Efficient capture and transport of biological targets by functionalized micromotors in microfluidic chips have emerged as to be promising for bioanalysis and detection of targets. However, the crucial step-target capture-is still inefficient due to the low utilization of active spots on the functionalized motor surfaces. Herein, we designed a multichannel microchip for integrating confined space with the oscillatory movement of micromotors to increase the capture efficiency. Acoustically driven, magnetically guided Au/Ni/Au micromotors were employed as the target carriers, while E. coli bacteria were chosen as the targets. Under optimized conditions, a capture efficiency of 96% and an average loading number of 3-4 (targets per single motor) could be achieved. The possibility of simple separation of targets from micromotors has also been demonstrated. This microfluidic system could facilitate the integration of multiple steps for bioanalysis and detection of targets.

Despite the intensive development of heterogeneous catalysts with transition metal for the Guerbet reaction, a detailed understanding of the metal species and reaction mechanism (rate-determining step and active sites) is still deficient. Herein, we have developed a series of Ni/Ca x Mg y O catalysts to upgrade n-butanol into branched 2-ethyl-1-hexanol and establish the structure–activity correlation. Given the formation of solid solution between NiO and MgO, the addition of Mg element contributes to the formation of highly dispersed Ni nanoparticles with a small mean size. After optimization in reaction conditions, the highest conversion and selectivity of 80.2 and 79.1%, respectively, were achieved at 240 °C. The pivotal role of Ni0 sites and base sites during the Guerbet reaction, as confirmed by the selective poison experiments could be attributed to their synergistic catalysis during the dehydrogenation of n-butanol, which is the rate-determining step of the whole process. Moreover, a possible reaction mechanism for this rate-determining step over Ni/Ca x Mg y O catalysts was proposed based on experimental results. Overall, this work pushes forward the understanding of the reaction mechanism of the Guerbet reaction over transition-metal-decorated catalysts, which would be constructive for the rational design of heterogeneous catalysts.

Water resistance and/or hydrothermal stability of catalysts are key concerns during the obtention of biofuels from fermentation products, which always involve considerable amounts of water. Herein, aimed at efficient upgrading of a water-containing acetone–butanol–ethanol (ABE) fermentation mixture to long-chain products, we designed and synthesized a series of 10 wt % Ni–MgO–SBA-16 catalysts, which were based on hydrophobic SBA-16 with highly condensed structures. These catalysts exhibited low water adsorptive capacities and relatively favorable hydrophobicity. As expected, the as-prepared catalysts showed excellent catalytic activity and water-tolerance: 76.4% conversion and 90.5% selectivity for C5–15 species were achieved under solvent-free conditions; when the initial water content increased to 7.4 wt %, comparable conversion and total selectivity for C5–15 species were also achieved. Besides, on account of the hydrophobic surface, monoalkylation products readily converted into doublealkylation ones even under conditions of high water content. The results demonstrated the 10 wt % Ni–MgO–SBA-16 catalysts acted as the role of “killing two birds with one stone”: promoting the water tolerance and exhibiting high hydrothermal stability; suppressing competitive adsorption of water molecules and facilitating the adsorption and transformation of hydrophobic intermediate 2-heptanone to long-chain hydrocarbons; replacing the rare noble metal by base metal and complying with the principles of “green chemistry”. Overall, this work not only makes significant progress in value-adding of water-containing ABE but also provides the rational synthetic direction of catalysts requiring high hydrothermal stability and/or water resistance in the biomass conversion process.

The shortage of fossil resources and strict environmental regulations have ignited great efforts in the production of bio-based fuels and chemicals via biorefinery. Herein, considering the strong interaction between Ni and Mg species, we specially designed and prepared Ni/CaMgO and Ni/MgSiO for alkylation and hydrodeoxygenation (HDO) reactions during the upgrading of the acetone−butanol− ethanol (ABE) fermentation mixture. Gratifyingly, the Mgdecorated catalysts exhibited great catalytic performance: a selectivity of 63.9% under a conversion of 94.2% was achieved for C 8 −C 15 ketones and alcohols, which is higher than that over other heterogeneous alkali-based catalysts, and the obtained mixture was completely converted into the corresponding alkanes at 190 °C (H 2 pressure: 1 MPa). It is worth noting that jet fuels or gasoline could be efficiently and selectively obtained by facile adjustment of the composition of the ABE fermentation product. Moreover, investigation on the structure−activity correlation confirmed that the outstanding activity of Ni/MgSiO for HDO could be attributed to the synergic catalysis between Ni 0 and strong acid sites. The Ni/CaMgO and Ni/MgSiO catalysts reported in this work offer three advantages: selectively upgrading zymotic biomass wastes into biofuels, replacing the expensive noble metal (Pd) by the base metal (Ni), and realizing the HDO process under mild conditions and complying with the principles of "green chemistry". Overall, this work opens a new possibility for biofuel production, which is conductive to the rational design and implementation of highly active heterogeneous catalysts.