ZnO‐MgO composite catalysts were prepared by the coprecipitation method and used for the synthesis of methyl ethyl oxalate (EMO) from dimethyl oxalate (DMO) and ethanol (EtOH). The results of the SEM, XRD, FT‐IR and XPS confirmed that Zn2+ ions were incorporated into the cubic MgO lattice to form the solid solution structure over ZnO‐MgO composites catalysts with 6–18 mol% ZnO. The ZnO‐MgO composite catalysts with a solid solution structure have a large specific surface area, high medium acidic density, and medium basic density according to the results of N2 adsorption‐desorption, pyridine‐IR (Py‐IR) and NH3/CO2 temperature‐programmed desorption (NH3‐TPD/CO2‐TPD). The ZnxMg1‐xO solid solution with 18 mol% ZnO‐MgO (Zn0.18Mg0.82O) catalyst showed the highest catalytic activity with 71.98 % conversion of DMO and 67.36 % selectivity to EMO (DMO: EtOH molar ratio=1 : 2, reaction time=20 min, reaction temperature=80 °C and catalyst amount=1.5 wt%). The high catalytic activity was attributed to the solid solution structure with high medium acidic density and medium basic density. The conversion of DMO showed a positive linear correlation with the medium acidic density and medium basic density according to the correlation between catalytic activity and acidity‐basicity.

Herein, Fe‐C3N4‐TU was prepared by one‐step pyrolysis of melamine (MA, carbon and nitrogen sources of g‐C3N4) and Fe(NO3)3 ⋅ 9H2O using thiourea (TU) as a pore‐forming agent. Fe‐C3N4‐TU exhibits a low Tafel slope of 82 mV ⋅ dec−1 and a low overpotential of 206 mV at the current density of 10 mA ⋅ cm−2. The good HER (Electrocatalytic hydrogen evolution reaction) catalytic performance of Fe‐C3N4‐TU is attributed to the high intrinsic activity of Fe−N(III) coordination structure and porous structure with the intersecting channels. The Fe−N(III) coordination structure is proved by the characterized results of the XRD, XPS, and FTIR, which originates from the strong affinity of rich pyridine N in the g‐C3N4 to Fe ions. Simultaneously, the addition of TU as a pore‐forming agent induces the formation of large specific surface area and mesoporous structures with large pore diameters, which facilitate the exposure of Fe−N bonds and promotes H adsorption in the HER process.

A series of HPW supported on ammonium hexafluorosilicate (AHFs) modified Hβ (30HPW/Hβ-Si(x)) was successfully prepared. After Hβ zeolite was pretreated with 0.1 molÁL À1 AHF's solution, the Brønsted/Lewis ratio of Hβ-Si (0.1) increased compared with those of Hβ, and the strong acid density of 30HPW/Hβ-Si(0.1) decreased compared with those of 30HPW/Hβ respectively.Strong acidic sites and Lewis acid sites are catalytic sites for by-products diisobutene and ethylene glycol oligomers, which deposited on the catalyst result in the deactivation of catalysts. According to the results of characterization, the internal Si-OH groups of Hβ (strong acidity sites) were filled with silicon of AHFs. The extraframework aluminum (strong acid sites) was removed by the H + , which is the hydrolysis of AHFs. In addition, the hydrophobicity of 30HPW/Hβ-Si(0.1) was also improved compared with that of 30HPW/Hβ due to the SiO 2 /Al 2 O 3 ratio of Hβ increased after treatment by 0.1 molÁL À1 AHFs solution. The 30HPW/Hβ-Si(0.1) maintained an 80% conversion of methyl tertbutyl ether and 100% selectivity to ethylene glycol mono-tert-butyl ether and DBE ethylene glycol bis-tert-butyl ether with 336 h of time on stream. K E Y W O R D Sammonium hexafluorosilicate, ethylene glycol bis-tert-butyl ether, ethylene glycol monotert-butyl ether, HPW, Hβ

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