Abstract. The Low Carbon Fuel Standard (LCFS) is designed to reduce greenhouse gas emissions in the transportation sector. It requires fuel producers and distributors to ensure that their fuel mix meets a specific carbon intensity (CI) target (e.g. CO2e/MJ) set by California Air Resource Board (CARB). Emission credits are provided for fuels with lower CI than required by the target. As the value of the LCFS credit lingers around $200 per credit and the Renewable Fuel Standard (RFS) renewable identification number (RIN) prices are ever-reducing, the importance of CI is more relevant than ever before. Participation in the LCFS relies heavily on the CI of a renewable fuel, as it dictates the amount of credits generated. In 2018, 1.12 billion gasoline gallon equivalent of ethanol was consumed in California (about 12% blend level of the gasoline fuel mix). It is unlikely that the volume of ethanol as a percentage of gasoline consumed will fall in the near future due to ethanol‘s value as an oxygenate. Considering this significant role ethanol plays in the transportation fuel pool, it is imperative to seriously discuss the value of lowering its CI to levels that will make the LCFS goals achievable. In this study, an economic assessment and market analysis are performed to estimate the necessary reductions in CI score needed by ethanol to remain competitive in the LCFS market. Conversely, it is also the CI needed by ethanol to make credit markets whole since ethanol is, by volume, the most dominant gasoline alternative available in the market. Two prospective scenarios were modeled and further discussed for 2022: a Steady Progress Scenario, where deployment of non-ethanol credit generation options develops at a baseline rate that matches recent historical trends; and a High-Performance Scenario, where several technologies, such as electricity and renewable natural gas (RNG), develop more quickly than in the Steady Progress Scenario and lead to a higher supply of low CI non-ethanol fuels.
Psidguajones A and B, a pair of dimeric sesquiterpene-based meroterpenoid epimers, have been isolated from the leaves of Psidium guajava for the first time.
In order to solve the problems of slow reaction rate and large reactor volume of traditional urea hydrolysis to ammonia, the urea catalytic hydrolysis was studied in this paper. The bimetallic solid catalyst TiO2@Al2O3 was synthesized firstly, in which the mesoporous ?-Al2O3 was selected as substrate and the TiO2 was inserted into the active site. The solid catalyst was characterized by Raman spectroscopy and TEM, and the intermediates were qualitatively detected by liquid NMR H-spectroscopy and C-spectroscopy, which was combined with DFT calculations to analysis the mechanism of the bimetallic solid catalyst. And then, the kinetic and thermodynamic properties of the urea catalytic hydrolysis by solid catalyst were investigated on a batch reactor and a continuous operation pilot plant. The kinetic parameters of the catalytic hydrolysis reaction were measured, and the influences of different catalysts on the hydrolysis reaction temperature, energy consumption and variable load response time were researched. The bimetallic solid catalyst proposed in this study can solve the problems of phosphorus-containing wastewater discharge and insufficient active sites of traditional catalysts, and will provide significant reference to the research of urea catalytic hydrolysis to ammonia for flue gas denitrification.
Abstract We report the selective electrocatalytic oxidation of glycerol for the cogeneration of mesoxalic acid and electricity on a gold anode catalyst in anion‐exchange membrane fuel cells (AEMFCs). Small Au nanoparticles (3.5 nm) were uniformly deposited onto carbon black with a loading of 40 wt % through a solution‐phase method. An AEMFC with this Au/C anode catalyst, together with an Fe‐based cathode catalyst, exhibited a peak power density of 57.9 mW cm −2 at 80 °C. Valuable mesoxalic acid was produced with high selectivity (46 %) from the electro‐oxidation of glycerol on Au/C at an operating voltage of 0.3 V, whilst very small amounts of mesoxalic acid (selectivity<3 %) were obtained on a Pt/C anode catalyst in AEMFCs. The product distribution was dependent on the anode overpotential. At 1.2 V versus the standard hydrogen electrode (SHE) in an electrolysis cell, glycolic acid was the major product (selectivity: 65 %) and no mesoxalic acid was observed. Based on the product analysis, we found that Au facilitated deeper‐oxidation of glycerol to afford the fully‐oxidized C 3 mesoxalic acid, rather than CC cleavage, under a mild potential range (0.4–0.7 V vs. SHE) that was fortunately within the working voltage range of the fuel cells.
Developing high-efficiency nonmetal electrocatalysts for the electrochemical N2 reduction reaction (NRR) is of great significance for the sustainable development of human society. Here, we demonstrate that surface modification of reduced graphene oxide by tannic acid is a mild and effective strategy to boost its NRR activity. Such electrocatalyst is stable with an NH3 formation rate of 17.02 μg h–1 mg–1cat. in 0.5 M LiClO4, and its Faradaic efficiency can reach 4.83% at an optimized potential. The work would provide an impressive new option to boost the electrocatalytic N2-fixing performances of carbon materials by organic molecules modification.
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