The activation and catalytic reduction of carbon dioxide (CO2) using silicon-based reducing agents is an important strategy for sustainable C1 chemistry and silicon waste upcycling. Tetraalkylammonium fluoride salts are highly effective promoters of silicon hydride formation; however, their direct use introduces challenges in terms of expense and handling. Here, we report the first example of in situ generation of fluoride catalysts for the reduction of CO2 to formic acid from a simple inorganic fluoride salt, such as NaF. A neutral precursor releases fluoride under mild conditions, enabling selective CO2 reduction using powdered silicon. Mechanistic studies reveal that the catalytically active fluoride species are generated in situ from three components: inorganic fluoride, amine, and acid. The method eliminates the need for expensive and unstable organic fluoride. This work establishes a new fluoride-mediated catalytic platform for coupling CO2 valorization with silicon waste utilization.
Highly oil-accumulative diatoms such as Fistulifera solaris JPCC DA0580 are considered promising biomass resources for biofuel production. To achieve high oil yields from diatoms, it is essential to understand their physiological status in terms of growth and photosynthesis under industrial cultivation conditions. Here, we focused on the lag phase observed in F. solaris growth after dilution during large-scale outdoor cultivation, and sought to characterize this physiological event by reproducing it under laboratory conditions with two dilution ratios and two light intensities. When the culture was inoculated into fresh medium at an initial OD₇₃₀ of 0.03, no distinct lag phase was observed under either low or high light. In contrast, dilution to an initial OD₇₃₀ of 0.003 induced a pronounced lag phase lasting approximately 1 and 2 days under low and high light, respectively. Thus, a higher dilution ratio prominently extended the lag phase in F. solaris. At the growth stage after the late logarithmic phase, photosynthetic properties were largely similar between the high- and low-dilution cultures and were mainly influenced by growth light intensity. Decreased photosynthetic activity within a day after dilution suggested that the prolonged lag phase was mainly caused by high-light induced photodamage in diluted cells. These results indicate that large-scale outdoor cultivation of F. solaris could be more efficient when initiated with higher cell densities, especially under high light.
In recent years, the integration of renewable energy and battery energy storage system (BESS) has been reshaping price formation in electricity markets because of their distinctive roles. These technologies increasingly act as price setters (marginal units), thereby altering the dynamics of price formation. To evaluate price formation in the Australian National Electricity Market (NEM) more precisely, we introduce new metrics—Negative Incremental Cost (NIC), Offset Incremental Cost (OIC), and Core Incremental Cost (CIC)—to decompose price formation with respect to an additional 1 MW of demand. Applying these metrics to NEMDE Price Setter data from 2021 to May 2025, we find that deviations of energy market prices from core price setters’ bids occur predominantly around zero prices. Renewable generators submitting negative bid prices sometimes exert upward pressure on prices, whereas BESS on average behaves in the opposite direction. Our analysis shows that the proposed decomposition framework provides a novel perspective for understanding the mechanisms behind price deviations and the contrasting contributions of renewable energy and BESS to price formation in electricity markets.
