03339nas a2200205 4500008004100000245006000041210005900101260000900160300001100169490000900180520269400189100001802883700002702901700002702928700003002955700002102985700001703006700002203023856008803045 2020 eng d00aAdvances in single-atom catalysts for lignin conversion0 aAdvances in singleatom catalysts for lignin conversion bACS  a93-1250 v13603 a

Single-atom catalysts (SACs) have drawn significant attention as promising surfaces for promoting observable reaction processes. As a guideline, SACs should have the proper nanoscale dimensionality to influence their effective and efficient performance, especially during lignin conversion to platform chemicals and other useful products. The development of SACs for functional applications still has many difficulties, such as harnessing and improving low-coordinated metal atoms to have controlled and observable activities per metal atom. Consequently, the need arises to ensure a decrease in the size of the metal particles and their uniform dispersion or coordination on a suitable support material. This has been an industrial target for a long time in the field of catalysis. Supported metal-based catalysts are not dimensionally uniform, thereby reducing their metal-atom efficiency and frequently leading to undesired side reactions that are sometimes difficult to observe. This makes the identification of the active sites responsible for the reaction of interest very difficult or even impossible. To ameliorate this challenge, the ultimate small-size limit for a metal particle is the SAC, which contains isolated metal atoms singly dispersed on any suitable support materials. It is expected that SACs should maximize the metal-atom efficiency with respect to the application, which is particularly significant for supported metal catalysts. Moreover, through uniform single-atom dispersion, SACs offer a great opportunity for achieving high activity and tuning selectivity to the desired product. This chapter provides a comprehensive overview of recent advances in using SACs for the conversion of lignin or lignin model compounds. The different support materials used for SACs, such as zeolites, metal oxides, and carbonaceous and siliceous materials, are discussed. This contribution also covers the catalytic reactions of lignin with an emphasis on cleaving its specific linkages, along with a systematic evaluation of SACs used in the relevant processes. The chapter also addressed key parameters essential for tailoring the particle size and acid–base and redox properties of the SACs used in lignin conversion. Special attention is paid to understanding the role of synthesis conditions in tailoring the size of SACs. It is expected that this contribution will provide future directions for practical SAC development and implementation in lignin conversion.

1 aHalilu, Ahmed1 aUmar, Ahmad, Abulfathi1 aBalarabe, Yahaya, Umar1 aHaniffa, Mhd., Abd. Cader1 aMunawar, Khadija1 aSunku, Kiran1 aSudarsanam, Putla uhttps://library.ncl.res.in/content/advances-single-atom-catalysts-lignin-conversion02335nas a2200265 4500008004100000022001400041245014000055210006900195260000900264300001100273490000800284520138200292653002101674653002601695653002201721653003201743653002101775100002301796700001801819700002201837700002701859700002701886700002501913856013101938 2020 eng d a0016-236100aBifunctional rice husk-derived SiO2-Cu-Al-Mg nanohybrid catalyst for one-pot conversion of biomass-derived furfural to furfuryl acetate0 aBifunctional rice huskderived SiO2CuAlMg nanohybrid catalyst for cSEP  a1179530 v2753 a

Developing one-pot reaction methodologies, which typically require multifunctional catalyst systems, is crucial for sustainable production of bio-derived fuels and chemicals. This work reports one-pot hydrogenation-esterification of furfural to furfuryl acetate using a bifunctional metal-based nanohybrid catalyst, composed of rice husk (RH) derived SiO2, Cu, Al, and Mg species (RHSiO2-Cu-Al-Mg). For comparison, the catalytic efficiency of RHSiO2-Cu and RHSiO2-Cu-Al were tested under similar reaction conditions. Various analytical techniques were used to elucidate the physicochemical, textural, and acid-redox properties of the catalysts. It was found that the RHSiO2-Cu-Al-Mg catalyst contains an optimum amount of acid and redox sites, as illustrated by NH3-TPD and H-2-TPR studies, respectively. Especially, Mg addition played a vital role in tailoring acidity of the RHSiO2-Cu-Al catalyst to promote in-situ esterification of furfuryl alcohol with acetic acid to yield furfuryl acetate. As a result, the RHSiO2-Cu-Al-Mg catalyst exhibited the best performance in one-pot conversion of furfural to furfuryl acetate, outperforming various noble metal/silica based catalysts. This study offers potential opportunities for the rational design of novel, bifunctional heterogeneous catalysts for efficient production of bio-derived fuels and value added chemicals.

10aAcid-redox sites10aBifunctional catalyst10aBio-oil upgrading10aOne-pot furfural conversion10aRice husk silica1 aHashim, Luqman, H.1 aHalilu, Ahmed1 aSudarsanam, Putla1 aUmar, Yahaya, Balarabe1 aBin Johan, Mohd, Rafie1 aBhargava, Suresh, K. uhttps://library.ncl.res.in/content/bifunctional-rice-husk-derived-sio2-cu-al-mg-nanohybrid-catalyst-one-pot-conversion-biomass