V onset potentials in 0.5 M H2SO4 and 0.1 M KOH, respectively. The Co-Mo-ON/NG nanodendrites show extreme electrochemical stability in terms of 96% and 97% current retention for 40 000 s in both acidic and alkaline media, respectively, long term durability for continuous 2000 cycles and greater resistance to methanol than the commercial Pt/C catalyst. Furthermore, Mo-ON/NG, Co-ON/NG, and Co-Mo-ON are also tested to evaluate the effect of Mo-doping and NG on the electrocatalytic activity of Co-Mo-ON/NG nanodendrites. Owing to their low cost, easy synthesis, outstanding ORR performance, and extreme durability, Co-Mo-ON/NG nanodendrites emerged as a promising non-precious and highly stable ORR electrocatalyst in fuel cell applications.

Pentacenequinone-Stabilized Silver Nanoparticles: A Reusable Catalyst for the Diels-Alder [4 + 2] Cycloaddition Reactions.

Silver nanoparticles (AgNPs) stabilized by aggregates of derivative 4 have been used as catalyst for the construction of synthetically and biologically important [4 + 2] cycloadducts at room temperature.

Aggregates of the pentacenequinone derivative as reactors for the preparation of Ag@Cu2O core-shell NPs: an active photocatalyst for Suzuki and Suzuki type coupling reactions.

Aggregates of the pentacenequinone derivative 1 act as reactors and stabilizers for rapid and facile preparation of Ag@Cu2O core-shell nanoparticles (NPs) in aqueous medium. The in situ generated Ag@Cu2O core-shell hybrid materials enabled efficient visible light harvesting to catalyse the palladium free Suzuki-Miyaura and Suzuki type cross coupling reactions at room temperature.