A review on plasma-based CO_(2) utilization:process considerations in the development of sustainable chemical production

Plasma-based processes,particularly in carbon capture and utilization,hold great potential for addressing environmental challenges and advancing a circular carbon economy.While significant progress has been made in understanding plasma-induced reactions,plasma-catalyst interactions,and reactor development to enhance energy efficiency and conversion,there remains a notable gap in research concerning overall process development.This review emphasizes the critical need for considerations at the process level,including integration and intensification,to facilitate the industrialization of plasma technology for chemical production.Discussions centered on the development of plasma-based processes are made with a primary focus on CO_(2) conversion,offering insights to guide future work for the transition of the technology from laboratory scale to industrial applications.Identification of current research gaps,especially in upscaling and integrating plasma reactors with other process units,is the key to addressing critical issues.The review further delves into relevant research in process evaluation and assessment,providing methodological insights and highlighting key factors for comprehensive economic and sustainability analyses.Additionally,recent advancements in novel plasma systems are reviewed,presenting unique advantages and innovative concepts that could reshape the future of process development.This review provides essential information for navigating the path forward,ensuring a comprehensive understanding of challenges and opportunities in the development of plasma-based CCU process.

Prospects for green steelmaking technology with low carbon emissions in China

The steel industry is a major source of CO_(2) emissions,and thus,the mitigation of carbon emissions is the most pressing challenge in this sector.In this paper,international environmental governance in the steel industry is reviewed,and the current state of development of low-carbon technologies is discussed.Additionally,low-carbon pathways for the steel industry at the current time are proposed,emphasizing prevention and treatment strategies.Furthermore,the prospects of low-carbon technologies are explored from the perspective of transitioning the energy structure to a“carbon-electricity-hydrogen”relationship.Overall,steel enterprises should adopt hydrogen-rich metallurgical technologies that are compatible with current needs and process flows in the short term,based on the carbon substitution with hydrogen(prevention)and the CCU(CO_(2) capture and utilization)concepts(treatment).Additionally,the capture and utilization of CO_(2) for steelmaking,which can assist in achieving short-term emission reduction targets but is not a long-term solution,is discussed.In conclusion,in the long term,the carbon metallurgical process should be gradually supplanted by a hydrogen-electric synergistic approach,thus transforming the energy structure of existing steelmaking processes and attaining near-zero carbon emission steelmaking technology.

Carbon footprinting of carbon capture and -utilization technologies: discussion of the analysis of Carbon XPRIZE competition team finalists

Life cycle assessments(LCAs)of early-stage technologies can provide valuable insights about key drivers of emissions and aid in prioritizing research into further emissions-reduction opportunities.Despite this potential value,further development of LCA methods is required to handle the increased uncertainty,data gaps,and confidentially of early-stage data.This study presents a discussion of the life cycle carbon footprinting of technologies competing in the final round of the NRG COSIA Carbon XPRIZE competition-a US$20 million competition for teams to demonstrate the conversion of CO_(2) into valuable products at the scale of a small industrial pilot using consistent deployment conditions,boundaries,and methodological assumptions.This competition allowed the exploration of how LCA can be used and further improved when assessing disparate and early-stage technologies.Carbon intensity estimates are presented for two conversion pathways:(i)CO_(2) mineralization and(ii)catalytic conversion(including thermochemical,electrochemical,photocatalytic and hybrid process)of CO_(2),aggregated across teams to highlight the range of emissions intensities demonstrated at the pilot for individual life cycle stages.A future scenario is also presented,demonstrating the incremental technology and deployment conditions that would enable a team to become carbon-avoiding relative to an incumbent process(i.e.reducing emissions relative to a reference pathway producing a comparable product).By considering the assessment process across a diverse set of teams,conversion pathways and products,the study presents generalized insights about opportunities and challenges facing carbon capture and-utilization technologies in their next phases of deployment from a life cycle perspective.

Efficient solar fuel production with a high-pressure CO_(2)-captured liquid feed

We demonstrated an efficient solar photovoltaic-powered electrochemical CO_(2) reduction device with a high-pressure CO_(2)-captured liquid feed.In an“air-to-barrel”picture,this device holds promise to avoid both high-temperature gaseous CO_(2) regeneration and high energy-cost gas product separation steps,while these steps are necessary for devices with a gaseous CO_(2) feed.To date,solar fuel production with a CO_(2)-saturated liquid feed suffers from high over-potential to suppress the hydrogen evolution reaction and consequently,low solar-to-chemical(STC)energy conversion efficiency.Here,we presented a distinct high-pressure operando strategy,i.e.,we took extra advantage of the high pressure in catalyst synthesis besides in the period of the CO_(2) reduction reaction(CO_(2)RR).The power of this strategy was demonstrated by a proof-of-concept device in which a representative copper catalyst was first synthesized in operando in a high-pressure(50 bar)CO_(2)-saturated KHCO3 solution,and then this high-pressure CO_(2)-captured liquid was converted to solar fuel using the operando synthesized Cu catalyst.This Cu catalyst achieved 95%CO_(2)RR selectivity at the recorded low potential of−0.3 V vs.RHE enabled by the combination of operando facet engineering and oxide derivation.Furthermore,this device achieved a record-high STC efficiency of 21.6%under outdoor illumination,superior to other CO_(2)-saturated liquid-fed devices,and compared favorably to gaseous CO_(2)-fed devices.

Theoretical Study About Effects of H20 and Na＋ on Adsorption of CO2 on Kaolinite Surfaces

The density functional theory（DFT） was used to investigate the adsorptions of carbon dioxide（CO2） on kaolinite surfaces and the influences ofNa＋ and HeO on the adsorption. Both cluster and periodic models of kaolinite were considered. The calculated results indicate that stable complexes can be formed between adsorbed CO2 and the surfaces of kaolinite in the presence or absence of sodium cation and water molecule. The Al-O octahedral surface has a larger adsorption affinity for CO2 than the Si-O tetrahedral surface of kaolinite because the hydroxyl groups of kaolinite Al-O surface present more activity than the basal O atoms of the Si-O tetrahedral surface in the intermolecular interactions. The existence of exchangeable sodium cations exerts the significant effect on the adsorption of CO2 with the dramatic increase of the adsorption energy, while the presence of water molecule decreases the adsorption strength insignificantly. The calculated Gibbs free energies of the adsorption reveal that the adsorptions of CO2 on all the investigated kaolinite surfaces are feasible thermodynamically in the gas phase. Surface free energy was calculated to provide the predictions of the surface stability as a function of temperature.

Microbial electrosynthesis of acetate from CO_(2)under hypersaline conditions

Microbial electrosynthesis(MES)enables the bioproduction of multicarbon compounds from CO_(2)using electricity as the driver.Although high salinity can improve the energetic performance of bioelectrochemical systems,acetogenic processes under elevated salinity are poorly known.Here MES under 35e60 g L^(-1)salinity was evaluated.Acetate production in two-chamber MES systems at 35 g L^(-1)salinity(seawater composition)gradually decreased within 60 days,both under-1.2 V cathode potential(vs.Ag/AgCl)and^(-1).56 A m^(-2)reductive current.Carbonate precipitation on cathodes(mostly CaCO3)likely declined the production through inhibiting CO_(2)supply,the direct electrode contact for acetogens and H2 production.Upon decreasing Ca2t and Mg2t levels in three-chamber reactors,acetate was stably produced over 137 days along with a low cathode apparent resistance at 1.9±0.6 mU m^(2)and an average production rate at 3.80±0.21 g m^(-2)d^(-1).Increasing the salinity step-wise from 35 to 60 g L^(-1)gave the most efficient acetate production at 40 g L^(-1)salinity with average rates of acetate production and CO_(2)consumption at 4.56±3.09 and 7.02±4.75 g m^(-2)d^(-1),respectively.The instantaneous coulombic efficiency for VFA averaged 55.1±31.4%.Acetate production dropped at higher salinity likely due to the inhibited CO_(2)dissolution and acetogenic metabolism.Acetobacterium up to 78%was enriched on cathodes as the main acetogen at 35 g L^(-1).Under high-salinity selection,96.5%Acetobacterium dominated on the cathode along with 34.0%Sphaerochaeta in catholyte.This research provides a first proof of concept that MES starting from CO_(2)reduction can be achieved at elevated salinity.

Analysis of routes for electrochemical conversion of CO_(2) to methanol

In the context of peak carbon and carbon neutrality,the utilization of CO_(2)has attracted attention with the aim of reducing carbon emissions by converting CO_(2)into high-value chemicals or energy.Methanol(MeOH),which is both a hydrogen and a carbon carrier,is considered the most promising among the CO_(2)-conversion products.This paper focus on routes for electrochemical conversion of CO_(2)to MeOH using green power and green hydrogen to achieve negative CO_(2)emissions.Three feasible technical routes for electrochemical conversion of CO_(2)to MeOH are proposed in this paper:Route 1,electrolysis of water to H_(2)and hydrogenation of CO_(2)to MeOH;Route 2,electrochemical reduction of CO_(2)to MeOH;and Route 3,co-electrolysis of CO_(2)-H_(2)O to syngas and synthesis of MeOH from syngas.Techno-economic assessments of the three routes are conducted using technical maturity surveys,system simulations and cost analyses to provide reference data for route selection for CO_(2)conversion to MeOH in China.Compared with the other routes,Route 1 is advantageous in terms of technical maturity and commercial application prospects.Although Route 1 is presently economically unviable,it is expected to achieve profitability and commercial application in the future with decreases in the cost of renewable power and continuous development of water-electrolysis technology.