Conversion Of Biomass-derived Research Articles

Pt-Nb2O5-TiO2 based semiconductors for photo-reforming of glucose and fructose aqueous solutions

The conversion of biomass derivatives into fuels and valuable compounds under green conditions is increasingly attracting the attention of the scientific community. In this study, the photo-reforming of aqueous glucose and fructose solutions in the presence of 0.5 wt% Pt-loaded homemade bare and Nb2O5-TiO2 catalysts was investigated to maximize the activity of titania for both hydrogen production and valuable chemical production. The most efficient sample was the home-prepared Pt-4 %Nb2O5-HP, for both glucose and fructose conversion, with the highest H2 productivity and the highest selectivity towards partially oxidized compounds. The behaviour of the Pt-4 %Nb2O5-HP derives from a favourable compromise of some surface and intrinsic electronic properties as, for instance, photoluminescence, zeta potential and surface acidity. The presence of Nb2O5 decreased the recombination rate of photoproduced charges. Photo-deposition of Pt was essential for H2 production and, surprisingly, also increased the basicity of the TiO2 surface; an increase in surface acidity was measured when only niobium oxide was added, whereas stronger basic sites were observed in the simultaneous presence of Pt and niobium oxide.

Highly Selective Photocatalytic Oxidation Biomass Valorization Over Nb2O5/g‐C3N4Heterojunction

The selective biomass conversion of 5‐hydroxymethylfurfural (HMF) to 2,5‐diformylfurane (DFF) through photocatalysis is of immense importance and has attracted much interest recently. However, its selectivity and conversion are still limited at present due to the lack of efficient photocatalysts to controllably activate the alcohol hydroxyl groups. Herein, Nb2O5/g‐C3N4type‐II heterojunction photocatalysts to restrain the over‐oxidation are developed, which successfully adjust the active oxygen species and enhance the separation and transfer of photoexcited carriers. The system achieves selective oxidation of HMF to DFF with high selectivity (>99%) and conversion (53%) via the inhibition of hydroxyl radicals (·OH) production arising from the decomposition of H2O2. Moreover, h+is the main active species for photocatalytic selective oxidation of HMF, and ·O2−is the second for that. Herein, it offers an effective strategy to effectively improve the high‐selective conversion of biomass derivatives into high‐value‐added products.

UMA BREVE REVISÃO SOBRE A CATÁLISE POR ÁTOMOS ISOLADOS: CONCEITOS E APLICAÇÕES

A BRIEF OVERVIEW ON SINGLE-ATOM CATALYSIS: CONCEPTS AND APPLICATIONS. Catalytic processes became extremely important for the development of our society, especially after the second industrial revolution. Thus, the research for more efficient catalysts is an obstacle to overcome to achieve cheaper processes, higher yields, and selectivity of desired products. In this context, single-atom catalysis emerges as a promising alternative to unite the advantages of traditional homogeneous and heterogeneous catalysis. Catalysis by single-atoms is a bridge that unites in a single catalyst the ease of recovery and reuse (from heterogeneous catalysis) with the high exposure and uniformity of sites (from homogeneous catalysis). Thus, single-atom catalysts (SACs) and single-atom alloys (SAAs) have already found several applications in the literature, such as in hydrogenation, oxidation, conversion of biomass derivatives, electrocatalysis, and photocatalysis. However, it is essential to emphasize that it is still a field that is expanding and relatively new, with several opportunities and many barriers to surpass. In this review, concepts of homogeneous, enzymatic, and heterogeneous catalysis will be addressed, as well as fundamental aspects of single-atom catalysis, preparation methods, characterization, and current challenges.

Correction: Catalytic conversion of biomass derivatives to lactic acid with increased selectivity in an aqueous tin(ii) chloride/choline chloride system

Correction for ‘Catalytic conversion of biomass derivatives to lactic acid with increased selectivity in an aqueous tin(ii) chloride/choline chloride system’ by Asep Bayu et al., Green Chem., 2018, DOI: 10.1039/c8gc01022f.

Microbial Production of Short Chain Fatty Acids from Lignocellulosic Biomass: Current Processes and Market.

Biological production of organic acids from conversion of biomass derivatives has received increased attention among scientists and engineers and in business because of the attractive properties such as renewability, sustainability, degradability, and versatility. The aim of the present review is to summarize recent research and development of short chain fatty acids production by anaerobic fermentation of nonfood biomass and to evaluate the status and outlook for a sustainable industrial production of such biochemicals. Volatile fatty acids (VFAs) such as acetic acid, propionic acid, and butyric acid have many industrial applications and are currently of global economic interest. The focus is mainly on the utilization of pretreated lignocellulosic plant biomass as substrate (the carbohydrate route) and development of the bacteria and processes that lead to a high and economically feasible production of VFA. The current and developing market for VFA is analyzed focusing on production, prices, and forecasts along with a presentation of the biotechnology companies operating in the market for sustainable biochemicals. Finally, perspectives on taking sustainable product of biochemicals from promise to market introduction are reviewed.

Scaling relations between adsorption energies for computational screening and design of catalysts

Adsorption energies have significant value as predictors of catalytic performance. An important method of increasing efficiency of adsorption energy calculations is to employ scaling relations, which are linear relationships between adsorption energies of similar adsorbates. They are most commonly used to unify the description of adsorbates that bind to the surface through a particular type of atom. In this work, we review the development and applications of scaling relations. Scaling relations have been observed for a variety of adsorbates bonding through C, O, H, N, and S atoms to the surfaces of transition metals, oxides, nitrides, sulfides, carbides, and nanoparticles. They can be used to increase the efficiency of predictions, simplify descriptions of surface reactivity, and sometimes to derive limits on the effectiveness of a catalyst. Because scaling relations can impose a significant limitation on catalyst design, it is also useful to explore how to design active sites that significantly deviate from them. We discuss applications to a variety of processes, including methane reforming and synthesis, alcohol decomposition and synthesis, electrochemical systems, and conversion of biomass derivatives.