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The hydrogen economy is being pursued quite vigorously since hydrogen is an important and green energy source with a variety of applications as fuel for transportation, fuel cell, feedstock, energy vector, reforming in refineries, carbon dioxide valorization, biomass conversion, etc. Steam reforming of alcohols is a well-established technique to obtain syngas. Methanol is viewed to be a lucrative alternative for fossil fuels, due to its flexibility in being generated from multiple sources, high energy density, and low operating temperatures. The catalysts used for reforming govern the methanol conversion rate and the ratio of gaseous products, i.e., H2, CO, and CO2. Group VIII–XII metals have been widely utilized for methanol steam reforming as they have a higher hydrogen yield. Several other catalysts and novel techniques have been developed and used to date. Quite a few strategies to enhance the performance of catalysts and reduce deactivation have been discussed. This review focuses on the metallic catalysts, mainly Cu, Pd, Zn, with different formulations and compositions for steam reforming of methanol (SRM). Active catalyst components, supports, and their interactions, along with different promoters, are reviewed, and their performances are critically analyzed. The various reaction mechanisms and reaction pathways have been identified and elaborated. A fundamental understanding of the functionality and structure of catalysts is required no matter which alcohol is used as a feedstock, and some general inferences can be obtained from polyhydroxyl feed for the steam reforming of methanol, which is the subject matter of this review. Particularly, the role of copper as a component in mono and multimetallic systems and the nature of support must be studied fundamentally to get high hydrogen yields. It is important to determine how metal support interactions, including oxygen transfer from reducible oxides to the metal site, influence the catalyst activity, selectivity, and stability. Further, the mechanism by which alloying affects the selectivity in multimetallic catalysts must be understood by using high-end characterizations.

Magnetically separable sulfated zirconia catalysts were prepared by a two-step approach.

Hydrogenation of cinnamaldehyde yields hydrocinnamaldehyde, cinnamyl alcohol, and hydrocinnamyl alcohol, all having important applications in different industries. The selective synthesis of hydrocinnamaldehyde, which is a perfumery compound, from cinnamaldehyde is challenging. In the current work, bimetallic nanocatalyst Ni− Cu supported on reduced graphene oxide (RGO) was prepared via the solvothermal method. Different combinations of Ni−Cu@RGO were used for the hydrogenation of cinnamaldehyde in methanol as a solvent at 20 bar and 150 °C. Ni−Cu ratio was altered to understand its influence on the selectivity of the desired product hydrocinnamaldehyde. Hydrogenation of CC bond over the CO bond was favored over 5% Ni−Cu@RGO catalyst in the optimized ratio of Ni:Cu (1:1). Optimization of process parameters and characterization of fresh and reused catalyst was performed. The Langmuir−Hinshelwood−Hougen−Watson model was used to fit the reaction data. The catalyst is robust and reusable, and the process is green.

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In situ immobilization of laccase into metal‐organic framework (laccase‐MOF) was performed by assisting one‐pot synthesis strategy. A novel method to synthesize octahedral laccase‐MOF composite with enhanced thermostability is reported. The present work deals with entrapment of laccase into zeolitic imidazolate framework (ZIF‐8) by simply mixing solution of zinc acetate, 2‐methylimidazole, and laccase at room temperature (28 ± 2 °C). Fourier transform‐infrared spectroscopy (FT‐IR), Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), and Confocal scanning microscopy were employed to characterize laccase‐MOF composite. The thermostability of prepared composite was assessed concerning half‐life at varying temperatures which conferred 3.6‐fold enhancement over free enzyme. Also, kinetic studies of immobilized laccase showed a slightly higher Km and lower Vmax values along with the enhancement of thermodynamic parameters after non‐covalent interaction. Moreover, the immobilized laccase‐MOF maintained up to 48% of residual activity for seven subsequent cycles in batch mode, whereas the storage stability studies exhibited up to 83% up to 21 days of storage. Finally, FT‐IR data tool was employed to investigate the effect of encapsulation on fractions of secondary structure of protein.

Claisen‐Schmidt condensation have historical significance for over140 years and the scope was expanded due to the realization that chalcones so synthesized possess biological activity. The principles of green chemistry with emphasis on use of different solid catalysts with proper distribution of active centers such as acid, base, acid‐base, organo‐ were used along with solvent‐less systems. Among solid bases layered double hydroxides (LDH)/hydrotalcites are the most common. The limitations of solid bases are overcome by solid acids and superacids. A number of metal oxide supports are used. MOFs are increasingly being used. Complex organo‐catalysts are employed for getting excellent regio‐selectivity. In certain metal oxides, both acidic and basic sites co‐exist on the pore surface of catalyst which offer superior results. Synergism of solid catalysis using microwaves and ultrasound to intensify rates and selectivity is in vogue.Controlled pore structure and distribution of active catalytic centers, whether mono‐, bi‐ or tri‐functional catalysts, will give better green and smart processes. The review gives a critical analysis of the area and presents future directions for research.