Waste-Glycerol-Directed Synthesis of Mesoporous Silica and Carbon with Superior Performance in Room-Temperature Hydrogen Production from Formic Acid

Synthesis of Mesoporous Carbon Adsorbents Using Biowaste Crude Glycerol as a Carbon Source via a Hard Template Method for Efficient CO2 Capture

Biowaste utilization as a carbon source and its transformation into porous carbons have been of great interest to promote environmental remediation owing to biowaste's cost-effectiveness and useful physicochemical properties. In this work, crude glycerol (CG) residue from waste cooking oil transesterification was employed to fabricate mesoporous crude glycerol-based porous carbons (mCGPCs) using mesoporous silica (KIT-6) as a template. The obtained mCGPCs were characterized and compared to commercial activated carbon (AC) and CMK-8, a carbon material prepared using sucrose. The study aimed to evaluate the potential of mCGPC as a CO₂ adsorbent and demonstrated its superior adsorption capacity compared to AC and comparable to CMK-8. The X-ray diffraction (XRD) and Raman results clearly depicted the structure of carbon nature with (002) and (100) planes and defect (D) and graphitic (G) bands, respectively. The specific surface area, pore volume, and pore diameter values confirmed the mesoporosity of mCGPC materials. The transmission electron microscopy (TEM) images also clearly revealed the porous nature with the ordered mesopore structure. The mCGPCs, CMK-8, and AC materials were used as CO₂ adsorbents under optimized conditions. The mCGPC adsorption capacity (1.045 mmol/g) is superior to that of AC (0.689 mmol/g) and still comparable to that of CMK-8 (1.8 mmol/g). The thermodynamic analyses of the adsorption phenomena are also carried out. This work demonstrates the successful synthesis of a mesoporous carbon material using a biowaste (CG) and its application as a CO₂ adsorbent.

Label-Free Isolation and Single Cell Biophysical Phenotyping Analysis of Primary Cardiomyocytes Using Inertial Microfluidics

To advance the understanding of cardiomyocyte (CM) identity and function, appropriate tools to isolate pure primary CMs are needed. A label-free method to purify viable CMs from mouse neonatal hearts is developed using a simple particle size-based inertial microfluidics biochip achieving purities of over 90%. Purified CMs are viable and retained their identity and function as depicted by the expression of cardiac-specific markers and contractility. The physico-mechanical properties of sorted cells are evaluated using downstream real-time deformability cytometry. CMs exhibited different physico-mechanical properties when compared with non-CMs. Taken together, this CM isolation and phenotyping method could serve as a valuable tool to progress the understanding of CM identity and function, and ultimately benefit cell therapy and diagnostic applications.

Nanopore-Supported Metal Nanocatalysts for Efficient Hydrogen Generation from Liquid-Phase Chemical Hydrogen Storage Materials

Hydrogen has emerged as an environmentally attractive fuel and a promising energy carrier for future applications to meet the ever-increasing energy challenges. The safe and efficient storage and release of hydrogen remain a bottleneck for realizing the upcoming hydrogen economy. Hydrogen storage based on liquid-phase chemical hydrogen storage materials is one of the most promising hydrogen storage techniques, which offers considerable potential for large-scale practical applications for its excellent safety, great convenience, and high efficiency. Recently, nanopore-supported metal nanocatalysts have stood out remarkably in boosting the field of liquid-phase chemical hydrogen storage. Herein, the latest research progress in catalytic hydrogen production is summarized, from liquid-phase chemical hydrogen storage materials, such as formic acid, ammonia borane, hydrous hydrazine, and sodium borohydride, by using metal nanocatalysts confined within diverse nanoporous materials, such as metal-organic frameworks, porous carbons, zeolites, mesoporous silica, and porous organic polymers. The state-of-the-art synthetic strategies and advanced characterizations for these nanocatalysts, as well as their catalytic performances in hydrogen generation, are presented. The limitation of each hydrogen storage system and future challenges and opportunities on this subject are also discussed. References in related fields are provided, and more developments and applications to achieve hydrogen energy will be inspired.

Sustainable Low-Temperature Hydrogen Production from Lignocellulosic Biomass Passing through Formic Acid: Combination of Biomass Hydrolysis/Oxidation and Formic Acid Dehydrogenation

Hydrogen production from renewable resources, such as lignocellulosic biomass, is highly desired, under the most sustainable and mildest reaction conditions. In this study, a new sustainable three-step process for the production of hydrogen has been proposed. In the first step, a crude formic acid (CF) solution, which included typical reaction byproducts, in particular, acetic acid, levulinic acid, saccharides, 5-hydroxymethylfurfural, furfural, and lignin, was obtained through the combined hydrolysis/oxidation of the biomass, in the presence of diluted sulfuric acid/hydrogen peroxide, as homogeneous catalysts. In the second one, the distilled formic acid (DF) solution was obtained by distillation of the CF solution, for example, by isolating liquid byproducts, or the lignin-free CF (LCF) solution was recovered by CF filtration for the elimination of only solid lignin particles. In the final step, hydrogen was produced from the DF or LCF solutions through formic acid dehydrogenation over Pd supported on amine-functionalized mesoporous silica catalysts, in the presence of sodium formate, as an additive. The clean hydrogen, which is produced from biomass passing through formic acid, could be applied as an energy source of fuel cells. This new hydrogen production process is smart, allowing the hydrogen production with mild reaction conditions, eventually starting from different lignocellulosic feedstocks, and it could be integrated within the existing hydrothermal technology for levulinic acid production, which has been already recognized as efficient and sustainable. In addition to the production of hydrogen as an energy source of fuel cells, formic acid derived from biomass could be utilized as a platform chemical for chemical, agricultural, textile, leather, pharmaceutical, and rubber industries.

Mesoporous Silica Supported Pd-MnOx Catalysts with Excellent Catalytic Activity in Room-Temperature Formic Acid Decomposition

For the application of formic acid as a liquid organic hydrogen carrier, development of efficient catalysts for dehydrogenation of formic acid is a challenging topic, and most studies have so far focused on the composition of metals and supports, the size effect of metal nanoparticles, and surface chemistry of supports. Another influential factor is highly desired to overcome the current limitation of heterogeneous catalysis for formic acid decomposition. Here, we first investigated the effect of support pore structure on formic acid decomposition performance at room temperature by using mesoporous silica materials with different pore structures such as KIE-6, MCM-41, and SBA-15, and achieved the excellent catalytic activity (TOF: 593 h⁻¹) by only controlling the pore structure of mesoporous silica supports. In addition, we demonstrated that 3D interconnected pore structure of mesoporous silica supports is more favorable to the mass transfer than 2D cylindrical mesopore structure, and the better mass transfer provides higher catalytic activity in formic acid decomposition. If the pore morphology of catalytic supports such as 3D wormhole or 2D cylinder is identical, large pore size combined with high pore volume is a crucial factor to achieve high catalytic performance.

Reducing-Agent-Free Instant Synthesis of Carbon-Supported Pd Catalysts in a Green Leidenfrost Droplet Reactor and Catalytic Activity in Formic Acid Dehydrogenation

The development of green synthesis methods for supported noble metal catalysts remains important challenges to improve their sustainability. Here we first synthesized carbon-supported Pd catalysts in a green Leidenfrost droplet reactor without reducing agents, high-temperature calcination and reduction procedures. When the aqueous solution containing Pd nitrate precursor, carbon support, and water is dripped on a hot plate, vapor layer is formed between a solution droplet and hot surface, which allow the solution droplet to be levitated on the hot surface (Leidenfrost phenomena). Subsequently, Pd nanoparticles can be prepared without reducing agents in a weakly basic droplet reactor created by the Leidenfrost phenomena, and then the as-prepared Pd nanoparticles are loaded on carbon supports during boiling down the droplet on hot surface. Compared to conventional incipient wetness and chemical synthetic methods, the Leidenfrost droplet reactor does not need energy-consuming, time-consuming, and environmentally unfriendly procedures, which leads to much shorter synthesis time, lower carbon dioxide emission, and more ecofriendly process in comparison with conventional synthesis methods. Moreover, the catalysts synthesized in the Leidenfrost droplet reactor provided much better catalytic activity for room-temperature formic acid decomposition than those prepared by the incipient wetness method.