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BACKGROUND Hydrolysis of polysaccharides is a key step in biorefineries processes. In this study, an economic and green approach was developed to hydrolyze soluble polysaccharides (starch, inulin, etc.) into monosaccharides by a natural clay of attapulgite (ATP) modified with H2SO4(ATPS), and the catalysts were characterized by Fourier Transform Infrared Spectroscopy (FT‐IR), Pyridine FTIR Spectroscopy (pyridine‐FTIR), Temperature Programmed Desorption of Ammonia (NH3‐TPD), Thermo‐Gravimetric/Differential Thermal Analyze (TG‐DTA). The hydrolysis of different substrate over ATP‐S was evaluated. RESULTS: After H2SO4 modification, the total acid sites of the catalyst ATP‐S increased from 65.33 to 109.46 umol g–1, and the surface area also increased from 81.4 to 137.3 m2 g–1. ATP‐S shows excellent activity and stability for polysaccharides hydrolysis in aqueous system. As for inulin as reactant, 98.5% of hydrolysis ratio was obtained at the moderate temperature of 95 °C for 210 min, and 75.8% hydrolysis ratio was achieved for starch. More importantly, there is no apparent decline of the catalytic activity after 4 recycles in aqueous system. In addition, the kinetic analysis was carried out, and the activation energy of the substrates were calculated. CONCLUSION: Compared with other hydrolysis processes involving enzymes and homogeneous catalysis, the process in this paper is more cost‐efficient and environmentally friendly, and it can easily be scaled‐up and implemented in chemical and bio‐based industries. © 2021 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

• Co 3 O 4 loaded on different forms of Ta 2 O 5 (amorphous, mesoporous, crystalline, crystalline mesoporous) are used for CO oxidation. • Crystalline mesoporous structure of Co/Ta-cm could promote CO conversion. • Co/Ta-cm exhibited the good CO conversion, and the temperature of 90% CO conversion was approximately 130 ℃ at the high space velocity of 780,000 h−1. Because the combination of Co and common support (Al, Ti, et al.) usually shows poor catalytic activity, tantalum has been introduced for CO conversion as a novel carrier due to the excellent performance. In this work, Co 3 O 4 was loaded on four forms of tantalum support (amorphous, mesoporous, crystalline and crystalline mesoporous, abbreviated as Co/Ta-am, Co/Ta-me, Co/Ta-cry and Co/Ta-cm, respectively). And among these four states, Co/Ta-cm presents the highest CO conversion rate. The temperature of 90% CO conversion rate of Co/Ta-cm is approximately 130 ℃ at the high space velocity of 780,000 h−1, which is 70%, 82% and 88% higher than that of Co/Ta-cry, Co/Ta-me and Co/Ta-am, respectively. Moreover, the characteristics of the catalyst have been studied by XRD, SEM, BET, TGA, and H 2 -TPR, and the results reveal that Co/Ta-cm has the excellent crystallinity and stability, and the morphology is regular. X-ray photon spectroscopy and in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) have been performed to investigate the reaction mechanism, which indicates that Co3+ is the active component and lattice oxygen plays a critical role in CO oxidation. [ABSTRACT FROM AUTHOR]

Small size cobalt nanoparticles are highly dispersed on different crystalline forms of Ta 2 O 5 (amorphous, T, M, H) by impregnation method, which is then introduced to catalytic oxidation of CO. The experimental results show that Co 3 O 4 /M-Ta 2 O 5 exhibits the highest CO conversion efficiency compared with Co 3 O 4 loaded on amorphous-, T-, and H-Ta 2 O 5 , and the pure Co 3 O 4 and M-Ta 2 O 5. The temperature of 90 % CO conversion rate is approximately 170 °C at the high space velocity of 780,000 h−1. Besides, the effect of oxygen concentration, space velocity, CO concentration, as well as different ratio of Co: Ta on CO conversion have been studied. Moreover, XRD, SEM, TGA, BET and H 2 -TPR characterizations reveal that Co 3 O 4 is uniformly distributed and does not change the structure crystalline of Ta 2 O 5 , and there is strong interaction between cobalt active component and Ta 2 O 5 support, which might be beneficial for CO conversion. Furthermore, the reaction mechanism has been investigated by X-ray photon spectroscopy and in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs), which suggest that Co3+ is the active component and lattice oxygen as well as adsorbed oxygen play a critical role in CO oxidation. [ABSTRACT FROM AUTHOR]