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At present, the research on aquathermolysis catalysts mainly focuses on the catalytic effect of external catalysts on the reaction, ignoring the fact that external catalysts will form complexes with in situ inorganic minerals after entering the reservoir. In this paper, we investigated the effects of transition metal complexes as external catalysts and bentonite as in situ catalysts on aquathermolysis, respectively. Meanwhile, the aquathermolysis reaction co-catalyzed by external and in situ catalysts was further investigated. The results show that the transition metal complexes exhibited good co-catalysis with bentonite. The viscosity reduction rate can reach 73.47% at 200 °C and 4 h with 0.1 wt.% of catalyst (NAD–Zn) addition. The addition of ethanol under the same reaction conditions will further increase the viscosity reduction rate to 84.59%. The results of thermogravimetric analysis, component analysis and boiling range analysis of heavy oil show that the heavy components in heavy oil are cracked into light components after the aquathermolysis. The results of elemental analysis show that the heteroatoms in the heavy oil were removed and the quality of the crude oil was improved. The results of GC–MS analysis of the model compounds showed that the process of aquathermolysis was mainly through the cleavage of C–C, C–N and C–S bonds to crack the macromolecules into small molecules, and then achieve the effect of viscosity reduction. The main mechanism of catalyst action is the acidic center on the surface of the bentonite and the coordination bonds formed by the transition metal complexes with the heteroatoms.

Hetero-nanomaterials constructed by plasmonic metals and functional semiconductors show enormous potential in photocatalytic applications, such as in hydrogen production, CO2 reduction, and treatment of pollutants. Their photocatalytic performances can be better regulated through adjusting structure, composition, and components’ arrangement. Therefore, the reasonable design and synthesis of metal/semiconductor hetero-nanostructures is of vital significance. In this mini-review, we laconically summarize the recent progress in efficiently establishing metal/semiconductor nanomaterials for improved photocatalysis. The defined photocatalysts mainly include traditional binary hybrids, ternary multi-metals/semiconductor, and metal/multi-semiconductors heterojunctions. The underlying physical mechanism for the enhanced photocatalysis of the established photocatalysts is highlighted. In the end, a brief summary and possible future perspectives for further development in this field are demonstrated.

This research aims at developing an efficient and reusable catalyst to improve biodiesel production processes. To achieve this, a vanadium-substituted polyoxometalate (POM) acid, namely H6PV3MoW8O40, was firstly prepared, and then the heterogenzation of the homogeneous Keggin-type heteropoly acids was performed by the partial proton substitution by monovalent large cesium cations with the formation of solid Cs2H4PV3MoW8O40 catalysts. Several techniques, such as X-ray diffractometer, Fourier transform infrared, coupled plasma–atomic emission spectrometry, Diffuse reflectance ultraviolet–visible spectrum, thermal gravimetric analysis and N2 adsorption–desorption techniques, were employed to characterize the as-prepared solid catalyst. The solid acid catalyst had the capacity to catalyze both the transesterification of soybean oil and esterification of free fatty acids (FFAs) simultaneously, providing an efficient production process for the production of biodiesel from low-quality oils. Under the operational conditions of a methanol/oil molar ratio of 30:1, a catalyst dosage of 5 wt.%, a reaction temperature of 140 °C, and a reaction duration of 8 h, an oil conversion of 92.2% was attained with the total FFA transformation to biodiesel. Furthermore, the catalyst could be reutilized for several cycles with no significant drop in its activity, thus having great potential for application with a bright perspective in the production of biodiesel, especially from low-quality oil feedstocks.

To delve into the law of hydrocarbon production in microwave-assisted catalytic fast pyrolysis (MACFP) of corn straw, physical mixed Mesoporous Crystalline Material-41 (MCM-41) and Zeolite Socony Mobile-5 (ZSM-5) catalyst prototypes were exploited in this study. Besides, the effects exerted by temperature of reaction and MCM-41/ZSM-5 mass ratio were explored. As revealed from the results, carbon outputs of hydrocarbons rose initially as the temperature of MACFP rose and reached the maximal data at 550 °C; subsequently, it declined as reaction temperature rose. Moreover, the MCM-41/ZSM-5 mass ratio of 1:2 was second-to-none for hydrocarbon formation in the course of biomass MACFP. It was reported that adding MCM-41 can hinder coke formation on ZSM-5. Furthermore, MCM-41/ZSM-5 mixture exhibited more significant catalytic activity than ZSM-5/MCM-41 composite, demonstrating that hydrocarbon producing process can be stimulated by a simple physical MCM-41 and ZSM-5 catalysts mixture instead of synthesizing complex hierarchically-structured ZSM-5/MCM-41 composite.

We investigated the structural evolution of molybdenum carbides subjected to hot aqueous environments and their catalytic performance in low-temperature hydroprocessing of acetic acid. While bulk structures of Mo carbides were maintained after aging in hot liquid water, a portion of carbidic Mo sites were converted to oxidic sites. Water aging also induced changes to the non-carbidic carbon deposited during carbide synthesis and increased surface roughness, which in turn affected carbide pore volume and surface area. The extent of these structural changes was sensitive to the initial carbide structure and was lower under actual hydroprocessing conditions indicating the possibility of further improving the hydrothermal stability of Mo carbides by optimizing catalyst structure and operating conditions. Mo carbides were active in acetic acid conversion in the presence of liquid water, their activity being comparable to that of Ru/C. The results suggest that effective and inexpensive bio-oil hydroprocessing catalysts could be designed based on Mo carbides, although a more detailed understanding of the structure-performance relationships is needed, especially in upgrading of more complex reaction mixtures or real bio-oils.

The electrochemical reduction of CO2 to value-added chemicals renewable electricity is a promising and ecofriendly strategy to achieve the national strategic goal of “carbon peak and carbon neutrality” and solve the greenhouse effect. Due to the variety of products in CO2 electroreduction (CO2ER), catalytic selectivity has become a key factor in the design of electrode structure. Herein, a systematic investigation of CO2ER on the nanoporous gold films with different thicknesses prepared by the self-deposition method developed by ourselves. Mass transfer effects are found to play an important role in determining product selectivity and activity. The specific activity for CO evolution (jCO) with exponential declination has more dramatic tendency than the specific activity for hydrogen evolution (jH2) with linear decay with increasing nanoporous gold film thickness. Different from the behaviors within the mesoporous structures in previous studies, the retarded transport of HCO3− ions within the nanoscale pores is more sensitive than that of protons. This phenomenon implies the necessity of considering mass transfer effects in the design of outstanding electrocatalysts for CO2ER as well as for understanding the geometrical infrastructure-performance relationships.

Furfural (FF) is a strategic product for the development of highly valued chemicals from biomass. The oxidation product of FF, furoic acid (FA), is an important precursor for the synthesis of green esters, such as methyl furoate. Taking into account issues with the direct furfural oxidation, furfural derivatives, such as alkyl furoates, can be easily prepared via oxidative esterification. Here, Au nanoparticles that were immobilized on alkaline-earth metal oxide supports were studied for the oxidative esterification of furfural while using alcohol as both reactant and solvent. The formation of esters is favored by the presence of basic sites on catalyst surface, resulting in high selectivity, preventing the formation of the acetal as a by-product. The Au/MgO sample provided up to 95% methyl furoate (MF) yield, a fast reaction rate, and high performance for furfural:Au molar ratios between 50 and 300. Furthermore, this catalyst was stable during reuse, since both the selectivity and the activity were maintained after four cycles. Oxidative esterification products were achieved in the presence of other alcohols, leading to the formation of esters of up to C5 (isopentyl furoate) with high selectivity (>99%). Linear and branched esters were formed, but the long-chain linear alcohols resulted in higher yields, such as n-butyl furoate in 94% yield.