Assessment of Methanol Synthesis Utilizing Exhaust CO2 for Chemical Storage of Electrical Energy

Implications in the production of defossilized methanol: A study on carbon sources

The transition of the current fossil based chemical industry to a carbon-neutral industry can be done by the substitution of fossil carbon for defossilized carbon in the production of base chemicals. Methanol is one of the seven base chemicals, which could be used to produce other base chemicals (light olefins and aromatics). In this research, we evaluated the synthesis of methanol based on defossilized carbon sources (maize, waste biomass, direct air capture of CO2 (DAC), and CO2 from the cement industry) by considering carbon source availability, energy, water, and land demand. This evaluation was based on a carbon balance for each of the carbon sources. Our results show that maize, waste biomass, and CO2 cement could supply 0.7, 2, 15 times the carbon demand for methanol respectively. Regarding the energy demand maize, waste biomass, DAC, and CO2 from cement demand 25, 21, 48, and 45GJtonMeOH separately. The demand for water is 5300, 220, 8, and 8m3tonMeOH. And lastly, land demand was estimated to 1031, 36, 83, and 77m2tonMeOH per carbon source. The high-demanding-resource production of defossilized methanol is dependent on the availability of resources per location. Therefore, we analyzed the production of defossilized methanol in the Netherlands, Saudi Arabia, China, and the USA. China is the only country where CO2 from the cement industry could provide all the demand of carbon. But as we envision society becoming carbon neutral, CO2 from the cement industry would diminish in time, as a consequence, it would not be sufficient to supply the demand for carbon. DAC would be the only source able to provide the demand for defossilized carbon.

Engineered 2D Metal Oxides for Photocatalysis as Environmental Remediation: A Theoretical Perspective

Modern-day society requires advanced technologies based on renewable and sustainable energy resources to meet environmental remediation challenges. Solar-inspired photocatalytic applications such as water splitting, hydrogen evolution reaction (HER), and carbon dioxide reduction reaction (CO2RR) are unique solutions based on green and efficient technologies. Considering the special electronic features and larger surface area, two-dimensional (2D) materials, especially metal oxides (MOs), have been broadly explored for the abovementioned applications in the past few years. However, their photocatalytic potential has not been optimized yet to the level required for practical and commercial applications. Among many strategies available, defect engineering, including cation and anion vacancy creations, can potentially boost the photocatalytic performance of 2D MOs. This mini-review covers recent advancements in 2D engineered materials for various photocatalysis applications such as H2O2 oxidation, HER, and CO2RR for environmental remediation from theoretical perspectives. By thoroughly addressing the fundamental aspects, recent developments, and associated challenges—the author’s recommendations in compliance with future challenges and prospects will pave the way for readers.

One-step sonochemical fabrication of biomass-derived porous hard carbons; towards tuned-surface anodes of sodium-ion batteries

A facile one-step sonochemical activation method is utilized to fabricate biomass-derived 3D porous hard carbon (PHC-1) with tuned-surface and is compared with the conventional two-step activation method. As raw biomass offers good KOH impregnation, ultrasonication power diffuses both K⁺ and OH^- ions deep into its interior, creating various nanopores and attaching copious functional groups. In contrast, conventional activation lacks these features under the same carbonization/activation parameters. The high porosity (1599 m²/g), rich functional groups (O = 8.10%, N = 0.95%), and well-connected nanoporous network resulting from sonochemical activation, remarkably increased specific capacity, surface wettability, and electrode stability, consequently improved electrochemical performance. Benefiting from its suitable microstructure, PHC-1 possesses superior specific capacity (330 mAh/g at 20 mA/g), good capacity retention (89.5%), and excellent structural stability over 500 sodiation/desodiation cycles at high current density (1000 mA/g). Apart from modus operandi comparison, the two activation methods also provide mechanistic insights as the low-voltage plateau region and graphitic layers decrease simultaneously. This work suggests a scalable and economical approach for synthesizing large-scale activated porous carbons that are used in various applications, be it energy storage, water purification, or gas storage, to name a few.

A Review of The Methanol Economy: The Fuel Cell Route

This review presents methanol as a potential renewable alternative to fossil fuels in the fight against climate change. It explores the renewable ways of obtaining methanol and its use in efficient energy systems for a net zero-emission carbon cycle, with a special focus on fuel cells. It investigates the different parts of the carbon cycle from a methanol and fuel cell perspective. In recent years, the potential for a methanol economy has been shown and there has been significant technological advancement of its renewable production and utilization. Even though its full adoption will require further development, it can be produced from renewable electricity and biomass or CO2 capture and can be used in several industrial sectors, which make it an excellent liquid electrofuel for the transition to a sustainable economy. By converting CO2 into liquid fuels, the harmful effects of CO2 emissions from existing industries that still rely on fossil fuels are reduced. The methanol can then be used both in the energy sector and the chemical industry, and become an all-around substitute for petroleum. The scope of this review is to put together the different aspects of methanol as an energy carrier of the future, with particular focus on its renewable production and its use in high-temperature polymer electrolyte fuel cells (HT-PEMFCs) via methanol steam reforming.

Recent Advances in Power-to-X Technology for the Production of Fuels and Chemicals

Environmental issues related to greenhouse gas emissions are progressively pushing the transition toward fossil-free energy scenario, in which renewable energies such as solar and wind power will unavoidably play a key role. However, for this transition to succeed, significant issues related to renewable energy storage have to be addressed. Power-to-X (PtX) technologies have gained increased attention since they actually convert renewable electricity to chemicals and fuels that can be more easily stored and transported. H2 production through water electrolysis is a promising approach since it leads to the production of a sustainable fuel that can be used directly in hydrogen fuel cells or to reduce carbon dioxide (CO2) in chemicals and fuels compatible with the existing infrastructure for production and transportation. CO2 electrochemical reduction is also an interesting approach, allowing the direct conversion of CO2 into value-added products using renewable electricity. In this review, attention will be given to technologies for sustainable H2 production, focusing on water electrolysis using renewable energy as well as on its remaining challenges for large scale production and integration with other technologies. Furthermore, recent advances on PtX technologies for the production of key chemicals (formic acid, formaldehyde, methanol and methane) and fuels (gasoline, diesel and jet fuel) will also be discussed with focus on two main pathways: CO2 hydrogenation and CO2 electrochemical reduction.

Climate change mitigation potential of carbon capture and utilization in the chemical industry

Chemical production is set to become the single largest driver of global oil consumption by 2030. To reduce oil consumption and resulting greenhouse gas (GHG) emissions, carbon dioxide can be captured from stacks or air and utilized as alternative carbon source for chemicals. Here, we show that carbon capture and utilization (CCU) has the technical potential to decouple chemical production from fossil resources, reducing annual GHG emissions by up to 3.5 Gt CO₂-eq in 2030. Exploiting this potential, however, requires more than 18.1 PWh of low-carbon electricity, corresponding to 55% of the projected global electricity production in 2030. Most large-scale CCU technologies are found to be less efficient in reducing GHG emissions per unit low-carbon electricity when benchmarked to power-to-X efficiencies reported for other large-scale applications including electro-mobility (e-mobility) and heat pumps. Once and where these other demands are satisfied, CCU in the chemical industry could efficiently contribute to climate change mitigation.

Two-dimensional-related catalytic materials for solar-driven conversion of COx into valuable chemical feedstocks

The discovery of improved chemical processes for CO and CO2 hydrogenation to valuable hydrocarbon fuels and alcohols is of paramount importance for the chemical industry. Such technologies have the potential to reduce anthropogenic CO2 emissions by adding value to a waste stream, whilst also reducing our consumption of fossil fuels. Current thermal catalytic technologies available for CO and CO2 hydrogenation are demanding in terms of energy input. Various alternative technologies are now being developed for COx hydrogenation, with solar-driven processes over two-dimensional (2D) and 2D-related composite materials being particularly attractive due to the abundance of solar energy on Earth and also the high selectivity of defect-engineered 2D materials towards specific valuable products under very mild reaction conditions. This review showcases recent advances in the solar-driven COx reduction to hydrocarbons over 2D-based materials. Optimization of 2D catalyst performance demands interdisciplinary research that embraces catalyst electronic structure manipulation and morphology control, surface/interface engineering, reactor engineering and density functional theory modelling studies. Through improved understanding of the structure-performance relationships in 2D-related catalysts which is achievable through the application of modern in situ characterization techniques, practical photo/photothermal/photoelectrochemical technologies for CO and CO2 reduction to high-valuable products such as olefins could be realized in the not-too-distant future.

Sustainable Conversion of Carbon Dioxide: An Integrated Review of Catalysis and Life Cycle Assessment

CO₂ conversion covers a wide range of possible application areas from fuels to bulk and commodity chemicals and even to specialty products with biological activity such as pharmaceuticals. In the present review, we discuss selected examples in these areas in a combined analysis of the state-of-the-art of synthetic methodologies and processes with their life cycle assessment. Thereby, we attempted to assess the potential to reduce the environmental footprint in these application fields relative to the current petrochemical value chain. This analysis and discussion differs significantly from a viewpoint on CO₂ utilization as a measure for global CO₂ mitigation. Whereas the latter focuses on reducing the end-of-pipe problem "CO₂ emissions" from todays' industries, the approach taken here tries to identify opportunities by exploiting a novel feedstock that avoids the utilization of fossil resource in transition toward more sustainable future production. Thus, the motivation to develop CO₂-based chemistry does not depend primarily on the absolute amount of CO₂ emissions that can be remediated by a single technology. Rather, CO₂-based chemistry is stimulated by the significance of the relative improvement in carbon balance and other critical factors defining the environmental impact of chemical production in all relevant sectors in accord with the principles of green chemistry.

Nitrogen-Based Fuels: A Power-to-Fuel-to-Power Analysis

What are the fuels of the future? Seven representative carbon- and nitrogen-based fuels are evaluated on an energy basis in a power-to-fuel-to-power analysis as possible future chemical hydrogen-storage media. It is intriguing to consider that a nitrogen economy, where hydrogen obtained from water splitting is chemically stored on abundant nitrogen in the form of a nontoxic and safe nitrogen-based alternative fuel, is energetically feasible.

Environmental potential of carbon dioxide utilization in the polyurethane supply chain

Potential environmental benefits have been identified for the utilization of carbon dioxide (CO2) as a feedstock for polyurethanes (PUR). CO2 can be utilized in the PUR supply chain in a wide variety of ways ranging from direct CO2 utilization for polyols as a PUR precursor, to indirect CO2 utilization for basic chemicals in the PUR supply chain. In this paper, we present a systematic exploration and environmental evaluation of all direct and indirect CO2 utilization options for flexible and rigid PUR foams. The analysis is based on an LCA-based PUR supply chain optimization model using linear programming to identify PUR production with minimal environmental impacts. The direct utilization of CO2 for polyols allows for large specific impact reductions of up to 4 kg CO2-eq. and 2 kg oil-eq. per kg CO2 utilized, but the amounts of CO2 that can be utilized are limited to 0.30 kg CO2 per kg PUR. The amount of CO2 utilized can be increased to up to 1.7 kg CO2 per kg PUR by indirect CO2 utilization in the PUR supply chain. Indirect CO2 utilization requires hydrogen (H2). The environmental impacts of H2 production strongly affect the impact of indirect CO2 utilization in PUR. To achieve optimal environmental performance under the current fossil-based H2 generation, PUR production can only utilize much less CO2 than theoretically possible. Thus, utilizing as much CO2 in the PUR supply chain as possible is not always environmentally optimal. Clean H2 production is required to exploit the full CO2 utilization potential for environmental impact reduction in PUR production.

Carbon dioxide recycling: emerging large-scale technologies with industrial potential

This Review introduces this special issue of ChemSusChem dedicated to CO(2) recycling. Its aim is to offer an up-to-date overview of CO(2) chemical utilization (inorganic mineralization, organic carboxylation, reduction reactions, and biochemical conversion), as a continuation and extension of earlier books and reviews on this topic, but with a specific focus on large-volume routes and projects/pilot plants that are currently emerging at (pre-)industrial level. The Review also highlights how some of these routes will offer a valuable opportunity to introduce renewable energy into the existing energy and chemical infrastructure (i.e., "drop-in" renewable energy) by synthesis of chemicals from CO(2) that are easy to transport and store. CO(2) conversion therefore has the potential to become a key pillar of the sustainable and resource-efficient production of chemicals and energy from renewables.