Publications
5 results found
Xie J, Martin M, Rogelj J, et al., 2023, Distributional labor challenges and opportunities of decarbonizing the US power system, Nature Climate Change, Vol: 13, Pages: 1203-1212, ISSN: 1758-678X
The transition towards a low-carbon power system presents challenges and opportunities to the workforce with important implications for Just Transitions. Studies of thesedistributional labor impacts could benefit from tighter linkages between energy and employment modeling. Here, we couple a power sector optimization model, an employment impact model, and demographic databases to understand state-level job characteristics and societal implications of low-carbon transitions in the US. While decarbonization brings consistent job growth, it heightens the need for human capital investments and supply chainrestructuring. Major fossil fuel-producing states need to prepare for fewer mining jobs under the US Long-Term Strategy, so other opportunities should be created or seized. Lowest-skilled workers will experience more uncertain employment outcomes. Expanding renewable energy could improve opportunities for women in fossil fuel-dependent states, but not enough to disrupt the national gender status quo. This work provides a new quantitative perspective to inform proactive Just Transition policies.
Xie JJ, Martin M, Rogelj J, et al., 2023, Decarbonizing the US power system presents diverse challenges and opportunities in the changing employment landscape
<jats:title>Abstract</jats:title> <jats:p>The transition towards a low-carbon power system presents immense challenges and opportunities to the workforce. Studies of the energy transition’s regional and distributional employment impacts are mainly qualitative or disconnected from prevailing energy modeling scenarios. Here, we couple a power sector optimization model, an employment impact model, and demographic databases to further understand the state-level job characteristics and societal implications in the US. Major fossil fuel producers risk job losses even without new emission reduction policies, requiring the reskilling of up to 30% of the current workforce. The results highlight the need for investments in human capital and a supply chain restructuring. Blue-collar workers are crucial to delivering the transition. Expanding renewable energy could improve job opportunities for women in states dependent on fossil fuels, but not enough to disrupt the national status quo. This work sets a new quantitative perspective to inform proactive local Just Transition policymaking.</jats:p>
Nezam I, Xie J, Golub KW, et al., 2021, Chemical kinetics of the autoxidation of poly(ethylenimine) in CO2 sorbents, ACS Sustainable Chemistry & Engineering, ISSN: 2168-0485
The oxidative degradation rates of a CO2 sorbent composed of a mesoporous alumina impregnated with poly(ethylenimine) (PEI) are measured under systematically varied conditions and a reaction rate law is created. Good agreement is shown between the rate of oxidation obtained via in situ calorimetric heat measurement during oxidative degradation reactions and the loss of CO2 capture performance presented as amine efficiency (mol CO2/mol amine). PEI mass loss and elemental composition are tracked over the course of the reaction and used in conjunction with the oxidation rate measurements to shed insight into the oxidation reaction(s). These data, in combination with measurements of the heat of reaction, suggest a common reaction set across the range of temperatures, oxygen concentrations, and sorbent compositions tested. The data are consistent with the basic autoxidation scheme (BAS), the accepted mechanism of autoxidation of aliphatic polymers. We propose a lumped kinetic model to describe the oxidation reaction set and estimate an activation energy of 105 kJ/mol and an oxygen reaction order of 0.5–0.7 from the data accordingly. These parameters can be incorporated into process cycle models to estimate the material lifetime, a critical uncertainty in the deployment of DAC technologies.
Scholz D, Xie J, Kröcher O, et al., 2019, Mechanochemistry-assisted hydrolysis of softwood over stable sulfonated carbon catalysts in a semi-batch process, RSC Advances: an international journal to further the chemical sciences, Vol: 9, Pages: 33525-33538, ISSN: 2046-2069
The hydrolysis of lignocellulose is the first step in saccharide based bio-refining. The recovery of homogeneous acid catalysts imposes great challenges to the feasibility of conventional hydrolysis processes. Herein, we report a strategy to overcome these limitations by using stable sulfonated carbons as solid acid catalysts in a two-step process, composed of mechanocatalytic pretreatment and secondary hydrolysis in a semi-batch reactor. Without mechanocatalytic pre-treatment the hydrolysis of the insoluble substrate largely occurs through homogeneously catalyzed reactions. Ball-milling induced amorphization promotes a substantially higher substrate reactivity, because homogeneous hydrolysis occurs preferentially from less ordered structural domains in cellulose. In contrast, concerted ball-milling (CBM) of cellulose with the sulfonated carbon promotes a heterogeneously catalyzed hydrolysis to soluble oligosaccharides. By performing an in-depth physicochemical characterization of cellulose subjected to CBM treatment with different carbons, we reveal the crucial role of strong Brønsted acid sites in facilitating mechanocatalytic depolymerization. Recyclability experiments confirmed that despite being subject to profound structural changes during repeated pre-treatment/semi-batch hydrolysis cycles, the sulfonated carbon retained its catalytic activity. The combination of mechanocatalytic pretreatment with strong solid acids and hydrolysis in the semi-batch reactor was successfully extrapolated for the first time to the hydrolysis of real lignocellulose to achieve quantitative yields in C5 and high yields in C6 derived products.
Xie J, Ellebracht NC, Jones CW, 2019, Inter- and intramolecular cooperativity effects in alkanolamine-based acid–base heterogeneous organocatalysts, ACS Omega, Vol: 4, Pages: 1110-1117, ISSN: 2470-1343
Intramolecular cooperativity in heterogeneous organocatalysts is investigated using alkanolamine-functionalized silica acid–base catalysts for the aldol condensation reaction of 4-nitrobenzaldehyde and acetone. Two series of catalysts, one with and one without silanol-capping, are synthesized with varied alkyl linker lengths (two to five) connecting secondary amine and terminal hydroxyl functionalities. The reactivity of these catalysts is assessed to determine the relative potential for intermolecular (silane amine–surface silanol) vs intramolecular (amine–hydroxyl within a single silane) cooperativity, the impact of inhibitory surface–silane interactions, and the role of alkyl linker length and flexibility. For the array of catalysts tested, those with longer linker lengths generally give increased catalytic activity, although the turnover frequency trends differ between catalysts with and without surface silanol capping. Catalysts with alkyl-substituted amines lacking a terminal hydroxyl demonstrate an adverse effect of chain length, where the larger alkyl substituent on the amine provides steric hindrance depressing catalytic activity, while giving additional evidence for improved rates afforded by intramolecular cooperativity in the alkanolamine materials. The silanol-capped alkanolamine catalyst with the longest alkyl linker is found to be the most active alkanolamine catalyst due to its hydrophobized surface, which removes hypothesized silanol–alkanolamine inhibitory interactions, with the sufficient length and flexibility of its amine–hydroxyl linker allowing for favorable conformations for cooperativity. This study demonstrates the feasibility of and important factors affecting intramolecular cooperative activity in acid–base heterogeneous organocatalysis.
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