No abstract

Furfural (FUL) is substantially produced by the polymeric xylan fraction of hemicellulose with the presence of acids, and 2-methyl furan (2-MF) produced from FUL is an important biogasoline additive. Here, we report that 2-MF can be selectively formed from FUL with a 90% yield at 220 °C within 2 h over Cu0/Cu2O·SiO2 sites via a copper phyllosilicate precursor without extraneous gas. Methanol is used for in situ generating of highly pure hydrogen (92% content), and the almost CO free atmosphere avoids the poison on the Cu sites. The structure–activity relationship shows that Cu0 or Cu2O or physically mixed Cu0 and Cu2O is inactive, but the hydrogen-reduced copper phyllosilicate sample comprising abundant Cu0/Cu2O·SiO2 sites with interfaces demonstrates high activities in both reactions of methanol decomposition and FUL hydrodeoxygenation (HDO). The network for converting FUL to 2-MF includes tandem steps of FUL hydrogenation and furfural alcohol (FOL) hydrogenolysis to target 2-MF, accompanied by the side-reactions of hydrogenation of furan rings and ring opening of 2-MF. The kinetics modeling shows that the rational manipulation of reaction parameters of temperatures, reaction times, and H2 amounts is the key for attaining high yields of 2-MF. Eventually, the crude aqueous FUL solution with 10 wt % water can be selectivity hydrodeoxygenated to 2-MF (close to 90% yield) at the used catalytic conditions.

A high performance gas sensor based on a metal phthalocyanine/graphene quantum dot hybrid material was fabricated for NO2 detection at room-temperature.

A hydrothermally stable Ru/LaCO3OH catalyst consisting of Ru nanoparticles partially encapsulated by the support with a strong metal–support interaction is developed.

Two-dimensional (2D) transition metal dichalcogenide (TMD)-based gas sensors have received much attention due to their high sensitivity at room temperature. However, the long-term stability is limited by their poor stability against oxidation and hydration. This work develops a facile and practical strategy for the construction of reliable WS2-sensing devices under air conditions. A surface functionalization strategy for WS2 nanoflakes has been demonstrated, where WO3 nanosheets are aligned on the surface of WS2 nanoflakes via a facile sonochemical method. The synthesis method and structure–response relationship of the WS2–WO3 nanohybrid are carefully studied. The optimal device displays brilliant long-term stability and relatively stable sensing characteristics under the humidity conditions. Moreover, the WS2–WO3 sensor exhibits a remarkably enhanced response, a quick response time, and an excellent recoverability compared with the WS2 sensor. The impressive NO2-sensing performance of the WS2–WO3 nanohybrid is ascribed to the special hierarchical structure, the strong interlayer electronic coupling, and the formed p–n heterojunctions. This study offers a perspective for the structural design of TMD-based gas sensors, which exhibit not only an enhanced NO2-sensing performance but also an environmental stability.