Furfural and 5-hydroxymethylfurfural (HMF) have been identified as promising bio-platform furans that have a wide range of potential applications as biofuels, bioplastics, and biochemicals. Furfural and HMF are typically synthesized from the substrates of C₅ sugars and C₆ sugars, respectively. Furfural can also be produced from C₆ sugars, which is technically more challenging owing to the higher energy requirement for carbon–carbon bond cleavage. In this study, the simultaneous production of furfural and HMF from glucose was conducted over different binary catalyst systems of Brønsted acids and Lewis acids using γ-valerolactone (GVL) as the solvent. A promising performance was achieved by a SnSO₄-H₂SO₄ coupling catalyst, with an optimized furfural yield of 42% and an HMF yield of 34% at 443 K in GVL. In addition, a kinetics study was performed in order to understand the mechanism of the simultaneous formation of furfural and HMF from glucose at different temperatures and GVL/water ratios. The results showed that the ratio of furfural to HMF production rate at different temperatures (433 to 463 K) or GVL/water ratios (90 to 80%) was constant close to 1, suggesting that the production of furfural and HMF might follow similar reaction pathways. Finally, the reaction pathway of glucose conversion to furfural and HMF was proposed based on the experimental and kinetics studies.

Solid oxide electrolysis cells (SOECs) are considered one of the most promising technologies for carbon neutralization, as they can efficiently convert CO₂ into CO fuel. Sr₂Fe_1.5Mo_0.5O_6−δ (SFM) double perovskite is a potential cathode material, but its catalytic activity for CO₂ reduction needs further improvement. In this study, Cu ions were introduced to partially replace Mo ions in SFM to adjust the electrochemical performance of the cathode, and the role of the Cu atom was revealed. The results show Cu substitution induced lattice expansion and restrained impurity in the electrode. The particle size of the Sr₂Fe_1.5Mo_0.4Cu_0.1O_6−δ (SFMC0.1) electrode was about 500 nm, and the crystallite size obtained from the Williamson–Hall plot was 75 nm. Moreover, Cu doping increased the concentration of oxygen vacancies, creating abundant electrochemical active sites, and led to a reduction in the oxidation states of Fe and Mo ions. Compared with other electrodes, the SFMC0.1 electrode exhibited the highest current density and the lowest polarization resistance. The current density of SFMC0.1 reached 202.20 mA cm⁻² at 800 °C and 1.8 V, which was 12.8% and 102.8% higher than the SFM electrodes with and without an isolation layer, respectively. Electrochemical impedance spectroscopy (EIS) analysis demonstrated that Cu doping not only promoted CO₂ adsorption, dissociation and diffusion processes, but improved the charge transfer and oxygen ion migration. Theory calculations confirm that Cu doping lowered the surface and lattice oxygen vacancy formation energy of the material, thereby providing more CO₂ active sites and facilitating oxygen ion transfer.