Here we galvanically replace liquid galinstan with Pt to create PtGa nanoparticles via expulsion from the liquid metal surface. These nanomaterials are active for a variety of electrocatalytic reactions.
The high dependence on fossil fuels has escalated the challenges of greenhouse gas emissions and energy security. Biohydrogen is projected as a future alternative energy as a result of its non-polluting characteristics, high energy content (122 kJ/g), and economic feasibility. However, its industrial production has been hampered by several constraints such as low process yields and the formation of biohydrogen-competing reactions. This necessitates the search for other novel strategies to overcome this problem. Cell immobilization technology has been in existence for many decades and is widely used in various processes such as wastewater treatment, food technology, and pharmaceutical industry. In recent years, this technology has caught the attention of many researchers within the biohydrogen production field owing to its merits such as enhanced process yields, reduced microbial contamination, and improved homogeneity. In addition, the use of immobilization in biohydrogen production prevents washout of microbes, stabilizes the pH of the medium, and extends microbial activity during continuous processes. In this short review, an insight into the potential of cell immobilization is presented. A few immobilization techniques such as entrapment, adsorption, encapsulation, and synthetic polymers are discussed. In addition, the effects of process conditions on the performance of immobilized microbial cells during biohydrogen production are discussed. Finally, the review concludes with suggestions on improvement of cell immobilization technologies in biohydrogen production.
A carbon dioxide capture, conversion, and utilization technology has been developed that can be powered by renewable energy with the potential to mitigate CO2 emissions. This relies on an electrochemical process whereby the dissolution of carbon dioxide into carbonate ions is accelerated by a locally induced pH change at the cathode. The carbonate ions can then complex with metal cations, such as Ca2+, Sr2+, or Mn2+, present in solution to form their respective metal carbonates, which precipitate out of solution. To ensure the cathode is not fouled by deposition of the insulating metal carbonate, the process is operated under hydrogen evolution conditions, thereby alleviating any significant attachment of the solid to the electrode. This process is demonstrated in CO2‐saturated solutions while the possibility of direct air capture is also shown, where the precipitation of CaCO3 from atmospherically dissolved CO2 during electrolysis is observed. The latter process can be significantly enhanced by using 5 vol.% of monoethanolamine (MEA) in the electrochemical cell. Finally, the process is investigated using seawater, which is also successful after the initial precipitation of metal sulfates from solution. In particular, the use of renewable energy to capture CO2 and create CaCO3 while also generating hydrogen may be of particular interest to the cement industry, which has a significant CO2 footprint.
The fabrication of low cost and highly active photocatalysts for the degradation of synthetic dyes that are effective under visible light is an ongoing challenge. Here, the synthesis of a...
Carbon capture and storage (CCS) is amongst the possible options to reduce CO 2 emission. In the application of CCS, CO 2 capture techniques such as adsorption and membrane system have been proposed due to less energy requirement and environmental benign than the absorption process. However, membrane system has drawbacks such as poor membrane reproducibility, scale-up difficulty and high cost of the membrane supports. In this study synthesis and characterization of nanocomposite sodalite (HS)/ceramic membrane via ''pore-plugging'' hydrothermal synthesis (PPH) protocol for precombustion CO 2 capture is reported. The morphology and crystallinity of the as-prepared membranes were checked with scanning electron microscopy and X-ray diffraction. Surface chemistry of the membrane was examined with Fourier Transform Infrared spectroscopy. In nanocomposite architecture membranes, zeolite crystals are embedded within the pores of the supports instead of forming thin-film layers of the zeolite crystals on the surface of the supports. Compared to the conventional in situ direct hydrothermal synthesis, membranes obtained from PPH possess higher mechanical strength and thermal stability. In addition, defect control with nanocomposite architecture membranes is possible because the zeolite crystals are embedded within the pores of the support, thereby limiting the maximum defect size to the pore size of the support. Furthermore, the nanocomposite architecture nature of the membranes safeguards the membrane from shocks or abrasion that could promote formation of defects. The aforementioned advantages of the nanocomposite architecture membranes could be beneficial in developing high performance and cost-effective membrane materials for pre-combustion CO 2 capture.
Room temperature liquid metals are an emerging class of materials for a variety of heterogeneous catalytic reactions. In this work we explore the use of Ga based liquid metals as...
The effective degradation of synthetic dyes via photocatalysis using abundant cheap materials is an ongoing challenge. Often photocatalysts are costly and employ complex fabrication processes that give limited efficiency which therefore inhibits widespread industrial proliferation. To address this issue, a simple room temperature alloying process followed by sonication for the preparation of photocatalytically active GaZnO nanosheets confined on a metallic GaZn core is reported. The material is characterized with X‐ray diffraction, X‐ray photoelectron spectroscopy, inductively coupled plasma optical emission spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and electrochemical techniques. These analyses confirm the presence of a metallic GaZn core decorated with GaZnO nanosheets. The resultant GaZn/GaZnO catalyst exhibits excellent photocatalytic activity for the degradation of methyl orange. A high degradation efficiency of 73% is achieved under solar simulated conditions which is attributed to the GaZn core acting as an electron sink allowing for effective charge carrier separation at the surface confined GaZnO sheets and the production of reactive oxygen species.
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